Masters Degrees (Physiology)

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Investigating the association between diet-induced “leaky gut” and the development of prediabetes.
(2023) Dimba, Nosipho Rosebud.; Khathi, Andile.; Ngubane, Philani Smangaliso.
Introduction Type 2 diabetes (T2D) is the most common type of diabetes mellitus, which is reported to be associated with life-threatening co-morbidities. This condition is characterized by hyperglycaemia due to a defect of the insulin receptor, and its often preceded by prediabetes. Chronic consumption of a calorie diets is the primary cause of T2D, and this diet has been associated with altered intestinal permeability in diabetic patient. However, it remains unknown whether increased intestinal permeability complications begin in the prediabetic state. Previous studies done in our laboratory developed a high-fat high carbohydrate (HFHC) diet-induced prediabetic animal model, using male Sprague Dawley rats. This model was found to mimic the human condition of prediabetes. In this model, the animals develop prediabetes after 20 weeks of ingesting a HFHCdiet. Using this HFHC diet-induced animal model of prediabetes, this study sought to investigate the changes on gut microbiota and the association between prediabetes and markers associated with intestinal permeability. Furthermore, this study sought to investigate changes in concentration level of markers associated with a leaky gut and glucose homeostasis, following change to a low carbohydrate, high unsaturated fat (LCHUF) diet. Method and Materials 12 male Sprague Dawley rats (3 weeks old) were randomly assigned into the non-prediabetic group and diet-induced prediabetic group (n=6). Group A animals were exposed to a standard diet with normal drinking water for 20 weeks, and group B animals were exposed to a HFHC diet supplemented with 15% fructose for a period of 20 weeks. After 20 weeks, the American Diabetes Association criteria for diagnosis of prediabetes was used to diagnose prediabetes in all animals. The fecal samples were analyzed to measure the gut microbiota composition of Firmicutes, Bacteroidetes, and Proteobacteria in both animal groups. Furthermore, blood glucose, plasma insulin, serum zonulin, plasma lipopolysaccharide (LPS), soluble CD14 (sCD14), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), and intestinal fatty-acid binding protein (IFABP) concentrations were measured. The first manuscript measured all these parameters at 20 weeks. In the second manuscript, 12 male Sprague Dawley rats were used and fed a HFHC diet for 20 weeks. The prediabetic animals were subdivided into two groups. Group A animals remained on the HFHC diet (the prediabetic control group), while the other 6 animals in group B were switched to a low carbohydrate, high unsaturated fat (LCHUF) diet. Group B was then categorized as the prediabetic group that had dietary intervention (PD+DI). All animals were then maintained on their respective diets and monitored for further 12 weeks. The fecal samples were analyzed to measure the gut microbiota composition of Firmicutes, Bacteroidetes, and Proteobacteria in both animal groups. Furthermore, blood glucose, glycated haemoglobin (HbA1c), serum zonulin, plasma LPS, sCD14, TNFxvii α, IL-6, CRP, and IFABP concentrations were measured. The second manuscript measured all these parameters at 32 weeks. Results and Discussion Prolonged consumption of a HFHC diet results in the development of prediabetes. This was evidenced by a significant increase in fasting blood glucose and plasma insulin in the prediabetic animals compared to the non-prediabetic animals. The HFHC diet also showed to dysregulate the gut microbiota causing gut dysbiosis which enhances translocation of endotoxins from the gut lumen into the bloodstream that elicits an inflammatory response. In the prediabetic group (PD), there was a reduction in the Firmicutes levels and an increase in Bacteroidetes and Proteobacteria compared to the nonprediabetic group (NPD). Serum zonulin, plasma sCD14, TNF-α, IL-6, CRP, and IFABP concentrations in the PD group were increased compared to the NPD group, while plasma LPS concentrations were similar. The low-grade inflammation that is observed in the prediabetic state is suggested to further progresses onset of prediabetes. However, to reverse prediabetes and to combat a leaky gut problem, the second manuscript illustrated that switching to a LCHUF diet can effectively improve glucose homeostasis thus reverse prediabetes. This was evidenced by a significant decrease in fasting blood glucose and HbA1c concentration. These results were accompanied by a decrease of Firmicutes and an increase of Bacteroidetes and Proteobacteria suggesting that a LCHUF diet effectively improved gut microbiome composition. This caused the release of serum zonulin and its effect on disassembling the tight junctions to decrease. This was evidenced by a decrease in plasma LPS and sCD14 concentration. In addition, we also observed a decrease in plasma TNF-α, IL-6, CRP, and IFABP indicating another beneficial effect of this diet on reducing intestinal inflammation, and risks of insulin resistance. Conclusion Taken together, these results suggest that chronic consumption of the HFHC diet may be associated with the dysregulation of gut microbiota, leading to increased intestinal permeability. This could be associated with chronic subclinical inflammation that have been reported to result in the development of insulin resistance in the pre-diabetic stage. In addition, a LCHSF diet markedly improved intestinal permeability as well as the glucose regulation
The association between incretin hormones concentrations and the development of diet-induced Prediabetes.
(2023) Mzimela, Nhlakanipho Mphatheni.; Khathi, Andile.; Sosibo, Aubrey Mbulelo.
The increase in the prevalence of type two diabetes mellitus(T2DM) is attributed to unhealthy lifestyles and high-calorie diets. T2DM is a chronic metabolic condition characterised by impaired insulin function and high blood glucose concentration. Prediabetes is an intermediate hyperglycemic condition that frequently occurs before the onset of T2DM. This condition is characterised by a gradual reduction of insulin sensitivity by insulin receptors in insulin-dependent cells, frequently followed by significantly high plasma glucose levels. In this condition, the blood glucose concentration is insufficient to diagnose T2DM. Studies have looked at how incretin peptides affect the pathology of T2DM. However, the link between incretin peptide levels and the onset of prediabetes remains unknown. Additionally, the effect of a low carbohydrate, high unsaturated fat diet on incretin levels during the reversal of prediabetes has not been established. Thus, this study aimed to assess the role of incretin levels in the emergence of prediabetes and the effect of a low carbohydrate, high unsaturated fat diet on incretin levels during the reversal of prediabetes. Methods The first study was conducted using 24 male Sprague-Dawley rats, divided into two groups given a standard rat diet (NPD) (=12), while the other group was given a high-fat high carbohydrate (HFHC) (n=12) diet. Six animals from each group were sacrificed at week 10 and week 20, and blood was collected for biochemical analysis at each time interval. After 20 weeks, the HFHC fed group was found to be prediabetic and were therefore named the prediabetic group (PD). At week 10, the NPD group had the following mean measurements for the NPD and HFHC groups respectively: Glucose (4.3mmol/L and 5.9mmol/L), Insulin (40.26 and 118.32pmol/L), HbAc1 (4.9 and 5.15%), GIP (9.308 and 12.91pmol/L),GLP-1 (18.53 and 15.73pmol/L), Leptin(1.92 and 1.08mmol/L), and Ghrelin (122.1 and 186.5pmol/L ). At week 20, the PD group had the following mean measurements for the NPD and PD groups: Glucose (4.4mmol/L and 7.35mmol/L), Insulin (41.18 and 159.42pmol/L), HbAc1 (4.7 and 6.65%), GIP (10.03 and15.1pmol/L),GLP-1 (21.52 and 6.73pmol/L), Leptin (2.16 and 0.78mmol/L ), Ghrelin (124.2and 210.63pmol/L). After 20 weeks of pre-diabetes induction, the second study began with 18 male Sprague-Dawley rats. Group A continued with the standard diet and was used as a non-prediabetic control (NPDC) (n=6). The pre-diabetic group B (n=12) was split into two experimental groups. One of the groups continued a HFHC diet and served as the pre-diabetic control group (PD)(n=6). In contrast, the other group had a diet intervention where the diet was changed to a low carbohydrate-high unsaturated fats diet (PD+DI) (n=6). All groups were then maintained on their respective diets for a further 12 weeks. At week 32, the PD+DI group had the following mean measurements: Glucose (5.367mmol/L), Insulin (188.5ng/ml), HbAc1 (4.62%), GIP (24.08pg/ml) , GLP-1, Leptin (1.267ng/ml) , and Ghrelin (17.09pg/ml). XVI Results In the first study, after 20 weeks, the HFHC diet resulted in moderate hyperglycaemia, elevated plasma insulin, elevated HbA1c and insulin resistance in the PD group compared to the NPD group. There were also significantly increased GIP and ghrelin concentrations with significantly low GLP-1 and leptin concentrations in the PD group compared to the NPD group. Interestingly, at week 10, there was moderate hyperglycaemia, elevated plasma insulin, elevated HbA1c and insulin resistance in the HFHC group. There were also significant GIP and ghrelin levels with significantly low GLP-1 and leptin concentrations, but there was no prediabetes. In the second study, there were significantly reduced blood glucose levels, plasma insulin levels, HOMA-IR index, and HbA1c in the PD+DI group compared to the PD group. In the PD+DI group, there are significantly reduced GIP and ghrelin levels with significantly increased GLP-1 and leptin concentrations compared to the PD group. However, when the PD-DI group is compared to the NPDC group, there is no significant difference in all measured parameters. Conclusion The first study's findings show that chronic ingestion of a HFHC diet causes dysregulation of incretin hormones from week 10, while prediabetes was only diagnosed at week 20. This dysregulation of incretin hormones precedes the onset of prediabetes and may trigger chronic insulin stimulation, leading to prediabetes development. In the second study, we observed the effect of diet on incretins as they play a significant role in developing and reversing pre-diabetes. Chronic consumption of a HFHC diet led to elevated blood glucose and insulin concentration, resulting in abnormal concentrations of incretins. The abnormal incretins then maintained this state of hyperglycemia and hyperinsulinemia, resulting in prediabetes. Chronic consumption of a LCHF by the pre-diabetic rats led to reduced concentrations of incretins, which could have led to a reduced HbA1c and eventually to the reversal of pre-diabetes. The results of this study suggest that incretin concentrations preceded the development of prediabetes and may even have a role in its development as well as its reversal.
Investigating Genetic Predisposition to Gestational Diabetes Mellitus Among Black Women Residing eThekwini, KwaZulu-Natal, South Africa.
(2023) Moloi, Angeline Nozipho.; Xulu, Khethelo Richman.; Mbongwa, Hlengiwe Prosperity.; Ghai, Meenu.
Gestational Diabetes Mellitus (GDM) is regarded as a “silent killer” determined by an abnormal glucose tolerance firstly recognised at any time during pregnancy and disappear after delivery. Carrying a large baby (>4000g), being obese (BMI: .>40kg), HIV positive and multiple pregnancy may increase the risk of postpartum haemorrhage (Hadley et al., 2021). Postpartum haemorrhage is a leading cause of maternal death , affecting 75% of maternal death worldwide (Maternal Mortality, Who Fact sheet, February 2023). Women previously diagnosed with GDM are at higher risk of subsequent type 2 diabetes mellitus (T2DM), and development of GDM in the early gestational week of pregnancy. Babies born from GDM mothers may develop T2DM, and GDM (Farahvar et al., 2019) and become obese or overweight in their young and adolescence life ( Egeland & Meltzer, 2010; Lowe at al., 2019; Martinez-Cruz et al., 2021). Previous studies have shown that genetic polymorphisms, obesity /overweight, and environmental risk factors may predispose women to GDM. However, the data in KwaZulu-Natal is limited. Furthermore, screening of GDM in women previously diagnosed with GDM has become compulsory every third year to help those mothers who may have pre-existing DM during pregnancy. Therefore, in this study, we selected black African women previously diagnosed with GDM and aimed to determine the prevalence rate and associated risk factors of GDMin the eThekwini district. Again, we investigated the association between SNP genotypes (MTNR1B rs1387153, PPARα rs4253778, and TCF7L2 rs12255372) and the development of GDM and obesity. Methods Firstly, primary data- the self-data report (a well-structured questionnaire) was performed to determine the GDM prevalence amongst black SA women living eThekwini district. Pregnant and non-pregnant women were randomly recruited from three local health district facilities: KwaMashu CHC, KwaDabeka CHC, and KEVIII Tertiary hospital in KwaZulu-Natal. This study used 87 black South African women with GDM history which included experimental group (twenty-five women with GDM) and control group (sixty-two women without GDM); aged 15- 45 years of age, residing in eThekwini district and, attending clinics from the first to the third trimester of pregnancy. The GDM confirmation was performed by the relevant antenatal care clinic on women with GDM, using a standard procedure of 2hr- 75g OGTT as per the Guideline xvi for maternity Care in SA, (2016:98). Blood samples between 2-4ml were collected from each participant into vacutainer EDTA tube (BD Diagnostic, SA) for molecular analysis. The blood samples were collected for DNA extraction to perform the genetic polymorphisms’ investigation and GDM and quantitative metabolic traits in pregnant and non-pregnant women within eThekwini district and its impacts on maternal health. The secondary data was obtained from the healthcare registry system for the pregnant women in the antenatal care clinic. The aim was to measure the initial maternal data of antenatal visits and compare those data with the existing data during the research collection. Secondly, the data was analysed using R. Statistical Computing Software of the R. core Team, 2020, version 3.6.3. Women with a previous diagnosis of GDM were regarded as current GDM and analysed as dependent variables and risk factors as independent predictive variables. Thirdly, BMI was measured as kg/m2, and the following genetic variants: MTNR1B (rs1387153), PPARα (rs4253778), and TCF7L2 (rs12255372) were genotyped for each participant using the PCR-RFLP technique. Sanger Sequencing confirmed results at Central Analytical Facilities (CAF), Stellenbosch University, SA. All results of p-value <0.05 were considered statistically significant. Results Approximately 25 women reported GDM, and sixty two had no GDM. GDM prevalence rate is estimated at 28.7 %. GDM was significantly associated with older age above 36 years (p˂0.05), family history of diabetes mellitus (p˂0.05), women with 1 or 2 children (p<0.01), pre-existing diabetes mellitus (p<0.01). BMI (≥25 kg/m2) odds ratio: 6.9; 95%CI; 1.35-5.48; p=0.03, ARV treatment (OR: 3.3 95%CI: 1.10-11.310; p=0.010), and pre-existing DM (OR: 0.23; 95CI: 0.07- 0.71; p=0.014) remained risk factors for GDM. All pregnant women with and without GDM had a homozygous G-allele of TCF7L2 rs12255372. Genetic polymorphism C-allele of MTNR1B (rs1387153) and PPARα (rs4253778) were not associated with the risk of GDM and obesity (p>0.05). After the combination of three SNPs profiles (rs1387153, rs12255372, 4253778), genotype CC (rs4253778), CC (rs1387153), and GG (rs12255372) were significantly higher in the pregnant women without gestational diabetes mellitus and obese participants (p<0.05). Conclusion The GDM prevalence rate was 28.7%, and associated risk factors were as follows: age, parity, pre-existing DM, and family history of diabetes mellitus. ARV treatment, pre-existing DM, and overweight were independent risk factors of GDM. In this study G homozygous of TCF7L2 xvii rs12255372 was a genetic marker in the population of black SA women in eThekwini, KwaZulu- Natal. Women with CC and GG genotype are at high risk of developing GDM and obesity. This study shows that SNP genotypes CC MTNR1B rs1387153, PPARα rs4253778 CC genotype, and GG genotype of TCF7L2 rs12255372 are susceptible to women developing obesity.
The influences of paternal prenatal chronic stress on offspring selected metabolic, behavioural and neurochemistry changes.
(2022) Perumal, Malishca Devani.; Mabandla, Musa Vuyisile.; Luvuno, Mluleki.
Exposure to past stress and trauma during early developmental stages can permanently affect the performance and advancements of core systems in humans. Whilst many studies are investigating the lasting effects of maternal prenatal stress, there is a paucity of information on the long-term effects of paternal prenatal stress. Therefore, the present study sought to investigate the effects of parental prenatal stress on the offspring’s psychiatric behaviour, particularly the fathers, whether these can be transferred to offspring and a number of parameters commonly associated with prenatal stress. Furthermore, we evaluated the effects of parental prenatal stress on body weight, feeding behaviour and stress response. Animals had access to food and fluids ad libitum during experimentation and were randomly assigned to different groups (n=8 per group). We found that the behavioural and neurochemical manifestations in the offspring of prenatally stressed fathers suggest that stressed fathers can transfer feelings of anhedonia and social anxiety to their offspring mediated, in part, by offspring behavioural changes of depression and social anxiety as well as, a blunted serotonin response. Furthermore, when both parents were prenatally stressed their stress effect to their offspring’s behavioural and neurochemistry is augmented. This was confirmed by the behavioural manifestations of extreme anxiety, depression and social anxiety as well as, the subdued serotonin concentration. Additionally, we found that prenatally stressed fathers can impact on offspring feeding behaviour and body weight changes mediated, in part, by the offspring’s reduced food intake and body weight as well as, a dysregulated corticosterone response. Moreover, when both parents were prenatally stressed their stress effect to their offspring’s development is intermediary. This was confirmed by metabolic manifestations of increased food intake and body weight which may have primarily been accomplished by modifying the glucocorticoid system. Therefore, the prenatally stressed fathers decreased the offspring’s sociability and increased anhedonia however, they did not transfer their anxiogenic behaviour. The prenatally stressed fathers also decreased the offspring’s appetite and as a consequence their however, they did not affect the stress response.
Respiratory patterns and cytokine profiles among recreational athletes and a sedentary group.
(2021) Padayachee, Joel.; Mackraj, Irene.; Moodley, Kogie.
Background: An increasing trend in sedentary lifestyles and physical inactivity has contributed to a higher incidence of obesity, a major health concern. Despite the fact that a sedentary lifestyle poses a considerable health risk and contributes to the prevalence of various diseases, sedentary populations are reluctant to modify health behaviours. An array of behaviour adaption models attest to the importance of knowledge and awareness cues regarding the positive physiological effects of exercise when addressing behaviour modification. Within this context, the cross-sectional study intends to describe the physiological effects of three recreational sport disciplines and one sedentary group on respiratory patterns and cytokine profiles within a South African cohort as a means to create knowledge and awareness cues for a sedentary population. Methods: The sample for the study comprising four sub-groups (swim-20, soccer-20, volleyball-20, sedentary-20) included 80 participants. Standardized anthropometric techniques were used to complete height (metres), weight (kilograms) and BMI measurements. The spirometry measurements were performed in accordance with the American Thoracic Society (ATS) recommendations using a MIR SPIROLAB II spirometer. The cytokine measurements were completed using the Beckman Coulter Access Immuno-Assay South African Manufacturer Kit as per the commercial laboratory recommendation. Data was analysed with IBM Statistical Package for Social Sciences version 27 (Chicago IL, USA). Results and Discussion: The respiratory patterns in the swim, soccer and volleyball sport groups were significantly different (p<0.01). All the recreational sport groups had significantly increased lung parameters compared to the sedentary group (p<0.01). The cytokine expression for the swim, soccer, volleyball and sedentary groups were significantly different (p<0.01). Conclusion: The findings of the study support the use of recreational swimming as a means to reduce obesity caused by sedentary lifestyles which has been identified as a global problem. Swimming is also beneficial for improving respiratory patterns over and above the soccer and volleyball group which is beneficial for the management of restrictive lung conditions. The cytokine expression differed in the recreational sport groups. Recreational swimming, soccer and volleyball support low levels of systemic inflammation but studies with larger samples are required to corroborate the findings, in terms of the influence of cytokine levels on spirometry values.
The experiences and social factors influencing the behavior of incarcerated rapists in a male prison in KwaZulu-Natal, South Africa.
(2022) Ngubane, Lindokuhle Blessing.; Qulu, Lihle.; Mabandla, Musa Vuyisile.
Introduction: South Africa is amongst the leading countries in the world to record high rate of sexual violence against women and children. South Africa has been labelled “the rape capital of the world” with 116 rape cases reported daily. Sexual violence against women and children is a global pandemic with severe health problems, economic burden and a major violation of women’s / children’s human right. The overwhelming majority of sexual offences against women and children is perpetrated by men. However, international and South African research has been largely focused on exploring the victims behaviour and recovery after rape, with scarcely any research investigating factors that influence the behaviour of the rape perpetrator. To fully explore factors that influence the rape perpetrator The Integrated Theory of Sexual Offending approach must be considered. Methods: Men incarcerated for rape were interviewed with a Semi-Structured Interview questions with focal domains of 1) Personal History, 2) Family upbringing and 3) Reason for Incarceration. Questions for domains were drawn from: their personal history and lifepath, childhood history and family history of violence, their perspectives on sexual behaviour, myths or beliefs related to sexual violence and rape, their mentors or role models, perspective on criminal behaviour and cultural contextualization and their religious and spiritual background. Each participant was interviewed privately after voluntary consent. The interview was voice recorded. The data were translated and transcribed. The data were analysed using Thematic and Content analysis methods. Results: Our findings described the experiences of various factors that potentially drive the antisocial and aggressive behaviour on men incarcerated for rape. We found that all participants were exposed to at least one form of childhood trauma. Most participants were exposed to family and/or community violence. The majority of participants avoided taking responsibility for their rape actions and often blamed the victim, and recidivism was common. Conclusion: The study demonstrates a complex personality cycle from being abused to being an abuser. Additionally, the study reveals the need for intervention for children at risk of trauma, neglect and abuse. Finally, the study provides a foundation to explore interlocking biological factors and neuropsychosocial functions and social leaning of the rape perpetrator.
The role of neuroinflammation, serotonin deficiency and gene expression in the pathology of L-dopa-induced dyskinesia with prolonged Levodopa treatment in a Parkinsonian rat model.
(2023) Mthembu, Nombulelo Agata.; Msibi, Zama Ndlondlo Princess.; Mabandla, Musa Vuyisile.
Parkinson’s disease (PD) is a neurodegenerative disorder, which globally affects 2% of the population above 65 years old. It is characterized by motor symptoms (bradykinesia, tremor, and rigidity) and nonmotor symptoms (cognitive deficit, sleeping, and mood disorders). There is no cure for PD, however, levodopa (L-dopa) therapy is a gold-standard pharmacotherapy for managing motor symptoms. Despite its effective results, its long-term consumption causes L-dopa-induced dyskinesias (LID). The pathology of LID is not clear, however growing evidence has indicated that neuroinflammation and cognitive decline may be significant factors. This study aimed to investigate the role of dysregulated Nptx2, TH, and FosB genes in the L-dopa-induced cognitive impairment and to assess the role of serotonin deficiency and neuroinflammation in LID pathology in a Parkinsonian rat model. 72 Male Sprague-Dawley rats were divided into two equal phases (n=36 per phase), each phase had 3 groups with n=12 per group. Phase 1 had 3 groups of rats that were injected with L-dopa for 14 days (pre-LID phase) while phase 2 had rats that were injected with L-dopa for 28 days (LID phase). Animals went through behavioral assessments and were sacrificed by decapitation to obtain the hippocampus, prefrontal cortex, and striatum for neurochemical analysis (ELISA and PCR). Overall, results from this study showed that the continuation of L-dopa triggers a neuroinflammatory response, hence highly expressing proinflammatory cytokine TNF-α. We found that Nptx2, TH, and FosB genes are downregulated in the PFC with continued L-dopa therapy. This downregulation was correlated with LID-induced cognitive decline. Findings from this study suggest that expression of TNF-α and deficiency of serotonin may play a significant role in the pathology of LID and downregulation of Nptx2, FosB, and TH genes contribute to LID-induced cognitive decline.
Investigating platelet and endothelial activation in ART-treated women living with HIV and obesity.
(2022) Mfusi, Snenhlanhla Angel.; Nkambule, Bongani Brian.; Hanley, Sherika.
Background: Antiretroviral therapy (ART) has reduced morbidity and mortality in people living with Human immunodeficiency virus (PLWH). However, metabolic and thrombotic complications have now become prevalent in the aging population of PLWH. The spectrum of cardiovascular disease in patients with HIV is broad and the mechanisms underlying the risk of cardiovascular disease (CVD) in PLWH remains complex and multifactorial. This includes an interplay between traditional risk factors such as obesity which in the general population is more prevalent in women. This study aimed to assess the association between platelet activation, endothelial activation and CVD-risk in women living with HIV. Methods: In this study we included 66 female participants living with HIV (n=33 normal weight and n=33 overweight/obese) enrolled in the prospective multi-country PEPFAR PROMise Ongoing Treatment Evaluation (PROMOTE) study from the Umlazi clinical research site. The time of blood draws ranges from December 2018- November 2019. We measured the levels of high sensitivity creactive protein (hsCRP), lipid profiles, platelet activation (P-selectin, CD36 and platelet factor-4) and markers of endothelial activation (endothelin-1, von Willebrand factor). Results:Women living with HIV(WLHIV) and obesity showed significantly elevated levels of soluble CD36 4.36[2.71-9.53] when compared to the control group 2.79[2.24-3.55], p=0.0064. Furthermore, the levels of (vWF) were elevated in WLHIV and obesity 8.83[1.59-9.78] when compared to controls 5.34[0.65-7.7] p=0.0009. However, the levels of soluble P-selectin, platelet factor-4 (PF4) and endothelin-1 (ET-1) were comparable between two study groups (p>0.05). Lastly, the levels of hsCRP levels were significantly higher in WLHIV and obesity (7.71±9.95) when compared to controls (3.68±5.89) p= 0.0005. Conclusion: The levels of platelet and endothelial activation are elevated in WLHIV and obesity despite successful ART. Moreover, the levels of inflammation remain persistently high even during ART. Therefore, WLHIV and obesity are at an increased risk of developing CVD.
Investigating markers of T-Cell activation due to chronic inflammation in Type 2 Diabetes.
(2020) Mbatha, Nonkululeko Avril.; Nkambule, Bongani Brian.
Background: Type 2 diabetes (T2D) is amongst the leading causes of mortality associated with non-communicable diseases. Insulin resistance, low-grade chronic inflammation, together with T cell activation, play an essential role in the pathogenesis of T2D and cardiovascular diseases. However, the role of T cells in the pathogenesis of T2D remains unclear. Study Design and Methods: Thirty-four (n = 34) male C57BL/6 mice were obtained from the UKZN, Biomedical Resource Unit in Westville. The mice were randomized into a six-week low-fat diet (LFD) fed control group and a high-fat diet (HFD) fed experimental group. Body weights, plasma, glucose levels, T cell activation, and exhaustion markers were compared amongst the two groups before and post-treatment with either low dose aspirin (LDA), a combination of low-dose aspirin and metformin or Clopidogrel. Results: HFD-fed mice demonstrated weight gain, elevated plasma glucose (p = 0.008), and insulin levels (p=0.026) within two weeks of consuming the diet. CD69 expression levels on T cells were lower in the HFD-fed group when compared to the LFD-fed group (p = 0.0208). All the treated groups demonstrated elevated levels of CD69 expression on T cells. Only the LDA treated group showed a tendency towards a reduction in PD-1 levels of expression on T cells when compared to the untreated HFD-fed group (p = 0.0711). Discussion: Impaired glucose tolerance is associated with increased T cell activation in prediabetes. The HFD fed mice had reduced levels of CD69 expression on T cells, indicating T cell activation and chronic inflammation. CD69 modulates T cell egress to inflamed tissue. Expression levels of CD69 in T cells was ameliorated post-treatment with LDA, a combination of LDA and metformin or Clopidogrel, therefore preventing cardiovascular complications. Conclusion: T cell-mediated inflammatory responses can be attenuate by treatment with LDA, a combination of LDA and metformin or Clopidogrel in T2D. Increased T cell activation markers in hyperglycemic conditions demonstrated that chronic activation of T cells poses a risk to develop T cell dysfunction and T2D. Therefore, more focus should be given to the chronic activation of T cells in order to prevent the development of T2D rather than only focusing on obesity as a potential predisposing factor.
Effects of moderate treadmill activity on cardiovascular factors in spontaneously hypertensive rats.
(2016) Mwewa, Kibwe.; Nadar, Anand.; Channa, Mahendra Lala.
Hypertension is a major health problem throughout the world because of its high prevalence and its association with increased risk of cardiovascular disease. Oxidative stress due to either increase of reactive oxygen species (ROS) or a compromised antioxidant status has also been positively correlated with cardiovascular diseases. The beneficial effect of physical activity has been well documented in the literature but studies have shown that in the SHR physical activity leads to oxidative stress. The SHR is an excellent model of essential hypertension and hence the present study was designed to investigate the effect of moderate treadmill activity on various cardiovascular factors in SHR. Sixteen male SHR and male Wistar rats (n=16) weighing between 70 and 90 g were used and they were randomly divided into four groups: The SHR exercised group (n=8), Wistar exercised group (n=8), SHR group (n=8) and Wistar (n=8). All the rats in exercised group were subjected to a weekly increase in the rate of activity on the treadmill. Blood pressure, blood glucose and body mass were recorded weekly. At the end of the 8 week experimental protocol, animals were fasted for 12 hours, anaesthetized with halothane and blood and tissue samples harvested. The C-reactive protein (CRP) and antioxidant-associated trace elements such as copper (Cu), iron (Fe), manganese (Mn), selenium (Se), and zinc (Zn) were measured in the blood, brain and skeletal muscle. Cardiotrophin-1 (CT-1) was determined in the plasma, total antioxidant capacity (TAC) and malonyldialdehyde (MDA) were determined in blood and skeletal muscle, plasma TAC levels was also measured. The superoxide dismutase (SOD), IkB and nuclear factor-kappa (NF-kB) gene expression were also measured in skeletal muscle and liver. Kidney sections were stained with Haematoxylin-Eosin (H&E) and sections of aorta were stained with Verhoeff-van Gieson (VVG). The results show that physical activity did not significantly change both the systolic and diastolic blood pressures in SHR. Plasma levels of CRP and NF-kB mRNA expression were increased in both SHR and Wistar exercised groups. An increase in oxidative stress due to physical activity was evident by an increase in TAC and MDA levels in the skeletal muscle. A significant decrease in blood TAC and SOD mRNA expression was also evident in the SHR exercise group. Physical activity also resulted in significant shifts in trace elements that are associated with a compromised antioxidant system.
Effect of titanium dioxide nanoparticle aggregation on mouse myoblast cellular cytotoxicity and nitric oxide synthesis.
(2017) Phoswa, Wendy.; Mackraj, Irene.
ABSTRACT Introduction: The emerging interest of engineered titanium dioxide nanoparticles (TiO2 NPs) in medical, agricultural, industrial and manufacturing sectors have raised health questions worldwide. Therefore, the objective was to assess the effect of physiochemical properties of titanium dioxide nanoparticles (TiO2 NPs) on the cellular cytotoxicity, proliferation and physiological properties. Methods: TiO2 NPs were suspended in varying concentrations of bovine serum albumin (BSA γ-globulin) and characterised using nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM) for the determination of particle size, aggregation state, and zeta potential. The effect of TiO2 physiochemical properties on cellular cytotoxicity and proliferation was assessed in vitro on mouse myoblast (C2C12) cells using the MTT [3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide] and BrdU assay respectively. Nitric oxide (NO), a major signalling molecule was measured using a biochemical test. in vitro. Results: There was an increase in size, distribution, surface charge and reduced aggregation in BSA stabilised TiO2 NPs in comparison to non-stabilised TiO2 NPs. Increased cytotoxicity of cells treated with monodispersed TiO2 NPs compared to cells treated with aggregated TiO2 NPs (p<0.001) was observed. A significant decrease in cell viability in cells treated with BSA (0.5, 0.8 and 1.0 mg/ml) stabilised TiO2 NPs (40, 120, 240, 320 and 400 mg/ml) in a dose-dependent manner in contrast to cells treated with BSA (0.3 and 1.5 mg/ml) stabilised TiO2 NPs (40, 120, 240, 320 and 400 mg/ml) dose dependent manner was observed (p<0.05). However, there was a greater decrease in cell viability in BSA (0.8 mg/ml) stabilised TiO2 NPs (40, 120, 240, 320 and 400 mg/ml) compared to other BSA concentration (p<0.05). In addition, there was a significant difference in DNA proliferation of the control and treated cells. A significant difference in DNA damage was observed in cells treated with BSA compared to non-treated cells, especially at BSA concentrations of 0.8 and 1.5 mg/ml. A significant difference in DNA damage in cells treated with TiO2 NPs in combination with BSA (0.8 and 1.5 mg/ml) was obtained. There was greater difference in DNA damage of cells exposed to TiO2 NPs in combination with 0.8 mg/ml compared to TiO2 NPs in combination with 1.5 mg/ml. More interestingly there was a significant difference between the levels of nitric oxide (NO) in 40 and 400 mg/ml TiO2 NPs treated cells in comparison to cells treated with BSA (0.3-1.5 mg/ml) stabilised TiO2 NPs (40 and 400 mg/ml) (p<0.05). There was a significance difference in the levels of NO between cells treated with 40 mg/ml TiO2 NPs vs (0.3, 0.5, 0.8 and 1.0 mg/ml) BSA stabilised TiO2 NPs (40 mg/ml) (p<0.05). However, there was greater significant difference between 400 mg/ml TiO2 treated cells vs BSA (0.5, 0.8 and 1.0 mg/ml) stabilised 400 mg/ml TiO2 NPs (400 mg/ml) (p<0.05). Discussion/Conclusion: The use of BSA as a nanoparticle stabiliser impacted upon physiochemical properties for the determination of in vitro cytotoxicity. These findings indicate that particle size needs to be taken into consideration when assessing nanoparticle toxicity. The results also indicate that less aggregated TiO2 NPs are more toxic than more aggregated TiO2 NPs and have a potential to inhibit cellular signalling mechanisms such as NO signalling and cellular proliferation.
The effects of multivitamin-multimineral supplementation on the spontaneously hypertensive rat model of hypertension.
(2015) Höfler, Rosemarie Ursula.; Channa, Mahendra Lala.
ABSTRACT The nutraceutical industry has proliferated in recent years with the most popular form of supplementation being the multivitamin-multimineral (MVMM) supplement. In the animal health sector, supplement use has also expanded. The objective of this study was to determine the effects of MVMM supplementation, beneficial or otherwise, on the general health status of the spontaneously hypertensive rat (SHR) strain, an animal model used in hypertension research. A commercially prepared MVMM supplement was given tri-weekly via oral dosing for eight weeks to two groups of seven adult female SHR and Wistar rats. Their corresponding control groups were dosed with deionised water only. Systolic and diastolic blood pressure, fasting blood glucose, growth rate and food and water intake were measured weekly. At the end of eight weeks, the animals were euthanized and a full blood profile, urine sodium potassium ratio, blood urea nitrogen levels and total plasma cholesterol was measured for all groups. Further biochemical tests included determining plasma C-reactive protein, angiotensin-converting enzyme and kidney lipid peroxidation levels. Blood and tissue trace element profiles were determined by ICP and EDX analysis. A histological study was conducted on the kidney and aorta. MVMM supplementation had significant metabolic, cardiovascular and renal effects in the SHR group. It increased growth and caused a significant reduction in the diastolic blood pressure of both SHR S and WIS S groups over the eight week period. It also lowered total cholesterol and increased RBC count in the SHR S group. Supplementation also had some renoprotective properties as the SHR S group exhibited lesser hypertension related morphological changes in the kidney due to lowered blood pressure and possible antioxidant effects of the supplement. This was however not translated into any improvement in renal function. No adverse effects on the general health status of the animals were observed. MVMM supplementation may therefore be useful in aiding growth and delaying the onset of hypertension and the related complications. It may also assist in the longevity of the breeding stock of SHR rats.
Comparison of the effects of oral and transdermal adminstration of chloroquine on selected haematological parameters and inflammatory cytokines in P.berghei- infected male Sprague-Dawley rats.
(2016) Gumede, Nontobeko Myllet.; Mabandla, Musa Vuyisile.
Introduction Chloroquine (CHQ), the mainstay antimalarial drug accumulates in organs and alters physiological function. Hypoglycaemia, impairment of kidney function and anaemia are among an array of pathophysiological manifestations caused by malaria infection or oral CHQ treatment. However, it is unclear whether this anaemia is solely due to the parasite or by CHQ. Therefore, there is need to investigate and distinguish between the pathophysiological effects of malaria alone and those of CHQ treatment. The purpose of the current study was to investigate and compare the effects of using oral CHQ treatment or a transdermal CHQ patch in the treatment of malarial infection. To this effect, we evaluated changes in haematological parameters as well as plasma cytokine concentrations in male Sprague-Dawley rats. We also looked at the morphological effects of various visceral organs following malarial infection and subsequent treatment with CHQ. The study duration was 3 weeks divided into pre-treatment (days 0-7), treatment (8-12) and post treatment (13-21) periods. CHQ treatment was either administrated orally (30mg/kg, twice daily) or via a once off CHQ matrix patch (56mg/kg). Oral CHQ treatment reduced red blood cell count, haematocrit, haemoglobin and mean corpuscular haemoglobin in non-infected and infected animals. Topical application increased the above parameters in infected rats. Oral CHQ decreased pro-inflammatory cytokine concentration in infected rats on the day (day 8 of the experiment) of the treatment period in comparison to pretreatment (baseline) measurements. However, on the last day (day 12) of the treatment period and during the post-treatment period there was an increase in pro-inflammatory cytokine concentration while patch application decreased pro-inflammatory cytokine concentration in infected rats throughout the experimental period. P.berghei-infected rats following oral and transdermal CHQ delivery showed mild morphological changes on the liver, heart, kidney and spleen by comparison to infected control animals. In non-infected rats oral CHQ treatment showed adverse morphological effects on the architecture of these organs, while no changes were observed following transdermal CHQ delivery. C-reactive protein is an acute phase protein, a component of innate immune response and is useful in early detection of inflammation. Oral CHQ administration increased CRP concentration. However, CRP concentration was not affected in patch treated animals. The results of the current study have demonstrated that the once off patch application of the CHQ-formulation has no morphological effects when compared to oral administration of CHQ on various organs. The ability of the pectin-CHQ matrix patch to provide slow, sustained CHQ releases into the circulation, avoids drug dumping in various tissue organs therefore circumventing the adverse effects associated with oral administration of CHQ. In addition, our results show that both CHQ and malaria parasite result in the development of anaemia by affecting RBCs and plasma pro-inflammatory cytokines. These findings suggest that transdermal CHQ delivery could therefore be used in conjunction with or as an alternative treatment in the management of malaria.
T cell function and immune checkpoint inhibition in chronic lymphocytic leukaemia.
(2021) Mkhwanazi, Zekhethelo Alondwe.; Nkambule, Bongani Brian.
Background: The global burden of lymphoid malignancies gradually increased over the past decade, with chronic lymphocytic leukaemia (CLL) accounting for a quarter of the burden of all haematological malignancies. Chemotherapy in combination with rituximab has been used as standard care for patients with CLL. This regimen has been characterized by variable responses, relapses, and remissions. The exploration of the predictive value of prognostic factors in patients on chemoimmunotherapy (CIT) is crucial, however, such studies on the multi-ethnic group remain scant. Methods: This study consist of two phases, firstly we performed a systematic review and meta-analysis on the predictive value of protein biomarkers in patients with CLL on rituximab-based therapy. A total of 10 prognostic factors were identified and evaluated. In a subsequent prospective cross-sectional study comprising of treatment-naïve patients with CLL, we evaluated immune checkpoint profiles on T helper and cytotoxic T cells. The expression of selected inhibitory proteins (Programmed death 1; PD-1, programmed death ligand 1; PD-L1, cytotoxic T lymphocyte-associated antigen 4; CTLA-4 and CD56) were measured at baseline, and post-stimulation with phorbol 12-myristate 13-acetate (PMA), and following ex vivo blockade with monoclonal antibody therapy (anti-PD1 and anti-PDL1). Furthermore, correlations between beta-2-microglobulin (B2M), a marker of disease progression, and immune checkpoints was evaluated. Results: In our meta-analysis, chemoimmunotherapy with rituximab improved progression-free survival (PFS) (HR= 0.58; 95% Cl 0.49 – 0.68; p <0.001) and overall survival (OS) (HR= 0.77; 95% Cl 0.63 – 0.91; p <0.001) in patients with CLL. The following prognostic factors were confirmed and associated with poor patient outcomes; deletion 17p (HR = 4.88), Immunoglobulin heavy chain variable region gene mutation status (HR = 0.96), WCC (HR = 1.27), β2-microglobulin (HR = 0.96), and lactate dehydrogenase levels (HR = 1.20). Our results from the cross-sectional study demonstrated an increase in expression levels of PD-1, PD-L1 and CTLA-4 (p > 0.05) and no significant differences in expression levels of CD56 (p = 0.4126) on CD4+ T cells following stimulation. There were no statistically significant differences in the expression levels of PD-1 (p = 0.1826), while there were significant reductions in the expression levels of CTLA-4 and CD56 (p > 0.05), conversely, there was an increase in the expression levels of PD-L1 following CD8+ T cells stimulation. PD-1 and PD-L1 immune checkpoint blockade failed to reduce the expression levels of PD-1, PD-L1 and CTLA-4 on CD4+ and CD8+ T cells. Furthermore, the results showed novel positive correlation between B2M and soluble PD-1 (r = 0.65, p = 0.022), PD-L1 (r = 0.60, p = 0.036) and CD56 expression (r = 0.63, p = 0.033) on CD8+ T cells. Conclusions: Prognostic factors such as deletion 17p and 11q, white cell count, LDH, and most importantly B2M retained predictive value in patients with CLL on rituximab-containing CIT. These factors should be included in future prognostic factors in CIT and chemotherapy-free era of patient management. Our novel findings of the correlation between B2M and PD-1/PD-L1 suggests that monitoring B2M levels in patients with CLL may also be valuable in predicting patient responses to immunotherapy targeting the PD-1/PD-L1 axis
The acute effects of dioxidovanadium on blood glucose concentration and oxidative stress in the hippocampus of non-diabetic male Sprague Dawley rats and the chronic effects of dioxidovanadium on selected markers associated with hippocampal dysfunction in male streptozotocin-induced diabetic rats.
(2022) Dayanand, Yalka.; Ngubane, Phikelelani Siphosethu.; Khathi, Andile.; Sibiya, Ntethelelo Hopewell.
Diabetes mellitus is a disease associated with derangements in glucose metabolism and chronic hyperglycaemia. Chronic hyperglycaemia induces oxidative stress and inflammation that affect glucose sensitive hippocampal neurons resulting in generation of amyloid plaques and tau tangles. These are the primary markers used in the detection of neurodegenerative diseases such as Alzheimer’s and dementia. Hence, there is a strong correlation between diabetes and memory impairment. Current therapeutic options such as bolus insulin have been successful in the management of the disease. Despite the efficacy of these therapies, they however have been shown to possess undesirable effects that exacerbate the secondary pathological effects of diabetes on the hippocampus thereby contributing to the detriment of cognitive tasks such as learning and memory. Therefore, there is a need to explore alternative treatments. Transition metals have been shown to possess therapeutic effects with vanadium possessing the greatest potency in lowering blood glucose concentrations. However, studies have demonstrated toxic accumulation of vanadium in the hippocampus which result in the generation of oxidative stress and neurodegeneration. In our laboratory, we have synthesised dioxidovanadium (V) complex by attaching organic ligands to reduce the toxicity and improve potency of the metal. This complex has been shown to efficiently reduce blood glucose and elicit cardio and reno-protective properties. Despite these advancements the effects of this complex on the hippocampus and learning and memory are yet to be established. Therefore, in this study the aim was to evaluate the effect of dioxidovanadium complex on selected learning and memory parameters. Methodology The effect of vanadium on the brain was studied acutely and chronically. In the acute study, animals were separated into 2 groups, non-diabetic control group and a non-diabetic animal group which was were treated with vanadium complex (40 mg.kg-1 p.o). The treatment was administered at time 0. Subsequently an n=3 from each group was sacrificed at regular time intervals (1 hour, 2 hours, 6 hours, 24 hours, 5 days, 10 days) in each group. Blood glucose concentration was monitored before sacrificing and hippocampal tissue was harvested for malonaldehyde (MDA) analysis and glutathione peroxidase (GPx1) and tumour necrosis alpha (TNF-α). The second study was conducted over 5 weeks and consisted of an untreated non-diabetic control, a diabetic control, a positive insulin treated group (0.175 mg.kg-1 s.c) and two dioxidovanadium (V) treated groups (40 mg.kg-1 p.o), a non-diabetic and a diabetic group. Blood glucose was monitored weekly and the Morris water maze was conducted on the last week of the study. After 5 weeks the animals were sacrificed and hippocampal tissue was harvested for malonaldehyde (MDA) analysis, glutathione peroxidase (GPx1) tumour necrosis alpha (TNF-α), amyloid beta (Aβ) and hyperphosphorylated tau (pTau) ELISA’s. Results Acutely, dioxidovandium (V) did not lower blood glucose significantly in comparison to the control group. Interestingly, MDA, GPx1 and (TNF-α) were also not significantly different from the control group over all time periods in the study. Chronically, the glucose concentration of the dioxidovandium (V) treated diabetic group was significantly lowered when compared to the untreated group which displayed significantly increased glucose concentration in comparison to the non-diabetic control. The non-diabetic dioxidovanadium (V) treated group did not show a significant difference in glycaemic level. Increased MDA concentration in the diabetic group was significantly lowered by dioxidovanadium(V) treatment. GPx1 concentration in the dioxidovanadium (V) treated group significantly improved in comparison to the diabetic untreated control. The non-diabetic dioxidovandium (V) treated group showed no significant change in MDA and Gpx1 after the 5-week period. There was no significant difference in TNF-α in dioxidovanadium (V) treated groups, diabetic and non-diabetic. The concentration of Amyloid β was significantly lower in the diabetic control when compared to the non-diabetic control. The dioxidovanadium (V) treated groups, both diabetic and non-diabetic did not have a significant difference in comparison to the diabetic control. pTau concentrations in all groups did not significantly differ. Latency times for the last day of training the Morris water maze followed the same trend. The probe test results, which measured spatial memory, for the diabetic untreated and dioxidovanadium (V) treated groups were significantly reduced in comparison to the non-diabetic control group. The non-diabetic untreated and non-diabetic dioxodivanadium (V) treated were not significantly different. Conclusion Dioxidovanadium (V) treatment in non-diabetic animals did not induce hypoglycaemia acutely however reduced blood glucose concentration in diabetic animals when administered chronically. Dioxidovanadium (V) did not induce oxidative stress and may protect against neurodegeneration by enhancing antioxidant status and therefore was considered as a pro-oxidant in the hippocampus.
Investigating the effects of diet-induced pre-diabetes on calcium homeostasis in male Sprague Dawley rats.
(2022) Naidoo, Karishma.; Khathi, Andile.; Ngubane, Phikelelani.
Diabetes mellitus (DM) affects over 400 million people worldwide with 90-95% being type 2 diabetes mellitus (T2DM) in South Africa. T2DM is positively correlated with the chronic consumption of a high caloric diet, often preceded by pre-diabetes. Pre-diabetes is a long-term intermediate stage of hyperglycaemia which is usually asymptomatic. One of the key aetiologies for the complications of physiological systems seen in T2DM has been found to be the chronic intake of high caloric diets. However, dysregulation of these physiological systems seen in T2DM have been reported to begin in pre-diabetes. Calcium homeostasis has been demonstrated to be one of the body's mechanisms that is disrupted in T2DM, leading to changes in calciotropic hormone levels and the functioning of calcium regulating organs. Altered levels of calciotropic hormones in diabetes have been shown to increase the risk of developing insulin resistance and hyperglycaemia. Furthermore, disrupted functioning of calcium-regulating organs in diabetes impairs their responsiveness to calciotropic hormones. A prediabetic rat model was utilized in our laboratory to explore numerous systems and mechanisms in the body, including glucose homeostasis, the cardiovascular system, and immunity, using a high-fat highcarbohydrate diet to induce pre-diabetes. However, there is a paucity in literature elucidating the changes to calcium homeostasis in pre-diabetes. Hence, the present study aimed to investigate the effects of diet-induced pre-diabetes on calcium homeostasis by looking at calciotropic hormones and the functioning of calcium-regulating organs. Materials and Methods Twelve male Sprague-Dawley rats were randomly divided into 2 groups (n=6, each group) whereby the first group: non-pre-diabetic (NPD) group was subjected to standard rat chow and the second group: pre-diabetic (PD) group was subjected to a high-fat high-carbohydrate (HFHC) for 20 weeks. At week 20, the American diabetes association criteria (ADA) were employed for pre-diabetes diagnosis. Plasma was collected for biochemical analysis to measure glucose, insulin, glycated haemoglobin (HbA1c) and the homeostatic model assessment for insulin resistance (HOMA-IR) in addition to urine and plasma calcium concentrations. This was accompanied by measurement of plasma parathyroid hormone (PTH), calcitonin, vitamin D, 1,25-dihydroxyvitamin D3 (calcitriol), osteocalcin and deoxypyridinoline via enzyme linked immunosorbent assay (ELISA). Correlation analysis of calciotropic hormones with HbA1c and HOMA-IR were performed. Furthermore, small intestine and kidney tissue were harvested after the experimental period for analysis of gene expression. Renal expressions of transient receptor potential vanilloid 5 (TRPV5), 1-alpha hydroxylase along with intestinal expressions of vitamin D receptor (VDR) and calbindin-D9k were measured via reverse transcriptase quantitative polymerase chain reaction (RT-qPCR). Results and discussion The HFHC diet resulted in moderate hyperglycaemia, elevated plasma insulin, elevated HbA1c and insulin resistance in the PD group by comparison to the NPD group. In the first study, there were increased calciotropic hormone concentrations; plasma PTH, calcitonin, calcitriol and vitamin D in addition to elevated urine calcium and unchanged plasma calcium in the PD group by comparison to NPD. This suggested that elevated calciotropic hormone concentrations in pre-diabetes may compensate for changes to plasma calcium. Furthermore, plasma PTH and calcitonin levels were positively correlated with HbA1c but not insulin resistance in the PD group. Plasma calcitriol concentrations were negatively correlated with HbA1c in the PD group. Altered levels of calciotropic hormones in pre-diabetes may exacerbate the moderate hyperglycaemia in pre-diabetes. In the second study, plasma fasting glucose, insulin, OGT response and HOMA-IR were higher in PD group compared to the NPD. It was observed that normal plasma calcium levels in the pre-diabetic group were accompanied by an upregulation in renal TRPV5, 1-alpha hydroxylase, intestinal VDR and calbindin-D9K expression in addition to increased plasma osteocalcin and decreased urine deoxypyridinoline. Calcium-regulating organs may have responded to disturbed calcium homeostasis by promoting increased intestinal calcium absorption, renal calcium reabsorption in addition to decreasing bone resorption and increasing bone formation. Conclusion The findings suggest that normocalcaemia is maintained in the pre-diabetic state due to compensation from calciotropic hormones and calcium-regulating organs. However, altered levels of calciotropic hormones in pre-diabetes may play a role in the onset of hyperglycemia in T2DM. Due to the cumulative evidence produced in study 1 and study 2, we accept the hypothesis which states that during the pre-diabetic state there will be changes to calciotropic hormones and calcium-regulating organs indicative of disturbed calcium homeostasis.
The alteration of dopamine receptors in L-DOPA (L-3,4-dihydroxyphenylalanine) induced dyskinesias.
(2021) Mokgokong, Makwena.; Mabandla, Musa Vuyisile.; Msibi, Zama Ndlondlo Princess.
L-3,4-dihydroxyphenylalanine (L-DOPA) can ease symptoms of Parkinson’s disease (PD), butextended use of L-DOPA causes abnormal involuntary movements (AIMs) called L-DOPA induced dyskinesias (LIDs). The present study aims to investigate alterations in HPA axis stimulation, neuroinflammation, DA signalling, and cholinergic signalling using molecular markers in a rat model of LIDs. A unilateral 6-hydroxydopamine (6-OHDA) lesion in the medial forebrain bundle of male Sprague-Dawley rats was used to model Parkinsonism. The PD rat model was treated with L-DOPA to further model LIDs. L-DOPA treated groups included rodents treated for 14 days and rats that developed AIMs during 28 days of treatment. LIDs severity was rated using the AIMs score. Motor skills were assessed using the elevated beam walking test. Cognitive functions were assessed using the Morris water maze test and the novel object recognition test. The concentrations of tumour necrosis factor-alpha (TNF-α), corticosterone, acetylcholinesterase (AChE), and dopamine (DA), and the expressions of D1 receptor (D1R) and D2 receptor (D2R) were quantified. L-DOPA treatment for 14 days improved the 6-OHDA-induced hypokinesia, incoordination, spatial learning, and spatial memory but did not improve recognition memory impairment. Prolonged (28 days) L-DOPA treatment led to AIMs development and failed to improve 6-OHDA-induced spatial memory impairment. L-DOPA treatment significantly increased striatal TNF-α and striatal DA concentration, cerebellar TNF-α and DA concentration, prefrontal cortex (PFC) DA and AChE concentration, but significantly reduced striatal AChE concentration, the concentration of TNF-α and D1R expression in the PFC, plasma corticosterone, and hippocampal AChE concentration. When treatment was prolonged for 28 days, striatal D2R expression significantly increased, while cerebellar TNF-α and DA concentration significantly decreased. Increased striatal D2R signalling increases motor output since the direct basal ganglia (BG) pathway is activated in LIDs. The present study showed significantly increased cerebellar DA concentration in response to BG hypoactivity; however, as striatal D2R increased cerebellar DA decreased. The connectivity between the BG and cerebellum in PD increases off L-DOPA and lowers On L-DOPA. The cognitive decline in the 6-OHDA lesioned rodents and those treated with L-DOPA results from increased AChE concentration. High AChE concentration leads to increased ACh catabolism which impairs cognitive function.
Biomarkers and histopathologic changes in rats with monocrotaline-induced pulmonary hypertension following administration of antiretroviral medications.
(2020) Adeoti, Adekunle Olatayo.; Nadar, Anand.
Pulmonary hypertension (PH) is a progressive life-threatening vasculopathy characterized by dysregulated pulmonary vascular remodelling that results in an increased pulmonary vascular resistance, right ventricular hypertrophy, right heart failure and untimely death. Human Immunodeficiency Virus (HIV) is a recognized cause of PH with a relatively stable prevalence of HIV associated PH of 0.5% in most developed countries. One of the animal models of PH is comprises a once off monocrotaline (MCT) in rats, which leads to PH that mimics typical PH presentation observed in humans. Early administration of antiretroviral medication has been shown to prevent the development of PH in human subjects, however, in advanced cases no significant improvement was reported. The impact of antiretroviral medications is controversial; however, nucleoside reverse transcriptase inhibitors (NRTI) and protease inhibitors (PI) have been shown to improve outcome in PH animal models. A potential connection between combination antiretroviral and PH in human subjects has been established which was contrary the protective effects of solely administer NRTI. The study was conducted to test the hypothesis that antiretroviral medications could ameliorate MCT induced PH in rat models and identify potential biomarker for PH. An approval was given by the Animal Research Ethics Committee of the institution (AREC/066/018M) of University of KwaZulu-Natal, Durban, South Africa, to conduct the study. Forty adult male Sprague-Dawley rats (body weight: 200-250 g) were randomly divided into five groups (n=8 per group). The treatment groups received a single intraperitoneal injection of MCT (60 mg kg-1) while the control group received an equivalent volume of intraperitoneal saline injection. Zidovudine (100 mg kg-1), ritonavir (30 mg kg-1), or combination of both drugs (zidovudine 100 mg kg-1 and ritonavir 30 mg kg-1) were administrated daily for the study period of 28 days to the rats in three of the four groups with MCT for 28 days respectively. On the twenty-eighth day of the study, rats were sacrificed, and the harvested lungs and hearts organ were analyzed. Gene expression was conducted using RT-PCR for the antioxidant’s enzymes, ASK-1 and a laboratory assay for lipid peroxidation was performed. A significantly higher mRNA gene expression of catalase, superoxide dismutase, and glutathione peroxidase in the heart tissue of the antiretroviral treated rats was observed and compared to the untreated groups. There was an increase in malondialdehyde (MDA) in the heart tissues of untreated rats (37.01±1.16 nmol/g, p<0.0001) compared to the control group (3.46±0.97 nmol/g) with an associated reduction in MDA by the antiretrovirals. Furthermore, an increase in the total antioxidant capacity (TAC) in AZT (0.85±0.02 nmol/g, p<0.0001), RTV (0.63±0.03 nmol/g, p<0.0001) and combination of AZT/RTV (0.77±0.06 nmol/g, p<0.0001) compared to untreated (0.28±0.025) rats. Furthermore, lower relative mRNA gene expression of ASK-1 was observed in the heart of the treated rats with zidovudine (2.67 ± 0.09, p < 0.0001), ritonavir (2.57 ±0.11, p < 0.0001) and a combination of both (2.75 ± 0.06, p < 0.0001) when compared to rats in the untreated group. An overexpressed mRNA gene of ASK-1 in the untreated rats (12.0 ± 0.90, p < 0.0001) when compared to the control. This study shows evidence that zidovudine and ritonavir ameliorate MCT-induced PH in rats by suppressing oxidative stress. Also, ASK-1 is a potential biomarker for anti-apoptotic characteristics of PH. Our findings indicate the antioxidative role of antiretroviral medications in PH and the role of biomarkers in PH.
The possible role of fumonisin B1 in pre-eclampsia.
(2000) Coumi, Nicola.; Dutton, Michael Francis.; Moodley, Jagidesa.; Chuturgoon, Anil Amichund.
Abstract available in PDF.
The determination of unilateral ratios (knee and shoulder muscle strength), of provincial cricketers.
(2002) Lock, Natasha.; Mars, Maurice.
Abstract available in PDF.

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