Nireshni Chellan

Dr. Nireshni Chellan


Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2021 in Oxidative Medicine and Cellular Longevity
Verified
Journal Article
Open access
PDF file
YNYonela Ntamo
Yonela Ntamo
Khanyisani ZiqubuKhanyisani Ziqubu
Khanyisani Ziqubu
NCNireshni Chellan
Nireshni Chellan
BNBongani Nkambule
Bongani Nkambule
TNTawanda Nyambuya
Tawanda Nyambuya
PDPhiwayinkosi V. Dludla
Phiwayinkosi V. Dludla
Oxidative stress is a key pathological feature implicated in both acute and chronic liver diseases, including drug‐induced liver injury (DILI). The latter describes hepatic injury arising as a direct toxic effect of administered drugs or their metabolites. Although still underreported, DILI remains a significant cause of liver failure, especially in developed nations. Currently, it is understood that mitochondrial‐generated oxidative stress and abnormalities in phase I/II metabolism, leading to glutathione (GSH) suppression, drive the onset of DILI. N‐Acetyl cysteine (NAC) has attracted a lot of interest as a therapeutic agent against DILI because of its strong antioxidant properties, especially in relation to enhancing endogenous GSH content to counteract oxidative stress. Thus, in addition to updating information on the pathophysiological mechanisms implicated in oxidative‐induced hepatic injury, the current review critically discusses clinical evidence on the protective effects of NAC against DILI, including the reduction of patient mortality. Besides injury caused by paracetamol, NAC can also improve liver function in relation to other forms of liver injury such as those induced by excessive alcohol intake. The implicated therapeutic mechanisms of NAC extend from enhancing hepatic GSH levels to reducing biomarkers of paracetamol toxicity such as keratin‐18 and circulating caspase‐cleaved cytokeratin‐18. However, there is still lack of evidence confirming the benefits of using NAC in combination with other therapies in patients with DILI.

2 June 2017 in Critical Reviews in Food Science and Nutrition
Verified
Journal Article
Closed access
Christo MullerChristo Muller
Christo Muller
Christiaan MalherbeChristiaan Malherbe
Christiaan Malherbe
NCNireshni Chellan
Nireshni Chellan
KYKazumi Yagasaki
Kazumi Yagasaki
YMYutaka Miura
Yutaka Miura
EJElizabeth Joubert
Elizabeth Joubert
Risk factors of type 2 diabetes mellitus (T2D) and cardiovascular disease (CVD) cluster together and are termed the metabolic syndrome. Key factors driving the metabolic syndrome are inflammation, oxidative stress, insulin resistance (IR), and obesity. IR is defined as the impairment of insulin to achieve its physiological effects, resulting in glucose and lipid metabolic dysfunction in tissues such as muscle, fat, kidney, liver, and pancreatic β-cells. The potential of rooibos extract and its major C-glucosyl flavonoids, in particular aspalathin, a C-glucoside dihydrochalcone, as well as the phenolic precursor, Z-2-(β-D-glucopyranosyloxy)-3-phenylpropenoic acid, to prevent the metabolic syndrome, will be highlighted. The mechanisms whereby these phenolic compounds elicit positive effects on inflammation, cellular oxidative stress and transcription factors that regulate the expression of genes involved in glucose and lipid metabolism will be discussed in terms of their potential in ameliorating features of the metabolic syndrome and the development of serious metabolic disease. An overview of the phenolic composition of rooibos and the changes during processing will provide relevant background on this herbal tea, while a discussion of the bioavailability of the major rooibos C-glucosyl flavonoids will give insight into a key aspect of the bioefficacy of rooibos.

1 December 2021 in Molecules
Verified
Journal Article
Open access
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NSNonhlakanipho Sangweni
Nonhlakanipho Sangweni
PDPhiwayinkosi V. Dludla
Phiwayinkosi V. Dludla
NCNireshni Chellan
Nireshni Chellan
LMLawrence Mabasa
Lawrence Mabasa
Jyoti SharmaJyoti Sharma
Jyoti Sharma
Rabia JohnsonRabia Johnson
Rabia Johnson
Although numerous studies have demonstrated the biological and multifaceted nature of dimethyl sulfoxide (DMSO) across different in vitro models, the direct effect of “non-toxic” low DMSO doses on cardiac and cancer cells has not been clearly explored. In the present study, H9c2 cardiomyoblasts and MCF-7 breast cancer cells were treated with varying concentrations of DMSO (0.001–3.7%) for 6 days. Here, DMSO doses < 0.5% enhanced the cardiomyoblasts respiratory control ratio and cellular viability relative to the control cells. However, 3.7% DMSO exposure enhanced the rate of apoptosis, which was driven by mitochondrial dysfunction and oxidative stress in the cardiomyoblasts. Additionally, in the cancer cells, DMSO (≥0.009) led to a reduction in the cell’s maximal respiratory capacity and ATP-linked respiration and turnover. As a result, the reduced bioenergetics accelerated ROS production whilst increasing early and late apoptosis in these cells. Surprisingly, 0.001% DMSO exposure led to a significant increase in the cancer cells proliferative activity. The latter, therefore, suggests that the use of DMSO, as a solvent or therapeutic compound, should be applied with caution in the cancer cells. Paradoxically, in the cardiomyoblasts, the application of DMSO (≤0.5%) demonstrated no cytotoxic or overt therapeutic benefits.

28 May 2021 in South African Journal of Science
Verified
Journal Article
Open access
PDF file
ESEbrahim Samodien
Ebrahim Samodien
YAYoonus Abrahams
Yoonus Abrahams
Christo MullerChristo Muller
Christo Muller
JLJohan Louw
Johan Louw
NCNireshni Chellan
Nireshni Chellan
Non-communicable diseases contribute significantly to the disease burden within South Africa. In the most unequal of societies in the world, poverty and socio-economic disparity are amongst the greatest obstacles facing South Africans, impacting heavily on health care. Adverse socio-environmental factors, especially those experienced during early life, can, through neurobiological and epigenetic mechanisms, developmentally programme the outcome of obesity, diabetes, cardiovascular disease and mental health disorders in adulthood. In this narrative review, we describe the social environment experienced by South Africans and discuss the potential contribution of epigenetics to the current and future prevalence of non-communicable diseases. A large part of the population (including 60% of young children) lives in poverty and endures challenging socio-economic environments, due to high unemployment, alcohol and substance abuse, and inter-partner violence. It is imperative that socio-economic factors be considered as risk factors for strategies aimed at reducing or preventing these disorders. If the current situation is left unchecked, the disease incidences could be exacerbated, and be potentially catastrophic for future generations. The consequences can be widespread and can have a direct effect on the future health and economic development of the country. Thus, child and adolescent health requires urgent attention and should be placed at the centre of the healthcare system. Early interventions providing optimum nutrition, a secure environment, together with physical activity and education should be the cornerstones for creating a healthier population for the future.Significance: South Africa already has a high non-communicable diseases burden. Non-communicable diseases – like cardiovascular diseases, cancer, diabetes, respiratory illnesses and mental disorders – are known to be caused by the interaction of socio-environmental factors, physiology, behaviour and genetics. About 60% of South Africa’s children currently live in poverty, with adverse socio-environmental factors known to have a negative effect on development, leading to a plethora of health problems in adulthood. The implications for the current situation are widespread: a future population with deteriorated physical and mental health, presenting with co-morbidities that render these individuals more susceptible to infectious diseases. It is important to recognise the potential repercussions on the health prognosis of future generations. Endeavours should focus on early interventions that can provide optimum nutrition, education, and physical activity within a safe environment. These interventions can have favourable effects on children’s brain development and genetics, thereby promoting their well-being and increasing their life prospects.

Verified
Journal Article
Open access
PDF file
Christo MullerChristo Muller
Christo Muller
EJElizabeth Joubert
Elizabeth Joubert
NCNireshni Chellan
Nireshni Chellan
YMYutaka Miura
Yutaka Miura
KYKazumi Yagasaki
Kazumi Yagasaki
In the pursuit of bioactive phytochemicals as a therapeutic strategy to manage metabolic risk factors for type 2 diabetes (T2D), aspalathin, C-glucosyl dihydrochalcone from rooibos (Aspalathus linearis), has received much attention, along with its C-glucosyl flavone derivatives and phlorizin, the apple O-glucosyl dihydrochalcone well-known for its antidiabetic properties. We provided context for dietary exposure by highlighting dietary sources, compound stability during processing, bioavailability and microbial biotransformation. The review covered the role of these compounds in attenuating insulin resistance and enhancing glucose metabolism, alleviating gut dysbiosis and associated oxidative stress and inflammation, and hyperuricemia associated with T2D, focusing largely on the literature of the past 5 years. A key focus of this review was on emerging targets in the management of T2D, as highlighted in the recent literature, including enhancing of the insulin receptor and insulin receptor substrate 1 signaling via protein tyrosine phosphatase inhibition, increasing glycolysis with suppression of gluconeogenesis by sirtuin modulation, and reducing renal glucose reabsorption via sodium-glucose co-transporter 2. We conclude that biotransformation in the gut is most likely responsible for enhancing therapeutic effects observed for the C-glycosyl parent compounds, including aspalathin, and that these compounds and their derivatives have the potential to regulate multiple factors associated with the development and progression of T2D.

28 January 2021 in Frontiers in Cell and Developmental Biology
Verified
Journal Article
Open access
PDF file
YNYonela Ntamo
Yonela Ntamo
ESEbrahim Samodien
Ebrahim Samodien
JBJoleen Burger
Joleen Burger
NMNolan Muller
Nolan Muller
CMChristo J. F. Muller
Christo J. F. Muller
NCNireshni Chellan
Nireshni Chellan
Over the years, immortalized rodent β-cell lines such as RIN, HIT, MIN, βTC, and INS-1 have been used to investigate pancreatic β-cell physiology using conventional two-dimensional (2D) culture techniques. However, physical and physiological limitations inherent to 2D cell culture necessitates confirmatory follow up studies using sentient animals. Three-dimensional (3D) culture models are gaining popularity for their recapitulation of key features of in vivo organ physiology, and thus could pose as potential surrogates for animal experiments. In this study, we aimed to develop and characterize a rat insulinoma INS-1 3D spheroid model to compare with 2D monolayers of the same cell line. Ultrastructural verification was done by transmission electron microscopy and toluidine blue staining, which showed that both 2D monolayers and 3D spheroids contained highly granulated cells with ultrastructural features synonymous with mature pancreatic β-cells, with increased prominence of these features observed in 3D spheroids. Viability, as assessed by cellular ATP quantification, size profiling and glucose utilization, showed that our spheroids remained viable for the experimental period of 30 days, compared to the limiting 5-day passage period of INS-1 monolayers. In fact, increasing ATP content together with spheroid size was observed over time, without adverse changes in glucose utilization. Additionally, β-cell function, assessed by determining insulin and amylin secretion, showed that the 3D spheroids retained glucose sensing and insulin secretory capability, that was more acute when compared to 2D monolayer cultures. Thus, we were able to successfully demonstrate that our in vitro INS-1 β-cell 3D spheroid model exhibits in vivo tissue-like structural features with extended viability and lifespan. This offers enhanced predictive capacity of the model in the study of metabolic disease, β-cell pathophysiology and the potential treatment thereof.