scholarly journals Impact of Magnesium Deficiency on Pancreatic β-Cell Function in Type 2 Diabetic Nigerians

Author(s):  
Abdullahi Mohammed ◽  
Ibrahim M. Bello

Objective: Pancreatic β-cell dysfunction is described to be present at the diagnosis of type 2 diabetes mellitus (T2DM) and progressively deteriorated with disease duration. However, its progression is variable and potentially influenced by several factors. The Magnesium (Mg) deficiency mediates insulin resistance but reports regarding its role in pancreatic β-cell dysfunction are scarce and conflicting. The aim of this study was to evaluate Mg deficiency effect on pancreatic β-cell function in T2DM patients at a specialist hospital in north eastern Nigeria. Materials and Methods: Study subjects were categorized in to two groups according to plasma Mg levels; 34 subjects with hypomagnesemia and 45 subjects with normal magnesium levels. Fasting blood samples were analyzed for Mg, glucose and insulin. Pancreatic β-cell function was estimated as HOMA-β. Results: Degree of pancreatic β-cell function, as measured by HOMA-β, was significantly lower among T2DM subjects with hypomagnesemia compared to the subjects with normal magnesium levels (38.1± 5.5 vs. 41.2± 6.2, Pvalue< 0.05). Lower plasma Mg was associated with decreased pancreatic β-cell function among the study subjects independent of age, BMI and duration of diabetes. Conclusion: We concluded that among subjects with T2DM in this study, Mg deficiency might be linked with worsening of pancreatic β-cell function.

2011 ◽  
Vol 300 (2) ◽  
pp. E255-E262 ◽  
Author(s):  
Adria Giacca ◽  
Changting Xiao ◽  
Andrei I. Oprescu ◽  
Andre C. Carpentier ◽  
Gary F. Lewis

The phenomenon of lipid-induced pancreatic β-cell dysfunction (“lipotoxicity”) has been very well documented in numerous in vitro experimental systems and has become widely accepted. In vivo demonstration of β-cell lipotoxicity, on the other hand, has not been consistently demonstrated, and there remains a lack of consensus regarding the in vivo effects of chronically elevated free fatty acids (FFA) on β-cell function. Much of the disagreement relates to how insulin secretion is quantified in vivo and in particular whether insulin secretion is assessed in relation to whole body insulin sensitivity, which is clearly reduced by elevated FFA. By correcting for changes in in vivo insulin sensitivity, we and others have shown that prolonged elevation of FFA impairs β-cell secretory function. Prediabetic animal models and humans with a positive family history of type 2 diabetes are more susceptible to this impairment, whereas those with severe impairment of β-cell function (such as individuals with type 2 diabetes) demonstrate no additional impairment of β-cell function when FFA are experimentally raised. Glucolipotoxicity (i.e., the combined β-cell toxicity of elevated glucose and FFA) has been amply demonstrated in vitro and in some animal studies but not in humans, perhaps because there are limitations in experimentally raising plasma glucose to sufficiently high levels for prolonged periods of time. We and others have shown that therapies directed toward diminishing oxidative stress and ER stress have the potential to reduce lipid-induced β-cell dysfunction in animals and humans. In conclusion, lipid-induced pancreatic β-cell dysfunction is likely to be one contributor to the complex array of genetic and metabolic insults that result in the relentless decline in pancreatic β-cell function in those destined to develop type 2 diabetes, and mechanisms involved in this lipotoxicity are promising therapeutic targets.


2020 ◽  
Author(s):  
Ada Admin ◽  
Rong Huang ◽  
Xinxiu Bai ◽  
Xueyan Li ◽  
Xiaohui Wang ◽  
...  

Pancreatic β cell dysfunction plays a decisive role in progression of type 2 diabetes. Retinol binding protein 4 (RBP4) is a prominent adipokine in type 2 diabetes while its effect on β cell function remains elusive and the underlying mechanisms are unknown. Here, we found that elevated circulating RBP4 levels were inversely correlated with pancreatic β cell function in db/db mice across different glycemic stages. RBP4 directly suppressed glucose stimulated insulin secretion (GSIS) in primary isolated islets and INS-1E cells in a dose- and time-dependent manner. RBP4-transgenic overexpressing mice (RBP4-Tg) showed a dynamic decrease of GSIS which appeared as early as 8-week-old preceding the impairment of insulin sensitivity and glucose tolerance. Islets isolated from RBP4-Tg mice showed a significant decrease of GSIS. Mechanistically, we demonstrated that the stimulated by retinoic acid 6(STRA6), RBP4’s only known specific membrane receptor, is expressed in β cells and mediates the inhibitory effect of RBP4 on insulin synthesis via JAK2/STAT1/ISL-1 pathway. Moreover, decreasing circulating RBP4 level could effectively restore β cell dysfunction and ameliorate hyperglycemia in db/db mice. These observations revealed a role of RBP4 in pancreatic β cell dysfunction which provided new insight into the diabetogenic effect of RBP4.


2020 ◽  
Author(s):  
Ada Admin ◽  
Rong Huang ◽  
Xinxiu Bai ◽  
Xueyan Li ◽  
Xiaohui Wang ◽  
...  

Pancreatic β cell dysfunction plays a decisive role in progression of type 2 diabetes. Retinol binding protein 4 (RBP4) is a prominent adipokine in type 2 diabetes while its effect on β cell function remains elusive and the underlying mechanisms are unknown. Here, we found that elevated circulating RBP4 levels were inversely correlated with pancreatic β cell function in db/db mice across different glycemic stages. RBP4 directly suppressed glucose stimulated insulin secretion (GSIS) in primary isolated islets and INS-1E cells in a dose- and time-dependent manner. RBP4-transgenic overexpressing mice (RBP4-Tg) showed a dynamic decrease of GSIS which appeared as early as 8-week-old preceding the impairment of insulin sensitivity and glucose tolerance. Islets isolated from RBP4-Tg mice showed a significant decrease of GSIS. Mechanistically, we demonstrated that the stimulated by retinoic acid 6(STRA6), RBP4’s only known specific membrane receptor, is expressed in β cells and mediates the inhibitory effect of RBP4 on insulin synthesis via JAK2/STAT1/ISL-1 pathway. Moreover, decreasing circulating RBP4 level could effectively restore β cell dysfunction and ameliorate hyperglycemia in db/db mice. These observations revealed a role of RBP4 in pancreatic β cell dysfunction which provided new insight into the diabetogenic effect of RBP4.


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