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Oxidative damage to mitochondrial DNA (mtDNA) has been linked to the pathogenicity of diabetic nephropathy. We tested the hypothesis that mtDNA copy number may be increased in human mesangial cells in response to high glucose-induced reactive oxygen species (ROS) to compensate for damaged mtDNA. The effect of manganese superoxide dismutase mimetic (MnTBAP) on glucose-induced mtDNA copy number was also examined. The copy number of mtDNA was determined by real-time PCR in human mesangial cells cultured in 5 mM glucose, 25 mM glucose, and mannitol (osmotic control), as well as in cells cultured in 25 mM glucose in the presence and absence of 200 μM MnTBAP. Intracellular ROS was assessed by confocal microscopy and flow cytometry in human mesangial cells. The copy number of mtDNA was significantly increased when human mesangial cells were incubated with 25 mM glucose compared to 5 mM glucose and mannitol. In addition, 25 mM glucose rapidly generated ROS in the cells, which was not detected in 5 mM glucose. Furthermore, mtDNA copy number was significantly decreased and maintained to normal following treatment of cells with 25 mM glucose and MnTBAP compared to 25 mM glucose alone. Inclusion of MnTBAP during 25 mM glucose incubation inhibited mitochondrial superoxide in human mesangial cells. Increased mtDNA copy number in human mesangial cells by high glucose could contribute to increased mitochondrial superoxide, and prevention of mtDNA copy number could have potential in retarding the development of diabetic nephropathy.

Objective: High prevalence of hypovitaminosis D has been reported to be common in different regions of the Middle East. The objective of the present study was to examine the predictors of vitamin D deficiency and insufficiency in Bahrainis. Design: A cross-sectional study. Setting: Blood transfusion volunteers at a blood bank. Subjects: Serum levels of total 25-hydroxyvitamin D, bone markers and other parameters such age, sex, season and clothing style in the 500 healthy Bahrainis were investigated. Results: In the entire cohort the prevalence of vitamin D deficiency was 49?4 % and the relative risk of vitamin D deficiency increased significantly by 1?1, 1?2, 1?5, 1?7 and 1?2 fold with younger age group (P 5 0?03), hyperparathyroidism (P 5 0?01), low serum Ca (P , 0?001), warm and hot months of the year (P , 0?0001) and female sex (P 5 0?002), respectively. In females the prevalence of vitamin D deficiency was 67?6 % and the relative risk of vitamin D deficiency increased significantly by 1?1, 1?2, 1?2, 1?2 and 1?4 fold with younger age group (P 5 0?04), hyperparathyroidism (P 5 0?03), low serum Ca (P 5 0?001), warm and hot months of the year (P 5 0?001) and conservative clothing style (P 5 0?04), respectively. In contrast, in males the prevalence of vitamin D deficiency was 31?2 % and the relative risk of vitamin D deficiency was increased by 1?6 fold in warm and hot months of the year (P , 0?0001). Conclusions: High prevalence of low circulating levels of vitamin D and the relative risk factors associated with vitamin D deficiency and insufficiency observed in the present study suggest an urgent need for public health interventions including vitamin D food fortification in Bahrain.

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Objective: Tandem mass spectrometry is increasingly used in the Middle East in newborn screening for inborn errors of metabolism using dried blood spots. The sensitivity and specificity of this system for analyzing fatty and amino acids, screening for more than 40 metabolic conditions, is known. However, the short term stability of acylcarnitines and amino acids in dried blood spots in extreme heat and humid conditions is not well documented. We examined the short term effect of heat and humidity on the levels of 7 amino acids and 10 acylcarnitines used in newborn screening for inherited metabolic disorders. Methods: Dried blood spots were exposed with humidity <30% to temperatures of 4 C, room temperature, 37 C, and 45 C, and also with humidity >70% at 37 C and 45 C. Amino acids and acylcarnitines in the dried blood spots were analyzed by tandem mass spectrometry. Results: During the eight days of the study in high temperature and high humidity storage, most acylcarnitines and amino acids lost almost 50% of initial concentration. After eight days' exposure at 37 C and 45 C with humidity >70%, methionine was determined to be the most sensitive, and phenylalanine and leucine were the least sensitive amino acids. At 37 C with humidity >70% C6 was the most sensitive and free carnitine (C0) was the least sensitive acylcarnitine; at 45 C with humidity >70% C16 was the most sensitive and C0 was the least sensitive. Conclusion: Low humidity and low temperature conditions are required for transportation and storage of dried blood spots.