Maternal Vitamin D Deficiency Impairs the Development of ß Cells in Offspring Rats in a Sex-Dependent Manner.

Recent studies have shown that maternal vitamin D deficiency (VDD) causes long-term metabolic changes in offspring. However, little is known about the impact of maternal VDD on offspring endocrine pancreas development and insulin secretion in the adult life of male and female animals. Female rats (Wistar Hannover) were fed either control (1000 IU Vitamin D3/kg), VDD (0 IU Vitamin D3/kg), or a Ca2+-enriched VDD diet (0 IU Vitamin D3/kg + Ca2+ and P/kg) for 6 weeks and during gestation and lactation. At weaning, VDD status was confirmed based on low serum calcidiol levels in dams and pups. Next, male and female offspring were randomly separated and fed a standard diet for up to 90 days. At this age, serum calcidiol levels were restored to normal levels in all groups, but serum insulin levels were decreased in VDD males without affecting glucagon levels, glycemia, or glucose tolerance. Islets isolated from VDD males showed lower insulin secretion in response to different glucose concentrations, but this effect was not observed in VDD females. Furthermore, VDD males, but not females, showed a smaller total pancreatic islet area and lower ß cell mass, an effect that was accompanied by reduced gene expression of Ins1, Ins2, Pdx1, and SLC2A2. The decrease in Pdx1 expression was not related to the methylation profile of the promoter region of this gene. Most of these effects were observed in the male VDD+Ca2+ group, indicating that the effects were not due to alterations in Ca2+ metabolism. These data show that maternal VDD selectively impairs the morphology and function of ß cells in adult male offspring rats and that female offspring are fully protected from these deleterious effects.

Previous Exercise Effects in Cisplatin-Induced Renal Lesions in Rats.

BACKGROUND/AIMS: Physical training has beneficial effects on endothelial function and can influence the regeneration of the endothelial cell. We investigated the effect of physical training on cisplatin (CP)-induced acute kidney injury and assessed the impact of training on endothelial structure and function, and on the inflammatory processes in rats. METHODS: We injected male Wistar rats subjected to previous physical training in treadmill running (trained, TR) or not (sedentary, SED) with CP (5 mg/kg) (TR+CP and SED+CP groups, respectively). Five days after the injections, blood and urine samples were collected to evaluate renal function and kidneys were harvested for morphological, immunohistochemical, enzyme-linked immunosorbent assay, and analysis of nitric oxide (NO) levels. RESULTS: Rats treated with CP showed increased levels of plasma creatinine and sodium and potassium fractional excretion. These alterations were associated with increase in tubulointerstitial lesions and macrophage number, reduction of endothelial cells, and increased VEGF, vimentin, and α-smooth muscle actin expression in the outer renal medulla in the SED+CP group. We also found increased levels of renal IL-1ß and increased excretion of monocyte chemoattractant protein-1 and transforming growth factor-ß compared with controls. These changes were milder in trained rats, associated with increased levels of renal tissue NO, and increased expression of p-eNOS and stromal cell-derived factor-1α (a chemokine involved in kidney repair) in the kidneys of CP-injected trained rats. CONCLUSIONS: The protective effect of previous training in CP-treated rats was associated with reduced endothelial cell lesions and increased renal production of NO in trained rats.

Hepatic noradrenergic innervation acts via CREB/CRTC2 to activate gluconeogenesis during cold.

BACKGROUND AND AIM: Although it is well established that hormones like glucagon stimulates gluconeogenesis via the PKA-mediated phosphorylation of CREB and dephosphorylation of the cAMP-regulated CREB coactivators CRTC2, the role of neural signals in the regulation of gluconeogenesis remains uncertain. METHODS AND RESULTS: Here, we characterize the noradrenergic bundle architecture in mouse liver; we show that the sympathoexcitation induced by acute cold exposure promotes hyperglycemia and upregulation of gluconeogenesis via triggering of the CREB/CRTC2 pathway. Following its induction by dephosphorylation, CRTC2 translocates to the nucleus and drives the transcription of key gluconeogenic genes. Rodents submitted to different models of sympathectomy or knockout of CRTC2 do not activate gluconeogenesis in response to cold. Norepinephrine directly acts in hepatocytes mainly through a Ca2+-dependent pathway that stimulates CREB/CRTC2, leading to activation of the gluconeogenic program. CONCLUSION: Our data demonstrate the importance of the CREB/CRTC2 pathway in mediating effects of hepatic sympathetic inputs on glucose homeostasis, providing new insights into the role of norepinephrine in health and disease.

Maternal vitamin D deficiency affects the morphology and function of glycolytic muscle in adult offspring rats.

BACKGROUND: Fetal stage is a critical developmental window for the skeletal muscle, but little information is available about the impact of maternal vitamin D (Vit. D) deficiency (VDD) on offspring lean mass development in the adult life of male and female animals. METHODS: Female rats (Wistar Hannover) were fed either a control (1000 IU Vit. D3/kg) or a VDD diet (0 IU Vit. D3/kg) for 6 weeks and during gestation and lactation. At weaning, male and female offspring were randomly separated and received a standard diet up to 180 days old. RESULTS: Vitamin D deficiency induced muscle atrophy in the male (M-VDD) offspring at the end of weaning, an effect that was reverted along the time. Following 180 days, fast-twitch skeletal muscles [extensor digitorum longus (EDL)] from the M-VDD showed a decrease (20%; P < 0.05) in the number of total fibres but an increase in the cross-sectional area of IIB (17%; P < 0.05), IIA (19%; P < 0.05) and IIAX (21%; P < 0.05) fibres. The fibre hypertrophy was associated with the higher protein levels of MyoD (73%; P < 0.05) and myogenin (55% %; P < 0.05) and in the number of satellite cells (128.8 ± 14 vs. 91 ± 7.6 nuclei Pax7 + in the M-CTRL; P < 0.05). M-VDD increased time to fatigue during ex vivo contractions of EDL muscles and showed an increase in the phosphorylation levels of IGF-1/insulin receptor and their downstream targets related to anabolic processes and myogenic activation, including Ser 473 Akt and Ser 21/9 GSK-3ß. In such muscles, maternal VDD induced a compensatory increase in the content of calcitriol (two-fold; P < 0.05) and CYP27B1 (58%; P < 0.05), a metabolizing enzyme that converts calcidiol to calcitriol. Interestingly, most morphological and biochemical changes found in EDL were not observed in slow-twitch skeletal muscles (soleus) from the M-VDD group as well as in both EDL and soleus muscles from the female offspring. CONCLUSIONS: These data show that maternal VDD selectively affects the development of type-II muscle fibres in male offspring rats but not in female offspring rats and suggest that the enhancement of their size and fatigue resistance in fast-twitch skeletal muscle (EDL) is probably due to a compensatory increase in the muscle content of Vit. D in the adult age.