Is the Association between Vitamin D and Cardiovascular Disease Risk Confounded by Obesity? Evidence from the Andhra Pradesh Children and Parents Study (APCAPS)

Background

Evidence of an association between serum vitamin D and cardiovascular disease risk is inconsistent and comes predominantly from studies in high-income settings. We assessed the association between serum levels of 25-hydroxyvitamin D₃ (25(OH)D) and cardiovascular disease risk factors in a population of young Indian adults.

Methods

Cross-sectional analyses of data from APCAPS (Andhra Pradesh Children and Parents Study); a prospective birth cohort study in rural south India. Participants were 1038 (40.3% females) adults aged 18-24 years. Main outcome measures were blood pressures, fasting serum lipids (cholesterols and triglycerides), fasting glucose, insulin, measures of arterial stiffness (aortic augmentation index and aortic pulse wave velocity (aPWV)), carotid intima-media thickness, body mass index (BMI) and body fat (dual X-ray absorptiometry).

Results

Vitamin D deficiency (≤20ng/ml) was observed in 41.1% of this lean (mean BMI: 19.5) and active (mean minutes of moderate or vigorous physical activity per day: 186) population. Vitamin D deficiency was associated with higher median body fat in both males (15.9% body fat in vitamin D deficient males vs. 14.6% in non-deficient males, p<0.05) and females (29.1% body fat in vitamin D deficient females vs. 27.8% in non-deficient females, p<0.05) but no associations were observed between vitamin D deficiency and mean BMI or median fat mass index (FMI). Except a weak inverse association with fasting insulin in males, there was no clear association between serum vitamin D levels and cardiovascular disease risk factors in fully adjusted models.

Conclusions

We did not find clear evidence for an association between serum vitamin D levels and cardiovascular disease risk factors. Our results, consistent with the limited evidence from randomised trials of vitamin D supplementation and Mendelian randomisation experiments, suggest that the postulated link between serum vitamin D and cardiovascular disease may be non-causal. Instead, it may be attributable to confounding by lifestyle factors such as obesity and physical inactivity which may provide more fruitful targets for cardiovascular disease prevention.     

Biased Recognition of Facial Affect in Patients with Major Depressive Disorder Reflects Clinical State

Cognitive theories of depression posit that perception is negatively biased in depressive disorder. Previous studies have provided empirical evidence for this notion, but left open the question whether the negative perceptual bias reflects a stable trait or the current depressive state. Here we investigated the stability of negatively biased perception over time. Emotion perception was examined in patients with major depressive disorder (MDD) and healthy control participants in two experiments. In the first experiment subjective biases in the recognition of facial emotional expressions were assessed. Participants were presented with faces that were morphed between sad and neutral and happy expressions and had to decide whether the face was sad or happy. The second experiment assessed automatic emotion processing by measuring the potency of emotional faces to gain access to awareness using interocular suppression. A follow-up investigation using the same tests was performed three months later. In the emotion recognition task, patients with major depression showed a shift in the criterion for the differentiation between sad and happy faces: In comparison to healthy controls, patients with MDD required a greater intensity of the happy expression to recognize a face as happy. After three months, this negative perceptual bias was reduced in comparison to the control group. The reduction in negative perceptual bias correlated with the reduction of depressive symptoms. In contrast to previous work, we found no evidence for preferential access to awareness of sad vs. happy faces. Taken together, our results indicate that MDD-related perceptual biases in emotion recognition reflect the current clinical state rather than a stable depressive trait.     

Phenotype and growth behavior of residual β-catenin-positive hepatocytes in livers of β-catenin-deficient mice

Signaling through the Wnt/β-catenin pathway is a crucial determinant of hepatic zonal gene expression, liver development, regeneration, and tumorigenesis. Transgenic mice with hepatocyte-specific knockout of Ctnnb1 (encoding β-catenin) have proven their usefulness in elucidating these processes. We now found that a small number of hepatocytes escape the Cre-mediated gene knockout in that mouse model. The remaining β-catenin-positive hepatocytes showed approximately 25% higher cell volumes compared to the β-catenin-negative cells and exhibited a marker protein expression profile similar to that of normal perivenous hepatocytes or hepatoma cells with mutationally activated β-catenin. Surprisingly, the expression pattern was observed independent of the cell's position within the liver lobule, suggesting a malfunction of physiological periportal repression of perivenously expressed genes in β-catenin-deficient liver. Clusters of β-catenin-expressing hepatocytes lacked expression of the gap junction proteins Connexin 26 and 32. Nonetheless, β-catenin-positive hepatocytes had no striking proliferative advantage, but started to grow out on treatment with phenobarbital, a tumor-promoting agent known to facilitate the formation of mouse liver adenoma with activating mutations of Ctnnb1. Progressive re-population of Ctnnb1 knockout livers with wild-type hepatocytes was seen in aged mice with a pre-cirrhotic phenotype. In these large clusters of β-catenin-expressing hepatocytes, perivenous-specific gene expression was re-established. In summary, our data demonstrate that the zone-specificity of a hepatocyte's gene expression profile is dependent on the presence of β-catenin, and that β-catenin provides a proliferative advantage to hepatocytes when promoted with phenobarbital, or in a pre-cirrhotic environment.     

Multiple-level regulation of genes for protocatechuate degradation in Acinetobacter baylyi includes cross-regulation

The bacterium Acinetobacter baylyi uses the branched beta-ketoadipate pathway to metabolize aromatic compounds. Here, the multiple-level regulation of expression of the pca-qui operon encoding the enzymes for protocatechuate and quinate degradation was studied. It is shown that both activities of the IclR-type regulator protein PcaU at the structural gene promoter pcaIp, namely protocatechuate-dependent activation of pca-qui operon expression as well as repression in the absence of protocatechuate, can be observed in a different cellular background (Escherichia coli) and therefore are intrinsic to PcaU. The regulation of PcaU expression is demonstrated to be carbon source dependent according to the same pattern as the pca-qui operon. The increase of the pcaU gene copy number leads to a decrease of the basal expression at pcaIp, indicating that the occupancy of the PcaU binding site is well balanced and depends on the concentration of PcaU in the cell. Luciferase is used as a reporter to demonstrate strong repression of pcaIp when benzoate, a substrate of the catechol branch of the pathway, is present in addition to substrates of the protocatechuate branch (cross-regulation). The same repression pattern was observed for promoter pcaUp. Thus, three promoters involved in gene expression of enzymes of the protocatechuate branch (pobAp upstream of pobA, pcaIp, and pcaUp) are strongly repressed in the presence of benzoate. The negative effect of protocatechuate on pobA expression is not based on a direct sensing of the metabolite by PobR, the specific regulator of pobA expression.     

Vector bionomics and malaria transmission in the Upper Orinoco River, Southern Venezuela

A longitudinal epidemiological and entomological study was carried out in Ocamo, Upper Orinoco River, between January 1994 and February 1995 to understand the dynamics of malaria transmission in this area. Malaria transmission occurs throughout the year with a peak in June at the beginning of the rainy season. The Annual Parasite Index was 1,279 per 1,000 populations at risk. Plasmodium falciparum infections accounted for 64% of all infections, P. vivax for 28%, and P. malariae for 4%. Mixed P. falciparum/P. vivax infections were diagnosed in 15 people representing 4% of total cases. Children under 10 years accounted for 58% of the cases; the risk for malaria in this age group was 77% higher than for those in the greater than 50 years age group. Anopheles darlingi was the predominant anopheline species landing on humans indoors with a biting peak between midnight and dawn. A significant positive correlation was found between malaria monthly incidence and mean number of An. darlingi caught. There was not a significant relationship between mean number of An. darlingi and rainfall or between incidence and rainfall. A total of 7295 anophelines were assayed by ELISA for detection of Plasmodium circumsporozoite (CS) protein. Only An. darlingi (55) was positive for CS proteins of P. falciparum (0.42%), P. malariae (0.25%), and P. vivax-247 (0.1%). The overall estimated entomological inoculation rate was 129 positive bites/person/year. The present study was the first longitudinal entomological and epidemiological study conducted in this area and set up the basic ground for subsequent intervention with insecticide-treated nets.     

Increased arginase activity and endothelial dysfunction in human inflammatory bowel disease

Nitric oxide (.NO) generation from conversion of l-arginine to citrulline by nitric oxide synthase isoforms plays a critical role in vascular homeostasis. Loss of .NO is linked to vascular pathophysiology and is decreased in chronically inflamed gut blood vessels in inflammatory bowel disease (IBD; Crohn's disease and ulcerative colitis). Mechanisms underlying decreased .NO production in IBD gut microvessels are not fully characterized. Loss of .NO generation may result from increased arginase (AR) activity, which enzymatically competes with nitric oxide synthase for the common substrate l-arginine. We characterized AR expression in IBD microvessels and endothelial cells and its contribution to decreased .NO production. AR expression was assessed in resected gut tissues and human intestinal microvascular endothelial cells (HIMEC). AR expression significantly increased in both ulcerative colitis and Crohn's disease microvessels and submucosal tissues compared with normal. TNF-alpha/lipopolysaccharide increased AR activity, mRNA and protein expression in HIMEC in a time-dependent fashion. RhoA/ROCK pathway, a negative regulator of .NO generation in endothelial cells, was examined. The RhoA inhibitor C3 exoenzyme and the ROCK inhibitor Y-27632 both attenuated TNF-alpha/lipopolysaccharide-induced MAPK activation and blocked AR expression in HIMEC. A significantly higher AR activity and increased RhoA activity were observed in IBD submucosal tissues surrounding microvessels compared with normal control gut tissue. Functionally, inhibition of AR activity decreased leukocyte binding to HIMEC in an adhesion assay. Loss of .NO production in IBD microvessels is linked to enhanced levels of AR in intestinal endothelial cells exposed to chronic inflammation in vivo.     

A possible novel function of dominance behaviour in queen-less colonies of the primitively eusocial wasp Ropalidia marginata

Unlike the queens of other primitively eusocial species, Ropalidia marginata queens are strikingly docile and non-aggressive individuals, never at the top of the behavioural dominance hierarchy of their colonies. Nevertheless, these queens are completely successful at suppressing worker reproduction, suggesting that they do not use aggression but employ some other mechanism (e.g. pheromones) to do so. Upon removal of the queen from a colony, a single worker, the 'potential queen', immediately begins to display highly elevated levels of aggression towards her nest mates. This individual becomes the next docile queen if the original queen is not returned. We attempt to understand the function of the temporary and amplified dominance behaviour displayed by the potential queen. We find that the dominance behaviour shown by the potential queen is unrelated to the number of her nest mates, their dominance ranks or ovarian condition. This suggests that aggression may not be used to actively suppress other workers and counter threat. Instead we find evidence that dominance behaviour is required for the potential queen's rapid ovarian development, facilitating her speedy establishment as the sole reproductive individual in the colony.     

Mineralization process during acellular cementogenesis in rat molars: a histochemical and immunohistochemical study using fresh-frozen sections

This study was designed to detect tissue non-specific alkaline phosphatase (TNSALP) by Azo-dye staining, calcium by glyoxal bis (2-hydroxyanil) (GBHA) staining, bone sialoprotein (BSP) and osteopontin (OPN) by immunoperoxidase staining in developing rat molars, and also to discuss the mineralization process during acellular cementogenesis. To restrain a reduction in histochemical and immunohistochemical reactions, fresh-frozen undemineralized sections were prepared. Where the epithelial sheath was intact, TNSALP reaction was observed in the dental follicle, but not in the epithelial sheath. With the onset of dentin mineralization, the BSP- and OPN-immunoreactive, initial cementum layer appeared. At this point, cementoblasts had shown intense TNSALP reaction and GBHA reactive particles (=calcium-GBHA complex) appeared on the root surface. With further development, the reaction of TNSALP and GBHA became weak on the root surface. Previous studies have shown that the initial cementum is fibril-poor and that matrix vesicles and calciferous spherules appear on the root surface only during the initial cementogenesis. The findings mentioned above suggest that: during the initial cementogenesis, cementoblasts release matrix vesicles which result in calciferous spherules, corresponding to the GBHA reactive particles. The calciferous spherules trigger the mineralization of the initial cementum. After principal fiber attachment, mineralization advances along collagen fibrils without matrix vesicles.     

SHANK3 genetic polymorphism and susceptibility to ASD: evidence from molecular,in silico,and meta-analysis approaches

Molecular Biology Reports - The SHANK3 gene encodes a master synaptic scaffolding protein at the excitatory synapse’s postsynaptic density, which is predominantly responsible for constructing...