Down regulation of VDR gene expression in metabolic syndrome and atherosclerosis' patients: Cause or consequence?

BACKGROUND: Metabolic syndrome (MS) features a set of clinical manifestations with an increased risk of atherosclerosis development. Vitamin D3 (VD3) pathway influences upon clinical features in MS as well in the formation of atherosclerotic plaque. VD3 acts through the vitamin D receptor (VDR), regulating the transcription of several genes involved in the immune response, growth and homeostasis. AIM: To evaluate whether VDR mRNA levels vary in MS patients according clinical features and atherosclerosis severity. METHODS: We included eighty individuals distributed into four groups: 1 group with MS (n = 20), 2 groups with atherosclerosis based on the report from the angiography (severe lesions - SL and primary lesions - PL) and 1 group enclosing healthy individuals (HC). The expression assays of VDR gene was performed using Real Time qPCR, with specific Taqman probes. We applied the Shapiro-Wilk, Chi-Squared and Student's T-tests for statistical analyses considering as statistically significant p < 0.05. RESULTS: Patients with MS as well with coronary stenosis present a down-regulation of VDR gene expression (-9.01 FC, p = 2.497 × 10-13; -13.62 FC, p = 7.489 × 10-13, respectively) when compared to control group. We also evaluated the VDR gene expression according to atherosclerosis severity, SL and PL patients present a downregulation of -31.51 FC and -8.48 FC, respectively, when compared with healthy controls group (p = 1.369 × 10-11; p = 1.647 × 10-11). When compared different degrees of atherosclerosis severity (SL versus PL) SL present a downregulation of -3.71 FC, when compared to PL group (p = 0.006). CONCLUSION: VDR is downregulated in patients with MS and according atherosclerosis severity. The differential expression of this gene is related to this hormone functions being an ex-vivo gene target for assessment in MS and atherosclerosis.

Caveolin-1 (CAV-1) up regulation in metabolic syndrome: all roads leading to the same end.

Metabolic syndrome (MS) is a set of clinical conditions such as insulin resistance, hyperglycemia, systemic arterial hypertension (SAH), dyslipidemia, obesity and high abdominal circumference. Some of these clinical characteristics have been associated with caveolin-1, a caveolae structural protein, responsible for insulin activation, storage and degradation of cholesterol, and so on. Herein we assessed CAV-1 mRNA levels in MS patients comparing to healthy controls (HC) and according patients' clinical features. We included 87 patients in the study, 25 patients with MS, 30 patients with at least one clinical condition (diabetes, SAH, dyslipidemia, obesity and high abdominal circumference), 13 with two clinical conditions and 19 HC. CAV-1 mRNA levels from peripheral blood samples were assessed by Real Time qPCR using specific Taqman probe. The analysis was performed using ∆Cq method and the statistical tests Shapiro-Wilk, One-Way ANOVA and Mann-Whitney. We found CAV-1 increased mRNA levels in patients with MS (1.645 FC, p = 9.794 × 10-20) and even higher in patients with only one or two clinical conditions (2.215 FC, p = 1.215 × 10-32 and 1.716 FC, p = 4.197 × 10-05, respectively). When individual clinical conditions were observed, individuals with high abdominal circumference and obesity present a significantly up regulation when compared to HC (2.956 FC, p = 0.0004 and 3.643 FC, p = 0.002, respectively). This work indicates that CAV-1 gene expression from whole blood samples is associated to MS clinical conditions and may become a potential target for MS treatment and prevention.

Differential distribution in vitamin D receptor gene variants and expression profile in Northeast Brazil influences upon active pulmonary tuberculosis.

Tuberculosis is an infectious disease with variable outcomes. This variability is due to host immune capacity in containing the infection process initiated by the Mycobacterium tuberculosis (MTB). Vitamin D is able to modulate a very specific immune response against MTB infection, and its action relies on vitamin D receptor (VDR) binding. Altered VDR forms may compromise vitamin D pathway and proper immune response after MTB infection. Herein we assessed the relationship of five potentially functional polymorphisms from VDR: rs2228570 FokI, rs11568820 Cdx-2, rs2248098, rs1540339 and rs4760648, with tuberculosis susceptibility. The SNP rs4760648 T/T was associated with differential susceptibility to tuberculosis (OR = 2.50, 95%CI = 1.20-5.36, p = 0.01). The SNP rs1540339 presented association to both T allele (OR = 0.55, 95%CI = 0.35-0.88, p = 0.01) and the T/T genotype (OR = 0.404, 95%CI = 0.20 - 0.78, p = 0.005). The FokI T allele was identified as associated to diminished susceptibility (OR = 0.67, 95% CI = 0.45-0.99, p = 0.04) to active TB, as well as T/T genotype (OR = 0.15, 95%CI = 0.04-0.45, p = 9.58 × 10-5). We also performed the expression analyses and observed a down-regulation of VDR in patients (-10.717 FC, p = 8.42e-12), and according to the presence of associated FokI SNP, we observed that the C/T and T/T genotypes presence increases VDR expression (+ 1.25 and + 2.35 FC, p = 0.425 and p = 0.506, respectively). This study shows that vitamin D receptor variants can influence upon pulmonary tuberculosis susceptibility and VDR mRNA levels are decreased in those patients.

Mechanism of inflammatory response in associated comorbidities in COVID-19.

BACKGROUND AND AIMS: The outbreak of the new coronavirus, SARS-CoV-2, causes a respiratory disease and individuals with pre-existing cardiometabolic disorders display worse prognosis through the infection course. The aim of this minireview is to present epidemiological data related to metabolic comorbidities in association with the SARS-CoV-2. METHODS: This is a narrative mini-review with Pubmed search until April 23, 2020 using the keywords COVID-19, SARS-CoV-2, treatment of coronavirus and following terms: diabetes mellitus, obesity, arterial hypertension, ACE-inhibitors, cytokine storm, immune response and vitamin D. RESULTS: Studies indicate that obese individuals are more likely to develop infections, and that adipose tissue serves as a pathogen reservoir. In diabetic individuals higher rate of inflammatory processes is seen due to constant glucose recognition by C type lectin receptors. Hypertensive individuals, usually grouped with other conditions, are treated with drugs to reduce blood pressure mostly through ACEi and ARB, that leads to increased ACE2 expression, used by SARS-CoV-2 for human's cell entry. Until now, the studies have shown that individuals with those conditions and affected by COVID-19 present an uncontrolled release of pro-inflammatory cytokines and an unbalanced immune response, leading to the cytokine storm phenomenon. Vitamin D is highlighted as a potential therapeutic target, because in addition to acting on the immune system, it plays an important role in the control of cardiometabolic diseases. CONCLUSION: Currently, since there is no proven and effective antiviral therapy for SARS-CoV-2, the efforts should focus on controlling inflammatory response and reduce the risks of associated complications.