Vitamin D – ABC CARDIOL

IJCS

Original Article

Body Adiposity and Endothelial Dysfunction Assessed By Laser Speckle Contrast Imaging in Obese and Overweight Individuals With Suboptimal Vitamin D Status: Sex Differences

Adriana de Castro Carvalho Faria et al. Michelle Rabello Cunha Caroline Lyra Moreira Samanta Souza Mattos … Clara Castro Carvalho Oliveira Faria Leticia Castro Carvalho Oliveira Faria Wille Oigman Mario Fritsch Neves

Abstract

Background:

Low Vitamin D levels are prevalent in obesity and have been linked to adverse cardiovascular and metabolic outcomes.

Objective:

This cross-sectional study aimed to assess anthropometric indices, vascular, autonomic function in obese and overweight individuals with suboptimal vitamin D status.

Methods:

Participants of both sexes, 40-69 years, Body Mass Index (BMI) 25-40 kg/m², were divided into two groups above and under the median vitamin D level (22,6 ng/ml), named Suboptimal (SUB-D) and Lower (LOW-D) vitamin D, respectively. Vascular function was assessed using central hemodynamic parameters (Mobil-O-Graph®), endothelial function (microvascular reactivity; Laser Speckle Contrast Image system), and heart rate variability (Polar® monitor). The groups were compared using an unpaired Student’s t-test, and p-values < 0,05 were considered statistically significant.

Results:

The groups (n = 90) had similar ages and blood pressures. The LOW-D group had a higher body fat percentage (%BF; 29 ± 4 vs. 33 ± 3, p = 0.020) and glycated Hb (5.4 ± 0.4 vs. 5.8 ± 0.4, p = 0.029) in males. Females had higher Visceral Adiposity Index (VAI; 2.33 ± 0.86 vs. 3.32 ± 1.86, p = 0.008) and Lipid Accumulation Products (LAP; 39 ± 23 vs. 63 ± 40, p = 0.005). The LOW-D group showed a lower percentage increase in the area under the curve in post-occlusive reactive hyperemia (%AUC-PORH) (70 ± 30 vs. 55 ± 32%, p = 0.034). Females showed inverse correlation of vitamin D levels and VAI and LAP, and a positive correlation with %AUC-PORH.

Conclusions:

In obese and overweight individuals, lower vitamin D content was associated with higher levels of body adiposity in males. Furthermore, impaired metabolic functions and endothelial dysfunction were related to lower vitamin D levels in females, as in the central illustration.

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Editorial

Vitamin D and the Cardiovascular System

Claudio Leinig Pereira da Cunha

Vitamin D (or calciferol) is a fat-soluble vitamin. It is a generic term and refers to a group of fat-soluble compounds with a four-ring cholesterol structure. Dermal synthesis, under the action of UV-B light on the skin, is the main natural source of this vitamin, as very few foods contain vitamin D naturally (fatty fish, such as salmon, tuna, sardines, trout, are the exception). This vitamin D, whether derived from the diet or dermal synthesis, is biologically inactive. It is presented as vitamin D3 (cholecalciferol) and vitamin D2 (ergocalciferol), which are enzymatically converted in the liver into 25(OH)D (25-hydroxyvitamin D = calcidiol), the main circulating form of vitamin D. Then, in the kidney, calcidiol is converted into calcitriol (1,25-dihydroxyvitamin D), the active form of vitamin D, which increases intestinal absorption of calcium, increases bone reabsorption and decreases renal excretion of calcium and phosphate.

The best laboratory indicator of vitamin D adequacy is the serum 25(OH)D concentration. However, there is no consensus on the ideal concentration; the National Academy of Medicine indicated that 20 ng/ml is suficiente, but most experts (Endocrine Society, National Osteoporosis Foundation, International Osteoporosis Foundation, American Geriatrics Society) suggest that a minimum level of 30ng/ml is necessary for adults.

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Original Article

Effects of Vitamin D Supplementation on Central Hemodynamic Parameters and Autonomic Nervous System in Obese or Overweight Individuals

Adriana C. C. Faria et al. Caroline Lyra Moreira Michelle Rabello da Cunha Samanta Mattos … Wille Oigman Mario Fritsch Neves

Abstract

Background

Previous studies have been inconsistent in demonstrating beneficial cardiovascular effects of vitamin D supplementation.

Objective

To evaluate the effects of vitamin D3 supplementation on central hemodynamic parameters and autonomic activity in obese/overweight individuals with low vitamin D levels (<30ng/dl).

Methods

Adults 40-65 years old with body mass index ≥25<40 kg/m² were enrolled in this prospective, randomized, double-blind clinical trial (NCT 05689632). Central hemodynamics was assessed using the oscillometric method (Mobil-O-Graph^®), and heart rate variability using a Polar heart rate monitor (Kubios^® software). Patients (n=53) received a placebo in the control group (CO, n=25) or vitamin D3 (VD, n=28) 7000 IU/day, and were evaluated before (W0) and after 8 weeks (W8) with a significance level of 0.05.

Results

The groups were homogeneous regarding age (51±6 vs 52±6 years, p=0.509) and vitamin D levels (22.8±4.9 vs 21.7±4.5ng/ml, p=0.590). At W8, the VD group had significantly higher levels of vitamin D (22.5 vs 35.6ng/ml, p0.05). VD group showed an increase in the parasympathetic nervous system index (PNSi) (-0.64±0.94 vs -0.16±1.10, p=0.028) and the R-R interval (866±138 vs 924±161 ms, p= 0.026).

Conclusion

In this sample, eight weeks of daily vitamin D supplementation resulted in an improvement in blood pressure levels and autonomic balance.

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Original Article

Vitamin D Supplementation Induces Cardiac Remodeling in Rats: Association with Thioredoxin-Interacting Protein and Thioredoxin

Priscila P. dos Santos et al. Bruna P. M. Rafacho Andrea F. Gonçalves Vanessa C. M. Pires … Meliza G. Roscani Paula S. Azevedo Bertha F. Polegato Marcos F. Minicucci Ana Angélica H. Fernandes Suzana E. Tanni Leonardo A. M. Zornoff Sergio A. R. de Paiva

Abstract

Background:

Vitamin D (VD) has been shown to play an important role in cardiac function. However, this vitamin exerts a biphasic “dose response” curve in cardiovascular pathophysiology and may cause deleterious effects, even in non-toxic doses. VD exerts its cellular functions by binding to VD receptor. Additionally, it was identified that the thioredoxin-interacting protein (TXNIP) expression is positively regulated by VD. TXNIP modulate different cell signaling pathways that may be important for cardiac remodeling.

Objective:

To evaluate whether VD supplementation lead to cardiac remodeling and if TXNIP and thioredoxin (Trx) proteins are associated with the process.

Methods:

A total of 250 Male Wistar rats were allocated into three groups: control (C, n=21), with no VD supplementation; VD3 (n = 22) and VD10 (n=21), supplemented with 3,000 and 10,000 IU of VD/ kg of chow respectively, for two months. The groups were compared by one-way analysis of variance (ANOVA) and Holm-Sidak post hoc analysis, (variables with normal distribution), or by Kruskal-Wallis test and Dunn’s test post hoc analysis. The significance level for all tests was 5%.

Results:

TXNIP protein expression was higher and Trx activity was lower in VD10. The animals supplemented with VD showed increased lipid hydroperoxide and decreased superoxide dismutase and glutathione peroxidase. The protein Bcl-2 was lower in VD10. There was a decrease in fatty acid β-oxidation, tricarboxylic acid cycle and electron transport chain with shift to increase in glycolytic pathway.

Conclusion:

VD supplementation led to cardiac remodeling and this process may be modulated by TXNIP and Trx proteins and consequently oxidative stress.

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Editorial

Supplementation of Vitamin D

Marina P. Okoshi et al. Rosana M. Cortez Luana U. Pagan Paula F. Martinez Filipe W. L. Pereira

Vitamin D (Vit D) is a fat-soluble vitamin that is essential in mineral and bone metabolism. Vit D status is evaluated by measuring serum 25-hydroxyvitamin D [25(OH)D]) levels. Currently, Vit D supplementation is mainly indicated in cases of vitamin deficiency. However, there are two main issues concerning Vit D supplementation. The first is related to the definition of the lower limit of normal for serum 25(OH) D. In recent years, extensive clinical research has revealed that large percentages of global populations have low Vit D levels, i.e., serum [25(OH)D] concentrations below 20 ng/mL. However, several investigators have considered that this value is probably overestimated, therefore putting more people in need for supplementation. Several medical societies are now intensively debating on when to screen for Vit D deficiency and when to supplement Vit D.^,

The other issue concerning Vit D supplementation relates to the fact that convincing experimental and epidemiological studies have suggested that Vit D deficiency is associated with increased risk of chronic cardiovascular and immunological diseases and cancer. Therefore, Vit D has been supplemented in the general population without a specific indication. However, more recent studies have reported that Vit D supplementation for preventing or controlling chronic diseases such as cancer, diabetes mellitus, dementia or cardiovascular disease has failed to provide benefits.^– Furthermore, not only were no benefits found. In advanced heart failure, a daily Vit D supplement was associated with a greater need for mechanical circulatory support devices, which indicates caution regarding long-term supplementation.

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