Vitamin D and Ageing

Vitamin D3 application and factors of its activity in the adrenal cortex of andropausal rats: A functionally-histological study

INTRODUCTION AND AIM

Vitamin D supplementation in aging subjects manifests a positive effect on various health-related parameters. We performed a functionally-histological analysis of the adrenal cortex regarding the factors of vitamin D activity and corticosterone output after vitamin D3 application in a rat model of the andropause.

MATERIAL AND METHODS

Middle-aged Wistar rats were divided into sham operated (SO; n=8), orchidectomized (Orx; n=8) and vitamin D3-treated orchidectomized (Orx+vit. D; n=8) groups. Vitamin D3 (5 μg/kg b.m.) was administered subcutaneously for three weeks, while the SO and Orx groups received the vehicle alone. Set objectives were achieved using histochemistry/immunohistochemistry, stereology, ultrastructural and biochemical analyses.

RESULTS

Orchidectomy (Orx) decreased the adrenal cortex-related volume densities of vascular (p<0,0001), vitamin D receptor (VDR; p<0,0166), cytochrome P450 oxidase 2R1 (CYP 2R1; p<0,0001) and cytochrome P450 oxidase 24 (CYP 24; p<0,0001) depots, but increased the volume density of cytochrome P450 27B1 (CYP 27B1; p<0,0001) depots. In Orx+vit. D rats, increase of the adrenal cortex-related volume densities of collagen (p<0,0001), VDR (p<0,0001) and CYP 2R1 (p<0,0001) depots as well as the lipid-droplet diameter (p<0,0001) in adrenocortical outer zona fasciculata cells was observed, while a decrease of volume densities of the vascular (p<0,0001), CYP 27B1 (p<0,0001) and CYP 24 (p<0,0001) depots was registered, all versus Orx group. Plasma level of ACTH was decreased (p=0,0155) and serum concentrations of 25-hydroxyvitamin D3 and corticosterone were increased (p<0,0001 and p=0,0187, respectively), all after the same treatment.

CONCLUSIONS

Increased corticosterone output after vitamin D3 application to andropausal rats appears not to be related to increased availability of 25-hydroxyvitamin D3 and decreased degradation of 1,25-dihydroxyvitamin D3 in adrenal tissue, but rather involves the central regulatory mechanisms.

Targeting Cell Senescence and Senolytics: Novel Interventions for Age-Related Endocrine Dysfunction

Multiple changes occur in hormonal regulation with aging and across various endocrine organs. These changes are associated with multiple age-related disorders and diseases. A better understanding of responsible underling biological mechanisms could help in the management of multiple endocrine disorders over and above hormone replacement therapy (HRT). Cellular senescence is involved in multiple biological aging processes and pathologies common in elderly individuals. Cellular senescence, which occurs in many older individuals but also across the lifespan in association with tissue damage, acute and chronic diseases, certain drugs, and genetic syndromes, may contribute to such endocrine disorders as osteoporosis, metabolic syndrome, and type 2 diabetes mellitus. Drugs that selectively induce senescent cell removal, "senolytics,", and drugs that attenuate the tissue-destructive secretory state of certain senescent cells, "senomorphics," appear to delay the onset of or alleviate multiple diseases, including but not limited to endocrine disorders such as diabetes, complications of obesity, age-related osteoporosis, and cancers as well as atherosclerosis, chronic kidney disease, neurodegenerative disorders, and many others. More than 30 clinical trials of senolytic and senomorphic agents have already been completed, are underway, or are planned for a variety of indications. Targeting senescent cells is a novel strategy that is distinct from conventional therapies such as HRT, and thus might address unmet medical needs and can potentially amplify effects of established endocrine drug regimens, perhaps allowing for dose decreases and reducing side effects.

Can Vitamin D Supplementation Improve Inflammation in Relapsing-Remitting Multiple Sclerosis Patients?

(1) Background: Studies indicate that vitamin D (VitD) may reduce inflammation in multiple sclerosis (MS). The aim of the study was to assess the effect of supplementation with different doses of VitD on inflammation in relapsing-remitting MS (RRMS) patients. (2) Methods: The effect of 6-month supplementation with different doses of oral VitD (2000 IU/day) in a high-dose group (HD, n = 23) and a low-dose group (15,960 IU/month) (LD, n = 29) on selected markers of inflammation was assessed in 52 RRMS patients. (3) Results: Females constituted the majority of participants (63.46%). The median age [years] was 39.5 [34.5-49.8] and 47 [40.0-55.0] in the HD and LD groups, respectively. Significant differences were observed in age (p = 0.028), body weight (p = 0.014) and height (p = 0.001) between the study groups. Considering the BMI, statistically significant differences were not found (p = 0.496). The median 25(OH)D concentration [ng/mL] increased from 23.023 [15.578-25.76] in the HD group and 28.318 [20.644-32.232] in the LD group to 29.819 [24.937-38.064] and 30.837 [25.382-36.789], respectively (p < 0.01), and the increase was significantly higher in the HD group (p = 0.01). Hypovitaminosis D was found in most patients (71.2%) initially, and serum VitD levels were still <30.0 ng/mL in 46.2% of the participants at the follow-up. A significant increase in the levels of IL-4, IL-6, IL-17A, IL-22, IL-23 and TNF -α [pg/mL] and a decrease in IL-10 levels were reported during the study (p < 0.01). A significant positive correlation was observed between 25(OH)D serum levels and sCD40L (R = 0.33; p < 0.05) and TNF-α (R = 0.28; p < 0.05), and a significant negative correlation was reported between 25(OH)D and IL-23 (R = -0.32; p < 0.01) at the beginning of the study. (4) Conclusions: In RRMS patients, the doses of VitD were probably too low to induce beneficial effects on inflammation. Further studies are warranted to determine the effect of VitD supplementation on inflammatory markers in MS patients.

A hypothesis: MiRNA-124 mediated regulation of sirtuin 1 and vitamin D receptor gene expression accelerates aging

Objectives

Specific miRNAs are evident to be overexpressed with age, lifestyle, and environmental changes. Previous studies reported miR-124 overexpression in different scenarios in aged skin, age-related cognitive impairment, ischemic heart disease, muscle atrophy, and fractures. Thus miR-124 was considered to be a reliable miRNA target to establish a hypothesis on aging epigenome. Parallelly the hypothesis focuses on the expression of SIRT1 and VDR genes as a target for this specific miRNA expression as these genes were believed to be related to aging. This study aims to derive facts and evidence from past studies on aging. The objective was to establish a hypothetical linkage between miR-124 with age-related genes like SIRT1 and VDR.

Methods

An in silico search was performed in the TargetScan and miRbase databases to analyze the aging-associated miRNAs and their gene targets, the Python seaborn library was used, and the results were represented in terms of a bar plot.

Results

Based on an in silico analysis and studies available in the literature, we identified that miR-124-3p.1 and miR-124-3p.2 targets 3' UTR of VDR and SIRT1 genes, and hence thereby indicates that the miR-124 can regulate the expression of these genes. Further, few in vitro research studies have observed that miR-124 overexpression leads to the downregulation of VDR and SIRT1 gene expression. These results indicate that the suppression of these target genes accelerates early aging and age-related disorders.

Conclusions

Overall, this study hypothesizes that the overexpression of miR-124 diminishes the expression of VDR and SIRT1 genes, and thereby advances the process of aging, resulting in the development of age-associated complications.

Hormones and Aging: An Endocrine Society Scientific Statement

Multiple changes occur across various endocrine systems as an individual ages. The understanding of the factors that cause age-related changes and how they should be managed clinically is evolving. This statement reviews the current state of research in the growth hormone, adrenal, ovarian, testicular, and thyroid axes, as well as in osteoporosis, vitamin D deficiency, type 2 diabetes, and water metabolism, with a specific focus on older individuals. Each section describes the natural history and observational data in older individuals, available therapies, clinical trial data on efficacy and safety in older individuals, key points, and scientific gaps. The goal of this statement is to inform future research that refines prevention and treatment strategies in age-associated endocrine conditions, with the goal of improving the health of older individuals.

Genetic variants of the vitamin D receptor are related to dynapenia in postmenopausal women

BACKGROUND

Dynapenia increases with age and in the case of women is possibly influenced by menopause, yet whether vitamin D affects this increase remains controversial. The influence of genetic variants (single nucleotide polymorphisms) of the vitamin D receptor on dynapenia is an understudied area.

AIM

To analyze the association between genetic variants of the vitamin D receptor gene and dynapenia in a cohort of community-dwelling postmenopausal women.

METHODS

We performed a cross-sectional study of 463 women in a university hospital. Grip strength was used as an indicator of dynapenia. Differences in grip strength among single nucleotide polymorphisms rs11568820 and rs2228570 genotypes of the vitamin D receptor gene were assessed after adjusting for confounding variables, and the percentage of phenotypic variance was estimated by linear regression.

RESULTS

Dynapenia (grip strength <20 kg) was diagnosed in 178 of the women (38.45 %). A difference in grip strength, corresponding to variants of the vitamin D receptor gene single nucleotide polymorphism rs11568820, was found when using an additive model of inheritance, with lower grip strength for the TT genotype (ANOVA, p = 0.030, close to the 0.025 significance level determined by Bonferroni correction). Assuming a recessive inheritance model for allele T, the between-group difference in grip strength was significant (TT = 19.79 ± 3.10 kg vs. CC/CT = 21.58 ± 3.49 kg, p = 0.008) after adjusting for age, body mass index, comorbidities, and sociodemographic variables. More women with dynapenia had the TT genotype (60.71 %) than the CC or CT genotype (37.01 %) (p = 0.012).

CONCLUSION

This study demonstrates that the TT genotype of the rs11568820 SNP of the vitamin D receptor gene was associated with decreased grip strength in community-dwelling postmenopausal women.

Vitamin D attenuates COVID-19 complications via modulation of proinflammatory cytokines, antiviral proteins, and autophagy

INTRODUCTION

Global emergence of coronavirus disease-19 (COVID-19) has clearly shown variable severity, mortality, and frequency between and within populations worldwide. These striking differences have made many biological variables attractive for future investigations. One of these variables, vitamin D, has been implicated in COVID-19 with rapidly growing scientific evidence.

AREAS COVERED

The review intended to systematically explore the sources, and immunomodulatory role of vitamin D in COVID-19. Search engines and data sources including Google Scholar, PubMed, NCBI, Scopus, and Web of Science were used for data collection. The search terms used were Vitamin D, COVID-19, immune system, and antiviral mechanism. Overall, 232 sources of information were collected and 188 were included in this review.

EXPERT OPINION

Interaction of vitamin D and vitamin D receptor (VDR) triggers the cellular events to modulate the immune system by regulation of many genes. Vitamin D operates as a double-edged sword against COVID-19. First, in macrophages, it promotes the production of antimicrobial and antiviral proteins like β-defensin 2 and cathelicidin, and these proteins inhibit the replication of viral particles and promote the clearance of virus from the cells by autophagy. Second, it suppresses cytokine storm and inflammatory processes in COVID-19.

Memorable Food: Fighting Age-Related Neurodegeneration by Precision Nutrition

Healthcare systems worldwide are seriously challenged by a rising prevalence of neurodegenerative diseases (NDDs), which mostly, but not exclusively, affect the ever-growing population of the elderly. The most known neurodegenerative diseases are Alzheimer's (AD) and Parkinson's disease, multiple sclerosis, and amyotrophic lateral sclerosis, but some viral infections of the brain and traumatic brain injury may also cause NDD. Typical for NDD are the malfunctioning of neurons and their irreversible loss, which often progress irreversibly to dementia and ultimately to death. Numerous factors are involved in the pathogenesis of NDD: genetic variability, epigenetic changes, extent of oxidative/nitrosative stress, mitochondrial dysfunction, and DNA damage. The complex interplay of all the above-mentioned factors may be a fingerprint of neurodegeneration, with different diseases being affected to different extents by particular factors. There is a voluminous body of evidence showing the benefits of regular exercise to brain health and cognitive functions. Moreover, the importance of a healthy diet, balanced in macro- and micro-nutrients, in preventing neurodegeneration and slowing down a progression to full-blown disease is evident. Individuals affected by NDD almost inevitably have low-grade inflammation and anomalies in lipid metabolism. Metabolic and lipid profiles in NDD can be improved by the Mediterranean diet. Many studies have associated the Mediterranean diet with a decreased risk of dementia and AD, but a cause-and-effect relationship has not been deduced. Studies with caloric restriction showed neuroprotective effects in animal models, but the results in humans are inconsistent. The pathologies of NDD are complex and there is a great inter-individual (epi)genetic variance within any population. Furthermore, the gut microbiome, being deeply involved in nutrient uptake and lipid metabolism, also represents a pillar of the gut microbiome-brain axis and is linked with the pathogenesis of NDD. Numerous studies on the role of different micronutrients (omega-3 fatty acids, bioactive polyphenols from fruit and medicinal plants) in the prevention, prediction, and treatment of NDD have been conducted, but we are still far away from a personalized diet plan for individual NDD patients. For this to be realized, large-scale cohorts that would include the precise monitoring of food intake, mapping of genetic variants, epigenetic data, microbiome studies, and metabolome, lipidome, and transcriptome data are needed.

Hypoxia-inducible factor-2α mediates senescence-associated intrinsic mechanisms of age-related bone loss

Aging is associated with cellular senescence followed by bone loss leading to bone fragility in humans. However, the regulators associated with cellular senescence in aged bones need to be identified. Hypoxia-inducible factor (HIF)-2α regulates bone remodeling via the differentiation of osteoblasts and osteoclasts. Here, we report that HIF-2α expression was highly upregulated in aged bones. HIF-2α depletion in male mice reversed age-induced bone loss, as evidenced by an increase in the number of osteoblasts and a decrease in the number of osteoclasts. In an in vitro model of doxorubicin-mediated senescence, the expression of Hif-2α and p21, a senescence marker gene, was enhanced, and osteoblastic differentiation of primary mouse calvarial preosteoblast cells was inhibited. Inhibition of senescence-induced upregulation of HIF-2α expression during matrix maturation, but not during the proliferation stage of osteoblast differentiation, reversed the age-related decrease in Runx2 and Ocn expression. However, HIF-2α knockdown did not affect p21 expression or senescence progression, indicating that HIF-2α expression upregulation in senescent osteoblasts may be a result of aging rather than a cause of cellular senescence. Osteoclasts are known to induce a senescent phenotype during in vitro osteoclastogenesis. Consistent with increased HIF-2α expression, the expression of p16 and p21 was upregulated during osteoclastogenesis of bone marrow macrophages. ChIP following overexpression or knockdown of HIF-2α using adenovirus revealed that p16 and p21 are direct targets of HIF-2α in osteoclasts. Osteoblast-specific (Hif-2α^fl/fl;Col1a1-Cre) or osteoclast-specific (Hif-2α^fl/fl;Ctsk-Cre) conditional knockout of HIF-2α in male mice reversed age-related bone loss. Collectively, our results suggest that HIF-2α acts as a senescence-related intrinsic factor in age-related dysfunction of bone homeostasis.

Poor Status of Vitamin D: A Survey of Area With Lowest Sunlight Radiation in Sichuan, China

OBJECTIVE

Vitamin D plays an important role in bone and mineral metabolism. Ultraviolet B (UVB) is the primary determinant for vitamin D synthesis. However, population-based data of vitamin D status was sparse in areas with sunlight deprivation in China. This study aimed to assess serum 25-hydroxyvitamin D [25(OH)D] levels among adult women in Sichuan basin with the lowest sunlight radiation in China, and the associations with sunlight exposure and age.

METHODS

In the context of the same ethnicity, similar latitude and lifestyle in sunlight-limited basin and sunlight-abundant plateau, 1,057 women in basin and 337 in plateau aged 29-95 years were included in this study, from November 2012 to February 2013. Daily sunlight exposure duration of previous month was obtained using questionnaires. Serum 25(OH)D was measured by enzyme-linked immunosorbent assay.

RESULTS

The prevalence of vitamin D severe deficiency [25(OH)D <30 nmol/L] and deficiency [30 ≤ 25(OH)D <50 nmol/L] was significantly higher in basin than plateau (21.85% vs. 10.09%, and 59.32% vs. 40.36%; P<0.0001). Women from basin exhibited lower serum 25(OH)D levels than those from plateau (40.66 ± 15.62 vs. 52.54 ± 19.94 nmol/L, P<0.0001). In basin, women more than 50 years old had higher 25(OH)D than younger counterparts, and 25(OH)D level of these groups was not associated with sunlight exposure duration. While in plateau, women younger than 60 years old had higher 25(OH)D than the older women. Furthermore, for those younger groups, women with long sunlight exposure (≥3 h daily) had higher 25(OH)D concentration than those with short sunlight exposure (<3 h daily). Serum PTH was negatively associated with 25(OH)D in basin, but not in plateau.

CONCLUSIONS

Alarmingly high prevalence of vitamin D deficiency was observed in women in sunlight-deprived basin in Sichuan. Only the vitamin D status of younger women from plateau with adequate solar radiation could benefit from sunlight exposure. Vitamin D supplementation and vitamin D-fortified food should be encouraged to improve vitamin D status for women living in sunlight-limited areas, or with old age.

Prevalence of obesity and hypovitaminosis D in elderly with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)

BACKGROUND & AIM

Verify the prevalence of hypovitaminosis D and obesity in elderly patients infected by new coronavirus. The patients developed severe symptoms and were admitted in intensive care unit (ICU) to receive invasive ventilation due to diagnosis of acute respiratory distress syndrome (ARDS).

METHODS

A cross-sectional descriptive study composed of elderly (age ≥ 60 years) admitted to the ICU. Were collected demographic (sex, age), anthropometric data, presence of comorbidities (hypertension, diabetes, heart disease, lung, neurological and oncological diseases), severity score in ICU (SAPS III), PaO2/FiO2 ratio, analysis of C-reactive protein (CRP) and serum dosage of 25-hydroxy vitamin D (25 OHD) in the first day of hospitalization to identify elderly with hypovitaminosis D (low values < 30 ng/mL). The diagnosis of obesity in elderly was determined by calculating the body mass index (BMI) ≥ 30 kg/m2.

RESULTS

A total of 176 elderly met the inclusion criteria. 54% were elderly men and mean age of 72.9 ± 9.1 years. The median BMI was 30.5 (28.1-33) kg/m2 with 68.7% having a nutritional diagnosis of obesity and 15.3% had BMI ≥ 35 kg/m2. The most prevalent comorbidities were hypertension (72.2%) and diabetes (40.9%). Prevalence of hypovitaminosis D with values of 25 OHD <30 ng/mL, < 20 ng/mL and <10 ng/mL was 93.8%, 65.9% and 21% respectively. The prevalence of hypovitaminosis D (<30 ng/mL) in obese elderly was 94.2%. There was a negative and significant bivariate correlation between BMI and levels of 25 OHD (r = - 0.15; p = 0.04).

CONCLUSION

Hypovitaminosis D and obesity in elderly have a high prevalence in critically ill patients in ICU infected by the new coronavirus. Laboratory investigation of vitamin D becomes important, especially in obese elderly patients.

Vitamin D Synthesis Following a Single Bout of Sun Exposure in Older and Younger Men and Women

Older adults are frequently cited as an at-risk population for vitamin D deficiency that may in part be due to decreased cutaneous synthesis, a potentially important source of cholecalciferol (vitamin D₃). Previous studies found that cutaneous D₃ production declines with age; however, most studies have been conducted ex vivo or in the photobiology lab. The purpose of this study was to characterize the response of vitamin D metabolites following a 30-min bout of sun exposure (15-min each to the dorsal and ventral sides) at close to solar noon in younger and older adults.

METHODS

30 healthy individuals with skin type II/III were recruited; a younger cohort, aged 20-37 (n = 18) and an older cohort (n = 12), age 51-69 years. Exposure was at outer limits of sensible sun exposure designed to enhance vitamin D synthesis without increasing risk of photo ageing and non-melanoma skin cancer. Serum D₃ concentration was measured at baseline, 24, 48 and 72 h post-exposure. Serum 25(OH)D was measured at baseline and 72 h post-exposure plus 168 h post-exposure in the older cohort.

RESULTS

D₃ increased in response to sun exposure (time effect; p = 0.002) with a trend for a difference in D₃ between cohorts (time*group; p = 0.09). By regression modeling of continuous data, age accounted for 20% of the variation in D₃ production. D₃ production decreased by 13% per decade. Despite changes in D₃, however, serum 25(OH)D did not change from baseline to 72 or 168 h post exposure (p > 0.10).

CONCLUSIONS

Serum D₃ concentration increased significantly in response to outdoor sun exposure in younger and older adults. While ageing may dampen cutaneous synthesis, sunlight exposure is still a significant source of vitamin D₃.

Decreased circulating vitamin D reflects adverse outcomes of hepatitis C virus infection: A systematic review and meta-analysis

OBJECTIVES

This study aimed to clarify associations of circulating vitamin D and its status with severity of HCV infection.

METHODS

We performed systemic literature search in PubMed, Scopus, and Cochrane library databases from inception until the end of December 2019 with terms related to vitamin D and hepatitis C.

RESULTS

A total of 28 studies consisting of 7736 HCV-infected patients and 14061 control subjects without liver diseases were included. Compared to controls, circulating vitamin D levels were significantly lessened in HCV-infected patients (mean difference, MD=-14.15, 95% CI: -20.51 to -7.80). Remarkably decreased circulating vitamin D was found in the patients with severe fibrosis (MD=-3.38, 95% CI: -4.51 to -2.25), non-achieving SVR (MD=-2.99, 95%CI: -5.55 to -0.42), and advanced inflammation (MD=-4.68, 95% CI: -8.50 to -0.86). Low vitamin D status (<20 ng/mL) was significantly associated with increased odds of HCV infection (pooled OR=2.41, 95% CI: 1.48 to 3.95). Besides, HCV-infected patients with low vitamin D status showed significantly escalated odds of severe fibrosis and non-achieving SVR (pooled OR=1.70, 95% CI: 1.27 to 2.26; pooled OR=2.04, 95% CI: 1.62 to 2.57, respectively).

CONCLUSION

HCV-infected patients with declined circulating vitamin D levels were associated with severe fibrosis, non-achieving SVR, and advanced inflammation.

Vitamin D Supplementation for Extraskeletal Indications in Older Persons

Low levels of vitamin D have been implicated in a wide variety of conditions highly prevalent in the geriatric population, including fractures, functional limitations, cancer, cardiovascular disease, and depression. Vitamin D supplementation is often considered integral to the prevention of falls and fractures in the setting of osteoporosis. For other conditions, however, consensus is lacking, and the clinician may struggle to balance competing recommendations around screening, supplementation, and monitoring. This review seeks to provide an overview of the available evidence on the use of vitamin D supplementation to ameliorate sarcopenia, enhance cognition, treat depression, prevent cancer, and reduce mortality-outcomes that are common concerns in the geriatric population for which the merits of treatment are not always certain. Evidence suggests vitamin D supplementation may decrease mortality. Therefore, it may be reasonable to prescribe routine supplementation with oral cholecalciferol 800 to 1000 IU daily to all patients aged ≥65 years who do not have a contraindication. No screening or monitoring would be recommended for this population. We additionally recommend the use of oral cholecalciferol over ergocalciferol for any routine supplementation as this benefit was only observed with cholecalciferol. For patients with depression or cognitive disorders, we recommend screening for vitamin D deficiency, treating with oral cholecalciferol if present, and monitoring periodically to target a level of >30 ng/mL as an adjunct to usual care. The level of evidence certainly would not justify the use of vitamin D in place of more evidence-based therapies, but given the burden of these conditions in the geriatric population, we believe the potential benefit justifies the minimal risk.