25-Hydroxyvitamin D-1-α-hydroxylase in apoliporotein E knockout mice: The role of protecting vascular smooth muscle cell from calcification

Vitamin D and Its Analogues: From Differences in Molecular Mechanisms to Potential Benefits of Adapted Use in the Treatment of Alzheimer’s Disease

Lifestyle habits and insufficient sunlight exposure lead to a high prevalence of vitamin D hypovitaminosis, especially in the elderly. Recent studies suggest that in central Europe more than 50% of people over 60 years are not sufficiently supplied with vitamin D. Since vitamin D hypovitaminosis is associated with many diseases, such as Alzheimer’s disease (AD), vitamin D supplementation seems to be particularly useful for this vulnerable age population. Importantly, in addition to vitamin D, several analogues are known and used for different medical purposes. These vitamin D analogues differ not only in their pharmacokinetics and binding affinity to the vitamin D receptor, but also in their potential side effects. Here, we discuss these aspects, especially those of the commonly used vitamin D analogues alfacalcidol, paricalcitol, doxercalciferol, tacalcitol, calcipotriol, and eldecalcitol. In addition to their pleiotropic effects on mechanisms relevant to AD, potential effects of vitamin D analogues on comorbidities common in the context of geriatric diseases are summarized. AD is defined as a complex neurodegenerative disease of the central nervous system and is commonly represented in the elderly population. It is usually caused by extracellular accumulation of amyloidogenic plaques, consisting of amyloid (Aβ) peptides. Furthermore, the formation of intracellular neurofibrillary tangles involving hyperphosphorylated tau proteins contributes to the pathology of AD. In conclusion, this review emphasizes the importance of an adequate vitamin D supply and discusses the specifics of administering various vitamin D analogues compared with vitamin D in geriatric patients, especially those suffering from AD.

Abdominal aortic calcification is associated with decline in handgrip strength in the U.S. adult population ≥40 years of age

BACKGROUND AND AIMS

The present study investigated the association between abdominal aortic calcification (AAC) and handgrip strength (HGS) and the ability of HGS to predict an increased AAC phenotype in adults.

METHODS AND RESULTS

The analysis consisted of data for 3140 men and women aged ≥40 years (51.7% women) from the 2013-2014 NHANES. Lateral scans of the thoraco-lumbar spine (L1-L4) were scored for AAC using a validated 8-point scale (AAC-8); subjects with a score of ≥3 were considered at increased risk for cardiovascular disease due to a high AAC phenotype. HGS was assessed using a grip dynamometer. The prevalence of severe AAC in the population was 9.0%. Decline in HGS was associated with higher AAC-8 scores in men and women (p < 0.001). General linear model analysis showed that HGS levels were negatively associated with high AAC (p < 0.001) and AAC-8 status for both sexes. Likewise, for each 5-kg higher HGS, there lower odds of a high AAC phenotype (in men OR = 0.73, CI95%, 0.64-0.84) and (women OR = 0.58, CI95%, 0.47-0.70). Receiver operating characteristic curve analysis showed that the HGS threshold value to detect high risk of AAC in adults was ≥37.3 kg (AUC = 0.692) in men and 25.1 kg (AUC = 0.705) in women.

CONCLUSION

Lower muscular strength, as measured by HGS, is associated with higher AAC scores in the U.S. population ≥40 years of age. Accordingly, maintenance of muscular strength during aging may protect adults against vascular calcification, an independent predictor of cardiovascular events. HGS measurement seems to be a valid screening tool for detecting a high ACC phenotype in adults.

Aortic Calcification is Associated with Five-Year Decline in Handgrip Strength in Older Women

The objective of the study was to determine the association between AAC and neuromuscular function over 5 years. Participants in this study were ambulant women over 70 years old residing in Perth, Western Australia who participated in the Calcium Intake Fracture Outcomes Study, a randomised controlled trial of calcium supplementation. 1046 women (mean age = 74.9 ± 2.6 years; BMI = 27.1 ± 4.4 kg/m²) were included. Lateral spine images captured during bone density testing were scored for AAC (AAC24; 0-24) at baseline. Severe AAC (AAC_sev) was defined using established cut points (AAC24 ≥ 6). At baseline and follow-up, isometric grip strength was assessed using a dynamometer. Mobility was assessed by the Timed-Up-and-Go (TUG) test. Using pre-defined criteria, muscle weakness was considered as grip strength < 22 kg and poor mobility defined as TUG > 10.2 s. A subset of women had appendicular lean mass (ALM) determined by dual-energy X-ray absorptiometry at baseline and follow-up (n = 261). AAC_sev was evident in 193 (18.5%) women. Average decline in grip strength after 5 years was greater in those with AAC_sev than those without (3.6 ± 3.7 vs. 2.9 ± 4.2 kg; p = 0.034). This remained significant after adjustment for age, treatment allocation, diabetes, smoking history, renal function, medical record-derived prevalent vascular disease, BMI and physical activity (β = - 0.184; 95% confidence interval: - 0.361, - 0.008; p = 0.040). AAC_sev was not associated with 5-year changes in TUG or ALM in univariable or multivariable analyses (all p > 0.05). In older women, severe aortic calcification was associated with greater 5-year decline in muscle strength, but not TUG or ALM. These findings support the concept that vascular disease may have an effect on the loss of muscular strength.

No effect of vitamin D supplementation on cardiovascular risk factors in subjects with metabolic syndrome: a pilot randomised study

Introduction

Patients with metabolic syndrome (MetS) may have lower 25-hydroxyvitamin D (25(OH)VitD) serum levels compared with non-MetS individuals. Vitamin D (VitD) deficiency is associated with various cardiovascular disease (CVD) risk factors. Yet, the effect of VitD supplementation on MetS remains uncertain. Our aim was to examine the effect of VitD supplementation on CVD risk factors in MetS subjects.

Material and methods

This pilot study had a PROBE (prospective, randomised, open-label, blinded end-point) design. Fifty patients with MetS were included and randomised either to dietary instructions (n = 25) (control group) or dietary instructions plus VitD 2000 IU/day (n = 25) (VitD group) for 3 months. This study is registered in ClinicalTrials.gov (NCT01237769).

Results

In both groups a similar small weight reduction was achieved. In the VitD group serum 25(OH)VitD levels significantly increased by 91% (from 16.0 (3.0–35.0) to 30.6 (8.4–67.0) ng/ml, p < 0.001), while in the control group no significant change was observed (from 10.0 (4.0–39.6) to 13.0 (3.5–37.0) ng/ml). In both groups triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, fasting glucose, haemoglobin A_1c, homeostasis model assessment index and diastolic blood pressure did not significantly change. Systolic blood pressure decreased by 3.7% (from 134 ±14 to 129 ±13 mm Hg, p = 0.05) in the VitD group, while it decreased by 1.5% (from 132 ±13 to 130 ±16 mm Hg, p = NS) in the control group (p = NS between groups). In the VitD group serum 25(OH)VitD increase was negatively correlated with SBP decrease (r = –0.398, p = 0.049).

Conclusions

VitD supplementation (2000 IU/day) did not affect various CVD risk factors in patients with MetS.