Serum 25(OH)D concentration and its association with inflammation and oxidative stress in the middle-aged Indian healthy and diabetic subjects

Vitamin D Determinants, Status, and Antioxidant/Anti-inflammatory-Related Effects in Cardiovascular Risk and Disease: Not the Last Word in the Controversy

Beyond its key role in calcium homeostasis, vitamin D has been found to significantly affect the cardiovascular (CV) system. In fact, low vitamin D levels have been associated with increased CV risk, as well as increased CV morbidity and mortality. The majority of effects of this molecule are related directly or indirectly to its antioxidative and anti-inflammatory properties. Generally, vitamin D insufficiency is considered for 25-hydroxyvitamin D (25(OH)D) levels between 21-29 ng/mL (corresponding to 52.5-72.5 nmol/L), deficiency as 25(OH)D levels less than 20 ng/mL (<50 nmol/L), and extreme deficiency as 25(OH)D less than 10 ng/mL (<25 nmol/L). However, the definition of an optimal vitamin D status, as defined by 25(OH)D, remains controversial for many extra-bone conditions, including CV disease. In this review, confounding factors affecting the 25(OH)D measurement and status will be discussed. In particular, available evidence on the mechanism and role of vitamin D in relation to CV risk and disease through its antioxidant effect will be reported, also facing the aspect regarding the debate on the minimum blood 25(OH)D level required to ensure optimal CV health.

Expression of TNF-α and IL-1β in Peripheral Blood of Patients with T2DM Retinopathy

Aims

The expression and clinical significance of tumor necrosis factor-α (INF-α) and interleukin 1-β (IL-1β) in retinal cells of patients with type 2 diabetes (T2DM) retinopathy were detected by flow cytometry.

Materials and Methods

Fifty patients with T2DM who attended our ophthalmology clinic between May 2021 and May 2022 were selected as the observation group. Another 50 healthy individuals who were examined at our hospital during the same period were selected as the comparison group. Tear film rupture time (BUT), fluorescein staining (FL), basal tear secretion (Schirmer I) test, and conjunctival impression cytology (CIC) were detected in both groups, and the expression of TNF-α and IL-1β in retinal cells was observed by immunohistochemical staining.

Results

The levels of IL13 and TNF-α in the two groups were not exactly the same. The serum levels of IL13 and TNF-α in the observation group were significantly higher than those in the control group, and there was a statistically significant difference (P < 0.05). TNF-α and IL-1B expressions in the observation group were positively correlated with the fluorescence staining, and the expression of TNF-α and IL-1β in the observation group was significantly negatively correlated with the BUT test and Schirmer I test.

Conclusion

Serums TNF-α and IL-1β are significantly elevated in patients with T2DM retinopathy and gradually increase with disease progression. Combined detection of serums TNF-α and IL-1β can help determine the severity of the disease and assess the prognosis.

Analytical, experimental and clinical aspects of total 25-hydroxyvitamin D measurement by two ligand assays are differentially biased by disease-related factors

BACKGROUND

Pathological concentrations of plasma proteins may confound the results of binding assays. We compared two routinely used total 25-hydroxyvitamin D [t-25(OH)D] methods: a chemiluminescence-immuno-(CLIA) and an electro-chemiluminescence-protein-binding-(ECLPBA) assay.

METHODS

Two sub-studies were performed: 1) In an "in vitro" study, exogenous albumin was added to pools of patients' sera with low albumin levels; and 2) In "ex vivo" studies of Cohort_1: sera of hospitalized patients with low albumin levels, and of healthy controls; and of Cohort_2: outpatients with chronic kidney disease in pre-dialysis stage, or on peritoneal dialysis and hemodialysis were investigated by the routine and LC_MS/MS methods.

RESULTS

When increasing albumin concentrations were "in vitro" added, t-25(OH)D levels were overestimated by ECLPBA, and underestimated by CLIA. In patients' sera, positive correlations were detected between t-25(OH)D-vitamin D binding protein (DBP) values by both routine methods, and between t-25(OH)D-albumin values by all three methods. Much higher t-25(OH)D was measured by LC_MS/MS in all subgroups. When altering albumin levels with constant DBP concentration, the "in vitro" experiment revealed a higher sensitivity of ECLPBA. The "ex vivo" measurements demonstrated clinically relevant differences between the routine methods.

CONCLUSION

Both routine methods are dependent of the matrix effect in hospitalized patients, which is predicted by the DBP/Albumin ratios. In hemodialysis, ECLPBA is recommended because its outcomes differ less from those of LC_MS/MS. The results of LC_MS/MS are reliable, but not routinely available. A guidance would be valuable on how levels measured by the binding methods differ from those by LC-MS/MS in various clinical conditions.

Vitamin D and its possible relationship to neuroprotection in COVID-19: evidence in the literature

Abstract:

Vitamin D is a hormone involved in the regulation of important biological processes such as signal transduction, immune response, metabolic regulation and also in the nervous and vascular systems. To date, coronavirus disease 2019 (COVID-19) infection does not have a specific treatment, however various drugs have been proposed, including those that attenuate the intense inflammatory response and recently the use of vitamin D, in clinical trials, as part of the treatment of COVID-19 has provided promising results. It has been observed in some clinical studies that the use of cholecalciferol (vitamin D3) and its two metabolites the circulating form, calcidiol or calcifediol (25-hydroxycalciferol, 25-(OH)-D) and the active form, calcitriol (1,25-(OH)2-D), in different doses, improve the clinical manifestations, prognosis and survival of patients infected with COVID-19 probably because of its anti-inflammatory, antiviral and lung-protective action. In relation to the central nervous system (CNS) it has been shown, in clinical studies, that vitamin D is beneficial in some neurological and psychiatric conditions because of its anti-inflammatory and antioxidant properties, modulation of neurotransmitters actions, regulation of calcium homeostasis between other mechanisms. It has been showed that COVID-19 infection induces CNS complications such as headache, anosmia, ageusia, neuropathy, encephalitis, stroke, thrombosis, cerebral hemorrhages, cytotoxic lesions and psychiatric conditions and it has been proposed that the use of dietary supplements, as vitamin and minerals, can be adjuvants in this disease. In this review the evidence of possible role of vitamin D, and its metabolites, as protector against the neurological manifestations of COVID-19 was summarized.