Vitamin D Insufficiency is Not Associated With Pediatric and Adolescent Immune Thrombocytopenia: A Study in Conjunction With its Receptor Genetic Polymorphisms

Evaluation of vitamin D status in adult patients with newly diagnosed immune thrombocytopenia

It has been shown that 25-OH vitamin D not only preserves calcium and bone homeostasis but also has immunomodulatory effects. The purpose of this study was to assess the association between adult patients with recently diagnosed immune thrombocytopenia (ITP) and vitamin D levels. Retrospective technique was employed in this study. The associations between 25(OH)D value and platelet count, as well as the clinical symptoms of ITP upon diagnosis and 25(OH)D value, were our main findings. A total of 60 patients diagnosed and followed up in our clinic were included in the study. Forty-one patients (68.3%) were female and 19 (31.7%) were male. The median age of the patients was 52.5 (19-88). The median vitamin D level of all patients at diagnosis of ITP was 11.5 (3-86). There was no statistically significant difference between the patients divided into three groups according to their vitamin D levels, in terms of laboratory parameters. There was no statistically significant difference in clinical findings according to vitamin D status in ITP patients. There was no statistically significant difference in terms of relapse-free survival in all three groups (p = 0.71). In conclusion, in our study, no correlation was found between laboratory and clinical findings at diagnosis and vitamin D levels in adult ITP patients. Additional investigations, particularly randomized controlled trials, are required to examine the relationship between 25(OH)D and the incidence and severity of ITP.

Relevance of Serum Levels and Functional Genetic Variants in Vitamin D Receptor Gene among Saudi Women with Gestational Diabetes Mellitus

Background: This study explored the association between ApaI-TaqI Single Nucleotide Polymorphisms (SNPs) in a Vitamin D receptor (VDR) and the risk of Gestational Diabetes Mellitus (GDM) in Saudi women, along with the serum levels of vitamin D. Methods: Ninety women with GDM and 90 non-GDM women were enrolled, based on the inclusion and exclusion criteria for pregnant women enrolled in a single-center study. Blood samples were retrieved from 180 pregnant women using ethylenediaminetetraacetic acid (EDTA) tubes. Serum samples were used to measure the vitamin D, 25-hydroxyvitamin D (25(OH)D or calcidiol), and lipid profiles. Blood was used to measure the hemoglobin A1c levels and to isolate the DNA. The polymerase chain reaction (PCR) was performed for the ApaI (rs79785232), BsmI (rs1544410), FokI (rs2228570), and TaqI (rs731236) SNPs in the VDR gene using restriction fragment length polymorphism analysis. Validation was performed using Sanger sequencing. Statistical analyses were performed between the patients with and without GDM using various statistical software packages. Results: The Hardy-Weinberg equilibrium analysis was statistically significant (p > 0.05). The ApaI, BsmI, and TaqI SNPs were associated with alleles, genotypes, and different genetic models (p < 0.05). Vitamin D levels were associated with deficient levels (p = 0.0002), as well as with a normal and overweight body mass index (p = 0.0004). When vitamin D levels were measured with GDM covariates, the fasting plasma glucose (FPG) (p = 0.0001), postprandial blood glucose (PPBG) (p < 0.0001), oral glucose tolerance test (OGTT)-1 h (p = 0.005), high-density lipoprotein (p = 0.022), and low-density lipoprotein cholesterol (LDLc) (p = 0.001) levels were significantly different. When similar vitamin D levels were measured for each genotype, we confirmed that the ApaI SNP was associated with sufficient levels (p < 0.0001), whereas the BsmI, FokI, and TaqI (p < 0.05) were associated with insufficient levels. The logistic regression model confirmed that the first hour of the OGTT (p = 0.005) was strongly associated with GDM, whereas the analysis of variance confirmed that FPG and PPBG (p < 0.05) were strongly associated with all the SNPs evaluated in the VDR gene. Additionally, the second hour of the OGTT (p = 0.048) and LDLc (p = 0.049) were associated with the ApaI and FokI SNP. Moreover, the first hour OGTT (p = 0.045) and lipid profile parameters (p < 0.05) were associated. Haplotype analysis revealed positive associations among the examined SNPs, which seemed compatible with the hypothesis that variants and combinations of multiple SNP genotypes enhance the risk of GDM in women. Haplotype analysis revealed that different combinations of alleles, such as AGCC, CATT, CGTC, AGTC, and CATT (p < 0.05), were strongly associated. The linkage disequilibrium (LD) analysis showed a strong association with all combinations (p < 0.05). Among the gene-gene interactions, all possible combinations showed a positive association (p < 0.05). Conclusions: Low vitamin D levels were observed in women with GDM. The ApaI, BsmI, and TaqI SNPs were associated with genotype and allele frequencies (p < 0.05). Vitamin D and the SNPs in the VDR gene were associated, according to the ANOVA, logistic regression, haplotype analysis, LD analysis, and the generalized multifactor dimensionality reduction model (p < 0.05).

Vitamin D receptor polymorphisms and vitamin D insufficiency are not associated with sepsis in critically ill children: a case-control study

Background

Vitamin D is a fat-soluble vitamin that regulates calcium and phosphorous homeostasis to maintain a healthy mineralized skeleton. It can also influence immune responses and has immunomodulatory properties. Vitamin D receptor (VDR) is a nuclear receptor that mediates the activities of the hormonal form of vitamin D. VDR polymorphisms can alter immunity and susceptibility to infections by modulating VDR expression and vitamin D activity. This study aimed to investigate the levels of serum vitamin D as well as four VDR polymorphisms: FokI, BsmI, ApaI, and TaqI in fifty children admitted to intensive care unit (ICU) with a diagnosis of sepsis and one-hundred age- and sex-matched healthy children.

Methods

Vitamin D levels were measured in serum, in both patients and controls, using an enzyme-linked immunosorbent assay (ELISA) approach. VDR polymorphisms were also studied in both groups using specific restriction enzymes.

Results

Vitamin D levels were low in both patients and controls. Moreover, serum levels were unaffected by VDR polymorphisms, and their distribution was similar in both groups. Neither the need for mechanical ventilation or inotropic treatment nor the sepsis outcome was impacted by serum vitamin D levels or VDR polymorphisms.

Conclusion

In children admitted to pediatric ICU, neither vitamin D levels nor VDR polymorphisms were associated with sepsis. Further larger studies including different types of sepsis are recommended.