ABSTRACT
ABSTRACT BACKGROUND: Vitamin D has relationships with pathogenesis and inflammation pathways in many diseases. Its deficiency may make clinicians think not only of supplementation but also of presence of other diseases. OBJECTIVE: To investigate the relationship between vitamin D levels and deep vein thrombosis (DVT), given that reduced levels are related to increased risk of cardiovascular diseases. DESIGN AND SETTING: Case-control study conducted in the cardiovascular surgery and family medicine departments of a hospital in Turkey. METHODS: A total of 280 participants were included: 140 each in the DVT and control groups. Basic clinical characteristics, comorbidities and serum 25-hydroxyvitamin D (25(OH)D) levels were recorded and then compared between the groups. Serum 25(OH)D levels were also evaluated separately in three subgroups (sufficient, insufficient and deficient). RESULTS: Serum 25(OH)D levels were significantly lower in the DVT group than in the controls (P < 0.001). Females in the DVT group had lower 25(OH)D levels than those in the control group (P = 0.002). Nonetheless, the median 25(OH)D level (16.41 ng/ml) of the control group was still below the reference value. Logistic regression analysis showed that 25(OH)D was a significant predictor of DVT. Weight, height and body mass index, which all presented interaction, were significant in the logistic regression analysis but not in individual analyses. CONCLUSION: The serum vitamin D levels of DVT patients were lower than those of controls. If the results obtained from our study are supported by further large-scale randomized controlled trials, vitamin D replacement may be brought into the agenda for protection against DVT.
Subject(s)
Humans , Male , Female , Vitamin D/blood , Vitamin D Deficiency/complications , Venous Thrombosis/etiology , Turkey , Case-Control Studies , ExtremitiesABSTRACT
Abstract Two siblings presented with clinical and biochemical features of rickets, initially suspected as hypophosphatemic rickets. There was no improvement initially, hence the siblings were reinvestigated and later diagnosed as having vitamin D-dependent rickets (VDDR) type 1 due to a rare mutation in the CYP27B1 gene encoding the 1α-hydroxylase enzyme. Both siblings improved with calcitriol supplementation. The initial presentation of VDDR is often confusing and algorithmic evaluation helps in diagnosis. We also present a brief review of the literature, including genetics.
Resumo Dois irmãos apresentaram características clínicas e bioquímicas do raquitismo, com suspeita clínica inicial de raquitismo hipofosfatêmico. Não houve melhora no início, portanto os irmãos foram reavaliados e, posteriormente, diagnosticados com raquitismo dependente de vitamina D (VDDR) tipo 1 devido a uma rara mutação no gene CYP27B1, que codifica a enzima 1a-hidroxilase. Ambos os irmãos melhoraram com a suplementação de calcitriol. A apresentação inicial do VDDR geralmente é confusa e a avaliação algorítmica ajuda no diagnóstico. Também apresentamos uma breve revisão da literatura, incluindo genética.
Subject(s)
Humans , Familial Hypophosphatemic Rickets/diagnosis , Familial Hypophosphatemic Rickets/genetics , 25-Hydroxyvitamin D3 1-alpha-Hydroxylase/genetics , Vitamin D , Siblings , MutationABSTRACT
Microglia are activated by inflammatory and pathophysiological stimuli in neurodegenerative diseases, and activated microglia induce neuronal damage by releasing cytotoxic factors like nitric oxide (NO). Activated microglia synthesize a significant amount of vitamin D3 in the rat brain, and vitamin D3 has an inhibitory effect on activated microglia. To investigate the possible role of vitamin D3 as a negative regulator of activated microglia, we examined the effect of 25-hydroxyvitamin D3 on NO production of lipopolysaccharide (LPS)-stimulated microglia. Treatment with LPS increased the production of NO in primary cultured and BV2 microglial cells. Treatment with 25-hydroxyvitamin D3 inhibited the generation of NO in LPS-activated primary microglia and BV2 cells. In addition to NO production, expression of 1-alpha-hydroxylase and the vitamin D receptor (VDR) was also upregulated in LPS-stimulated primary and BV2 microglia. When BV2 cells were transfected with 1-alpha-hydroxylase siRNA or VDR siRNA, the inhibitory effect of 25-hydroxyvitamin D3 on activated BV2 cells was suppressed. 25-Hydroxyvitamin D3 also inhibited the increased phosphorylation of p38 seen in LPS-activated BV2 cells, and this inhibition was blocked by VDR siRNA. The present study shows that 25-hydroxyvitamin D3 inhibits NO production in LPS-activated microglia through the mediation of LPS-induced 1-alpha-hydroxylase. This study also shows that the inhibitory effect of 25-hydroxyvitamin D3 on NO production might be exerted by inhibiting LPS-induced phosphorylation of p38 through the mediation of VDR signaling. These results suggest that vitamin D3 might have an important role in the negative regulation of microglial activation.
Subject(s)
Animals , Rats , Brain , Calcifediol , Cholecalciferol , Microglia , Negotiating , Neurodegenerative Diseases , Neurons , Nitric Oxide , Phosphorylation , Receptors, Calcitriol , RNA, Small InterferingABSTRACT
Vitamin D is present in two forms, ergocalciferol (vitamin D2) produced by plants and cholecalciferol (vitamin D3) produced by animal tissues or by the action of ultraviolet light on 7-dehydrocholesterol in human skin. Both forms of vitamin D are biologically inactive pro-hormones that must undergo sequential hydroxylations in the liver and the kidney before they can bind to and activate the vitamin D receptor. The hormonally active form of vitamin D, 1,25-dihydroxyvitamin D3 [1,25(OH)2D], plays an essential role in calcium and phosphate metabolism, bone growth, and cellular differentiation. Renal synthesis of 1,25(OH)2D from its endogenous precursor, 25-hydroxyvitamin D (25OHD), is the rate-limiting and is catalyzed by the 1alpha-hydroxylase. Vitamin D dependent rickets type I (VDDR-I), also referred to as vitamin D 1alpha-hydroxylase deficiency or pseudovitamin D deficiency rickets, is an autosomal recessive disorder characterized clinically by hypotonia, muscle weakness, growth failure, hypocalcemic seizures in early infancy, and radiographic findings of rickets. Characteristic laboratory features are hypocalcemia, increased serum concentrations of parathyroid hormone (PTH), and low or undetectable serum concentrations of 1,25(OH)2D despite normal or increased concentrations of 25OHD. Recent advances have showed in the cloning of the human 1alpha-hydroxylase and revealed mutations in its gene that cause VDDR-I. This review presents the biology of vitamin D, and 1alpha-hydroxylase mutations with clinical findings.
Subject(s)
Animals , Humans , Biology , Bone Development , Calcitriol , Calcium , Cholecalciferol , Clone Cells , Cloning, Organism , Dehydrocholesterols , Ergocalciferols , Hydroxylation , Hypocalcemia , Kidney , Liver , Muscle Hypotonia , Parathyroid Hormone , Receptors, Calcitriol , Rickets , Seizures , Skin , Ultraviolet Rays , Vitamin D , VitaminsABSTRACT
"Rickets" is the term applied to impaired mineralization at epiphyseal growth plate, resulting in deformity and impaired linear growth of long bones. Rickets may arise as a result of vitamin D deficiency or abnormality in metabolism. Vitamin D-dependent rickets (VDDR) is rare autosomal recessive disorder in which affected individuals have clinical features of vitamin D deficiency. In 1961, Prader first described this disorder including severe clinical features of rickets, such as hypophosphatemia, hypocalcemia, muscle weakness and seizure. Two distinctive hereditary defects, type I VDDR and type II VDDR have been recognized in vitamin D metabolism. Type I VDDR may be due to congenital defects of renal 1 alpha-hydroxylase, the enzyme responsible for conversion of 25 (OH) D3. These patients have low to detectable 1,25(OH)2D3 in presence of normal to raised 25 (OH) D3. In type II VDDR, renal production of 1,25(OH)2D3 is intact but 1,25(OH)2D3 is not used effectively and target organ resistant to 1,25(OH)2D3 is respectively derived from the abnormality in the vitamin D receptor. We report a case of a 25 month-old girl with typical clinical features of VDDR type I rickets, hypocalcemia, increased alkaline phosphatase and secondary hyperparathyroidism.
Subject(s)
Child, Preschool , Female , Humans , Alkaline Phosphatase , Congenital Abnormalities , Growth Plate , Hyperparathyroidism, Secondary , Hypocalcemia , Hypophosphatemia , Metabolism , Muscle Weakness , Receptors, Calcitriol , Rickets , Seizures , Vitamin D , Vitamin D Deficiency , VitaminsABSTRACT
Objective To investigate the change of renal 1-alpha hydroxylase and its effect on bone mineral density in the old rats with type 2 diabetic nephropathy. Methods Forty Wistar rats of 18 months old were randomly divided into normal control (N), diabetes (D), diabetes treated with vitamin D_ 3 (T1) and diabetes treated with 1-?(OH)D_ 3 (T2) groups, respectively. Ten rats in each group. Dual energy X-ray absorption (DEXA) was used to determine bone mineral density (BMD) of lumbar spines and femoral bone. 24 h urinary protein excretion, serum 25(OH)D_ 3 and 1,25(OH)_ 2 D_ 3 were measured by radioimmunoassay. Results Compared with controls, 24 h urinary protein excretion increased remarkably D, T1, T2 groups, while BMD greatly decreased, much lower in D group and T1 group than T2 group (P0.05). The level of 1,25(OH)_ 2 D_ 3 in N group was the same to T2 group, but higher than D, T1 groups (P