Calcitriol Research Articles

A Comprehensive Review on Oxysterols and Related Diseases.

The present review aims to provide a complete and comprehensive summary of current literature relevant to oxysterols and related diseases. Oxidation of cholesterol leads to the formation of a large number of oxidized products, generally known as oxysterols. They are intermediates in the biosynthesis of bile acids, steroid hormones, and 1,25- dihydroxyvitamin D3. Although oxysterols are considered as metabolic intermediates, there is a growing body of evidence that many of them are bioactive, and their absence or excess may be part of the cause of a disease phenotype. These compounds derive from either enzymatic or non-enzymatic oxidation of cholesterol. This study provides comprehensive information about the structures, formation, and types of oxysterols even when involved in certain disease states, focusing on their effects on metabolism and linkages with these diseases. The role of specific oxysterols as mediators in various disorders, such as degenerative (age-related) and cancer-related disorders, has now become clearer. Oxysterol levels may be employed as suitable markers for the diagnosis of specific diseases or in predicting the incidence rate of diseases, such as diabetes mellitus, Alzheimer's disease, multiple sclerosis, osteoporosis, lung cancer, breast cancer, and infertility. However, further investigations may be required to confirm these mentioned possibilities.

Differential effects of the 1,25D3-MARRS receptor (ERp57/PDIA3) on murine mammary gland development depend on the vitamin D3 dose

1,25 dihydroxyvitamin D3 (1,25D3) is the most potent biologically active form of vitamin D3. Its actions on the mammary gland include cell growth inhibition and anti-cancer effects. This study’s purpose was to explore the role of the 1,25D3-membrane associated rapid response steroid (MARRS) receptor in the mammary gland using a tissue-specific knockout mouse model and a vitamin D3 dietary intervention. Three genotype groups were created using the Cre/loxp system to knock-down (+/−) and knockout (−/−) the MARRS receptor in epithelial cells of mammary glands (MG). Abdominal MGs were collected from 6-week old female mice (n = 94) on diets of 10,000 IU/kg (excess), 1,000 IU/kg (sufficient) or 0 IU/kg (deficient) of D3. There was a significant interaction between genotype and diet regarding number of terminal end buds (TEBs) (p = 0.001) and ductal coverage of the fat pad (p = 0.03). MARRS -/- mice on the sufficient diet had significantly fewer TEBs (p = 0.001) compared to MARRS +/+ on the same diet, but the opposite effect was seen in mice on the excess diet. There were no effects of genotype on TEBs when animals were vitamin D3 deficient. These results suggest that there is an effect of MARRS on mammary gland development that is dependent on 25(OH)D status, specifically, altering the number of highly proliferative TEBs. Increased numbers of TEBs have been correlated with increased breast cancer risk later in life. Therefore the results of this study warrant further examination of 25(OH)D status and recommendations in adolescent humans to reduce dietary effects on future breast cancer risk.

1α, 25(OH)2D3 regulates agrin-induced acetylcholine receptor clustering through upregulation of rapsyn expression in C2C12 myotubes

The active form of vitamin D (1α, 25-dihydroxyvitamin D3 [1α, 25(OH)2D3], referred to as 1,25D) has been suggested to play a pivotal role in skeletal muscle function and metabolism. However, the mechanisms through which 1,25D functions in this tissue remain to be elucidated. Recent studies have shown that vitamin D signaling regulates neuromuscular maintenance and improves locomotion in mice. In the present study, we examined the effects of 1,25D on neuromuscular synaptogenesis by measuring clustering of acetylcholine receptors (AChRs) in C2C12 myotubes. 1,25D treatment enhanced the agrin-induced AChR clustering in myotubes compared to treatment with agrin alone. Furthermore, siRNA-mediated knockdown of the vitamin D receptor (VDR) decreased the agrin-induced AChR clustering. 1,25D increased the expression of rapsyn, which is necessary for AChR clustering, while demonstrating no effect on other neuromuscular junction-related genes. In addition, rapsyn expression was dependent on 1,25D-VDR signaling. These results suggest that 1,25D-VDR signaling may regulate rapsin expression, resulting in the up-regulation of agrin-induced AChR clustering.

Cathelicidin preserves intestinal barrier function in polymicrobial sepsis

ObjectivesThe intestinal epithelium compartmentalizes the sterile bloodstream and the commensal bacteria in the gut. Accumulating evidence suggests that this barrier is impaired in sepsis, aggravating systemic inflammation. Previous studies reported that cathelicidin is differentially expressed in various tissues in sepsis. However, its role in sepsis-induced intestinal barrier dysfunction has not been investigated.DesignTo examine the role of cathelicidin in polymicrobial sepsis, cathelicidin wild-(Cnlp+/+) and knockout (Cnlp−/−) mice underwent cecal-ligation and puncture (CLP) followed by the assessment of septic mortality and morbidity as well as histological, biochemical, immunological, and transcriptomic analyses in the ileal tissues. We also evaluated the prophylactic and therapeutic efficacies of vitamin D3 (an inducer of endogenous cathelicidin) in the CLP-induced murine polymicrobial sepsis model.ResultsThe ileal expression of cathelicidin was increased by three-fold after CLP, peaking at 4 h. Knockout of Cnlp significantly increased 7-day mortality and was associated with a higher murine sepsis score. Alcian-blue staining revealed a reduced number of mucin-positive goblet cells, accompanied by reduced mucin expression. Increased number of apoptotic cells and cleavage of caspase-3 were observed. Cnlp deletion increased intestinal permeability to 4kD fluorescein-labeled dextran and reduced the expression of tight junction proteins claudin-1 and occludin. Notably, circulating bacterial DNA load increased more than two-fold. Transcriptome analysis revealed upregulation of cytokine/inflammatory pathway. Depletion of Cnlp induced more M1 macrophages and neutrophils compared with the wild-type mice after CLP. Mice pre-treated with cholecalciferol (an inactive form of vitamin D3) or treated with 1alpha, 25-dihydroxyvitamin D3 (an active form of VD3) had decreased 7-day mortality and significantly less severe symptoms. Intriguingly, the administration of cholecalciferol after CLP led to worsened 7-day mortality and the associated symptoms.ConclusionsEndogenous cathelicidin promotes intestinal barrier integrity accompanied by modulating the infiltration of neutrophils and macrophages in polymicrobial sepsis. Our data suggested that 1alpha, 25-dihydroxyvitamin D3 but not cholecalciferol is a potential therapeutic agent for treating sepsis.

Nuclear import of NLS- RARα is mediated by importin α/β

The promyelocytic leukemia-retinoic acid receptor α (PML/RARα) is hypothesized to play a vital role in the pathogenesis of acute promyelocytic leukemia (APL). A previous study has demonstrated that PML/RARα is cleaved by neutrophil elastase (NE) in early myeloid cells, which leads to an increase in the nuclear localization signal (NLS) in RARα and in the incidence of APL. In this study, we explored the effects of NLS-RARα on acute myeloid leukemia (AML) cells and studied the mechanism of its localization. LV-NLS-RARα recombinant lentivirus and negative control LV-NC lentivirus were transfected into HL-60 cells and U937 cells while mutant NLS-RARα were transfected into U937 cells, and all groups were treated with 1α, 25-dihydroxyvitamin D3(1,25D3). The results showed that NLS-RARα was located mainly in the nucleus while mutant NLS-RARα was located in the cytoplasm. Overexpression of NLS-RARα downregulated the expression of CD11b, CD11c, CD14, and three forms of CEBPβ compared to the overexpression of NC and mutant NLS-RARα. It was speculated that the abnormal localization of NLS-RARα was mediated via importin-α/β in the pathogenesis of APL. By producing point mutations in the two NLSs in NLS-RARα, we showed that the nuclear import of NLS-RARα was mainly dependent on the NLS of the RARα portion. Subsequently, we found that importin-α1 (KPNA2)/importin-β1 (KPNB1) participates in the nuclear transport of NLS-RARα. Taken together, abnormal localization of NLS-RARα blocks the differentiation of APL cells, and nuclear localization of NLS-RARα depends on NLS of the RARα portion and is mediated via binding with importin-α/β.

Could CYP24A1 promoter methylation status affect the gene expression in the colorectal cancer patients?

CYP24A1 up-regulation has been reported in different cancers, including colorectal cancer (CRC). CYP24A1 initiates the degradation of 1, 25-dihydroxyvitamin D3 and is a candidate biomarker for the progression and prognosis of CRC. Despite many studies for discovering the exact mechanism underlying the CYP24A1 overexpression, the results are inconsistent. The present study aimed to determine whether the promoter methylation status of the CYP24A1 gene is the cause of CYP24A1 overexpression in CRC patients. In this regards, after quantification of the CYP24A1 expression by quantitative real-time polymerase chain reaction (qRT-PCR), we measured the methylation status of the CYP24A1 promoter region by methylation-specific PCR (MSP) in 50 cases of fresh human colorectal cancer and 34 paired adjacent tissues. CYP24A1 was overexpressed in the CRC tissues (Fold change = 17.2, P=0.001); however, we didn't find any significant differences regarding the CYP24A1 promoter methylation status between the CRC samples and the paired adjacent tissues. We concluded that the CYP24A1 promoter hypomethylation is not the reason for the gene up-regulation in our CRC patients; therefore, other mechanisms involved in the CYP24A1 overexpression should be investigated.

Epimers of Vitamin D: A Review.

In this review, we discuss the sources, formation, metabolism, function, biological activity, and potency of C3-epimers (epimers of vitamin D). We also determine the role of epimerase in vitamin D-binding protein (DBP) and vitamin D receptors (VDR) according to different subcellular localizations. The importance of C3 epimerization and the metabolic pathway of vitamin D at the hydroxyl group have recently been recognized. Here, the hydroxyl group at the C3 position is orientated differently from the alpha to beta orientation in space. However, the details of this epimerization pathway are not yet clearly understood. Even the gene encoding for the enzyme involved in epimerization has not yet been identified. Many published research articles have illustrated the biological activity of C3 epimeric metabolites using an in vitro model, but the studies on in vivo models are substantially inadequate. The metabolic stability of 3-epi-1α,25(OH)2D3 has been demonstrated to be higher than its primary metabolites. 3-epi-1 alpha, 25 dihydroxyvitamin D3 (3-epi-1α,25(OH)2D3) is thought to have fewer calcemic effects than non-epimeric forms of vitamin D. Some researchers have observed a larger proportion of total vitamin D as C3-epimers in infants than in adults. Insufficient levels of vitamin D were found in mothers and their newborns when the epimers were not included in the measurement of vitamin D. Oral supplementation of vitamin D has also been found to potentially cause increased production of epimers in mice but not humans. Moreover, routine vitamin D blood tests for healthy adults will not be significantly affected by epimeric interference using LC–MS/MS assays. Recent genetic models also show that the genetic determinants and the potential factors of C3-epimers differ from those of non-C3-epimers.Most commercial immunoassays techniques can lead to inaccurate vitamin D results due to epimeric interference, especially in infants and pregnant women. It is also known that the LC–MS/MS technique can chromatographically separate epimeric and isobaric interference and detect vitamin D metabolites sensitively and accurately. Unfortunately, many labs around the world do not take into account the interference caused by epimers. In this review, various methods and techniques for the analysis of C3-epimers are also discussed. The authors believe that C3-epimers may have an important role to play in clinical research, and further research is warranted.

Association of the calcitriol to calcifediol ratio with cardiac involvement in newly diagnosed sarcoidosis.

Association of the calcitriol to calcifediol ratio with cardiac involvement in newly diagnosed sarcoidosis.

Parathyroidectomy in Chronic Haemodialysis in the Nephrology and Haemodialysis Department at the University Hospital Center of Point G in Bamako, Mali

Introduction: Secondary hyperparathyroidism is a common complication in chronic hemodialysis patients. It is characterized by hypersecretion of parathormone by the parathyroid glands to maintain phosphocalcium homeostasis in response to hypocalcemia, lowering of 1.25 dihydroxy vitamin D3 and hyperphosphatemia. Objective: To analyze the results of parathyroidectomy (PTX) in cases of secondary hyperparathyroidism (HPTS), report the post-operative course and early and late complications. Patients and Methods: We conducted a retrospective study of ten (10) patients with chronic renal failure operated on at the CHU of Point G over a 32-month period, from January 1, 2016 to August 31, 2019. We analyzed the clinical, biological, radiological and histological parameters of the thyroid glands. Results: We have collected 33 cases of secondary hyperparathyroidism. Ten (10) patients met the inclusion criteria. They were 45 years old on average, seven (7) women and three (3) men, in dialysis for an average of 6.8 years before parathyroidectomy. Half of the initial kidney disease was of vascular origin (HTA). No cases of diabetic nephropathy were identified. Symptoms were in order of frequency: bone pain (60%), paresthesia (50%), functional impotence of the lower limbs (50%). Radiological signs included demineralisation (5 out of 6 cases) and brown tumour associated with a fracture (1 out of 6 cases). The most frequent indication for parathyroidectomy (100%) was persistence despite treatment of a serum PTH concentration above 1000 pg/ml. Subtotal PTX (7/8) was performed after cervical ultrasound in all patients. Histological analysis of the parathyroid glands showed adenoma (60%) and hyperplasia in 40% of cases. The evolution was marked by a progressive reduction of the parathormone level over twelve (12) months, without achieving normalization. This could be related to sub-dialysis (generator failure with reduction of dialysis time). There were no cases of complications or mortality. Conclusion: Parathyroidectomy is an effective treatment to curb hypersecretion of parathyroid hormone. Despite this satisfactory result, the management of phosphocalcic abnormalities in renal failure remains an ongoing concern.

1,25(OH)2D3 supports the osteogenic differentiation of hPDLSCs under inflammatory conditions through inhibiting PLAP-1 expression transcriptionally

BackgroundPeriodontal ligament-associated protein-1 (PLAP-1) is a newly identified negative regulator which is the mineralization of human periodontal ligament stem cells (hPDLSCs). The aim of the present study is to determine whether 1α, 25-dihydroxyvitamin D3 (1,25(OH)2D3) could enhances the osteoblastic differentiation of hPDLSCs under inflammatory condition, and if PLAP-1 is involved in this process. Materials and methodshPDLSCs were in combination or alone cultured with lipopolysaccharide (LPS) and 1,25(OH)2D3, in osteo-inductive medium. The expression levels of osteoblastic markers and PLAP-1 of hPDLCs during osteo-inductive culture were assessed by western blot and real-time quantitative PCR(qRT-PCR). The potential vitamin D receptor elements (VDREs) which were located in PLAP-1 promoter region were identified and confirmed. ResultsThe data showed that LPS inhibited osteoblastic differentiation and induced the expression of PLAP-1 in hPDLSCs. The increasing addition of 1,25(OH)2D3 reversed the LPS-induced inhibition of osteoblastic differentiation of hPDLSCs through the suppression of PLAP-1 expression. Moreover, a potential VDRE within the PLAP-1 promoter region was identified and shown to bind with VDR by chromatin immunoprecipitation (ChIP) assays. This negative region was also found to mediate suppressor reporter gene activity. Conclusions1,25(OH)2D3 could enhances the osteogenic differentiation of hPDLSCs under inflammatory condition through inhibiting PLAP-1 expression transcriptionally.

1\u03b1, 25-dihydroxy Vitamin D3 containing fractions of Catharanthus roseus leaf aqueous extract inhibit preadipocyte differentiation and induce lipolysis in 3T3-L1 cells

BackgroundTo investigate the potential of Catharanthus roseus leaf aqueous crude extract (CRACE) as a regulator of adipocyte development and function.Methods3T3-L1 adipogenesis model was used to investigate the effect of CRACE on adipogenesis. 3T3-L1 preadipocytes (for adipogenic differentiation) and mature 3T3-L1 adipocytes (for adipocyte function) were treated with non-toxic doses of CRACE. The outcomes were corroborated by intracellular lipid accumulation, expression of pro-and anti-adipogenic effector molecules. To investigate CRACE mediated lipolysis, cAMP accumulation, glycerol release and phosphorylation of key effector molecules were tested in treated mature adipocytes. Finally, the extract was fractionated to identify the active molecule/s in the extract.ResultsCRACE significantly reduced adipocyte differentiation by modulating PPARγ expression. At early stage CRACE directly targeted Lipin1 expression and consequently impacted KLF7, subsequently expression of GATA2, CEBPα, SREBP1c were targeted, with PPARγ expression, particularly curtailed. While CRACE significantly reduced several lipogenic genes like FAS and GPD1 in mature adipocytes, concomitantly, it greatly increased lipolysis resulting in decreased lipid accumulation in mature adipocytes. The increase in lipolysis was due to decreased Akt activation, increased cAMP level, and PKA activity. The fractionation of CRACE allowed identification of two fractions with potent anti-adipogenic activity. Both the fractions contained 1α, 25-dihydroxy Vitamin D3 as major component.Conclusions1α, 25-dihydroxy Vitamin D3 containing CRACE can be developed into an effective anti-obesity formulation that decreases adipogenesis and increases lipid catabolism.

Vitamin D Ameliorates Fat Accumulation with AMPK/SIRT1 Activity in C2C12 Skeletal Muscle Cells.

Excessive fat accumulation has been considered as a major contributing factor for muscle mitochondrial dysfunction and its associated metabolic complications. The purpose of present study is to investigate a role of vitamin D in muscle fat accumulation and mitochondrial changes. In differentiated C2C12 muscle cells, palmitic acid (PA) was pretreated, followed by incubation with 1,25-dihyroxyvitamin D (1,25(OH)2D) for 24 h. PA led to a significant increment of triglyceride (TG) levels with increased lipid peroxidation and cellular damage, which were reversed by 1,25(OH)2D. The supplementation of 1,25(OH)2D significantly enhanced PA-decreased mtDNA levels as well as mRNA levels involved in mitochondrial biogenesis such as nuclear respiratory factor 1 (NRF1), peroxisome proliferative activated receptor gamma coactivator-1α (PGC-1α), and mitochondrial transcription factor A (Tfam) in C2C12 myotubes. Additionally, 1,25(OH)2D significantly increased ATP levels and gene expression related to mitochondrial function such as carnitine palmitoyltransferase 1 (CPT1), peroxisome proliferator-activated receptor α (PPARα), very long-chain acyl-CoA dehydrogenase (VLCAD), long-chain acyl-CoA dehydrogenase (LCAD), medium-chain acyl-CoA dehydrogenase (MCAD), uncoupling protein 2 (UCP2), and UCP3 and the vitamin D pathway including 25-dihydroxyvitamin D3 24-hydroxylase (CYP24) and 25-hydroxyvitamin D3 1-alpha-hydroxylase (CYP27) in PA-treated C2C12 myotubes. In addition to significant increment of sirtuin 1 (SIRT1) mRNA expression, increased activation of adenosine monophosphate-activated protein kinase (AMPK) and SIRT1 was found in 1,25(OH)2D-treated C2C12 muscle cells. Thus, we suggest that the observed protective effect of vitamin D on muscle fat accumulation and mitochondrial dysfunction in a positive manner via modulating AMPK/SIRT1 activation.

Clinical analysis of 14 cases of pseudohypoparathyroidism in children

Objective To analyze the clinical characteristics and treatment of pseudohypoparathyroidism(PHP) in children and to increase clinicians′understanding of this disorder. Methods From January 2008 to November 2018, a total of 14 PHP patients at our hospital were retrospectively analyzed, as regarding the clinical manifestation, laboratory examination and imaging data.The patients were further divided into two groups according to onset age: group A(under 1 year) and group B(over or equal to 1 year). The laboratory findings were compared between the two groups. Results Of the 14 patients(10 boys and 4 girls), the median age of onset was 12 years(range: 1 day to 16 years). Epilepsy is one of the most common manifestations of PHP.Laboratory findings include hypocalcemia(1.06-2.18mmol/L), hyperphosphatemia(2.1-3.5 mmol/L), and elevated concentrations of PTH(105.6-733.0 pg/ml). PTH levels were significantly lower in the group A than in group B(Z=2.07, P=0.042). Five patients were found to have calcifications in bilateral basal ganglia and cerebral parenchyma by head CT.All the patients were improved after treatment, which included calcium gluconate injection to control tetany, calcium supplement combined with vitamin D and/or calcitriol orally. Conclusion For children who presented frequent hypocalcemia tetany and calcifications in head CT, serum calcium, phosphorus, PTH levels should be further investigated to make a correct diagnosis.Calcium supplement combined with vitamin D or its metabolites is an effective therapy for PHP children. Key words: Pseudohypoparathyroidism; Tetany; Children

NLS-RARα contributes to differentiation block and increased leukemogenic potential in vivo

The fusion oncogene, promyelocytic leukemia (PML)-retinoic acid receptor-α (RARα), is crucial for acute promyelocytic leukemia (APL) pathogenesis. Previous studies have reported that PML-RARα is cleaved by neutrophil elastase (NE), an early myeloid-specific serine protease, leading to translocation of the nuclear localization signal (NLS) of the PML protein to the N-terminal of RARα. This study was designed to evaluate the value of NLS-RARα in the early diagnosis of APL. To investigate the potential functional role of NLS-RARα in leukemogenesis, HL-60 and U937 cell lines were transfected with NLS-RARα lentivirus and negative control (LVNC). The results showed that the induced expression of NLS-RARα down-regulated expressions of CD11b, CD11c, and CD14 compared to the LVNC group induced by 1α, 25-dihydroxyvitamin D3(1,25(OH)2D3). This suggested that NLS-RARα overexpression inhibited granulocytic and monocytic differentiation of myeloid leukemia cells. In addition, Wright-Giemsa staining, flow cytometry, respiratory burst assay, and NBT reduction assay all confirmed the importance of NLS-RARα in differentiation. The mechanistic investigations revealed that induced NLS-RARα expression inhibited 1,25(OH)2D3-induced granulocytic differentiation by regulating the cell cycle regulators p19INK4D, p21WAF1/CIP1, cyclinD1, cyclin E1, and pRB. Furthermore, the cleaved protein NLS-RARα enhanced the oncogenicity of U937 cells in NOD/SCID mice. These findings collectively demonstrated that NLS-RARα blocked granulocytic and monocytic differentiation of myeloid leukemia cells by inhibiting the downstream targets of the RARα signal pathway and the cell cycle. This may provide a promising new target and method for diagnosing and treating APL.

1274 An Unusual Case of Sarcoidosis Involving the Pancreas

INTRODUCTION: Sarcoidosis is a multisystem disease primarily involving the lung. Skin, eyes, lymph nodes, spleen, liver, bones, exocrine glands, heart, kidneys, and central nervous system are the most common extrapulmonary sites involved. Clinically apparent gastrointestinal (GI) sarcoidosis is rare involving 0.1 to 0.9 percent of patients with sarcoidosis. The most commonly involved portion of the GI tract is the stomach, although sarcoidosis of the esophagus, appendix, colon, rectum, and pancreas have been reported in the literature. CASE DESCRIPTION/METHODS: A 73-year-old African American male was found to have pancreatic duct dilation on a computed tomography scan of abdomen done for investigation of mild epigastric abdominal pain that started a few months prior to presentation. He described the pain as dull, non-radiating, aggravated when hungry, subsided with food intake and associated with bloating. He had a past medical history of hypertension, hypothyroidism, and sarcoidosis involving lymph nodes and liver (not on treatment). He had no family history of GI cancer. He was a non-smoker and non-alcoholic. On presentation, his vital signs were normal; his abdomen was soft and non-tender, with normoactive bowel sounds and no masses or organomegaly. He had a normal calcium level of 9.7 mg/dL and his liver panel was significant for slightly elevated serum alkaline phosphatase, AST, ALT levels, with normal serum bilirubin. Magnetic resonance imaging showed 1.2 cm mass in the body of the pancreas obstructing the pancreatic duct and another 1.1 cm mass in the head of the pancreas concerning for malignancy. He underwent endoscopic ultrasonography with fine needle aspiration cytology of both pancreatic masses which showed numerous non-caseating granulomas consistent with sarcoidosis. Special stains for fungi and tuberculosis were negative. DISCUSSION: Less than 30 cases of biopsy-proven pancreatic sarcoidosis have been reported in the literature. Patients can have direct involvement of pancreas with sarcoidosis or 1, 25-dihydroxy vitamin D3 mediated hypercalcemia causing hypercalcemic pancreatitis. About three fourths of patients with pancreatic sarcoidosis have bilateral hilar adenopathy on chest radiography. On imaging, these patients demonstrate either a pancreatic mass (or masses) or a diffuse nodular pancreas. A biopsy is essential to distinguish between sarcoidosis, mycobacterial or fungal infection, and cancer. Treatment is usually conservative or with glucocorticoids.

Calcitriol enhances pyrazinamide treatment of murine tuberculosis.

Background:Tuberculosis is a leading cause of morbidity and mortality in humans worldwide. There is an urgent need for new and effective drugs to treat tuberculosis and shorten the duration of tuberculosis therapy. 1, 25-dihydroxy vitamin D3 (1,25 (OH)2D3) has been reported to have a synergistic effect with pyrazinamide (PZA) in killing tubercle bacilli in vitro. The addition of 1,25 (OH)2D3 to standard tuberculosis treatment should benefit patients if the adjunctive drug has a synergistic effect in vivo. Thus, in this study, calcitriol (bioactive 1,25 (OH)2D3) was administered to mice undergoing treatment for Mycobacterium tuberculosis (M.tb) infection with PZA, a first-line anti-tuberculosis drug, to determine whether vitamin D3 enhances the therapeutic effect.Methods:C57BL/6 female mice were infected with the M.tb H37Rv strain through aerosol exposure. Calcitriol and PZA, either alone or in combination, were orally administered to the M.tb infected mice. The effect of calcitriol on PZA activity was determined by evaluating the bacterial burden and analyzing the histopathological lesions in the lungs and spleen. To investigate the expression of inflammatory cytokines and anti-microbial peptide genes, we determined the transcriptional levels of interferon-γ (IFN-γ), interleukin-4 (IL-4), mouse β-defensin-2 (mBD2), and cathelicidin LL-37 through real-time quantitative polymerase chain reaction. The protein levels of IFN-γ were detected by enzyme-linked immunosorbent assay. Differences between groups were analyzed with independent samples t-test or one-way analysis of variance.Results:Calcitriol alone had little effect on tuberculosis infection, whereas PZA, compared with saline control treatment, decreased the bacterial burden (spleens: PZA vs. saline, 4.82 ± 0.22 vs. 5.22 ± 0.40 Log10 colony-forming units [CFU]/gram, t = 2.13, P < 0.05; lungs: PZA vs. saline, 5.55 ± 0.15 vs. 6.83 ± 0.46 Log10 CFU/gram, t = 6.56, P < 0.01) and pathological lesions in the lungs. Simultaneous administration of calcitriol with PZA, compared with PZA alone, decreased the bacterial load (spleen: calcitriol + PZA vs. PZA, 4.37 ± 0.13 vs. 4.82 ± 0.22 Log10 CFU/gram, t = 4.36, P < 0.01; lung: calcitriol + PZA vs. PZA, 5.03 ± 0.32 vs. 5.55 ± 0.15 Log10 CFU/gram, t = 3.58, P < 0.01) and attenuated the lung lesions (gross pathological score: calcitriol + PZA vs. PZA, 3.25 ± 0.50 vs. 2.50 ± 0.58, t = 1.96, P < 0.05; affected area of total lung area: calcitriol + PZA vs. PZA, 30.75% ± 6.50% vs. 21.55% ± 2.99%, t = 2.66, P < 0.05). Further studies demonstrated calcitriol significantly increased the expression of anti-inflammatory cytokine IL-4 but suppressed production of the pro-inflammatory cytokine IFN-γ (IL-4: calcitriol vs. saline, 5.69 ± 0.50 vs. 2.80 ± 0.56 fold of control, t = 6.74, P < 0.01; IFN-γ: calcitriol vs. saline, 1.36 ± 0.11 vs. 4.13 ± 0.83 fold of control, t = 5.77, P < 0.01). In addition, calcitriol alone or in combination with PZA significantly enhanced the transcriptional level of anti-microbial peptides (cathelicidin LL-37: calcitriol vs. saline, 10.59 ± 1.03 vs. 2.80 ± 0.90 fold of control, t = 9.85, P < 0.01; mBD2: calcitriol vs. saline, 7.92 ± 0.62 vs. 1.79 ± 0.45 fold of control, t = 13.82, P < 0.01), whereas PZA exerted a negative effect on anti-microbial peptide gene expression.Conclusions:Calcitriol as adjunctive treatment can result in beneficial treatment outcomes in M.tb infection by suppressing the inflammatory response and up-regulating the expression of anti-microbial peptides. These results indicate the feasibility of using calcitriol adjunctively with standard chemotherapy for the treatment of M.tb infection.

New advance in hypophosphatemic rickets

Hypophosphatemic rickets(HR) is a bone mineralization disorder caused by phosphate wasting, including hypophosphatemia, bone abnormalities and short stature.X-linked hypophosphatemia(XLH) is the most common inherited disease related to phosphate metabolism, which might result in elevated levels of fibroblast growth factor 23 (FGF23). FGF23 plays an important role in the disease mechanism, so a human anti-FGF23 antibody is developed as a potential treatment for XLH.In many clinical trials, subcutaneous Burosumab increased serum phosphorus levels in pediatric and adult patients with XLH.With the development of phase 1-3 clinical trials of Burosumab in children and adults with XLH, the efficacy and safety of Burosumab is proven to be superior to that of phosphate and calcitriol used in traditional therapy.This review aims to investigate the physiopathology and treatment of HR and to enhance the recognition of HR. Key words: Rickets; Hypophosphatemia; Fibroblast growth factor 23; Osteomalacia; 1, 25(OH)2D

Promoting Osteogenesis of Human Umbilical Cord Mesenchymal Stem Cells Using 1α, 25-(OH)₂D₃ to Change Intracellular Calcium Concentration.

Vitamin D plays a major role in the regulation of calcium homeostasis and affects bone metabolism. There is currently limited detailed knowledge about the vitamin D endocrine system in human bone cells. Here, we investigated the direct effects of 1α, 25-dihydroxyvitamin D₃ (1α, 25-(OH)₂D₃ or 'VD3') on osteogenesis of human umbilical cord mesenchymal stem cells (HUCMSCs). We also studied the impact of VD3 on intracellular Ca2+ concentrations in osteogenic cells. The results of alizarin red staining and alkaline phosphatase activity tests showed that VD3 could not induce osteogenic differentiation in HUCMSCs. However, addition of VD3 to the osteogenic differentiationinducing medium could promote HUCMSC to differentiate into osteoblasts. Calcium imaging showed that the addition of VD3 increased intracellular Ca2+ concentrations in osteogenic HUCMSCs. Thus, we concluded that adding VD3 increased intracellular Ca2+ concentrations in osteogenic HUCMSCs and promoted their osteogenesis.

Causal associations of autoimmune thyroiditis and papillary thyroid carcinoma: mRNA expression of selected nuclear receptors and other molecular targets.

Potential causal associations of autoimmune thyroiditis (AIT) and papillary thyroid carcinoma (PTC) have been studied previously. The mRNA expression patterns of thyroid hormone receptors (TR), retinoid receptors (RAR), rexinoid receptors (RXR), dihydroxyvitamin D3 receptors (VDR), and progesterone receptors (PR) in PTC tissue of patients without autoimmune thyroiditis (PTC/AIT-) and in PTC tissue of patients with coexisting AIT (PTC/AIT+) have been investigated in order to judge whether the observed changes may take part in the promotion and progression of thyroid cancer. Tumours with or without AIT were classified histologically and the semiquantitative PCR was performed. The results revealed that there was decreased expression of TRα, TRβα, RARα and PR mRNA in PTC/AIT+ tumours when compared with PTC/AIT- tumours. Decreased expression of RARα in PTC/AIT+ was detected when compared with PTC/AIT- patients. A similar effect of AIT was observed with a decrease in RARγ expression in PTC/AIT+ patients. On the other hand, there was an increased expression of VDR in thyroid tumours (PTC/AIT+) when compared with PTC/AIT-. PR mRNA was decreased in the thyroid tumours of PTC/AIT+ patients when compared with PTC/AIT- patients. In addition, there was an increased expression of MKi67 and complement C3 in PTC of PTC/AIT+ when compared with PTC/AIT-. In the PTC/AIT+ group, a decreased level of IGF-1 mRNA was found when compared with the PTC/AIT- group. According to the significant differences of the studied markers in PTC/AIT+ compared with PTC/AIT-, it was indicated that AIT may be a predisposing factor for the development of PTC.

TGF-β signaling proteins and CYP24A1 may serve as surrogate markers for progesterone calcitriol treatment in ovarian and endometrial cancers of different histological types

Background: Strategies are needed to coordinately block drivers and induce suppressors of cancer to reduce incidence and improve outcomes for individuals with inherited or acquired risk. We previously reported the chemopreventive and therapeutic efficacy of the combination of progestin and calcitriol in transformed and malignant endometrioid endometrial cancer (EC) and in ovarian cancer models involving attenuated expression of TGF-β signaling proteins and progestin-mediated inhibition of calcitriol-induced CYP24A1 expression. This study aims to expand the applications for this combination to other subtypes of endometrial and ovarian cancers, including those with mutations in ARID1A or PIK3CA, DNA mismatch repair (MMR) deficiency or BRCA1 null status. Methods: Ovarian and EC cell lines of different histotypes were cultured with either progesterone, calcitriol, or the combination of progesterone and calcitriol for 3 or 5 days. The end points for this in vitro investigation included assessments of cell growth by (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) (MTS) assays and the expression of TGF-β ligands, receptors, SMAD proteins and CYP24A1 by western blotting. Results: Treatment of ovarian clear cell carcinoma, endometrioid carcinoma, papillary serous adenocarcinoma, BRCA1 null, and DNA MMR deficient EC cell lines with progesterone alone or in combination with calcitriol inhibited cell growth and expression of TGF-β1, TGF-β2, TGF-Rβ1, TGF-βR2, pSMAD2/3 and CYP24A1. Expression of TGF-βR3, SMAD-4, progesterone receptor (PR) and vitamin-D receptor (VDR) was not altered in any cell line tested except, ES-2, where VDR expression was upregulated in response to treatment. Conclusions: These results suggest that progesterone alone and progesterone-calcitriol combination have broad application in both chemopreventive and therapeutic settings that merit further development in a wide variety of ovarian and ECs, including those derived from germline or somatic mechanisms. Moreover, our data suggest that TGF-β signaling proteins and CYP24A1 may be effective surrogate markers indicative of treatment response.