婴幼儿佝偻病VDR基因ApaI、BsmI位点多态性与连锁不平衡分析

目的 探讨婴幼儿佝偻病患者维生素D受体（VDR）基因ApaI、BsmI位点多态性分布特征及连锁不平衡关系及其与佝偻病的遗传易感因素.方法 应用聚合酶链反应-限制性片段长度多态性（PCR-RFLP）方法对56例佝偻病患儿和76例健康对照儿进行VDR基因ApaI、BsmI位点多态性的检测,分析两组VDR基因型和等位基因频率及两位点间连锁不平衡的关系.结果 两组VDR基因ApaI、BsmI位点基因型频率分布比较差异均无统计学意义（P＞0.05）.VDR基因ApaI、BsmI 位点等位基因频率在两组人群中的分布差异均无统计学意义（P＞0.05）.ApaI与BsmI二位点连锁不平衡系（D＇=0.230,r2=0.01）.结论 VDR基因ApaI、BsmI位点的多态性与维生素D缺乏性佝偻病无明显关系,且两位点不存在连锁不平衡关系.     

Genetic susceptibility to lead poisoning

Major strides have been taken in the regulation of lead intoxication in the general population, but studies using genetic markers of susceptibility to environmental toxicants raise the question of whether genes can make certain individuals more vulnerable to environmental toxins such as lead. At least three polymorphic genes have been identified that potentially can influence the bioaccumulation and toxicokinetics of lead in humans. The first gene to be discussed in this review is the gene coding for delta-aminolevulinic acid dehydratase (ALAD), an enzyme of heme biosynthesis, that exists in two polymorphic forms. The resulting isozymes have been shown to affect the blood and bone lead levels in human populations. The effects of ALAD in lead intoxication have also been studied in laboratory mice that differ in the genetic dose for this enzyme. The second gene reviewed here is the vitamin D receptor (VDR) gene. The VDR is involved in calcium absorption through the gut and into calcium-rich tissues such as bone. Recent findings suggest that VDR polymorphism may influence the accumulation of lead in bone. Finally, the third gene to be discussed here that may influence the absorption of lead is the hemochromatosis gene coding for the HFE protein. The presence of mutations in the HFE gene leads to hemochromatosis in homozygotic individuals. Because of the associations between iron and lead transport, it is possible that polymorphisms in the HFE gene may also influence the absorption of lead, but this has not yet been studied. More studies will be needed to define the role of these genes in lead intoxication.     

维生素D受体基因多态性与儿童哮喘相关性研究

目的通过研究维生素D受体(vitamin D receptor,VDR)基因多态性与湖南地区儿童支气管哮喘的相关性,探讨儿童支气管哮喘发病的遗传易感因素。方法应用聚合酶链反应-限制性长度多态性的方法检测71例支气管哮喘及71例正常对照儿童的维生素D受体ApaI、BsmⅠ基因多态性,比较两组的基因型及其等位基因的分布频率;采用酶联免疫方法检测维生素D(VD)及白介素-4(IL-4)、白介素-12(IL-12)。结果两组儿童ApaI基因多态性及其等位基因的分布频率差异均有统计学意义(P0.05),而BsmⅠ基因分布频率差异无统计学意义(P0.05);哮喘儿童血清25(OH)D3及IL-12平均水平显著低于正常对照组儿童,而IL-4平均水平显著高于正常对照组儿童,差异有统计学意义(P0.05)。结论 VDR-ApaI基因可能是儿童支气管哮喘的遗传易感基因,而与VDR-BsmI基因多态性无关;VD作为一种免疫调节剂与支气管哮喘的发生、发展关系密切,增加VD的摄入量在一定程度上可能降低哮喘发病率。     

儿童维生素D受体基因酶切位点多态性

目的：了解成都地区汉族人群VDR多态性分布情况,为进一步观察其与VDR遗传易感性疾病的相关性打下基础.方法：采用血清学方法,利用限制性内切酶TaqⅠ、ApaⅠ,应用聚合酶链反应（PCR）、限制性片段长度多态性（RFLP）分析、基因测序等技术,测定成都地区正常汉族儿童VDR基因多态性.结果：518名正常汉族儿童中TT、Tt、tt基因型分布频率分别为90.7%、9.1%、0.2%,T、t等位基因频率分别为95.3%、4.7%;AA、Aa、aa基因型分布频率分别为10.8%、36.7%、52.5%,A、a等位基因频率分别为29.2%、70.8%.结论：成都地区汉族儿童VDRTaqⅠ、ApaⅠ酶切位点多态性分布情况,与同属于蒙古人种的其它亚洲国家正常人群的分布频率相似;而与属于高加索人种的分布频率不同.     

维生素D受体基因多态性与慢性乙型肝炎患者的关联研究

目的：探讨维生素D受体（VDR）FokⅠ基因多态性与慢性乙型肝炎患者临床表型的关联。方法：应用聚合酶链反应-限制性片段长度多态性分析（PCR-RFLP）技术检测VDR FokⅠ基因的多态性在44例慢性乙型肝炎重度患者、46例中度患者和40例非活动性HBsAg携带者中的分布，并进行基因型分析。结果：慢性乙型肝炎重度组、慢性乙型肝炎中度组VDR FokⅠ基因的基因型与对照组（非活动性HBsAg携带者）比较差异有统计学意义（P〈0.01）；慢性乙型肝炎重度组、中度组与对照组VDR FokⅠ基因酶切位点的等位基因F/f分布存差异有统计学意义（P〈0.01）。Pearson列联系数=0.53，提示等位基因F/f分布与慢性乙型肝炎患者的不同临床表型存在相关性。慢性乙型肝炎重度组、中度组f等位基因分布频率高于对照组。结论：VDR FokⅠ基因的多态性与慢性乙型肝炎患者的不同临床表型存在一定的关系。     

Vitamin C Transporters and Their Implications in Carcinogenesis

Vitamin C is implicated in various bodily functions due to its unique properties in redox homeostasis. Moreover, vitamin C also plays a great role in restoring the activity of 2-oxoglutarate and Fe²⁺ dependent dioxygenases (2-OGDD), which are involved in active DNA demethylation (TET proteins), the demethylation of histones, and hypoxia processes. Therefore, vitamin C may be engaged in the regulation of gene expression or in a hypoxic state. Hence, vitamin C has acquired great interest for its plausible effects on cancer treatment. Since its conceptualization, the role of vitamin C in cancer therapy has been a controversial and disputed issue. Vitamin C is transferred to the cells with sodium dependent transporters (SVCTs) and glucose transporters (GLUT). However, it is unknown whether the impaired function of these transporters may lead to carcinogenesis and tumor progression. Notably, previous studies have identified SVCTs’ polymorphisms or their altered expression in some types of cancer. This review discusses the potential effects of vitamin C and the impaired SVCT function in cancers. The variations in vitamin C transporter genes may regulate the active transport of vitamin C, and therefore have an impact on cancer risk, but further studies are needed to thoroughly elucidate their involvement in cancer biology.     

维生素D与多囊卵巢综合征关系的研究进展

多囊卵巢综合征（polycystic ovary syndrome,PCOS）是一种常见的妇科内分泌疾病,主要特征是月经紊乱、高雄激素血症和胰岛素抵抗等,PCOS患者代谢和生殖功能障碍常同时存在。近年研究发现PCOS患者维生素D水平较正常妇女普遍偏低,维生素D对PCOS代谢和生殖功能障碍的影响可能是由胰岛素抵抗介导的。由于维生素D是通过维生素D受体（VDR）来调控基因转录的,所以维生素D对PCOS的影响可能与VDR基因多态性有关,但VDR基因多态性与PCOS的相关性存在种族差异性,在亚洲人群中这种相关性更加显著。维生素D与PCOS的相关性提示补充维生素D对于缓解PCOS的代谢异常及生育能力可能有益。     

Vitamin D and tuberculosis

Tuberculosis is highly prevalent worldwide, accounting for nearly two million deaths annually. Vitamin D influences the immune response to tuberculosis, and vitamin D deficiency has been associated with increased tuberculosis risk in different populations. Genetic variability may influence host susceptibility to developing active tuberculosis and treatment response. Studies examining the association between genetic polymorphisms, particularly the gene coding for the vitamin D receptor (VDR), and TB susceptibility and treatment response are inconclusive. However, sufficient evidence is available to warrant larger epidemiologic studies that should aim to identify possible interactions between VDR polymorphisms and vitamin D status.     

The role of estrogen receptor, vitamin D receptor and calcium receptor genotypes in the pathogenesis of colorectal cancer

In this study, the Xbal polymorphisms of the estrogen-, the Bsml polymorphism of the vitamin D- as well as the A986S polymorphism of the calcium-sensing receptor genes were investigated in 56 patients with colorectal cancer. The expression of erbB-2, epidermal growth factor receptor, ras, p53 and their relationship to estrogen-, vitamin D- and calcium-sensing receptor genotypes were also studied. In subjects exhibiting XX genotype of the estrogen receptor gene or bb genotype of the vitamin D receptor gene, erbB-2 expression was significantly lower compared to those with xx, Xx or BB, Bb (6/56 and 11/56 vs. 31/56 and 26/56; p = 0.0043 and 0.041). The presence of the XX alleles of estrogen receptor gene significantly correlated with the overexpression of the epidermal growth factor receptor expression in tumors, whereas in xx and Xx genotypes, significantly higher expression was seen (7/56 vs. 30/56; p = 0.049). Analyzing the combinations of the two gene allelic variants, we have found XXbb genotype to be associated with a significantly lower erbB-2 expression, compared to other combinations (Xxbb, XxBb, XXBb) (2/7 vs. 7/7, 4/5, 4/5; p = 0.0011). Patients with AA calcium-sensing receptor genotype were in higher UICC stages at the time of discovery of their disease than those with AS genotype. The AA allelic variant of the calcium-sensing gene was more frequent among patients with colorectal cancer compared to controls (36/56 vs. 36/112; p = 0.0004). Our observations raise the possibility that estrogen-, and vitamin D receptor gene polymorphisms accompanied with variable oncogene expression might influence the pathogenic processes resulting in the development of colorectal cancer. The A986S polymorphism of calcium-sensing receptor might also be a prognostic marker of the disease.     

维生素D受体基因与骨量的关系

近年来对维生素D受体(VDR)基因和骨量关系的研究颇有争议。有许多研究认为维生素D受体基因多态性与骨量有关联。但还有一部分研究未能证实VDR基因多态性与骨量的关联。本文就VDR基因与钙吸收、骨量、药物治疗的关系和VDR基因的协同作用以及与其它基因、环境因素的交互作用对骨量影响的研究进展进行了综述。     

Vitamin D,Vitamin D-Binding Proteins,and VDR Polymorphisms in Individuals with Hyperglycaemia

Vitamin D reportedly plays an important role in the pathogenesis of diabetes mellitus; however, this role is unclear and debated. This study investigated the association between 25(OH) vitamin D, vitamin D-binding proteins, and vitamin D receptor (VDR) polymorphisms in healthy individuals and those with prediabetes and type 2 diabetes mellitus (T2D) from South Africa. A cross-sectional study was conducted involving subjects of mixed ancestry aged ≥20 years. Males presented with higher mean 25(OH) vitamin D levels than females, while females exhibited significantly higher serum vitamin D-binding protein levels. Significant differences in mean 25(OH) vitamin D levels were observed in normo-glycaemic, prediabetes, screen-detected DM, and known DM individuals. Vitamin D receptor SNPs Fok1 and Taq1 were not associated with glycaemic status. Fok1 was not associated with 25(OH) vitamin D deficiency, while Taq1 was associated with vitamin D insufficiency. This study showed a high prevalence of vitamin D deficiency/insufficiency in this South African population, with decreased vitamin D levels observed in hyperglycaemic individuals, which was not linked to either vitamin D-binding protein or polymorphisms in Fok1 of the VDR gene. These results may be used as a platform for further research into diagnosis and treatment of hyperglycaemia.     

Investigating the Role of Functional Polymorphism of Maternal and Neonatal Vitamin D Binding Protein in the Context of 25-Hydroxyvitamin D Cutoffs as Determinants of Maternal-Neonatal Vitamin D Status Profiles in a Sunny Mediterranean Region

Recent results indicate that dysregulation of vitamin D-binding protein (VDBP) could be involved in the development of hypovitaminosis D, and it comprises a risk factor for adverse fetal, maternal and neonatal outcomes. Until recently, there was a paucity of results regarding the effect of maternal and neonatal VDBP polymorphisms on vitamin D status during pregnancy in the Mediterranean region, with a high prevalence of hypovitaminosis D. We aimed to evaluate the combined effect of maternal and neonatal VDBP polymorphisms and different maternal and neonatal 25-hydroxyvitamin D (25(OH)D) cut-offs on maternal and neonatal vitamin D profile. Blood samples were obtained from a cohort of 66 mother–child pairs at birth. Our results revealed that: (i) Maternal VDBP polymorphisms do not affect neonatal vitamin D status at birth, in any given internationally adopted maternal or neonatal cut-off for 25(OH)D concentrations; (ii) neonatal VDBP polymorphisms are not implicated in the regulation of neonatal vitamin D status at birth; (iii) comparing the distributions of maternal VDBP polymorphisms and maternal 25(OH)D concentrations, with cut-offs at birth, revealed that mothers with a CC genotype for rs2298850 and a CC genotype for rs4588 tended to demonstrate higher 25(OH)D (≥75 nmol/L) during delivery (p = 0.05 and p = 0.04, respectively), after adjustments for biofactors that affect vitamin D equilibrium, including UVB, BMI and weeks of gestation. In conclusion, this study from Southern Europe indicates that maternal and neonatal VDBP polymorphisms do not affect neonatal vitamin D status at birth, whereas mothers with CC genotype for rs2298850 and CC genotype for rs4588 demonstrate higher 25(OH)D concentrations. Future larger studies are required to establish a causative effect of these specific polymorphisms in the attainment of an adequate (≥75 nmol/L) maternal vitamin D status during pregnancy.     

维生素D与脑发育相关研究进展

近年来有关维生素D研究进展迅速,其中维生素D与大脑的发育之间的关系日益受到关注。维生素D是一种具有类固醇激素作用的物质,可参与调节细胞増殖、分化及凋亡,大量研究表明,维生素D除了具有促进钙磷吸收、骨骼发育及发挥免疫调节的作用,还可作为一类神经激素影响神经系统的发育和功能,本文将从大脑中的维生素D及维生素D受体、维生素D对脑发育可能的调控作用及维生素D与儿童神经精神障碍疾病的相关性等几方面进行阐述。     

Immune Modulation by Vitamin D and Its Relevance to Food Allergy

Apart from its classical function in bone and calcium metabolism, vitamin D is also involved in immune regulation and has been linked to various cancers, immune disorders and allergic diseases. Within the innate and adaptive immune systems, the vitamin D receptor and enzymes in monocytes, dendritic cells, epithelial cells, T lymphocytes and B lymphocytes mediate the immune modulatory actions of vitamin D. Vitamin D insufficiency/deficiency early in life has been identified as one of the risk factors for food allergy. Several studies have observed an association between increasing latitude and food allergy prevalence, plausibly linked to lower ultraviolet radiation (UVR) exposure and vitamin D synthesis in the skin. Along with mounting epidemiological evidence of a link between vitamin D status and food allergy, mice and human studies have shed light on the modulatory properties of vitamin D on the innate and adaptive immune systems. This review will summarize the literature on the metabolism and immune modulatory properties of vitamin D, with particular reference to food allergy.     

Vitamin D and cancer: current dilemmas and future research needs

A diversity of scientific literature supports a role for vitamin D in decreasing colorectal cancer incidence, but the available evidence provides only limited support for an inverse association between vitamin D status and the risk of other types of cancer. We need additional studies analyzing the dose-response relation between vitamin D status and cancer risk, the optimal level of 25-hydroxyvitamin D, the length of time required to observe an effect, and the time period of life when exposure is most relevant. Studies of vitamin D receptor polymorphisms have found that not all polymorphisms have the same association with cancer, and the cancer site could further dictate which polymorphisms might be most important; this indicates a need for more research on gene-environment interactions. Several dietary components and the balance between energy intake and expenditure influence vitamin D metabolism. These studies show that scientists need to identify confounders and modifiers of the biological response to vitamin D, including dietary factors, lifestyle factors such as exercise, and race or ethnicity. Transgenic and knockout animals are powerful tools for identifying the molecular targets of bioactive food components. Scientists should therefore make increased use of these models to identify molecular targets for vitamin D. Many research gaps relate to the need to develop predictive, validated, and sensitive biomarkers, including biomarkers that researchers can use to reliably evaluate intake or exposure to vitamin D, assess one or more specific biological effects that are linked to cancer, and effectively predict individual susceptibility as a function of nutrient-nutrient interactions and genetics.     

Vitamin D and the Athlete: Risks,Recommendations, and Benefits

Vitamin D is well known for its role in calcium regulation and bone health, but emerging literature tells of vitamin D’s central role in other vital body processes, such as: signaling gene response, protein synthesis, hormone synthesis, immune response, plus, cell turnover and regeneration. The discovery of the vitamin D receptor within the muscle suggested a significant role for vitamin D in muscle tissue function. This discovery led researchers to question the impact that vitamin D deficiency could have on athletic performance and injury. With over 77% of the general population considered vitamin D insufficient, it’s likely that many athletes fall into the same category. Research has suggested vitamin D to have a significant effect on muscle weakness, pain, balance, and fractures in the aging population; still, the athletic population is yet to be fully examined. There are few studies to date that have examined the relationship between vitamin D status and performance, therefore, this review will focus on the bodily roles of vitamin D, recommended 25(OH)D levels, vitamin D intake guidelines and risk factors for vitamin D insufficiency in athletes. In addition, the preliminary findings regarding vitamin D’s impact on athletic performance will be examined.     

儿童钙代谢相关激素与ER及VDR基因多态性关系

目的 探讨儿童钙代谢相关激素与雌激素受体(ER)及维生素D受体(VDR)基因多态性的关系.方法 选取河南省某地140名8～12岁中国汉族健康儿童作为研究对象,抽取空腹外周血,采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)方法检测ERα基因PvuⅡ,XbaⅠ以及VDR基因FokⅠ多态性;放免法测定血清骨钙素(OC)和降钙素(CT)浓度.结果 携带ER PvuⅡ3种基因型儿童血清OC浓度分别为PP 5.82μg/L,Pp5.01 μg/L,pp 6.21 μg/L,差异有统计学意义(P＜0.05),携带纯合PP基因型儿童血清OC浓度高于另外2组儿童;血清Ca、CT浓度在ER PvuⅡ各基因型间差异无统计学意义(P＞0.05);携带VDR FokⅠ不同基因型儿童血清Ca浓度分别为ff2.71 mmol/L,Ff 2.39 mmol/L,FF2.48 mmol/L,携带ff基因型儿童血清Ca浓度高于其余2种基因型儿童,差异有统计学意义(P ＜0.05);血清CT和OC浓度在FokⅠ各基因型差异无统计学意义(P＞0.05);结论 ER PvuⅡ不同基因型可能影响血清OC浓度;血清钙浓度可能受VDR基因Fokl多态性的影响.     

Circulating levels of vitamin D, vitamin D receptor polymorphisms, and colorectal adenoma: a meta-analysis

Growing evidence suggests an elevated risk for colorectal neoplasia among individuals with low levels of vitamin D, the biological actions of which are mediated by the vitamin D receptor (VDR). To investigate the association among vitamin D status, VDR polymorphisms (FokI, and BsmI), and colorectal adenoma, we conducted a meta-analysis of nine studies of circulating levels of 25-hydroxyvitamin D (25(OH)D) and five studies of FokI or BsmI polymorphisms in relation to colorectal adenomas. Study-specific relative risks (RRs) and 95% confidence intervals (CIs) were pooled using a random-effects model. A total of 3398 colorectal adenomas for 25(OH)D and 1754 colorectal adenomas for VDR were included in the meta-analysis. We identified a significant inverse association between colorectal adenoma (combined RR, 0.93; 95% CI, 0.87-0.98 per 10 ng/mL increase in 25(OH)D levels). When we examined FokI and BsmI polymorphisms in the meta-analysis, we found no association for either FokI (combined RR, 1.00; 95% CI, 0.95-1.06) or BsmI (combined RR, 0.99; 95% CI, 0.93-1.05) in the additive model. These data suggest an inverse association between circulating 25(OH)D levels and colorectal adenoma risk.