肾病综合征患儿血清25-羟维生素D的影响因素分析

目的了解肾病综合征(NS)患儿维生素D营养状况,并分析其影响因素。方法以2012年1月1日至12月31日华中科技大学同济医学院附属同济医院儿科收治的初诊或复诊NS患儿为NS组,体检儿童为对照组。根据血清25-羟维生素D［25(OH)D］水平判断维生素D营养状态,≤20 ng·mL-1为维生素D缺乏。从NS患儿病史中截取可能影响25(OH)D的因素行维生素D缺乏的单因素分析和Logistic回归分析;同时对25（OH）D的影响因素行多元线性回归分析。 结果NS组139例,男103例,女36例,年龄(6.1±3.7)岁;对照组83例,男49例,女34例,年龄(3.1±2.0)岁。①NS组和对照组血清25(OH)D水平分别为(10.3±7.5)和(29.4±9.9) ng·mL-1,差异有统计学意义(P<0.000 1)。维生素D缺乏检出率NS组和对照组分别为86.3%和19.3%,差异有统计学意义(P<0.000 1)。②单因素分析结果显示,NS病程、24 h尿蛋白定量、糖皮质激素累积剂量和使用时间、血清钙在维生素D缺乏和不缺乏NS患儿间差异有统计学意义;Logistic回归分析显示,体重Z评分(OR=0.151,95%CI:0.035~0.649)、NS病程(OR=0.143, 95%CI:0.035~0.592)和大量24 h蛋白尿(OR=28.177,95%CI:3.295~240.970)与维生素D缺乏相关。③多元线性回归显示,男性、24 h尿蛋白定量、血清钙和每公斤体重糖皮质激素累积剂量与血清25(OH)D水平相关(P<0.05)。④27例NS患儿服用阿法骨化醇前和3个月后均行血清25(OH)D水平检测,治疗前和治疗后分别为(7.2±5.0)和 (14.9±11.0) ng·mL-1,差异有统计学意义(P=0.001)。 结论NS患儿血清25(OH)D低于健康儿童,有部分可能与蛋白尿水平、NS病程和糖皮质激素累积剂量等因素相关,口服阿法骨化醇可提高血清25（OH）D水平。     

维生素D受体与佝偻病

维生素Ｄ缺乏性佝偻病是严重危害我国儿童健康的常见病之一,国外对维生素Ｄ受体（ＶＤＲ）基因型与１,２５（ＯＨ）２Ｄ３和钙代谢的研究已相当深入。本文借鉴国外的研究结果来推断佝偻病与ＶＤＲ基因型之间的关系,旨在为佝偻病的防治工作探索一条新途径。     

1,25-二羟维生素D3与自身免疫性疾病

1,25-二羟维生素D3对T细胞、B细胞、巨噬细胞、树突状细胞和角化细胞等均有调节作用,并与许多自身免疫性疾病包括类风湿性关节炎、青少年糖尿病、克罗恩病、多发性硬化等密切相关.1,25-二羟维生素D3可能成为治疗自身免疫性疾病的药物之一,但最佳用药剂量及疗程尚需进一步研究.     

1,25-二羟维生素D3与自身免疫性疾病

1,25-二羟维生素D3对T细胞、B细胞、巨噬细胞、树突状细胞和角化细胞等均有调节作用,并与许多自身免疫性疾病包括类风湿性关节炎、青少年糖尿病、克罗恩病、多发性硬化等密切相关.1,25-二羟维生素D3可能成为治疗自身免疫性疾病的药物之一,但最佳用药剂量及疗程尚需进一步研究.     

1,25-二羟维生素D的免疫调节和抗肿瘤作用

活性维生素D即 1 ,2 5(OH) 2 -D3,参与机体钙、磷代谢与骨质钙化。近年来的研究发现 ,1 ,2 5(OH) 2 -D3对免疫系统也有广泛的作用 ,通过结合靶细胞内特异的核受体—维生素D受体 (VDR)而产生免疫调节作用 ;与一些细胞因子联用对某些类型的白血病细胞有协同促分化作用。一、1 ,2     

维生素D受体基因ApaI位点多态性与维生素D缺乏性佝偻病的研究

目的研究山西汉族儿童维生素D受体(VDR)基因ApaI位点多态性与维生素D缺乏性佝偻病的关系,探讨个体遗传因素在佝偻病发病中的意义,为临床防治探索一条新途径。方法以血清25(OH)D3水平、骨源性碱性磷酸酶(BALP)以及临床症状和体征作为分组指标,确定佝偻病组(40例)、对照组(68例)作为研究对象。应用酶联免疫和放射免疫方法,采用聚合酶链反应和限制性片段长度多态性技术(PCRRFLP)检测VDR基因ApaI位点多态性,HardyWeinberg遗传平衡检验方法进行基因分布遗传平衡吻合度检验。结果佝偻病组AA、Aa、aa基因型分布频率分别为5.0%、52.5%和42.5%。对照组AA、Aa、aa基因型分布频率分别为4.4%、55.9%、39.7%。佝偻病组等位基因A、a分布频率分别为31.3%、68.7%,对照组等位基因A、a分布频率分别为32.3%、67.7%。VDR基因型分布频率、等位基因分布频率两组间差异无统计学意义(χ2=0.089,P>0.05;χ2=0.028,P>0.05)。两组间血清25(OH)D3水平差异有统计学意义(t=-8.919,P<0.01)。结论(1)本组汉族儿童VDR基因ApaI位点多态性分布相对较均衡,a等位基因频率为67.7%,是优势基因。(2)本组人群VDR基因多态性分布与高加索人种相比明显不同,存在种族差异。(3)提示VDR基因ApaI位点多态性在个体是否发生维生素D缺乏性佝偻病方面可能没有意义。     

维生素D受体多态性与晚发性佝偻病易感性研究

目的研究维生素D受体基因起始密码子（VDRSC）多态性在晚发性佝偻病组、维生素D缺乏状态组及正常对照组中分布频率的差异,探讨晚发性佝偻病的遗传易感因素。方法用聚合酶链反应——限制性长度多态性（RFLP）分析晚发性佝偻病组30例、维生素D缺乏状态组35例以及正常对照组60例VDRSC多态性的分布频率。结果三组VDRSC基因型分布频率差异有统计学意义（χ^2=13．184,P=0．010）;等位基因分布频率差异也有统计学意义（χ^2=8．975,P=0．011）。组间两两比较晚发性佝偻病组VDRSC基因型和等位基因与其他两组比较差异有统计学意义,其FF型频率（56．7％）明显高于正常对照组（21．7％,P=0．006）,也明显高于维生素D缺乏状态组（22．9％,P=0．002）;晚发性佝偻病组F型（70．0％）明显高于正常对照组（48．3％,P=0．006）,也明显高于维生素D缺乏状态组（47．1％,P=0．009）。多项分类Logistic回归分析结果显示,在调整了其他危险因素后,FF型仍是晚发性佝偻病的危险因素,相对危险度（OR）=3．120。结论VDRSC多态性可能决定晚发性佝偻病的遗传易感性。     

成纤维细胞生长因子-2在肾脏疾病中的作用

成纤维细胞生长因子-2(fibroblast growth factor-2，FGF-2)参与多种脏器的胚胎发育，具有致有丝分裂作用、促增殖和分化作用。近年来，关于FGF-2在各种肾脏疾病发病机制方面的研究逐步深入与明了。研究证明，FGF-2参与足细胞损伤、启动球囊黏连、导致肾小球硬化；参与肾小管上皮细胞损伤，介导肾小管上皮间质转分化，加速肾间质纤维化。     

维生素D受体基因多态性对儿童骨密度影响的研究

儿童阶段骨密度持续增长,是影响成年骨峰值的关键时期。防治儿童期低骨密度是减少成年后骨质疏松发生的重要环节。遗传是决定骨密度的重要因素之一,其中维生素D受体(VDR)的基因多态性对儿童骨密度的影响是近年来国外研究的热点。目前发现与骨密度相关的VDR四个等位基因分别对应内切酶BsmI、ApaI、TaqI、FokI的酶切位点。但世界各地的研究结果不一致,可能与种族差异、环境因素、研究方法各不相同有关。本文综合各种观点,分析造成这种不一致的可能原因,提示在研究VDR基因多态性与骨密度关系时应综合考虑的因素。     

Role of fetal 1,25-dihydroxyvitamin D production in intrauterine phosphorus and calcium homeostasis

During intrauterine life, fetal mineral accretion depends on active transfer from mother to fetus by the placenta. To evaluate the role of fetal production of 1,25-dihydroxyvitamin D in regulation of fetal phosphorus, calcium, and parathyroid homeostasis, studies were performed in ewes and their fetal lambs. Fetal nephrectomy caused a rise in fetal serum phosphorus and a fall in total calcium 5 days after nephrectomy. Fetal blood ionized calcium also fell and serum parathyroid hormone rose. In sham-nephrectomized fetuses, all four measurements were unchanged compared to control values. Simultaneous maternal values of ionized calcium were normal in control and nephrectomized fetuses. Fetal ureteral severance and drainage of urine into the fetal peritoneal cavity produced none of the effects of fetal nephrectomy. Daily intravenous injection of 1,25-dihydroxyvitamin D into fetuses after nephrectomy prevented the rise in serum phosphate, and serum calcium did not fall. The results suggest that fetal 1,25-dihydroxyvitamin D regulates fetal phosphate homeostasis, perhaps by the placenta, which in turn regulates blood-ionized calcium concentration.     

Bone disease induced by anticonvulsant therapy and treatment with calcitriol (1,25-dihydroxyvitamin D3)

To evaluate the effects of calcitriol (1,25-dihydroxyvitamin D3) therapy for the bone disease induced by long-term treatment with anticonvulsants, we reviewed the medical records of 330 institutionalized oligophrenic children and young adults under 26 years of age to identify the 144 children who required anticonvulsant therapy. Of this latter group, 52 children were found to have serum alkaline phosphatase levels elevated more than 2 SDs above normal and were enrolled into this prospective three-year study. To achieve rapid resolution of the bone disease, we elected to use calcitriol at 0.25 to 0.75 micrograms/d. After 1195 patient-months of treatment, our data suggest that the dystrophic process was reversed in 42.3% of the cases, as judged by decreases in serum alkaline phosphatase levels at six months, 65.4% of cases at 12 months, and 83.3% of cases at 13 to 18 months. By 30 months of follow-up, all patients showed significant lowering of serum alkaline phosphatase levels. The improvements were slow and gradual. Twenty-six patients in the treatment series of 52 patients initially showed signs of rickets or osteomalacia on roentgenograms of the wrists. Of these 26 patients, 12 (46%) showed improvement on roentgenograms within 24 months of the beginning of treatment. With reference to complications, hypercalcemia (calcium level, greater than 11 mg/dL [2.74 mmol/L]) was encountered at the rate of one episode per 44 patient-months of treatment. Our results strongly suggest that calcitriol is effective in healing anticonvulsant-related osteomalacia among children and youths, with a low incidence of complications.     

Vitamin D metabolism in biliary atresia: intestinal absorptions of 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3

In children with biliary atresia, defective intestinal absorption of vitamin D and impaired hepatic uptake and 25-hydroxylation of vitamin D lead to a deficiency of vitamin D and rickets. We recently observed severe rickets in a 3-year-old boy with corrected biliary atresia resulting in jaundice, despite oral treatment with 1 alpha-hydroxyvitamin D3 (1 alpha-OHD3) or 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3]. He had low 25-hydroxyvitamin D (25-OHD) and high 1,25-(OH)2D serum levels. Intramuscular vitamin D2 administration produced radiological and biochemical evidence of recovery. Oral 1,25-(OH)2D3 (0.1 microgram/kg) and 25-OHD3 (10 micrograms/kg) tolerance tests were done to assess the ability to absorb vitamin D and the effectiveness of using these drugs orally. Eleven children with corrected biliary atresia, aged 9 months to 7 years, were studied. In oral 1,25-(OH)2D3 tolerance tests, the increments above the baseline serum levels of 1,25-(OH)2D were 140.7 +/- 27.4 pg/ml in nonjaundiced patients (n = 5). In jaundiced patients (n = 3), 1,25-(OH)2D3 absorption in two patients with high basal 1,25-(OH)2D values was lower than that of nonjaundiced patients; however, the absorption in the third patient with a low basal value was similar to that of nonjaundiced patients. In oral 25-OHD3 tolerance tests, the mean increase of serum 25-OHD was 48.9 +/- 30.6 ng/ml in nonjaundiced patients (n = 5) and 23.7 +/- 9.5 ng/ml in jaundiced patients (n = 4), the peak serum 25-OHD levels being reached 6-12 h after 25-OHD3 loading.(ABSTRACT TRUNCATED AT 250 WORDS)     

活性维生素D及其类似物对足细胞的保护作用

1,25(OH)2D3产生不足是慢性肾脏病(CKD)的主要特征之一,不仅导致钙磷代谢异常及骨矿化障碍,而且加速肾疾病的进展。1,25(OH)2D3及其类似物可减轻CKD患者的蛋白尿,减轻动物模型足细胞的损伤、凋亡和脱落,促进裂孔隔膜蛋白的表达,维持肾小球滤过屏障的完整性。1,25(OH)2D3保护足细胞机制与抑制足细胞肾素-血管紧张素系统、阻断Wnt/β-Catenin和转化生长因子(TGF)-β1信号通路有关。     

Vitamin D dependent rickets: Decreased sensitivity to 1,25-dihydroxyvitamin D

A patient with vitamin D dependent rickets with decreased sensitivity to 1,25-Dihydroxyvitamin D was observed. She suffered from bone pain of two years duration beginning at 12 years of age and was found to be suffering from hypocalcemia, secondary hyperparathyroidism and osteomalacia. Laboratory findings revealed normal serum 25-hydroxyvitamin D (27 ng/ml) and markedly elevated serum 1,25-dihydroxyvitamin D (131.9 pg/ml). The hypocalcemia was refractory in spite of administration of 25,000 units of vitamin D₂, but therapy with high doses of oral 1-hydroxyvitamin D₃ resulted in significant elevation of the serum calcium level. The clinical findings and course of the patient's disease were quite different from those of other patients with vitamin D dependent rickets reported by other authors.     

Defective leukocyte fungicidal activity in end-organ resistance to 1,25-dihydroxyvitamin D

Recent studies have shown 1,25(OH)2D3 receptor-mediated modulation of leukocyte proliferation, differentiation, and function. We examined the phagocytosis and killing of microorganisms by neutrophils and monocytes from five patients of three families with hereditary resistance to 1,25(OH)2D3. Phagocytosis of microorganisms by patients' neutrophils and monocytes was normal. However, defective neutrophil killing activity toward Candida albicans (30-40% of controls) was found in all patients. The killing of Staphylococcus aureus was normal. The neutrophil chemiluminescence, nitroblue tetrazolium (NBT) dye reduction, and the generation of superoxide ions and hydrogen peroxide by neutrophils and monocytes after induction by either soluble stimuli or zymozan particles, did not differ from those in controls. The neutrophil myeloperoxidase activity was also normal. Monocytes obtained from two patients of different families before long-term calcium infusion therapy and after they became normocalcemic, demonstrated a similar impaired fungicidal activity toward Saccharomyces cerevisiae, indicating that hypocalcemia itself was not the cause of the killing defect. However, the addition of the Ca+2 ionophore A23187 (1 microM) to the test medium restored the monocyte fungicidal activity to normal. As patients' neutrophil cytosolic free calcium concentration was similar to that in controls, it is suggested that 1,25-(OH)2D3 exerts its effect on leukocyte function by a putative receptor-mediated regulation of subcellular calcium localization which may be important for fungicidal activity.     

1 alpha-hydroxyvitamin D3 treatment of three patients with 1,25-dihydroxyvitamin D-receptor-defect rickets and alopecia

Three patients with clinically different severities of vitamin D-dependent rickets, type II, with alopecia, which is 1,25-dihydroxyvitamin D-receptor-defect rickets and is particularly resistant to treatment with calciferol analogues, were treated with large doses of 1 alpha-hydroxyvitamin D3 (1 alpha-(OH)D3) and 2 g of calcium lactate. Except for the alopecia, all of the abnormalities of patients 1 and 2 were reversed by treatment with 3 micrograms/kg/d of 1 alpha-(OH)D3, and those of patient 3, who had the severest manifestations, were reversed by treatment with 6 micrograms/kg/d. The serum 24,25-dihydroxyvitamin D concentrations of the three patients were low before treatment and those of patients 1 and 2 increased during treatment. These findings suggest that in patients 1 and 2, 25-hydroxyvitamin D-24-hydroxylase was stimulated via a 1,25-dihydroxyvitamin D-receptor-mediated system by treatment with 1 alpha-(OH)D3.