Junli Liu

Vitamin D status in Chinese pregnant women and their newborns in Beijing and their relationships to birth size.

OBJECTIVE To evaluate the prevalence of vitamin D deficiency in pregnant women and their newborns in Beijing, China and the influence of vitamin D deficiency on birth size. DESIGN A cross-sectional study. SETTING Data were collected from pregnant women who delivered during April to May 2010 at 306 Hospital of PLA in Beijing, China. SUBJECTS Participants in the study were seventy healthy nulliparous pregnant women with singleton pregnancies who delivered healthy babies at full term and their newborns. RESULTS Severe vitamin D deficiency (25-hydroxyvitamin D (25(OH)D) < 25 nmol/l) was detected in 54·5 % of mothers and 46·6 % of newborns. Neither mothers nor newborns had serum 25(OH)D concentrations that reached the normal level (>75 nmol/l). The concentration of 25(OH)D in mothers was positively correlated with that in cord blood (r = 0·89, P < 0·001). Newborns of mothers with severe vitamin D deficiency had lower birth length and birth weight. The head circumference and birth weight were lower in vitamin D-deficient newborns. CONCLUSIONS The study indicates that pregnant women and neonates residing in Beijing are at high risk of vitamin D deficiency. Neonatal 25(OH)D concentrations are dependently related to maternal 25(OH)D levels. Maternal and neonatal vitamin D status influences newborn size.

THE HIGH PREVALENCE OF VITAMIN D DEFICIENCY AND ITS RELATED MATERNAL FACTORS IN PREGNANT WOMEN IN BEIJING

Maternal vitamin D deficiency has been suggested to influence fetal and neonatal health. Little is known about vitamin D status in Chinese pregnant women. The purpose of this study was to assess the vitamin D status of pregnant women residing in Beijing in winter and evaluate the impact of maternal factors on serum 25-hydroxyvitamin D [25(OH)D] levels. The study was conducted on 125 healthy pregnant women. For each individual, data concerning pre-pregnancy weight, educational status, use of multivitamins and behavioral factors such as daily duration of computer use, walking and sun exposure were obtained. Serum concentrations of 25(OH)D were measured by enzyme-linked immunosorbent assay. The prevalence of vitamin D deficiency (25(OH)D < 50 nmol/L) was 96.8% and almost half (44.8%) of women were severely vitamin D deficiency (25(OH)D < 25 nmol/L). The concentration of 25(OH)D was lower in women with shorter duration of sun exposure (≤ 0.5 h/day, 25.3 ± 8.9 nmol/L) than that in women with longer duration of sun exposure (> 0.5 h/day; 30.3± 9.5 nmol/L; P = 0.003). Thirty six women (28.8%) had sun exposure duration ≥ 1.5h/day. The 25(OH)D concentration in these women was 31.5 ± 9.4 nmol/L which was also much lower than the normal level. Women who reported taking a multivitamin supplement had significantly higher 25(OH)D concentrations (32.3 ± 9.5 nmol/L) when compared with non-users (24.9 ± 8.2 nmol/L; P < 0.001). Pregnant women in Beijing are at very high risk of vitamin D deficiency in winter. Duration of Sun exposure and the use of multivitamin were the most important determinants for vitamin D status. However, neither prolonging the time of sunlight exposure nor multivitamin supplements can effectively prevent pregnant women from vitamin D deficiency. Other measures might have to be taken for pregnant women to improve their vitamin D status in winter.

Bovine Collagen Peptides Compounds Promote the Proliferation and Differentiation of MC3T3-E1 Pre-Osteoblasts

Objective Collagen peptides (CP) compounds, as bone health supplements, are known to play a role in the treatment of osteoporosis. However, the molecular mechanisms of this process remain unclear. This study aimed to investigate the effects of bovine CP compounds on the proliferation and differentiation of MC3T3-E1 cells. Methods Mouse pre-osteoblast cell line MC3T3-E1 subclone 4 cells were treated with bovine CP compounds. Cell proliferation was analyzed by MTT assays and the cell cycle was evaluated by flow cytometry scanning. Furthermore, MC3T3-E1 cell differentiation was analyzed at the RNA level by real-time PCR and at the protein level by western blot analysis for runt-related transcription factor 2 (Runx2), a colorimetric p-nitrophenyl phosphate assay for alkaline phosphatase (ALP), and ELISA for osteocalcin (OC). Finally, alizarin red staining for mineralization was measured using Image Software Pro Plus 6.0. Results Cell proliferation was very efficient after treatment with different concentrations of bovine CP compounds, and the best concentration was 3 mg/mL. Bovine CP compounds significantly increased the percentage of MC3T3-E1 cells in G2/S phase. Runx2 expression, ALP activity, and OC production were significantly increased after treatment with bovine CP compounds for 7 or 14 days. Quantitative analyses with alizarin red staining showed significantly increased mineralization of MC3T3-E1 cells after treatment with bovine CP compounds for 14 or 21 days. Conclusions Bovine CP compounds increased osteoblast proliferation, and played positive roles in osteoblast differentiation and mineralized bone matrix formation. Taking all the experiments together, our study indicates a molecular mechanism for the potential treatment of osteoarthritis and osteoporosis.

The effect of different molecular weight collagen peptides on MC3T3-E1 cells differentiation

Our study aimed at investigating the effect of different molecular weight bovine collagen peptides, namely CH878, CH1370, CH2900, and CH7747 on the differentiation of MC3T3-E1 cells. Osteogenic differentiation of MC3T3-E1 cells was assessed by a series of specific assays, after culturing of cells in the presence of collagen peptides. Alkaline phosphatase activity (ALP) was evaluated by NBT/BCIP staining. Osteocalcin expression was determined by a radioimmunology method. Mineralization was quantified by Alizarin Red staining. ALP staining results demonstrated that the ALP staining of cells after culture in the presence of collagen peptides were significantly higher than the control group (P<0.05), indicating the promotion of ALP activity in MC3T3-E1 cells by these peptides. Radioimmunology results demonstrated that collagen peptides groups were all significantly higher than the control group (P<0.01). Alizarin Red staining results demonstrated that CH1370, CH2900, and CH7747 significantly promoted the formation of mineralized bone matrix. We therefore conclude that CH1370, CH2900, and CH7747 play an active role in the differentiation of MC3T3-E1 cells. Based on the above results, we provide molecular basis for further development of collagens with different molecular weight for the prevention and treatment of osteoporosis.

The Associations of Serum Lipids with Vitamin D Status.

Aims Vitamin D deficiency has been associated with some disorders including cardiovascular diseases. Dyslipidemia is a major risk factor for cardiovascular diseases. However, data about the relationships between vitamin D and lipids are inconsistent. The relationship of vitamin D and Atherogenic Index of Plasma (AIP), as an excellent predictor of level of small and dense LDL, has not been reported. The objective of this study was to investigate the effects of vitamin D status on serum lipids in Chinese adults. Methods The study was carried out using 1475 participants from the Center for Physical Examination, 306 Hospital of PLA in Beijing, China. Fasting blood samples were collected and serum concentrations of 25(OH)D, total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) were measured. AIP was calculated based on the formula: log [TG/HDL-C]. Multiple linear regression analysis was used to estimate the associations between serum 25(OH)D and lipids. The association between the occurrences of dyslipidemias and vitamin D levels was assessed by multiple logistic regression analysis. Confounding factors, age and BMI, were used for the adjustment. Results The median of serum 25(OH)D concentration was 47 (27–92.25) nmol/L in all subjects. The overall percentage of 25(OH)D ≦ 50 nmol/L was 58.5% (males 54.4%, females 63.7%). The serum 25(OH)D levels were inversely associated with TG (β coefficient = -0.24, p < 0.001) and LDL-C (β coefficient = -0.34, p < 0.001) and positively associated with TC (β coefficient = 0.35, p < 0.002) in men. The associations between serum 25(OH)D and LDL-C (β coefficient = -0.25, p = 0.01) and TC (β coefficient = 0.39, p = 0.001) also existed in women. The serum 25(OH)D concentrations were negatively associated with AIP in men (r = -0.111, p < 0.01) but not in women. In addition, vitamin D deficient men had higher AIP values than vitamin D sufficient men. Furthermore, the occurrences of dyslipidemias (reduced HDL-C, elevated TG and elevated AIP) correlated with lower 25(OH)D levels in men, whereas the higher TC and LDL-C associated with higher 25(OH)D levels in women. Conclusion It seems that the serum 25(OH)D levels are closely associated with the serum lipids and AIP. Vitamin D deficiency may be associated with the increased risk of dyslipidemias, especially in men. The association between vitamin D status and serum lipids may differ by genders.

Combined oral administration of bovine collagen peptides with calcium citrate inhibits bone loss in ovariectomized rats.

Purpose Collagen peptides (CPs) and calcium citrate are commonly used as bone health supplements for treating osteoporosis. However, it remains unknown whether the combination of oral bovine CPs with calcium citrate is more effective than administration of either agent alone. Methods Forty 12-week-old Sprague-Dawley rats were randomly divided into five groups (n = 8) for once-daily intragastric administration of different treatments for 3 months at 3 months after ovariectomy (OVX) as follows: sham + vehicle; OVX + vehicle; OVX + 750 mg/kg CP; OVX + CP-calcium citrate (75 mg/kg); OVX + calcium citrate (75 mg/kg). After euthanasia, the femurs were removed and analyzed by dual energy X-ray absorptiometry and micro-computed tomography, and serum samples were analyzed for bone metabolic markers. Results OVX rats supplemented with CPs or CP-calcium citrate showed osteoprotective effects, with reductions in the OVX-induced decreases in their femoral bone mineral density. Moreover, CP-calcium citrate prevented trabecular bone loss, improved the microarchitecture of the distal femur, and significantly inhibited bone loss with increased bone volume, connectivity density, and trabecular number compared with OVX control rats. CP or CP-calcium citrate administration significantly increased serum procollagen type I N-terminal propeptide levels and reduced serum bone-specific alkaline phosphatase, osteocalcin, and C-telopeptide of type I collagen levels. Conclusions Our data indicate that combined oral administration of bovine CPs with calcium citrate inhibits bone loss in OVX rats. The present findings suggest that combined oral administration of bovine CPs with calcium citrate is a promising alternative for reducing bone loss in osteopenic postmenopausal women.

Vitamin D improves immune function in immunosuppressant mice induced by glucocorticoid

Vitamin D is an essential fat-soluble vitamin with multiple functions. Vitamin D receptor has been shown to be expressed in several types of immune cells suggesting vitamin D may have immune regulatory roles. Vitamin D insufficiency has been suggested to increase the risk of autoimmune diseases. However, little is known regarding its immunomodulatory effects in the condition of immune suppression. The aim of the present study was to investigate the regulatory effects of vitamin D on immune function in immunosuppressant mice. An immunosuppressant mouse model was induced by intraperitoneal injection with glucocorticiod for 3 days. Immunosuppressant mice were intragastrically administered with 1,25-dihydroxy-vitamin D3 [1,25(OH)2D3; 0,4, 6 or 10 IU/g body weight] for 7 days. On day 8, the mice were decapitated. The body weight and the weights of thymus and spleen were measured. Thymus and spleen indexes were calculated. The ratio of CD4+/CD8+ T lymphocytes in the peripheral blood, proliferation and interleukin-2 (IL-2) production of spleen T lymphocytes was detected. Compared with the mice in the control group, the body weight, thymus and spleen indexes, the ratios of CD4+/CD8+ in peripheral blood and IL-2 production and proliferation of spleen T lymphocytes were decreased in immunosuppressant mice induced by glucocorticiod. However, in vitamin D-treated mice, the thymus indexes, the ratios of CD4+/CD8+, secretion of IL-2 and the proliferation index of spleen T lymphocytes were significantly increased (P<0.05). Among the three doses of 1,25(OH)2D3, 6 IU/g was most effective in improving the immune function. These results indicate that vitamin D supplementation can improve immune recovery in immunosuppressant mice by stimulating T-cell proliferation and elevating IL-2 production.