retinol

Primordial germ cells develop into oocytes and sperm cells. These cells are useful resources in reproductive biology and regenerative medicine. The mesenchymal stem cells (MSCs) have been examined for in vitro production of primordial germ cell-like cells. This study aimed to summarize the existing protocols for MSCs differentiation into primordial germ cell-like cells (PGLCs). In the limited identified studies, various models of mesenchymal stem cells, including those derived from adipose tissue, bone marrow, and Wharton's jelly, have been successfully differentiated into primordial germ cell-like cells. Although the protocols of specification induction are basically very similar, they have been adjusted to the mesenchymal cell type and the species of origin. The availability of MSCs has made it possible to customize conditions for their differentiation into primordial germ cell-like cells in several models, including humans. Refining germ cell-related signaling pathways during induced differentiation of MSCs will help define extension to the protocols for primordial germ cell-like cells production.

Some studies have examined the association between micronutrient deficiencies and overweight in children, but data in this regard are conflicting. This study was done to investigate the association between serum levels of vitamin D, A and zinc with overweight in a large sample of Iranian toddlers. A total of 4261 toddlers, aged 15-23 months, who had an Iranian birth certificate and attended primary health care, were included in the current cross-sectional study. Weight and height were measured by experts based on standard protocols and body mass index (BMI) was calculated. Based on WHO criteria, overweight was defined as BMI-z-score of ≥1SD. Serum levels of 25(OH)D3 , retinol and zinc were measured for each toddler. Binary logistic regression was applied to assess the association of 25(OH)D3 , retinol and zinc levels with overweight. Mean age of study participants was 19.2 ± 8.4 months. After controlling for potential confounders, children in the highest quartile of serum 25(OH)D3 levels had lower odds of overweight compared with those in the lowest quartile (OR: 0.79, 95% CI: 0.63–0.99). Furthermore, a marginally significant inverse association was found between serum levels of 25(OH)D3 and overweight among urban toddlers (OR: 0.75, 95%CI: 0.56–1.00). Such a relationship was not seen for rural children. No other significant association was seen between serum levels of retinol and zinc and overweight either before or after controlling for covariates. In conclusion, we found a significant inverse association between serum levels of vitamin D and overweight among toddlers. Further studies, particularly of prospective nature, are required to confirm our findings.

We aimed to examine the relationship between high levels of cystatin C, retinol-binding protein 4 (RBP4) and cardiovascular risk score [determined by Framingham Risk Score (FRS)] in postmenopausal women.
A total of apparently healthy 129 postmenopausal women (mean age 57.1 ± 4.6 years) were included. Serum cystatin C, RBP4, glucose, lipid parameters, creatinine, uric acid and high sensitivity C-reactive protein (hsCRP) were determined. Anthropometric parameters and blood pressure were also obtained. FRS was calculated. Multiple linear regression analysis (MLR) was performed to identify independent factors affecting FRS and to estimate the final predictors of its variability. Receiver Operating Characteristic (ROC) curve analysis was used with the purpose of testing discriminatory potential of a group of parameters selected in MLR analysis, with FRS level as dependent variable.
We found significantly higher levels of both proteins, cystatin C (P = 0.001) and RBP4 (P = 0.006), in the FRS higher (medium and high) risk groups (FRS ≥ 10%) compared to low risk FRS group (FRS High cystatin C and retinol-binding protein 4 may contribute significantly to cardiovascular risk burden in addition to traditional cardiovascular markers.

Retinol (ROH) and its derivatives named vitamin A are substantial for several cells’ functions. Retinol Binding Protein 4 (RBP4) is known as the career for vitamin A in blood. The main receptor for RBP4 is Stimulated by retinoid acid gene 6 (STRA6). RBP4 circulates in bound with Transports Thyroxine and Retinol (TTR) to form ternary ROH-RBP-TTR complex. Recently, RBP4 implicated in insulin resistance which may exerts its functions through inflammatory pathways. Although studies indicated that RBP4 may have role in inflammation as an adipocytokine. the cellular and molecular mechanisms including the interaction between Holo- or Apo-RBP4 and their receptor to induce inflammation is controversial. In this review, we focus on molecular structure of RBP4, STRA6, and their interaction to induce inflammation and insulin resistance to illustrate the potential conflicts in this area.

Serum levels of lipocalin 2 (LCN 2) and retinol-binding protein-4 (RBP 4), increase in type 2 diabetes mellitus (T2DM). We sought to determine whether serum LCN 2 and RBP 4 change after an intervention with omega-3 fatty acids supplementation in diabetic patients.
Forty-five type 2 diabetic patients from Iranian Diabetic Association in Tehran, Iran in 2013 were randomly recruited into two groups: one group received 4 g/d omega-3 for 10 wk; and the control group received placebo. Blood samples, food intake records, anthropometric measurements were obtained from all participants at the beginning and end of the study.
Fasting RBP 4 plasma levels significantly changed after 10 wk supplementation (P = 0.01). The LCN 2 concentrations decreased in omega-3 group, but the changes were not statistically significant. Omega-3 supplementation had no noticeable effect on anthropometric factors.
These findings provide a rationale for omega-3 supplements aimed at lowering serum RBP 4 levels in T2DM.

Serum levels of lipocalin 2 (LCN 2) and retinol-binding protein-4 (RBP 4), increase in type 2 diabetes mellitus (T2DM). We sought to determine whether serum LCN 2 and RBP 4 change after an intervention with omega-3 fatty acids supplementation in diabetic patients. Forty-five type 2 diabetic patients from Iranian Diabetic Association in Tehran, Iran in 2013 were randomly recruited into two groups: one group received 4 g/d omega-3 for 10 wk; and the control group received placebo. Blood samples, food intake records, anthropometric measurements were obtained from all participants at the beginning and end of the study. Fasting RBP 4 plasma levels significantly changed after 10 wk supplementation (P = 0.01). The LCN 2 concentrations decreased in omega-3 group, but the changes were not statistically significant. Omega-3 supplementation had no noticeable effect on anthropometric factors. These findings provide a rationale for omega-3 supplements aimed at lowering serum RBP 4 levels in T2DM.

Oxidative stress in reproductive system leads to sperm DNA damage and sperm membrane lipid peroxidation and may play an important role in the pathogenesis of male infertility, especially in idiopathic cases. Antioxidants such as carotenoids function against free radical damages.

The aim of this study was to determine the levels of lycopene, beta-carotene and retinol in serum and their relationship with sperm DNA damage and lipid peroxidation in infertile and normospermic males.

Sixty two infertile men and 71 normospermic men participated in this study. Blood and semen samples were collected from all subjects. Sperm DNA damage was measured using TUNEL method. Carotenoids, retinol, and malonedildehyde in serum were also determined.

DNA fragmentation was higher in infertile group comparing to control group. Serum levels of lycopene, beta-carotene and, vitamin A in infertile men were significantly lower than normospermic men (p< 0.001, =0.005, and =0.003 respectively). While serum MDA was not significantly different between two groups, MDA in seminal plasma of infertile men was significantly higher than control group (p< 0.001).

We concluded that lycopene, beta-carotene, and retinol can reduce sperm DNA fragmentation and lipid peroxidation through their antioxidant effect. Therefore the DNA fragmentation assay and determination of antioxidants factors such as lycopene, beta-carotene and retinol, along with sperm analysis can be useful in diagnosis and treatment of men with idiopathic infertility.

One of the major causes of mortality in children younger than 5 years old is acute lower respiratory tract infections (ALRI). ALRI clinical features are cough, tachypnea, fever, coryza, chest retraction, crackles and wheeze. Increased white blood cell count with left shift might happen in pneumonia. C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) might rise in children with respiratory tract infections. Vitamin A deficiency is associated with severe childhood infections. The effect of vitamin A supplementation in childhood pneumonia depends on the prevalence and the level of vitamin A deficiency in the population. Some studies confirmed that retinol levels were significantly higher after recovery from acute pneumonia compared to acute phase. But there were no significant association between serum retinol level and the clinical manifestation.

Vitamin A deficiency is an important dietary deficiency in the world. Thus, the ne cessity of screening for deficient populations is obvious. This paper introduces a fast, cheap and relatively reliable method called “dried blood spot” (DBS) method in screening the deficient populations. The validity of this method for retinol measurement was investigated. The “precision” and “agreement” criteria of the DBS method were assessed. The preci sion was calculated and compared with those of plasma using F-test. The agreement was eva luated using Bland-Altman plot. The imprecision of retinol measurements in dried spots was not significantly different from those of the control (plasma). A good correlation coefficient (r2=0.78) was obtained for dried spots’ retinol measurements versus plasma’s retinol analysis (P < 0.01). Paired t-test showed no significant difference between the DBS and retinol methods on a group level. Imprecision of DBS measurement was acceptable, compared to that of the plasma method. The difference be tween these two methods was not statistically significant on a group level. Application of DBS standard samples, in which a part of the plasma was replaced with the artificial plasma, was shown to be a reliable calibration mean for retinol measurements in DBS samples. Retinol in dried spots was stable for 90 days. Overall, the DBS method provided a precise measurement of retinol, showing results that were comparable with the measurement of retinol in plasma.