Serum X-box-binding protein 1 levels in PCOS patients.

OBJECTIVE: X-box binding protein-1 (XBP1) is a possible indicator of metabolic syndrome and diabetes. This study aimed to evaluate the relationship between serum XBP1 levels and polycystic ovary syndrome (PCOS). METHOD: A prospective observational study was conducted with 88 patients. The first group was defined as the control group with ovulatory and normal-BMI patients (n = 28). The second group comprised of nonobese PCOS patients (n = 30). The third group included overweight/obese patients with PCOS (n = 30). Fasting plasma glucose, serum lipids, follicle stimulating hormone, luteinizing hormone, total testosterone, dehydroepiandrosterone and XBP1 levels l were evaluated in all groups. RESULTS: There was a significant difference in XBP1 levels between the study groups, and higher levels were observed both in the nonobese and obese PCOS groups than in the healthy controls (p < .001). The median level of XBP1 was 73.7 pg/ml in the control group, 114.11 pg/ml in the nonobese PCOS group, and 151.61 pg/ml in the overweight/obese PCOS group. A cutoff level of XBP1 at 95.79 pg/ml level was determined with a significant AUC (area under the curve) level of 99% and high specificity and sensitivity rates to predict PCOS. Also, a significant positive correlation was observed between XBP1 levels and BMI, waist circumference, fasting plasma glucose and triglyceride levels (p < .05). CONCLUSIONS: XBP1 levels were significantly higher in PCOS patients, particularly in overweight/obese PCOS patients, than in the controls. Also, the parameters associated with metabolic syndrome were related to XBP1 levels.

Effect of vitamin B12 supplementation on retinal lesions in diabetic rats.

Purpose: Diabetic retinopathy (DR) is the most common complication of diabetes involving microvasculature and neuronal alterations in the retina. Previously, we reported that vitamin B12 deficiency could be an independent risk factor for DR in humans. However, the effect of vitamin B12 supplementation in experimental DR is unknown. Thus, in this study, we investigated the impact of dietary supplementation of vitamin B12 on retinal changes in diabetic rats. Methods: Diabetes was induced in 2-month-old Sprague-Dawley rats and maintained for 4 months. One group of diabetic rats were fed normal levels of vitamin B12, and one group double the quantity of vitamin B12 (50 µg/kg diet). Vitamin B12 and homocysteine levels in the plasma were analyzed with radioimmunoassay (RIA) and high-performance liquid chromatography (HPLC), respectively. At the end of 4 months of experimentation, the eyeballs were collected. Retinal changes were analyzed with hematoxylin and eosin (H&E) staining, immunoblotting, and immunofluorescence methods. Results: Dietary supplementation of vitamin B12 had no effect on food intake, bodyweight, fasting blood glucose, and plasma homocysteine levels in the diabetic rats. However, vitamin B12 supplementation prevented loss of rhodopsin, and overexpression of VEGF, and completely prevented overexpression of HIF1α, GFAP, and endoplasmic reticulum (ER) stress markers (GRP78, ATF6α, XBP1, CHOP, and caspase 12) in the diabetic rat retina. Further, vitamin B12 ameliorated apoptosis in the retina as shown with terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) and prevented retinal thinning. Conclusions: Vitamin B12 supplementation of diabetic rats appeared to be beneficial by circumventing retinal hypoxia, VEGF overexpression, and ER stress-mediated cell death in the retina. The present study adds another potential therapeutic strategy of vitamin B12 in diabetes.

Endoplasmic reticulum stress in bipolar disorder? - BiP and CHOP gene expression- and XBP1 splicing analysis in peripheral blood.

BACKGROUND: Endoplasmic Reticulum stress activates the Unfolded Protein Response, which is partially impaired in Bipolar Disorder (BD) according to previous in-vitro studies. Thus, BiP and CHOP gene expression and XBP1 splicing were analyzed in peripheral blood of study participants with BD and controls. METHODS: RNA was isolated from fasting blood of study participants with BD (n = 81) and controls (n = 54) and reverse transcribed into cDNA. BiP and CHOP gene expression was analyzed with quantitative RT-PCR. Atypical splicing of XBP1 mRNA was measured by semi-quantitative RT-PCR, gel-electrophoresis and densitometry. ANCOVAs with the covariates age, BMI, sex, lithium and anticonvulsants intake were used with SPSS. Bonferroni correction was used to correct for multiple testing (adjusted p = 0.0083). RESULTS: BiP gene expression was significantly higher in BD than in controls (F(1/128) = 10.076, p = 0.002, Partial η2 = 0.073). Total XBP1 (F(1/126) = 9.550, p = 0.002, Partial η2 = 0.070) and unspliced XBP1 (F(1/128)= 8.803, p= 0.004, Patial η2 = 0.065) were significantly decreased in BD. Spliced XBP1 (F(1/126) = 5.848, p = 0.017, Partial η2 = 0.044) and the ratio spliced XBP1/ unspliced XBP1 did not differ between BD and controls (F(1/126) = 0.599, p = 0.441, Partial η2 = 0.005). Gene expression did not differ between euthymia, depression and mania. DISCUSSION: BiP gene expression was significantly higher in BD compared to controls. Total and unspliced XBP1 were significantly lower in BD than in the control group. Thus, both genes may be considered as putative trait markers. Nevertheless, XBP1 splicing itself did not differ between both groups.

Stress kinases, endoplasmic reticulum stress, and Alzheimer's disease related markers in peripheral blood mononuclear cells from subjects with increased body weight.

We aimed to characterize endoplasmic reticulum stress, inflammation, and Alzheimer's disease (AD) related markers in peripheral blood mononuclear cells (PBMCs) from males with varied BMI; and to explore whether high glucose and fatty acids (FFAs) might be critical factors for inducing metabolic alterations in PBMCs under obese condition. Approximately 45 middle-aged men were enrolled with varied BMI. At the protein expression level, compared to the lean, the phosphorylation of AMPK, and p-Akt at serine 473 were significantly reduced from the overweight (OW) and/or obese (OB); while the protein expression of p-JNK, cleaved caspase 3, CHOP and p-eIF2α were elevated from the OW and/or OB. At the mRNA expression level, ER stress markers (i.e. GRP78, CHOP and XBP-1), inflammatory markers (i.e.TLR2, TLR4 and CCR2) and AD markers (i.e. APP, PS1 and PS2) were significantly higher in PBMCs from OB compared to lean. In cultured PBMCs, high glucose and FFAs induced GRP78, CHOP and XBP-1 mRNA, and high glucose also induced APP, PS1 and PS2 mRNA. In conclusion, altered markers including AMPK, ER stress and AD related makers under obese condition could be easily obtained from PBMCs. These markers might provide new mechanistic links between obesity and other metabolic complications including AD.