Abnormal expressions of AGEs, TGF-β1, BDNF and their receptors in diabetic rat colon-Associations with colonic morphometric and biomechanical remodeling

Prevention of colon enlargement by TNF-α antagonist in a streptozotocin-induced diabetic rat model

PURPOSE

We investigated the effect of tumor necrosis factor (TNF)-α antagonist on the structure and function of the streptozotocin-nicotinamide (STZ-NA)-induced diabetic rat colon.

METHODS

Thirty rats were divided into normal control (NC), diabetic control (DC), and diabetic etanercept (DE) groups. The DE group was injected with etanercept twice a week. Blood glucose, body weight, fecal pellet, colonic transit time, and plasma TNF-α were measured. The colon was dissected out, followed by weight and length measurements. Toluidine blue and Verhoeff's staining, immunohistochemistry for TNF-α, RAGE, iNOS, arginase, and western blot for RAGE were performed on the colonic tissue.

RESULTS

Administration of TNF-α antagonist had no significant effect on the body weight and blood glucose level of the diabetic groups. However, the DE group had a shorter and lighter colon and less coarse and less dense collagen fibers in the submucosal layer than the DC group. Weaker immunoreactivity of TNF-α, RAGE, iNOS, and arginase I was observed in colon tissue sections of the DE groups compared with the DC group. Although the etanercept effect on colonic function was not significantly different, the preventive effect size of etanercept on colon remodeling was considerably large, as shown by calculated-Cohen's d>0.8.

CONCLUSIONS

TNF-α signaling in the colonic tissue of diabetic rats has a strong effect on tissue remodeling, leading to colon enlargement. TNF-α antagonists may be beneficial in preventing diabetic-related pathology in the colon in combination with anti-diabetic drugs.

Effect of β-hydroxybutyrate on behavioral alterations, molecular and morphological changes in CNS of multiple sclerosis mouse model

Multiple sclerosis (MS) is a chronic inflammatory and degenerative disease of central nervous system (CNS). Aging is the most significant risk factor for the progression of MS. Dietary modulation (such as ketogenic diet) and caloric restriction, can increase ketone bodies, especially β-hydroxybutyrate (BHB). Increased BHB has been reported to prevent or improve age-related disease. The present studies were performed to understand the therapeutic effect and potential mechanisms of exogenous BHB in cuprizone (CPZ)-induced demyelinating model. In this study, a continuous 35 days CPZ mouse model with or without BHB was established. The changes of behavior function, pathological hallmarks of CPZ, and intracellular signal pathways in mice were detected by Open feld test, Morris water maze, RT-PCR, immuno-histochemistry, and western blot. The results showed that BHB treatment improved behavioral performance, prevented myelin loss, decreased the activation of astrocyte as well as microglia, and up-regulated the neurotrophin brain-derived neurotrophic factor in both the corpus callosum and hippocampus. Meanwhile, BHB treatment increased the number of MCT1+ cells and APC+ oligodendrocytes. Furthermore, the treatment decreased the expression of HDAC3, PARP1, AIF and TRPA1 which is related to oligodendrocyte (OL) apoptosis in the corpus callosum, accompanied by increased expression of TrkB. This leads to an increased density of doublecortin (DCX)+ neuronal precursor cells and mature NeuN+ neuronal cells in the hippocampus. As a result, BHB treatment effectively promotes the generation of PDGF-Ra+ (oligodendrocyte precursor cells, OPCs), Sox2+ cells and GFAP+ (astrocytes), and decreased the production of GFAP+ TRAP1+ cells, and Oligo2+ TRAP1+ cells in the corpus callosum of mouse brain. Thus, our results demonstrate that BHB treatment efficiently supports OPC differentiation and decreases the OLs apoptosis in CPZ-intoxicated mice, partly by down-regulating the expression of TRPA1 and PARP, which is associated with the inhibition of the p38-MAPK/JNK/JUN pathway and the activation of ERK1/2, PI3K/AKT/mTOR signaling, supporting BHB treatment adjunctive nutritional therapy for the treatment of chronic demyelinating diseases, such as multiple sclerosis (MS).

S-methyl cysteine sulfoxide ameliorates duodenal morphological alterations in streptozotocin-induced diabetic rats

Diabetes mellitus (DM) is a metabolic disease associated with several intestinal disorders. S-methyl cysteine sulfoxide (SMCS) ​​is an amino acid present in Allium cepa L with hypoglycemic effects. However, the effects of SMCS on diabetic intestinal changes are unknown. Thus, we aimed to investigate the effects of SMCS on duodenal morphology and immunomodulatory markers in diabetic rats. Twenty-six rats were divided into three groups: control (C), diabetic (D) and diabetic +200 mg/kg SMCS (DSM). DM was induced by intraperitoneal injection of streptozotocin (50 mg/kg). After 30 days, duodenum samples were processed to assess histopathological and stereological alterations in volume, villus length, and immunohistochemical expression of NF-kB, IL-10, BCL-2, and caspase-3. SMCS reduced hyperglycemia and mitigated the increase in total reference volume of the duodenum, the absolute volume of the mucosa, and the length of the intestinal crypts in the DMS group when compared to D. IL-10 immunostaining was reduced in D when compared to C, while NF-kB was increased in D in comparison to the other groups. SMCS ​​supplementation could decrease the NF-kB immunostaining observed in D. Positive staining for BCL-2 and caspase-3 were not statistically different between groups. In summary, SMCS decreased hyperglycemia and mitigated the morphological changes of the duodenum in diabetic animals, and these beneficial effects can be partially explained by NF-kB modulation.

Brain-Derived Neurotrophic Factor, a New Predictor of Coronary Artery Calcification

Brain-derived neurotrophic factor (BDNF) plays a functional role in vascular endothelium homeostasis and the alleviation of atherosclerosis. Matrix gla protein (MGP) and Nε-(1-carboxymethyl)-l-lysine (CML) are both confirmed to be VC predictors. This study investigated the association between BDNF, MGP, CML and coronary artery calcification (CAC). Plasma BDNF, MGP, and CML levels were measured in 274 patients who underwent computed tomography to determine the CAC score (Agatston score). It was found that patients with CAC exhibited lower BDNF and MGP and higher CML levels than those without CAC. Plasma BDNF levels in patients with diabetes or hypertension were lower compared with the control groups. In logistic regression analysis, age, hypertension, BDNF, and MGP were independent predictors of CAC. Plasma BDNF and MGP levels were both correlated with the Agatston score even after adjustment for age, total cholesterol level, triglycerides, low-density lipoprotein level, creatinine clearance rate, and the presence of hypertension and diabetes mellitus. In 167 patients with CAC, circulating BDNF level was inversely associated with CML level and positively related to MGP level. In the receiver operating characteristic analysis for CAC, the areas under the curves for BDNF, MGP, and CML were 0.757, 0.777 and 0.653, respectively. In summary, plasma BDNF levels are associated with the Agatston score, and BDNF further predicts the occurrence of CAC.