The paradox of dipeptidyl peptidase IV inhibition in enterocytic differentiation and epithelial-mesenchymal transition in rat cholestatic sepsis

The Safety and Efficacy of Combining Saxagliptin and Pioglitazone Therapy in Streptozocin-Induced Diabetic Rats

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a chronic progressive disease due to insulin resistance. Oxidative stress complicates the etiology of T2DM. Saxagliptin is a selective dipeptidyl peptidase-4 (DPP-4) inhibitor, while Pioglitazone is a thiazolidinedione insulin sensitizer. This study aimed to assess the effect of Saxagliptin and Pioglitazone monotherapy and combination therapy on the biochemical and biological parameters in streptozotocin (STZ)-induced diabetic rats.

METHODS

The study included thirty-five male albino rats. Diabetes mellitus was induced by intraperitoneal STZ injection (35 mg/kg). For a 1-month duration, rats were divided into five groups. Glucose homeostasis traits, lipid profiles, kidney functions, liver enzymes, and oxidative stress markers were measured. Gene expression of miRNA-29a, phosphoenolpyruvate carboxykinase (PEPCK), phosphoinositide-3-kinase (PI3K), and interleukin 1 beta (IL-1β) was assessed using qRT-PCR.

RESULTS

At a 1-month treatment duration, combination therapy improves oxidative stress markers more than either drug alone. The combination therapy had significantly higher levels of SOD, catalase, and GSH and lower levels of MDA compared to the monotherapy. Additionally, the diabetic group showed a significant increase in the expression levels of miRNA-29a, PEPCK, and IL-1β and a significant decrease in PI3K compared to the normal control group. However, combination therapy of Saxagliptin and Pioglitazone was more effective than either Saxagliptin or Pioglitazone alone in reversing these results, especially for PEPCK and IL-1β.

CONCLUSIONS

Our findings revealed that combining Saxagliptin and Pioglitazone improves glycemic control and genetic and epigenetic expression profiles, which play an essential regulatory role in normal metabolism.

Liraglutide limits the immunogenic cell death-mediated ROS propagation and PI3K/AKT inactivation after doxorubicin-induced gonadotoxicity in rats: Involvement of the canonical Hedgehog trajectory

Chemotherapy-accompanied reproductive dysfunction has lately begun to draw the attention of the scientific community owing to the irreversible impact on the patient's quality of life. Here we tended to investigate the potential role of liraglutide (LRG) in modulating the canonical Hedgehog (Hh) signaling in doxorubicin (DXR)-induced gonadotoxicity in rats. Female virgin Wistar rats were divided into 4 groups; control, DXR-treated (25 mg/kg, single i.p. injection), LRG-treated (150 μg/Kg/day, s.c) and itraconazole (ITC; 150 mg/kg/day, p.o)-pretreated group, as the Hh pathway inhibitor. Treatment with LRG potentiated the PI3K/AKT/p-GSK3β cascade and relieved the oxidative burden-induced by the DXR-driven immunogenic cell death (ICD). LRG also upregulated the expression of the Desert hedgehog ligand (DHh) and the patched-1 (PTCH1) receptor and augmented the protein level of Indian hedgehog (IHh) ligand, Gli1 and cyclin-D1 (CD1). Besides, hypertranscription of IHh, DHh, Ptch1, Smo, Gli1/2 and CD1 genes along with a transcriptional recession of Gli3 gene were reported in LRG-treated group. ITC pre-administration partially abrogated this positive effect of LRG, proving the implication of the examined pathway. Microscopically, LRG ameliorated the follicular atresia noticed in the DXR group; effect that was, at least partially, declined by ITC pre-treatment. These findings end to a conclusion that LRG treatment might hinder the DXR-associated reproductive toxicity, resultant from ROS generated by the cells undergoing ICD, and trigger follicular growth and repair by the PI3K/AKT- dependent switching-on of the canonical Hh pathway.

Application of glucagon-like peptide-1 receptor antagonists in fibrotic diseases

Fibrosis can occur in various organs, leading to structural destruction, dysfunction, and even organ failure. Hence, organ fibrosis is being actively researched worldwide. Glucagon-like peptide-1 (GLP-1), a naturally occurring hormone, binds to a G-protein-coupled receptor widely distributed in the pancreas, kidney, lung, heart, gastrointestinal tract, and other organs. Synthetic GLP-1 analogs can be used as GLP-1 receptor agonists (GLP-1RAs) for treating diabetes mellitus. In recent years, GLP-1RAs have also been found to exert anti-inflammatory, antioxidant, and cardiovascular protective effects. GLP-1RAs have also been shown to inhibit fibrosis of solid organs, such as the lung, heart, liver, and kidney. In this review, we discuss the advancements in research on the role of GLP-1RAs in the fibrosis of the heart, lung, liver, kidney, and other organs to obtain new clues for treating organ fibrosis.

Rifaximin protects SH-SY5Y neuronal cells from iron overload-induced cytotoxicity via inhibiting STAT3/NF-κB signaling

Acute or chronic liver disease-caused liver failure is the cause of hepatic encephalopathy (HE), characterized by neuropsychiatric manifestations. Liver diseases potentially lead to peripheral iron metabolism dysfunction and surges of iron concentration in the brain, contributing to the pathophysiological process of degenerative disorders of the central nervous system. In this study, the mechanism of rifaximin treating hepatic encephalopathy was investigated. Ferric ammonium citrate (FAC)-induced iron overload significantly reduced the proliferation and boosted the apoptosis in SH-SY5Y cells through increasing reactive oxygen species (ROS) levels and inducing iron metabolism disorder. Rifaximin treatment could rectify the FAC-induced iron overload and lipopolysaccharide (LPS)-induced iron deposition, therefore effectively protecting SH-SY5Y cells from ROS-induced cell injury and apoptosis. Signal transducer and activator of transcription 3 (STAT3)/nuclear factor-kappaB (NF-κB) signaling is involved in the protective function of rifaximin against LPS-induced iron deposition. The therapeutic effect of rifaximin on HE associated with acute hepatic failure in mouse model was ascertained. In conclusion, Rifaximin could effectively protect SH-SY5Y cells against injury caused by iron overload through the rectification of the iron metabolism disorder via the STAT3/NF-κB signaling pathway. This article is protected by copyright. All rights reserved.

Recombinant human growth hormone improves the immune status of rats with septic encephalopathy: The role of VEGFR2 in the prevalence of endoplasmic reticulum stress repair module

Septic encephalopathy results from the intense reaction of the immune system to infection. The role of growth hormone (GH) signaling in maintaining brain function is well established; however, the involvement of the vascular endothelial growth factor receptor-2 (VEGFR2) in the potential modulatory effect of GH on septic encephalopathy-associated endoplasmic reticulum stress (ERS) and blood-brain barrier (BBB) permeability is not well-understood. Therefore, after the induction of mid-grade sepsis by cecal ligation/perforation, rats were subcutaneously injected with recombinant human GH (rhGH)/somatropin alone or preceded by the VEGFR2 antagonist WAG-4S for 7 days. rhGH/somatropin reduced bodyweight loss and plasma endotoxin, maintained the hyperthermic state, and improved motor/memory functions. Additionally, rhGH/somatropin increased the junctional E-cadherin and β-catenin pool in the cerebral cortex to enhance the BBB competency, effects that were abolished by VEGFR2 blockade. Also, it activated cortical VEGFR2/mammalian target of the Rapamycin (mTOR) axis to mitigate ERS. The latter was reflected by the deactivation of the inositol-requiring enzyme-1α (IRE1α)/spliced X-box binding protein-1 (XBP1s) trajectory and the reduction in the protein levels of the death markers, C/EBP homologous protein (CHOP)/growth arrest and DNA damage-153 (GADD153), c-jun-N-terminal kinase (JNK), and caspase-3 with the simultaneous augmentation of expression of the unfolded protein response transducer proteinkinaseR-like ERkinase (PERK). Furthermore, rhGH/somatropin suppressed the phosphorylation of eukaryotic initiation factor-2α (eIF2α), upregulated the gene expression of activating transcription factor-4 (ATF4), GADD34, and glucose-regulated protein-78/binding immunoglobulin (GRP78/Bip). Moreover, it increased the glutathione level and reduced lipid peroxidation in the cerebral cortex. The VEGFR2 antagonist reversed the effect of rhGH/somatropin on PERK and IRE1α and boosted the apoptotic markers but neither affected p-eIF2α nor GADD34. Hence, we conclude that VEGFR2 activation by rhGH/somatropin plays a crucial role in assembling the BBB adherens junctions via its antioxidant capacity, ERS relief, and reducing endotoxemia in septic encephalopathy.

GLP-1 Analog Liraglutide Improves Vascular Function in Polymicrobial Sepsis by Reduction of Oxidative Stress and Inflammation

Sepsis causes high mortality in the setting of septic shock. LEADER and other trials revealed cardioprotective and anti-inflammatory properties of glucagon-like peptide-1 (GLP-1) analogs like liraglutide (Lira). We previously demonstrated improved survival in lipopolysaccharide (LPS)-induced endotoxemia by inhibition of GLP-1 degradation. Here we investigate the effects of Lira in the polymicrobial sepsis model of cecal ligation and puncture (CLP). C57BL/6J mice were intraperitoneally injected with Lira (200 µg/kg/d; 3 days) and sepsis induced by CLP after one day of GLP-1 analog treatment. Survival and body temperature were monitored. Aortic vascular function (isometric tension recording), protein expression (immunohistochemistry and dot blot) and gene expression (qRT-PCR) were determined. Endothelium-dependent relaxation in the aorta was impaired by CLP and correlated with markers of inflammation (e.g., interleukin 6 and inducible nitric oxide synthase) and oxidative stress (e.g., 3-nitrotyrosine) was higher in septic mice, all of which was almost completely normalized by Lira therapy. We demonstrate that the GLP-1 analog Lira ameliorates sepsis-induced endothelial dysfunction by the reduction of vascular inflammation and oxidative stress. Accordingly, the findings suggest that the antioxidant and anti-inflammatory effects of GLP-1 analogs may be a valuable tool to protect the cardiovascular system from dysbalanced inflammation in polymicrobial sepsis.