The proton pump inhibitor lansoprazole improves the skeletal phenotype in dystrophin deficient mdx mice

Revaprazan prevented indomethacin-induced intestinal damages by enhancing tight junction related mechanisms

Non-steroidal anti-inflammatory drugs (NSAIDs) are the most commonly prescribed medications for alleviating pain and inflammation but may cause gastrointestinal tract damage. Proton pump inhibitors (PPI) prevent NSAID-induced gastric damage but may aggravate intestinal damage via dysbiosis and intestinal permeability alteration. Currently, there is growing interest regarding the influence of potassium competitive acid blockers (PCAB) on NSAID-induced enteropathy. Here, we investigated the relative changes in indomethacin-induced enteropathy by combining indomethacin with pantoprazole (as PPI) or revaprazan (as PCAB). We examined intestinal permeability-related molecular changes in in vitro Caco-2 cell models and in an in vivo indomethacin-induced enteropathy rat model. Indomethacin alone or in combination with pantoprazole significantly increased relative lucifer yellow dye flux and decreased relative trans-epithelial electrical resistance and tight junction protein (TJP) expression compare to normal cells. In contrast, indomethacin combined with revaprazan significantly preserved TJPs compare to indomethacin-treated cells. MLC phosphorylation, Rho activation, and ERK activation responsible for TJP were significantly increased by indomethacin alone or a combination of indomethacin and pantoprazole but not by a combination of indomethacin and revaprazan. Intestinal damage scores significantly increased with indomethacin and pantoprazole combination but not with indomethacin and revaprazan combination. Indomethacin and pantoprazole combination significantly activated Rho-GTPase, p-MLC, and p-ERK but significantly decreased TJP expression. However, indomethacin and revaprazan combination significantly preserved TJPs and inactivated Rho-GTPase, MLC, and ERK. Hence, revaprazan rather than PPIs should be co-administered with NSAIDs to mitigate NSAID-induced intestinal damage.

Autophagy blockade mechanistically links proton pump inhibitors to worsened diabetic nephropathy and aborts the renoprotection of metformin/enalapril

AIM

Proton pump inhibitors (PPIs) are widely used drugs recently linked to chronic kidney disease. However, the invloved mechanisms remained elusive. Since defective autophagy is identified as a new culprit in the pathogenesis of diabetic nephropathy (DN), we aimed to trace the link of autophagy blockade by PPIs to the progression of DN with and without the standard therapy of metformin and enalapril.

MAIN METHODS

Male CD1 albino mice (20-25 g) were randomly assigned to normal control or diabetic mice. Diabetes was induced by intraperitoneal streptozotocin (35 mg/kg) injection combined with high fat diet. DN mice were randomized to receive vehicle, lansoprazole (5 mg/kg), metformin (200 mg/kg), lansoprazole + metformin, metformin + enalapril (0.5 mg/kg) or the three drugs together, orally daily for four weeks. At the study end, albuminuria, fasting plasma glucose, HbA1c, renal functions and malondialdehyde were assessed. Renal tissues were examined microscopically, and autophagic changes were evaluated by immunohistochemical detection of LC3-II and p62.

KEY FINDINGS

Consistent with autophagic blockade, lansoprazole increased both LC3II and p62 in the glomerular and tubular cells. This was associated with impaired creatinine clearance and renal functions, enhanced albuminuria, oxidative stress and augmented DN histopathological changes. Opposite effects on autophagy markers were observed by single or combined treatment of metformin with enalapril; which also ameliorated glycemic control and signs of DN. This improvement was mitigated by combination with lansoprazole.

SIGNIFICANCE

Autophagy blockade by lansoprazole augmented diabetic nephropathy and opposed the reno-protective effects of metformin and enalapril. The use of PPIs in diabetes should be considered with great caution.

Treatment with human immunoglobulin G improves the early disease course in a mouse model of Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a severe hereditary myopathy. Standard treatment by glucocorticosteroids is limited because of numerous side effects. The aim of this study was to test immunomodulation by human immunoglobulin G (IgG) as treatment in the experimental mouse model (mdx) of DMD. 2 g/kg human IgG compared to human albumin was injected intraperitoneally in mdx mice at the age of 3 and 7 weeks. Advanced voluntary wheel running parameters were recorded continuously. At the age of 11 weeks, animals were killed so that blood, diaphragm, and lower limb muscles could be removed for quantitative PCR, histological analysis and ex vivo muscle contraction tests. IgG compared to albumin significantly improved the voluntary running performance and reduced muscle fatigability in an ex vivo muscle contraction test. Upon IgG treatment, serum creatine kinase values were diminished and mRNA expression levels of relevant inflammatory markers were reduced in the diaphragm and limb muscles. Macrophage infiltration and myopathic damage were significantly ameliorated in the quadriceps muscle. Collectively, this study demonstrates that, in the early disease course of mdx mice, human IgG improves the running performance and diminishes myopathic damage and inflammation in the muscle. Therefore, IgG may be a promising approach for treatment of DMD. Two monthly intraperitoneal injections of human immunoglobulin G (IgG) improved the early 11-week disease phase of mdx mice. Voluntary running was improved and serum levels of creatine kinase were diminished. In the skeletal muscle, myopathic damage was ameliorated and key inflammatory markers such as mRNA expression of SPP1 and infiltration by macrophages were reduced. The study suggests that IgG could be explored as a potential treatment option for Duchenne muscular dystrophy and that pre-clinical long-term studies should be helpful.