Sitagliptin exerts anti-apoptotic effect in nephrotoxicity induced by cisplatin in rats

Sitagliptin alleviates renal steatosis and endoplasmic reticulum stress in high fat diet-induced obese rats by targeting SREBP-1/CD36 signaling pathway

High fat diet (HFD) consumption can cause dysregulation of glucose and lipid metabolism, coupled with increased ectopic lipid deposition in renal tissue leading to steatosis and dysfunction. Sitagliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor clinically used for type II diabetes therapy; however its effect on renal steatosis in obese state is still uncertain. Herein, obesity was induced by feeding male Wistar rats HFD for 18 weeks, thereafter received either drug vehicle, or sitagliptin (10 mg/kg, PO) along with HFD for further 6 weeks and compared with age-matched rats receiving normal chow diet (NCD). After 24 weeks, serum and kidneys were collected for histological and biochemical assessments. Compared to NCD-fed group, HFD-fed rats displayed marked weight gain, increased fat mass, insulin resistance, dyslipidemia, impaired kidney functions and renal histological alterations. Sitagliptin effectively ameliorated obesity and related metabolic perturbations and improved kidney architecture and function. There were increased levels of triglycerides and cluster of differentiation 36 (CD36) in kidneys of obese rats, that were lowered by sitagliptin therapy. Sitagliptin significantly repressed the expression of lipogenesis genes, while up-regulated genes involved in mitochondrial biogenesis and fatty acid oxidation in kidneys of HFD-fed rats. Sitagliptin was found to induce down-regulation of endoplasmic reticulum (ER) stress and apoptotic markers in kidneys of obese rats. These findings together may emphasize a novel concept that sitagliptin can be an effective therapeutic approach for halting obesity-related renal steatosis and CKD.

Cyclosporine-induced kidney damage was halted by sitagliptin and hesperidin via increasing Nrf2 and suppressing TNF-α, NF-κB, and Bax

Cyclosporine A (CsA) is employed for organ transplantation and autoimmune disorders. Nephrotoxicity is a serious side effect that hampers the therapeutic use of CsA. Hesperidin and sitagliptin were investigated for their antioxidant, anti-inflammatory, and tissue-protective properties. We aimed to investigate and compare the possible nephroprotective effects of hesperidin and sitagliptin. Male Wistar rats were utilized for induction of CsA nephrotoxicity (20 mg/kg/day, intraperitoneally for 7 days). Animals were treated with sitagliptin (10 mg/kg/day, orally for 14 days) or hesperidin (200 mg/kg/day, orally for 14 days). Blood urea, serum creatinine, albumin, cystatin-C (CYS-C), myeloperoxidase (MPO), and glucose were measured. The renal malondialdehyde (MDA), glutathione (GSH), catalase, and SOD were estimated. Renal TNF-α protein expression was evaluated. Histopathological examination and immunostaining study of Bax, Nrf-2, and NF-κB were performed. Sitagliptin or hesperidin attenuated CsA-mediated elevations of blood urea, serum creatinine, CYS-C, glucose, renal MDA, and MPO, and preserved the serum albumin, renal catalase, SOD, and GSH. They reduced the expressions of TNF-α, Bax, NF-κB, and pathological kidney damage. Nrf2 expression in the kidney was raised. Hesperidin or sitagliptin could protect the kidney against CsA through the mitigation of oxidative stress, apoptosis, and inflammation. Sitagliptin proved to be more beneficial than hesperidin.

Sitagliptin attenuates neuronal apoptosis via inhibiting the endoplasmic reticulum stress after acute spinal cord injury

Regulation of endoplasmic reticulum stress (ER) stress-induced apoptosis and nerve regeneration is a hopeful way for acute spinal cord injury (SCI). Sitagliptin (Sita) is one of dipeptidyl peptidase-4 (DPP-4) inhibitor, which is beneficial neurons damaged diseases. However, its protective mechanisms of avoiding nerve injury remain unclear. In this study, we further investigated the mechanism of the anti-apoptotic and neuroprotective effects of Sita in promoting locomotor recovery from SCI. In vivo results showed that Sita treatment reduced neural apoptosis caused by SCI. Moreover, Sita effectively attenuated the ER tress and associated apoptosis in rats with SCI. A striking feature was the occurrence of nerve fiber regeneration at the lesion site, which eventually led to significant locomotion recovery. In vitro results showed that the PC12 cell injury model induced by Thapsigargin (TG) also showed similar neuroprotective effects. Overall, sitagliptin showed potent neuroprotective effects by targeting the ER stress-induced apoptosis both in vivo and vitro, thus facilitating the regeneration of the injured spinal cord.

Beneficial effect of trimetazidine on folic acid-induced acute kidney injury in mice: Role of HIF-1α/HO-1

Acute kidney injury (AKI) is a complex syndrome associated with a decrease in renal function and a significant impact on patient outcomes. Injection of folic acid (FA) in mice is used for studying the pathogenesis of AKI. This study investigated the impact of trimetazidine (a metabolic modulator-antianginal drug; TMZ), against FA-induced AKI. AKI was induced by FA (250 mg/kg, ip) in mice. Two doses of TMZ were administered orally for 10 days. Administration of TMZ at a high dose (20 mg/kg) exhibited significant decreases in the renal somatic index (RSI), serum levels of lactate dehydrogenase (LDH), creatinine (Cr), blood urea nitrogen (1), and proteins level in urine. Moreover, TMZ significantly increased creatinine clearance (CCr), serum albumin, urine creatinine, and urine urea levels. This improvement in markers of kidney damage was associated with marked renal antioxidant effects (↓NO and ↓lipid peroxidation, normalized reduced glutathione (GSH) level and superoxide dismutase (SOD) activity, and increased HIF-1α/HO-1 level). Furthermore, TMZ significantly decreased FA-induced expression of MPO and inflammatory cytokine IL-18, TNF-α, and NF-κB p65 subunit. Renal apoptosis, along with apoptotic markers, were enhanced by FA injection and suppressed by TMZ administration (↓Caspase-3, ↓Bax, and ↑Bcl2 expression). Finally, TMZ amended FA-induced histopathological changes in kidneys. By mitigating functional alteration, oxidative stress, and preventing the development of inflammatory and apoptosis signals, TMZ provides dose-dependent defense against FA-induced AKI mainly via stimulation of hypoxia-inducible factor-1 alpha (HIF-1α)/heme oxygenase-1 (HO-1) pathway.

Ameliorative Effects of Gallic Acid on Cisplatin-Induced Nephrotoxicity in Rat Variations of Biochemistry, Histopathology, and Gene Expression

BACKGROUND

Cisplatin is a powerful chemotherapeutic drug mainly used in the treatment of solid tumors. Aggregation of the drug in renal proximal tubule cells causes nephrotoxicity and renal failure. Investigations showed nephrotoxicity as Cisplatin's dose-limiting side effect. One of the Cisplatin toxicity mechanisms is generation of reactive oxygen species, which leads to oxidative stress and renal damage. The purpose of this study was evaluation of the modulating effects of Gallic acid on Cisplatin-induced variations including Caspase-3 and Clusterin expression and histopathological and biochemical parameters in adult male Wistar rats.

METHOD

Rats were kept under standard condition of temperature, light, and humidity. The animals were divided into 4 groups: GpI: control group (received distilled water for 10 days); GpII: Gallic acid (alone) (50 mg/kg bw, once a day for 10 days); GpIII: Cisplatin (alone), single dose (6 mg/kg bw, I.P. on 5th day of study); GpIV: Gallic acid (50 mg/kg bw, once a day for 10 days) and also injected with single dose of Cisplatin (6 mg/kg bw, I.P., on 5th day of study). After 10 days, all rats were anaesthetized and plasma collected to estimate urea, creatinine, and uric acid. The right kidneys were removed for the study of gene expression and biochemical parameters. The left kidneys were used for histopathological studies.

RESULTS

The Cisplatin-induced nephrotoxicity was evident from the elevated levels of creatinine, urea, uric acid, and renal tissue MDA and also decreased levels of SOD, CAT, GPX, and GSH in renal tissue. Administration of Gallic acid significantly modulated nephrotoxicity markers, gene expression variations, and histopathological damage.

CONCLUSION

Outcomes of the present investigation suggest that Gallic acid provides protection against CP-induced nephrotoxicity, but for application in people, further studies are needed.

Impact of Sitagliptin in Non-Diabetic Covid-19 Patients

OBJECTIVE

In Coronavirus disease 2019 (Covid-19), SARS-CoV-2 may use dipeptidyl peptidase 4 (DPP4) as an entry-point in different tissues expressing these receptors. DPP4 inhibitors (DPP4Is), also named gliptins like sitagliptin, have anti-inflammatory and antioxidant effects; thereby lessen inflammatory and oxidative stress in diabetic Covid-19 patients. Therefore, the present study aimed to illustrate the potential beneficial effect of sitagliptin in managing Covid-19 in non-diabetic patients.

METHODS

A total number of 89 patients with Covid-19 were recruited from a single-center at the time of diagnosis. The recruited patients were assigned according to the standard therapy for Covid-19 and our interventional therapy into two groups; Group A: Covid-19 patients on the standard therapy (n=40) and Group B: Covid-19 patients on the standard therapy plus sitagliptin (n=49). The duration of this interventional study was 28 days according to the guideline in management patients with Covid-19. Routine laboratory investigations, serological tests, complete blood count (CBC), C-reactive protein (CRP), D-dimer, lactate dehydrogenase (LDH), and serum ferritin were measured to observed Covid-19 severity and complications. Lung computed tomography (CT) and clinical scores were evaluated.

RESULTS

The present study illustrated that sitagliptin add-on standard therapy improved clinical outcomes, radiological scores, and inflammatory biomarkers than standard therapy alone in non-diabetic patients with Covid-19 (P<0.01).

CONCLUSIONS

Sitagliptin add-on standard therapy in managing non-diabetic Covid-19 patients may have a robust beneficial effect by modulating inflammatory cytokines with subsequent good clinical outcomes.

The protective effect of protocatechuic acid on hepatotoxicity induced by cisplatin in mice

Cisplatin is one of the most potent anti-cancer drugs used for the treatment of various solid tumors, yet it has several side effects that may limit its clinical use. Hepatotoxicity is one of the most serious side effects as it may lead to liver failure. Several mechanisms including oxidative stress, inflammation, and apoptosis have been examined in cisplatin-induced hepatotoxicity. Protocatechuic acid (Proto) which is naturally occurring phenolic acid has shown different biological activity as antioxidant, anti-inflammatory, and anti-apoptotic. In this study, we investigate the protective effect of Proto at two doses 100 and 150 mg/kg on hepatotoxicity induced by a single injection of 10 mg/kg cisplatin in female albino mice. The present study demonstrates for the first time that Proto administration (100 and 150 mg/Kg) significantly attenuates cisplatin-induced changes in liver function [increase serum albumin and decrease liver injury markers ALT, AST, GGT, and bilirubin]. This was associated with marked hepatic antioxidant effects [decrease MDA and NO levels, increase GSH and SOD activity]. Moreover, Proto reduced cisplatin-induced apoptosis in the liver through decreasing caspase-3, annexin-V, and BAX. Both doses suppressed cisplatin-induced expression of iNOS and NF-ᴋB p65 subunit and pro-inflammatory cytokines (IL-6 and TNF-α). Also, Proto improved histopathological examination of the liver. The present findings reveal that the antioxidant, anti-inflammatory, and anti-apoptotic effects of Proto are the main mechanisms by which Proto can ameliorate cisplatin-induced liver injury.

The effects of dipeptidyl peptidase-4 inhibitors on kidney outcomes

AIMS

To summarize evidence from randomized controlled trials (RCTs) concerning the effects of dipeptidyl peptidase-4 (DPP-4) inhibitors on kidney outcomes in patients with type 2 diabetes mellitus (T2DM).

METHODS

The Medline, EMBASE and Cochrane databases were searched for RCTs comparing DPP-4 inhibitors with a placebo, active comparator or standard care, with at least 500 person-years follow-up in patients with T2DM and with reporting of kidney outcomes. Treatment effects were summarized using random-effects meta-analysis.

RESULTS

Ten trials including 47 955 patients (mean estimated glomerular filtration rate [eGFR] 71 mL/min/1.73m² , mean follow-up 10 762 patient-years per trial) were eligible for inclusion. DPP-4 inhibitors were compared with placebo (five trials), active comparator (three trials), and standard care (two trials). Overall, treatment with DPP-4 inhibitors was associated with a greater decline in eGFR than treatment with the comparators (weighted mean difference -1.12 mL/min/1.73m² , 95% confidence interval [CI] -1.61, -0.62; high-certainty evidence). There were no detectable effects of DPP-4 inhibitors on rates of doubling serum creatinine (risk ratio [RR] 1.10, 95% CI 0.90, 1.34; high-certainty evidence), end-stage kidney disease (RR 0.97, 95% CI 0.77, 1.23; high-certainty evidence), death from kidney causes (RR 1.81, 95% CI 0.67, 4.93; low-certainty evidence), or all-cause mortality (RR 1.01, 95% CI 0.95, 1.09; high-certainty evidence). DPP-4 inhibitors significantly reduced the risks of the surrogate kidney outcome of new albuminuria (RR 0.88, 95% CI 0.8, 0.98; moderate-certainty evidence) and worsening albuminuria (RR 0.88, 95% CI 0.82, 0.94; moderate-certainty evidence). There was no difference in the safety outcome of acute kidney injury (RR 1.04, 95% CI 0.57, 1.87; high-certainty evidence).

CONCLUSIONS

Dipeptidyl peptidase-4 inhibitors are associated with a greater decline in eGFR, despite reducing the development and progression of albuminuria, and have no clear effect on other key kidney outcomes.

Vinpocetine attenuates thioacetamide-induced liver fibrosis in rats

Liver fibrosis is associated with increased mortality and morbidity. However, there is not effective treatment so far. Vinpocetine (Vinpo) is a synthetic derivative of vinca alkaloid vincamine. Limited previous reports have shown some beneficial effects of Vinpo in different organ fibrosis, but the ability of Vinpo to inhibit liver fibrosis induced by thioacetamide (TAA) has not been reported, that is why we investigate the potential ability of this vinca alkaloid derivative to attenuate liver fibrosis. Hepatic fibrosis was induced in male Sprague Dawley rats by TAA (200 mg/kg; ip; 3 times/week) for 6 weeks. Daily treatments with Vinpo (10-20 mg/kg/day; orally) ameliorated TAA-induced hepatic oxidative stress and histopathological damage as indicated by a decrease in liver injury markers, LDH, hepatic MDA, and NOx levels, as well as increase anti-oxidative parameters. Besides, the anti-fibrotic efficacy of Vinpo was confirmed by decreasing hydroxyproline, and α-SMA. Also, the anti-inflammatory effect of Vinpo was explored by decreasing IL-6 and TNF-α levels. Our novel findings were that Vinpo decreased VEGF/Ki-67 expression in the liver confirming its effect on angiogenesis and proliferation. These findings reveal the anti-fibrotic effect of Vinpo against TAA-induced liver fibrosis in rats, and suggest the modulation of oxidative stress, inflammation, angiogenesis and proliferation as mechanistic cassette underlines this effect.

Anti-apoptotic effect of vinpocetine on cisplatin-induced hepatotoxicity in mice: The role of Annexin-V, Caspase-3, and Bax

Hepatic damage is one of the most common complications related to cisplatin (Cis) use. Recently, liver protection lines are being discovered to avoid hepatic cell death as a result of oxidative, inflammatory, and apoptotic disturbance. Limited data reported the hepatoprotective effect of vinpocetine (Vin) in acute liver injury models. This study was designed to determine the potential protective effect of Vin (10-30 mg/kg, orally) against Cis-induced liver injury (10 mg/kg, IP) in mice. Vin administration for 1 week before Cis injection until the end of the experiment. On the 6th day after Cis injection, mice were anesthetized, blood and tissue samples were collected. Hepatic function, histological changes, oxidative stress, inflammation, and apoptotic markers were investigated. Vin administration ameliorated liver injury as indicated by decreased liver injury parameters; serum aminotransferases, ALK-P, GGT, and bilirubin, restored the anti-oxidant status by decrease MDA and NO_x , and increased GSH and SOD, inhibited inflammation (IL-6, TNF-α, NFκB-p65, and iNOS) and apoptosis (Annexin-V, Bax, and Caspase-3) parameters. Vin confers dose-dependent protection against Cis-induced liver injury. The hepatoprotective effect of Vin involved anti-oxidative, anti-inflammatory, and anti-apoptotic activities.

Mechanistic perspective of protective effects of nilotinib against cisplatin-induced testicular injury in rats: Role of JNK/caspase-3 signaling inhibition

Cisplatin is an effective anticancer used widely in treatment of solid and germ cell tumors, however, the immense toxicity on healthy tissues discourages cisplatin use in prolonged treatment protocols. Testicular toxicity is amongst its undesired adverse effects. Nilotinib is a second generation multityrosine kinase inhibitor which is used as an anticancer agent with anti-inflammatory and antioxidant activities. In the present study, a single dose of cisplatin (7 mg/kg, I.P) to rats induced a significant testicular injury. Daily administration of nilotinib (20 mg/kg, orally) 24 h post cisplatin injection for 10 days ameliorated testicular damage. Nilotinib significantly increased serum testosterone and sperm concentration outside frame of oligospermia with simultaneous full recovery of sperm viability. Nevertheless, biomarkers of apoptosis such as JNKs and Caspase -3, were significantly reduced. Moreover, improved antioxidant status of the testes was inferred by significant elevation of GSR, SOD and TAC alongside with reduction in lipid peroxidation biomarkers; MDA and 4-HNE. Flow Cytometry analysis of the cell cycle confirmed a significant increase in the percentage of testicular cells present in G2/M phase and a significant decrease in the percentage of apoptotic testicular cells after nilotinib administration. Histopathologically, nilotinib preserved testicular architecture showing significant numbers of sperm and spermatids within lumens of seminiferous tubule. Furthermore, nilotinib enhanced testicular expression of Ki67 significantly, providing evidence of testicular regeneration. In conclusion, nilotinib refinement of cisplatin induced testicular toxicity is attributed to enhancing antioxidant capabilities, decreasing apoptotic signals and restoring regenerative capacity of testes suggesting nilotinib to be used in conjunction with cisplatin in treatment protocols to avoid cisplatin induced long term testicular toxicity.

Biochemical and morphological evaluation of the effects of propolis on cisplatin induced kidney damage in rats

Cisplatin (CP) is a chemotherapeutic agent used to treat various types of cancer; nephrotoxicity is the most common adverse effect of the drug. We investigated the protective effects of propolis against CP induced kidney injury. Thirty-six male rats were divided into six equal groups: untreated control group, 50 mg/kg/day propolis group, 100 mg/kg/day propolis group, single-dose 7 mg/kg CP group, 7 mg/kg CP + 50 mg/kg/day propolis and 7 mg/kg CP + 100 mg/kg propolis. Rats were sacrificed after 14 days and kidneys were removed for histopathological and biochemical analyses. We used hematoxylin & eosin and periodic acid-Schiff staining to evaluate kidney histopathology and we used the TUNEL technique to assess apoptosis. We also measured total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI), ischemia-modified albumin (IMA) and malondialdehyde (MDA) levels in tissue and blood specimens. Normal morphology was observed in the control, 50 mg/kg/day propolis and 100 mg/kg/day propolis groups by light microscopy. Degeneration of tubule cells, edema and tubule dilation were increased in the CP group compared to the control group. Degeneration of tubule cells and dilation of Bowman's spaces were decreased in the CP + 50 mg/kg/day propolis and CP + 100 mg/kg/day propolis groups compared to the CP group. Tubule dilation decreased significantly in the CP + 100 mg/kg propolis group compared to the CP group. Also, the 7 mg/kg CP group exhibited altered proximal tubule epithelial cells, loss of brush border and thickening of the parietal layer of Bowman's capsule in glomeruli and basal laminae of tubules. A normal brush border was observed in the CP + 50 mg/kg/day propolis and CP + 100 mg/kg/day groups. Serum OSI and MDA levels were increased in the CP group compared to the control group. Serum MDA levels decreased significantly in the CP + 50 mg/kg/day propolis and 100 mg/kg CP + propolis groups compared to the CP group. CP caused significant damage to kidney tissue; propolis exhibited dose-dependent prevention of tissue damage.