Mehmet Alkanat

Anti‐apoptotic and anti‐oxidant effects of grape seed proanthocyanidin extract in preventing cyclosporine A‐induced nephropathy

Aim:  Although the pathogenesis of cyclosporine (CsA) nephropathy is not completely understood, it is attributed to oxidative damage and apoptosis. Grape seed proanthocyanidin extract (GSPE) is a molecule with anti‐oxidant and anti‐apoptotic properties. Our aim was to demonstrate the effects of GSPE in preventing CsA nephropathy.

How Does Colistin-Induced Nephropathy Develop and Can It Be Treated?

ABSTRACT Colistin is an old antibiotic used in the treatment of Gram-negative infections. It was once suspended because of its nephrotoxic effect but has since been reintroduced due to multidrug-resistant bacterial infections. The pathogenesis of colistin-associated nephropathy has not been clarified, and there is currently no effective therapeutic or prophylactic agent available. The aim of this study was to investigate the roles of caspase-associated apoptosis and caspase 1, calpain 1, inducible nitric oxide synthase (iNOS), and endothelial nitric oxide synthase (eNOS) expression in the pathogenesis of colistin-associated nephrotoxicity and the effect of grape seed proanthocyanidin extract (GSPE) in preventing it. Twenty-four rats were divided into three groups: control, colistin, and colistin plus GSPE (colistin+GSPE). Colistin-associated nephropathy was induced by the administration of 300,000 IU/kg of body weight/day colistin intraperitoneally for 7 days. The experiment was discontinued on the seventh day. Blood was collected for measurements of blood urea nitrogen (BUN) and creatinine levels. Histopathological examination of kidney tissue and caspase 1 and 3, iNOS, eNOS, terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL), and calpain 1 staining was also performed. Significant increases in BUN levels; creatinine levels; renal histopathological scores; and TUNEL, caspase 1 and 3, calpain 1, iNOS, and eNOS staining were observed for the colistin group compared to the control group. Significant decreases in BUN levels; creatinine levels; renal histopathological scores; and TUNEL, caspase 1 and 3, calpain 1, iNOS, and eNOS staining were observed in the colistin+GSPE group compared to the colistin group. Our study shows, for the first time in the literature, that caspase-mediated apoptosis, iNOS, caspase 1, and calpain 1 are involved in the pathogenesis of colistin-associated nephropathy. GSPE had a renoprotective effect, as shown by the lowered levels of these mediators.

Protective Effect of the Grape Seed Proanthocyanidin Extract in a Rat Model of Contrast-Induced Nephropathy

Aim: Contrast-induced nephropathy (CIN) is a common cause of hospital-acquired acute renal failure. Although it is so common, there has been no approved therapy yet. We aimed to investigate the effect of grape seed proanthocyanidin extract (GSPE) on preventing CIN. Materials and Methods: 24 rats were divided into four groups as control group, GSPE group, contrast medium (CM) group, and CM+GSPE group. The experiment was discontinued on the ninth day. Blood samples were obtained for the measurement of renal function parameters. Renal tissues of the rats were removed for the analysis of oxidative system parameters. In addition to renal histopathology, transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) was performed to determine apoptosis. Results: There was a significant increase in BUN, creatinine, malondialdehyde (MDA) levels, apoptotic index (AI) and histopathological alteration in the CM group as compared to the control group. Furthermore, BUN, creatinine, MDA, total oxidant system and oxidative stress index levels, AI as well as renal histopathological alteration were significantly decreased in the CM+GSPE group. Conclusion: For the first time in the literature, we showed that GSPE provided biochemical and histopathological improvement in CIN. Our findings revealed that this improvement was associated with the decrease in oxidative damage and apoptosis.

Antiapoptotic and Antioxidant Effects of GSPE in Preventing Cyclosporine A-Induced Cardiotoxicity

Objectives: Cyclosporine A (CsA) is an immunosuppressive drug, but cardiotoxicity is one of its side effects. Free oxygen radical damage and apoptosis are considered to be responsible for CsA-induced cardiotoxicity. Grape seed proanthocyanidin extract (GSPE) displays antioxidant and antiapoptotic activities. Therefore, we aimed to evaluate the effect of GSPE on CsA-induced cardiotoxicity. Materials and methods: Twenty-four rats were divided into four groups, with six rats in each group. CsA-induced nephropathy was induced by administration of 25 mg/kg CsA. The experiment was discontinued on day 21, and total oxidant system (TOS), total antioxidant system (TAS), oxidative stress index (OSI), and malondialdehyde (MDA) were measured in order to evaluate oxidative damage to the heart tissue. In addition to cardiac histopathology, transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) was performed to determine apoptosis. Results: The CsA group showed a significant increase in TOS, OSI, MDA, cardiac histopathological score, and apoptotic index (AI); in the CsA + GSPE group, OSI, MDA, cardiac histopathological score, and AI decreased significantly, and TAS levels showed a significant increase. Conclusion: In this study, we demonstrated for the first time in the literature that GSPE prevents CsA cardiotoxicity and that this effect can be achieved by antiapoptotic and antioxidant activities

The effect of grape seed proanthocyanidin extract in preventing amikacin-induced nephropathy.

Background/Aims: Nephrotoxicity induced by aminoglycosides (AGs) limits their clinical use. As yet, no molecules have been approved to prevent AG nephropathy. We aim to investigate the effectiveness of grape seed proanthocyanidin extract (GSPE) in the prevention of amikacin (AK)-induced nephrotoxicity. Methods: A total of 24 rats were allocated into control, GSPE, AK, and AK + GSPE groups. While 1 mL saline was administered for 6 days in control and AK groups, 100 mg/kg GSPE was administered in GSPE and AK + GSPE groups. On day 7, intraperitoneal (i.p.) saline was administered in control and GSPE groups, while 1.2 g/kg i.p. AK was administered in AK and AK + GSPE groups. The experiment was terminated on day 9. Blood samples were taken for the measurement of renal functions. Renal tissues of the rats were removed for the analysis of malondialdehyde (MDA), total oxidant system (TOS), total antioxidant system, oxidative stress index (OSI), and for histopathological examination. Results: MDA level was found to be lower in GSPE group compared with other study groups. There was significantly more renal histopathological damage and higher blood urea nitrogen, creatinine, TOS, OSI, and MDA levels in the AK group compared with the control and AK + GSPE groups. The same parameters showed significant improvement in AK + GSPE group compared with AK group. Conclusion: Our findings demonstrate for the first time that GSPE reduces oxidative damage in AK nephropathy and provides biochemical and renal histopathological improvements.

GSPE is superior to NAC in the prevention of contrast-induced nephropathy: Might this superiority be related to caspase 1 and calpain 1?

AIMS Our study was intended to evaluate the role of inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), caspases 1 and 3 and calpain 1 in the pathogenesis of contrast-induced nephropathy (CIN) and to compare the protective effects of N acetyl cysteine (NAC) and grape seed proanthocyanidin extract (GSPE) against the development of CIN. MAIN METHODS 32 rats were divided into four groups; control, contrast media (CM), CM+NAC and CM+GSPE. CIN was induced by administration of 7 ml/kg diatrizoate. The experiment was discontinued on the ninth day. Blood was collected for blood urea nitrogen (BUN) and creatinine measurement. Rat kidney tissues were removed for histopathological evaluation and the investigation of caspases 1 and 3, iNOS, eNOS, TUNEL and calpain 1. KEY FINDINGS A significant increase in BUN, creatinine, renal histopathological injury, TUNEL, caspases 1, 3, calpain 1, iNOS and eNOS was observed in the CM group compared to the control group. There was amelioration in all these parameters in the CM+GSPE group, while there was no significant amelioration in BUN, creatinine and renal histopathological injury in the CM+NAC group. In addition, calpain 1 staining and creatinine were significantly lower in the CM+GSPE group compared to the CM+NAC group. SIGNIFICANCE Our study showed, for the first time in the literature, that GSPE has a greater renoprotective effect compared with NAC and that this effective protection may be related to decrease in calpain 1 levels.

Perspective on Rhabdomyolysis-Induced Acute Kidney Injury and New Treatment Options

Aim: The purpose of this study was to assess the role of caspase-dependent apoptosis, caspase 1, calpain 1, inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) and the protective effect of grape seed proanthocyanidin extract (GSPE) in the development of rhabdomyolysis-induced acute kidney injury (AKI). Materials and Methods: Twenty-one rats were divided into 3 groups - control, rhabdomyolysis and rhabdomyolysis + GSPE. Rhabdomyolysis was induced in the rhabdomyolysis and rhabdomyolysis + GSPE groups with the injection into both hind limbs of 10 ml/kg hypertonic (50%) glycerol following 24-hour dehydration on the 6th day. The rhabdomyolysis + GSPE group was given GSPE at 100 mg/kg by gavage for 7 days. The experiment was concluded 48 h after glycerol injection. Blood specimens were collected, and kidney tissues were extracted for histopathological examination. Results: We identified an increase in blood urea nitrogen, creatinine, histopathological score, iNOS, caspase 3, caspase 1 and calpain 1 expression in the rhabdomyolysis group compared to the controls and a decrease in eNOS expression. In the rhabdomyolysis + GSPE group, however, there was a decrease in these mediators, together with an increase in eNOS expression. Conclusion: This study shows for the first time in the literature that calpain 1 is involved in the pathogenesis of rhabdomyolysis-induced AKI, and that GSPE may have a renoprotective effect.

The effect of grape seed proanthocyanidin extract in preventing amikacin-induced nephropathy

Background/Aims: Nephrotoxicity induced by aminoglycosides (AGs) limits their clinical use. As yet, no molecules have been approved to prevent AG nephropathy. We aim to investigate the effectiveness of grape seed proanthocyanidin extract (GSPE) in the prevention of amikacin (AK)-induced nephrotoxicity. Methods: A total of 24 rats were allocated into control, GSPE, AK, and AK + GSPE groups. While 1 mL saline was administered for 6 days in control and AK groups, 100 mg/kg GSPE was administered in GSPE and AK + GSPE groups. On day 7, intraperitoneal (i.p.) saline was administered in control and GSPE groups, while 1.2 g/kg i.p. AK was administered in AK and AK + GSPE groups. The experiment was terminated on day 9. Blood samples were taken for the measurement of renal functions. Renal tissues of the rats were removed for the analysis of malondialdehyde (MDA), total oxidant system (TOS), total antioxidant system, oxidative stress index (OSI), and for histopathological examination. Results: MDA level was found to be lower in GSPE group compared with other study groups. There was significantly more renal histopathological damage and higher blood urea nitrogen, creatinine, TOS, OSI, and MDA levels in the AK group compared with the control and AK + GSPE groups. The same parameters showed significant improvement in AK + GSPE group compared with AK group. Conclusion: Our findings demonstrate for the first time that GSPE reduces oxidative damage in AK nephropathy and provides biochemical and renal histopathological improvements.