The antioxidant role of oral administration of garlic oil on renal ischemia-reperfusion injury

Plants with Therapeutic Potential for Ischemic Acute Kidney Injury: A Systematic Review

Acute kidney injury (AKI) is a complex condition which has an intricate pathology mostly involving hemodynamic, inflammatory, and direct toxic effects at the cellular level with high morbidity and mortality ratios. Renal ischemic reperfusion injury (RIRI) is the main factor responsible for AKI, most often observed in different types of shock, kidney transplantation, sepsis, and postoperative procedures. The RIRI-induced AKI is accompanied by increased reactive oxygen species generation together with the activation of various inflammatory pathways. In this context, plant-derived medicines have shown encouraging nephroprotective properties. Evidence provided in this systemic review leads to the conclusion that plant-derived extracts and compounds exhibit nephroprotective action against renal ischemic reperfusion induced-AKI by increasing endogenous antioxidants and decreasing anti-inflammatory cytokines. However, there is no defined biomarker or target which can be used for treating AKI completely. These plant-derived extracts and compounds are only tested in selected transgenic animal models. To develop the results obtained into a therapeutic entity, one should apply them in proper vertebrate multitransgenic animal models prior to further validation in humans.

Hydrogen Sulfide: A Potential Novel Therapy for the Treatment of Ischemia

Hydrogen sulfide (H2S) is a novel signaling molecule most recently found to be of fundamental importance in cellular function as a regulator of apoptosis, inflammation, and perfusion. Mechanisms of endogenous H2S signaling are poorly understood; however, signal transmission is thought to occur via persulfidation at reactive cysteine residues on proteins. Although much has been discovered about how H2S is synthesized in the body, less is known about how it is metabolized. Recent studies have discovered a multitude of different targets for H2S therapy, including those related to protein modification, intracellular signaling, and ion channel depolarization. The most difficult part of studying hydrogen sulfide has been finding a way to accurately and reproducibly measure it. The purpose of this review is to: elaborate on the biosynthesis and catabolism of H2S in the human body, review current knowledge of the mechanisms of action of this gas in relation to ischemic injury, define strategies for physiological measurement of H2S in biological systems, and review potential novel therapies that use H2S for treatment.

Renoprotective effect of a combination of garlic and telmisartan against ischemia/reperfusion-induced kidney injury in obese rats

Obesity enhances the frequency and severity of acute kidney injury (AKI). Telmisartan pre-treatment was used experimentally in the amelioration of ischemia/reperfusion (IR)-induced AKI. However, there is a lack of evidence regarding its beneficial effects on AKI in obese animals. The present study, therefore, aimed to explore the protective effects of garlic and/or telmisartan against renal damage induced by unilateral IR in obese rats. Meloxicam was used as a standard anti-inflammatory agent. Prophylactic oral administration of meloxicam (3 mg kg(-1)), garlic (500 mg kg(-1)) and/or telmisartan (5 and 10 mg kg(-1)) for 4 wk protected against renal function deterioration induced by IR in obese rats. Both doses of telmisartan significantly reduced serum total cholesterol and triacyglycerol levels as well as peri-renal adipocytes size and renal fibrosis. Renal nuclear factor-kappa B immunoreactivity, tumor necrosis factor-alpha content as well as interleukin-10, adiponectin receptor 1 and macrophages (M1, M2) polarization markers (CD11c, CD206) mRNA expressions were down-regulated in ischemic kidney tissues and white adipose tissues around them by all treatments. Moreover, garlic, telmisartan and their combinations significantly suppressed oxidative stress in renal ischemic tissues. Histological picture was also improved by these treatments. Interestingly, the combinations provided a greater protection than their monotherapy in a dose-dependent manner. We suppose that this combination may be a promising prophylactic regimen for managing AKI in case of obesity. Thus, future experimental and clinical large-scale studies are necessary.

Garlic oil polysulfides: H2S- and O2-independent prooxidants in buffer and antioxidants in cells

The health benefits of garlic and other organosulfur-containing foods are well recognized and have been attributed to both prooxidant and antioxidant activities. The effects of garlic are surprisingly similar to those of hydrogen sulfide (H2S), which is also known to be released from garlic under certain conditions. However, recent evidence suggests that polysulfides, not H2S, may be the actual mediator of physiological signaling. In this study, we monitored formation of H2S and polysulfides from garlic oil in buffer and in human embryonic kidney (HEK) 293 cells with fluorescent dyes, 7-azido-4-methylcoumarin and SSP4, respectively and redox activity with two redox indicators redox-sensitive green fluorescent protein (roGFP) and DCF. Our results show that H2S release from garlic oil in buffer requires other low-molecular-weight thiols, such as cysteine (Cys) or glutathione (GSH), whereas polysulfides are readily detected in garlic oil alone. Administration of garlic oil to cells rapidly increases intracellular polysulfide but has minimal effects on H2S unless Cys or GSH are also present in the extracellular medium. We also observed that garlic oil and diallyltrisulfide (DATS) potently oxidized roGFP in buffer but did not affect DCF. This appears to be a direct polysulfide-mediated oxidation that does not require a reactive oxygen species intermediate. Conversely, when applied to cells, garlic oil became a significant intracellular reductant independent of extracellular Cys or GSH. This suggests that intracellular metabolism and further processing of the sulfur moieties are necessary to confer antioxidant properties to garlic oil in vivo.

Hypoxia-pretreated human MSCs attenuate acute kidney injury through enhanced angiogenic and antioxidative capacities

Hypoxia preconditioning has been confirmed as an effective strategy to enhance the therapeutic potentials of mesenchymal stem cells (MSCs), such as for myocardial ischemia. However, whether hypoxia preconditioning would produce beneficial effects on MSC-based renal repair has not been demonstrated. In the study, we aimed to determine the feasibility and efficacy of hypoxia preconditioning to enhance MSC-based therapy of acute kidney injury (AKI). MSCs were isolated from human adipose tissues. The paracrine effects of MSCs under normoxia and hypoxia were determined in vitro. Rats of AKI were induced by kidney I/R surgery and randomly divided into three groups: I/R control receiving PBS injection; MSC group receiving normal MSC injection; hypoMSC group receiving hypoxia-preconditioned MSC injection. It was demonstrated in vitro that paracrine effects of MSCs were significantly enhanced, especially angiogenic factors. Dihydroethidium (DHE) staining showed that antioxidative activities of MSCs were significantly enhanced by hypoxia stimulation. Vascularization, apoptosis, and histological injury were all significantly improved in hypoMSC injected group compared with that in control and MSC injected groups. Finally, the renal function was also significantly improved in hypoMSC injected group compared with that in the other two groups as assessed by the serum creatinine and BUN levels.

Cigarette smoking and hyperglycemia increase renal response to low levels of cadmium in welders: cystatin C as a sensitive marker

The present study was undertaken to investigate the utility of cystatin C (CysC) as an early biomarker of cadmium (Cd)-induced renal injury. The study was carried out on 50 adult male individuals divided into five groups of 10 individuals as follows: control, welders, smoker welders, diabetic welders, and smoker diabetic welders. The results indicated that plasma levels of CysC, creatinine, urea, and uric acid were significantly higher in welders compared to control individuals. In addition, the levels of whole blood Cd, lipid peroxidation, and protein oxidation products as well as erythrocyte osmotic fragility were significantly higher in welders compared to control individuals. In contrast, the levels of plasma albumin and whole blood glutathione were significantly decreased in welders compared to control individuals. The alterations of the measured parameters were enhanced in the presence of smoking and hyperglycemia besides exposure to welding fumes. These results suggest that CysC can be used as a sensitive biomarker of the early stages of Cd-induced renal injury.

The protective effects of pomegranate extracts against renal ischemia-reperfusion injury in male rats

Aim:

To evaluate the possible protective effect of pomegranate extract (PE) on rats following renal ischemia–reperfusion (I/R) injury.

Materials and Methods:

Twenty-four Wistar rats were divided into three groups. Sham group underwent laparotomy then waited for 45 minutes without ischemia. I/R group were subjected to left renal ischemia for 45 minutes followed by 60 minutes of reperfusion. I/R + PE group were subjected to the same renal I/R as the I/R group were also given 225 mg/kg PE peroral 30 minutes prior to the ischemia. Malondialdehyde (MDA), total antioxidant capacity (TAC), total oxidant status (TOS), and oxidative stress index (OSI) were determined on the blood samples and kidney tissues. Histopathological analyses were conducted on the kidney tissues.

Results:

Serum TAC levels were significantly decreased in I/R group when compared with S group (P = 0.001). Serum MDA levels were increased in I/R group; however, it was not statistically significant. In rat kidney tissues, TOS levels and OSI index were significantly increased after I/R injury, while TAC levels were decreased. In I/R + PE group, PE reversed the negative effects of I/R injury. PE pretreatment was effective in decreasing tubular necrosis score.

Conclusion:

PE pretreatment ameliorated the oxidative damage and histopathological changes occurring following renal I/R injury.

Involvement of adenosine and standardization of aqueous extract of garlic (Allium sativum Linn.) on cardioprotective and cardiodepressant properties in ischemic preconditioning and myocardial ischemia-reperfusion induced cardiac injury

The present study investigated the effect of garlic (Allium sativum Linn.) aqueous extracts on ischemic preconditioning and ischemia-reperfusion induced cardiac injury, as well as adenosine involvement in ischemic preconditioning and garlic extract induced cardioprotection. A model of ischemia-reperfusion injury was established using Langendorff apparatus. Aqueous extract of garlic dose was standardized (0.5%, 0.4%, 0.3%, 0.2%, 0.1%, 0.07%, 0.05%, 0.03%, 0.01%), and the 0.05% dose was found to be the most effective. Higher doses (more than 0.05%) were highly toxic, causing arrhythmia and cardiodepression, whereas the lower doses were ineffective. Garlic exaggerated the cardioprotective effect of ischemic preconditioning. The cardioprotective effect of ischemic preconditioning and garlic cardioprotection was significantly attenuated by theophylline (1,000 µmol/L) and 8-SPT (10 mg/kg, i.p.) and expressed by increased myocardial infarct size, increased LDH level, and reduced nitrite and adenosine levels. These findings suggest that adenosine is involved in the pharmacological and molecular mechanism of garlic induced cardioprotection and mediated by the modulation of nitric oxide.

Netrin-1 pretreatment protects rat kidney against ischemia/reperfusion injury via suppression of oxidative stress and neuropeptide Y expression

Netrin-1 has been found to protect kidneys from ischemia/reperfusion injury. In this study, we aimed to address whether the protective effects were mediated through suppression of oxidative stress and neuropeptide Y. Compared to sham-operated animals, animals after ischemia/reperfusion showed marked kidney damage and significantly increased levels of serum creatinine, blood urea nitrogen, malondialdehyde, and neuropeptide Y. Renal myeloperoxidase activity was elevated in animals with ischemia/reperfusion relative to sham-operated animals, whereas renal superoxide dismutase activity was reduced. Netrin-1 pretreatment attenuated ischemia/reperfusion-induced functional and pathological changes in the kidney. Moreover, the ischemia/reperfusion-induced changes in the oxidative stress biomarkers and neuropeptide Y were significantly counteracted by prior administration of netrin-1. Taken together, our data showed that netrin-1 pretreatment prevented renal ischemia/reperfusion injury, at least partially through reduction of oxidative stress and neuropeptide Y expression.

Neuroprotective effects of diallyl sulfide against transient focal cerebral ischemia via anti-apoptosis in rats

OBJECTIVES

Diallyl sulfide (DAS) is the main organosulfur component of garlic and it is known for multiple pharmacological actions. Recent studies have demonstrated that DAS has neuroprotective effects against ischemia/reperfusion injury. While some of the possible mechanisms behind this protection have been explored, its ability to inhibit apoptosis has yet to be fully explained. In the present study, the effects of DAS on focal cerebral ischemia in rats were tested and its anti-apoptotic action was explored.

METHODS

To examine the protective effects of DAS, focal cerebral ischemia/reperfusion was induced in rats by transient middle cerebral artery occlusion for 2 hours followed by reperfusion for 24 hours. The animals received DAS in quantities of 100, 150, and 200 mg/kg (intraperitoneal; every day), for 7 days before transient middle cerebral artery occlusion. The neurological score and infarct volume were measured at 24 hours after the end of reperfusion. Apoptotic cells were counted by terminal dUTP nick end labeling staining and apoptotic mechanisms were studied by fluorescence immunohistochemistry staining and western blot analysis.

RESULTS

For animals with induced ischemia/reperfusion, those pretreated with 200 mg/kg DAS showed an infarct volume (22.36 ± 0.67%) significantly lower than that of the non-treated ischemia/reperfusion group (38.23 ± 0.72%), and the percentage of terminal dUTP nick-end labeling-positive cells (23.46 ± 1.02%) of the DAS-pretreated group was also significantly decreased compared to non-treated (36.41 ± 1.58%). Fluorescence immunohistochemistry staining and western blot analysis indicated that DAS reduced caspase-3 expression and increased Bcl-2 expression.

CONCLUSION

These results suggest that the mechanism by which DAS protects the brain from ischemia/reperfusion injury is related to its anti-apoptotic effects in part.

Garlic extract ameliorates renal and cardiopulmonary injury in the rats with chronic renal failure

Chronic renal failure (CRF) is associated with oxidative stress that promotes production of reactive oxygen species and cytokine release. We aimed to investigate the possible protective and antioxidant effects of aqueous garlic extract (AGE) in a rat model of CRF. Male Sprague-Dawley rats were randomly assigned as either CRF group with 5/6 reduction in the renal mass or sham-operated control group. CRF group received either saline or AGE (250 mg/kg/day/1 mL) orally for 3 weeks. At the end of the 3 weeks, rats were decapitated and trunk blood was collected. Creatinine, blood urea nitrogen (BUN) and lactate dehydrogenase (LDH) activity, and TNF-α and IL-1β levels were measured in the serum samples, while malondialdehyde (MDA), glutathione (GSH) levels, and myeloperoxidase (MPO) activity were determined in the kidney, lung, and heart samples. CRF caused significant decreases in tissue GSH, which were accompanied with significant increases in MDA levels and MPO activities, while the circulating levels of the LDH activity, creatinine, BUN, TNF-α, and IL-1β were elevated. AGE treatment alleviated CRF-induced oxidative changes in the injured tissues, while CRF-induced elevations in the blood levels of the pro-inflammatory cytokines and LDH were reduced. In conclusion, CRF-induced oxidative tissue injury occurs via the activation of pro-inflammatory mediators and by neutrophil infiltration into tissues and that the protective effects of garlic on CRF-induced injury can be attributed to its ability to inhibit neutrophil infiltration and pro-inflammatory mediators. These findings suggest that garlic, as a supplementary to diet, may have a potential therapeutic use in delimitating the systemic oxidant effects of CRF on remote organs.