Efficacy of carvedilol for ischemia/reperfusion-induced oxidative renal injury in rats

Testicular torsion in vivo models: Mechanisms and treatments

BACKGROUND

Testicular torsion is a condition in which a testis rotates around its longitudinal axis and twists the spermatic cord. This in turn results in a significant decrease in blood flow and perfusion of testicular tissue. During Testicular torsion, the testicular tissue is affected by ischemia, heat stress, hypoxia, and oxidative and nitrosative stress. The testicular torsion should be considered an emergency condition and surgical intervention (testicular detorsion ) as the sole treatment option in viable cases involves counter-rotation on twisted testes associated, when possible, to orchipexy, in order to avoid recurrence. Possible testicular detorsion side-effects occur due to reperfusion and endothelial cells injury, microcirculation disturbances, and intense germ cells loss.

OBJECTIVES

To discuss testicular torsion surgery-based methods, different time frames for testicular torsion induction, and the associated pathophysiology by emphasizing cellular and molecular events as well as different therapeutic agent applications for testicular torsion.

MATERIALS AND METHODS

We reviewed all original research and epidemiological papers related to testicular torsion condition.

RESULTS

Testicular torsion causes germ cell necrosis, arrested spermatogenesis, and diminished testosterone levels, with consequent infertility. Among different involved pathophysiological impacts, testicular torsion/detorsion-induced ischemia seems to play the key role by leading the tissue toward other series of events in testis. Numerous studies have used adjuvant antioxidants, calcium channel blockers, anti-inflammatory agents, or vasodilating agents in order to decrease these effects.

DISCUSSION AND CONCLUSION

To the best of our knowledge, no previously conducted study examined therapeutical agents' beneficial effects post clinical I/R condition in humans. Different agents targeting different pathophysiological conditions were used to ameliorate the ischemia/reperfusion-induced condition in animal models, however, none of the administrated agents were tested in human cases. Although considering testicular detorsion surgery is still the golden method to reverse the testicular torsion condition and the surgical approach is undeniable, the evaluated agents with beneficial effects, need to be investigated furthermore in clinical conditions. Thus, furthermore clinical studies and case reports are required to approve the animal models proposed agents' beneficial impacts.

Effect of a Low Dose of Carvedilol on Cyclophosphamide-Induced Urinary Toxicity in Rats—A Comparison with Mesna

One of the major side effects of cyclophosphamide (CPX)—an alkylating anticancer drug that is still clinically used—is urotoxicity with hemorrhagic cystitis. The present study was designed to evaluate the ability of carvedilol to protect rats from cyclophosphamide-induced urotoxicity. Rats were injected intraperitoneally (i.p.) with CPX (200 mg/kg) and administered carvedilol (2 mg/kg) intragastrically a day before, at the day and a day after a single i.p. injection of CPX, with or without mesna (40, 80, and 80 mg/kg i.p. 20 min before, 4 h and 8 h after CPX administration, respectively). Pretreatment with carvedilol partly prevented the CPX-induced increase in urinary bladder and kidney index, and completely protects from CPX-evoked alterations in serum potassium and creatinine level, but did not prevent histological alterations in the urinary bladder and hematuria. However, carvedilol administration resulted in significant restoration of kidney glutathione (GSH) level and a decrease in kidney interleukin 1β (IL-1β) and plasma asymmetric dimethylarginine (ADMA) concentrations. Not only did mesna improve kidney function, but it also completely reversed histological abnormalities in bladders and prevented hematuria. In most cases, no significant interaction of carvedilol with mesna was observed, although the effect of both drugs together was better than mesna given alone regarding plasma ADMA level and kidney IL-1β concentration. In conclusion, carvedilol did not counteract the injury caused in the urinary bladders but restored kidney function, presumably via its antioxidant and anti-inflammatory properties.

Quercetin and lithium chloride potentiate the protective effects of carvedilol against renal ischemia-reperfusion injury in high-fructose, high-fat diet-fed Swiss albino mice independent of renal lipid signaling

Renal ischemia-reperfusion injury (R-IRI) is the main cause of acute renal failure. Carvedilol has been shown to protect against R-IRI. However, the underlying mechanisms are still not completely clarified. This study aimed to investigate the role of lipid signaling in mediating carvedilol protective effects against R-IRI in insulin-resistant mice by using two different lipid signaling modulators, quercetin and lithium chloride (LiCl). Mice were fed high-fructose, high-fat diet (HFrHFD) for 16 weeks to induce insulin resistance. At the end of feeding period, mice were randomly distributed into five groups; Sham, R-IRI, Carvedilol (20 mg/kg, i.p.), Carvedilol + Quercetin (10 mg/kg, i.p.), Carvedilol + LiCl (200 mg/kg, i.p.). R-IRI was performed by applying 30 min of unilateral renal ischemia followed by one hour of reperfusion. Quercetin and LiCl were administered 30 min before carvedilol administration and carvedilol was administered 30 min before ischemia. Changes in kidney function tests, histopathology, fibrosis area, lipid signaling, inflammatory, apoptosis and oxidative stress markers in the kidney were measured. Results showed that R-IRI decreased kidney function, impaired renal tissue integrity, modulated lipid signaling and increased renal inflammation, apoptosis and oxidative stress. Carvedilol treatment decreased the detrimental effects induced by R-IRI. In addition, pre-injection of both quercetin and LiCl potentiated the reno-protective effects of carvedilol against R-IRI independent of changes in lipid mediators like phosphatidyl inositol 4,5 bisphosphate (PIP2) and diacylglycerol (DAG). In conclusion, quercetin and LiCl potentiate the protective effects of carvedilol against R-IRI in HFrHFD-fed mice by reducing inflammation and oxidative stress independent of lipid signaling.

Medical perspective in testicular ischemia-reperfusion injury

Testicular torsion or torsion of the spermatic cord is one of the most serious urological conditions. It causes testicular injury, which potentially leads to male subfertility. The turning of the spermatic cord and spermatic structures around themselves results in biochemical and histological changes; however, following testicular detorsion, tissues undergo reperfusion that causes more severe damage than that induced by ischemia. Since the primary causes of testicular damage are reactive oxygen species production, an increase in intra-mitochondrial calcium concentration and an increased rate of cellular apoptosis, different medications may potentially be effective. It seems that several medications, experimentally and sometimes clinically, serve an adjuvant role in the cellular damage that occurs following ischemia-reperfusion. Antioxidants, calcium channel blockers, phytotherapeutical medicinals, anaesthetics, hormones and platelet inhibitors may potentially create a solid basis for an adjuvant restoring therapy and ameliorate testicular function following torsion. The current study aimed to review the relevant literature and discuss the actions of a number of molecules that may protect the testes during ischemia/reperfusion injury.

Addition of N-acetyl cysteine to carvedilol decreases the incidence of acute renal injury after cardiac surgery

BACKGROUND

Oxidative stress and inflammation during cardiac surgery may be associated with acute renal injury (ARI). N-acetyl cysteine (NAC) and carvedilol have antioxidant and anti-inflammatory properties.

HYPOTHESIS

A combination of carvedilol and NAC should decrease the incidence of ARI more than metoprolol or carvedilol.

METHODS

Patients undergoing cardiac surgery were randomized to metoprolol, carvedilol, or carvedilol plus NAC. End points were occurrence of ARI and change in preoperative to postoperative peak creatinine levels.

RESULTS

ARI incidence was lower in the carvedilol plus NAC group compared with the metoprolol (21.0% vs 42.1%; P = 0.002) or carvedilol (21.0% vs 38.6%; P = 0.006) groups, but was similar between the metoprolol and carvedilol groups (P = 0.62). Preoperative and postoperative day 1 creatinine levels were similar among the metoprolol (1.02 [0.9-1.2] and 1.2 [0.92-1.45]) the carvedilol (1.0 [0.88-1.08] and 1.2 [0.9-1.5]) and the carvedilol plus NAC groups (1.06 [0.9-1.18] and 1.1 [1.0-1.21] mg/dL; all P values >0.05). Postoperative day 3, day 5, and peak creatinine levels were lower in the carvedilol plus NAC group (1.11 [1.0-1.23], 1.14 [1.0-1.25] and 1.15 [1.0-1.25]) as compared with the metoprolol (1.4 [1.3-1.49], 1.3 [1.0-1.54] and 1.3 [1.0-1.54]) or carvedilol groups (1.2 [1.0-1.52], 1.25 [1.0-1.52] and 1.25 [1.0-1.55] mg/dL; all P values <0.05), but were similar between the metoprolol and carvedilol groups (all P values >0.05).

CONCLUSIONS

Combined carvedilol and NAC decreased ARI incidence as compared with carvedilol or metoprolol. No difference was detected between carvedilol and metoprolol.

The effects of carvedilol on ischemia-reperfusion injury in the rat testis

OBJECTIVE

To analyze the oxidative damage and histopathological alterations caused by ischemia-reperfusion (I/R) injury and ameliorative effects of carvedilol (CVD) in the rat testis.

MATERIALS AND METHODS

Twenty-one male rats were randomized into 3 groups as follows: Group I (n = 7); control (sham) group, Group II (n = 7); I/R group, in which I/R injury was performed by torsing the left testis 720 ° clockwise for 2 hours and detorsing for 2 hours. Group III (n = 7); CVD treatment group; in addition to I/R process, one-dose of CVD was administered (2mg/kg, i.p) 30 min. before detorsion. Levels of antioxidant enzymes, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and levels of malondialdehyde (MDA) and protein carbonyl (PC) were determined in testicular tissues and serum of rats. Testicular tissues were also examined histopathologically and Johnsen scores were determined.

RESULTS

Activities of SOD and GSH-Px in serum and testicular tissues were increased by I/R, but administration of CVD decreased these levels (p < 0.001 and p = 0.001). Significantly increased MDA levels in serum and testicular tissues were decreased by CVD treatment (p < 0.001 and p = 0.001). Concerning PC levels in serum and testicular tissues, there was no statistically significant difference between the groups (p = 0.989 and p = 0.428). There was not a statistically significant difference in terms of mean Johnsen scores between the groups (p = 0.161).

CONCLUSIONS

Administration of CVD decreased oxidative damage biochemically in the rat testis caused by I/R injury, but histopathologically no change was observed betwe¬en all of the groups.

Anticancer drug 2-methoxyestradiol protects against renal ischemia/reperfusion injury by reducing inflammatory cytokines expression

Background. Ischemia/reperfusion (I/R) injury is a major cause of acute renal failure and allograft dysfunction in kidney transplantation. ROS/inflammatory cytokines are involved in I/R injury. 2-Methoxyestradiol (2ME2), an endogenous metabolite of estradiol, inhibits inflammatory cytokine expression and is an antiangiogenic and antitumor agent. We investigated the inhibitory effect of 2ME2 on renal I/R injury and possible molecular actions. Methods. BALB/c mice were intraperitoneally injected with 2ME2 (10 or 20 mg/kg) or vehicle 12 h before and immediately after renal I/R experiments. The kidney weight, renal function, tubular damages, and apoptotic response were examined 24 h after I/R injury. The expression of mRNA of interleukin-1β, tumor necrosis factor- (TNF) α, caspase-3, hypoxia inducible factor- (HIF) 1α, and proapoptotic Bcl-2/adenovirus E1B 19 kDa interacting protein 3 (BNIP3) in kidney tissue was determined using RT-PCR, while the expression of nuclear factor κB (NF-κB), BCL-2, and BCL-xL, activated caspase-9, and HIF-1α was determined using immunoblotting. In vitro, we determined the effect of 2ME2 on reactive oxygen species (ROS) production and cell viability in antimycin-A-treated renal mesangial (RMC) and tubular (NRK52E) cells. Results. Serum creatinine and blood urea nitrogen were significantly higher in mice with renal I/R injury than in sham control and in I/R+2ME2-treated mice. Survival in I/R+2ME2-treated mice was higher than in I/R mice. Histological examination showed that 2ME2 attenuated tubular damage in I/R mice, which was associated with lower expression TNF-α, IL-1β, caspase-9, HIF-1α, and BNIP3 mRNA in kidney tissue. Western blotting showed that 2ME2 treatment substantially decreased the expression of activated caspase-9, NF-κB, and HIF-1α but increased the antiapoptotic proteins BCL-2 and BCL-xL in kidney of I/R injury. In vitro, 2MR2 decreased ROS production and increased cell viability in antimycin-A-treated RMC and NRK52E cells. Conclusions. 2ME2 reduces renal I/R injury in mice because it inhibits the expression of ROS and proinflammatory cytokines and induces antiapoptotic proteins.

Carvedilol protects tubular epithelial cells from ischemia-reperfusion injury by inhibiting oxidative stress

OBJECTIVES

Renal ischemia-reperfusion injury (IRI), leading to acute kidney injury, is a frequent complication with renal transplantation and it is associated with graft function. Its pathogenesis involves ischemia, vascular congestion and reactive oxygen metabolites. Carvedilol is an antihypertensive drug with potent anti-oxidant properties. In this study we investigated the protective effects of carvedilol in a rat renal IRI model.

METHODS

Twenty-four rats were randomized into sham, untreated control and carvedilol (2 mg/kg 30 min before surgery and 12 hr after reperfusion) treatment groups and were subjected to 60 min of left renal ischemia followed by reperfusion at 24, 48, 96 and 168 hr.

RESULTS

Treatment with carvedilol significantly decreased plasma creatinine levels after IRI (up to 168 hr) compared to controls (P < 0.001), suggesting an improvement in renal function. Histopathological analysis revealed decreased IRI-induced damage in kidneys from carvedilol-treated rats. A significant increase in the expression levels of Cu/Zn superoxide dismutase and reduction of 8-hydroxydeoxyguanosine and apoptosis levels (P < 0.005) suggested a protective effect after treatment with carvedilol.

CONCLUSIONS

Our findings suggest that carvedilol ameliorates IRI resulting in improved renal function.

Carvedilol as a potential novel agent for the treatment of Alzheimer's disease

Oligomeric β-amyloid (Aβ) has recently been linked to synaptic plasticity deficits, which play a major role in progressive cognitive decline in Alzheimer's disease (AD). Here we present evidence that chronic oral administration of carvedilol, a nonselective β-adrenergic receptor blocker, significantly attenuates brain oligomeric β-amyloid content and cognitive deterioration in 2 independent AD mouse models. We found that carvedilol treatment significantly improved neuronal transmission, and that this improvement was associated with the maintenance of number of the less stable "learning" thin spines in the brains of AD mice. Our novel observation that carvedilol interferes with the neuropathologic, biochemical, and electrophysiological mechanisms underlying cognitive deterioration in AD supports the potential development of carvedilol as a treatment for AD.

Chick embryo partial ischemia model: a new approach to study ischemia ex vivo

BACKGROUND

Ischemia is a pathophysiological condition due to blockade in blood supply to a specific tissue thus damaging the physiological activity of the tissue. Different in vivo models are presently available to study ischemia in heart and other tissues. However, no ex vivo ischemia model has been available to date for routine ischemia research and for faster screening of anti-ischemia drugs. In the present study, we took the opportunity to develop an ex vivo model of partial ischemia using the vascular bed of 4(th) day incubated chick embryo.

METHODOLOGY/PRINCIPAL FINDINGS

Ischemia was created in chick embryo by ligating the right vitelline artery using sterile surgical suture. Hypoxia inducible factor- 1 alpha (HIF-1alpha), creatine phospho kinase-MB and reactive oxygen species in animal tissues and cells were measured to confirm ischemia in chick embryo. Additionally, ranolazine, N-acetyl cysteine and trimetazidine were administered as an anti-ischemic drug to validate the present model. Results from the present study depicted that blocking blood flow elevates HIF-1alpha, lipid peroxidation, peroxynitrite level in ischemic vessels while ranolazine administration partially attenuates ischemia driven HIF-1alpha expression. Endothelial cell incubated on ischemic blood vessels elucidated a higher level of HIF-1alpha expression with time while ranolazine treatment reduced HIF-1alpha in ischemic cells. Incubation of caprine heart strip on chick embryo ischemia model depicted an elevated creatine phospho kinase-MB activity under ischemic condition while histology of the treated heart sections evoked edema and disruption of myofibril structures.

CONCLUSIONS/SIGNIFICANCE

The present study concluded that chick embryo partial ischemia model can be used as a novel ex vivo model of ischemia. Therefore, the present model can be used parallel with the known in vivo ischemia models in understanding the mechanistic insight of ischemia development and in evaluating the activity of anti-ischemic drug.

Remifentanil, isoflurane, and preconditioning attenuate renal ischemia/reperfusion injury in rats

BACKGROUND

The purpose of this investigation was to examine the effect of isoflurane, remifentanil, and preconditioning in renal ischemia/reperfusion injury (IRI).

METHODS

All 52 male Wistar rats were anesthetized with isoflurane, intubated and mechanically ventilated. The animals were randomly divided into: S group (sham; n = 11) that underwent only right nephrectomy; as well as the I group of right nephrectomy and ischemia for 45 minutes by clamping of left renal artery. (n = 11); the IP (n = 9), the R (n = 10), and the RP (n = 11) groups. In addition, the R and RP animals received remifentanil (2 microg.kg(-1).min(-1)) during the entire experiment. The IP and RP group underwent ischemic preconditioning (IPC = three cycles of 5 minutes). Serum creatinine values were determined before and after IRI, as well as 24 hours later. In addition to an Histological study, cells from the left kidney were evaluated for apoptosis by flow cytometry (FCM).

RESULTS

The Creatinine value of 0.8 +/- 0.2 mg/dl in the S group was significantly lower at 24 hours than the I 3.9 +/- 1.5 mg/dl; IP 2.6 +/- 1.7 mg/dl; R 3.3 +/- 2.8 mg/dl; or RP 1.8 +/- 0.5 mg/dl groups. The RP group value was significantly lower than those of the I, IP, and R groups (p < 0.05). The S group showed less proximal tubular cell damage than the I, IP, R, and RP groups (p < 0.05). The percentages of apoptotic cells (FITC(+)/PI(-)) were: S group = 11.6 +/- 6.5; I = 16.7 +/- 7.3; IP = 37.0 +/- 28.4; R = 11.7 +/- 6.6, and RP = 8.8 +/- 1.5. The difference between the IP vs RP group was significant. Similar percentages of necrotic cells (FITC(+)/PI(+)) and intact cells (FITC(-)/PI(-)) were observed among the groups.

CONCLUSIONS

Ischemic preconditioning showed no protective effect in the isoflurane group (IP) but when isoflurane was administered associated with remifentanil (RP), there was a beneficial effect on the kidney, as demonstrated by flow cytometry and serum creatinine values.

Carvedilol protects against the renal mitochondrial toxicity induced by cisplatin in rats

The clinical use of cisplatin is highly limited by its nephrotoxicity, which has been associated with mitochondrial dysfunction. We investigated the protective effect of carvedilol, an antihypertensive with strong antioxidant properties, against the nephrotoxicity induced by cisplatin in rats. Carvedilol was able to counteract the renal damage by preventing the mitochondrial dysfunction induced by cisplatin. The mitochondrial eletrochemical potential, calcium uptake, respiration and the phosphorylative capacity were preserved by the co-administration of carvedilol. The mechanism of protection probably does not involve alterations in the cellular and sub-cellular distribution of cisplatin. The study suggests that carvedilol is a potential drug for the adjuvant nephroprotective therapy during cisplatin chemotherapy.