Mannitol attenuates kidney damage induced by xanthine oxidase-associated pancreas ischemia-reperfusion

Evaluating acetate as a renoprotective agent following kidney ischemia in a porcine model

OBJECTIVE Renoprotection from reperfusion injury appears to be conferred by HIF-2A activation, which can be stimulated by exogenous acetate administration. The study objective was to assess whether administration of acetate in a porcine model can mitigate kidney injury related to ischemia-reperfusion following renal hilar occlusion. METHODS A porcine single-kidney model was created by performing a laparoscopic nephrectomy followed by animal recovery. After seven days, the animals underwent laparoscopic hilar dissection. Block randomization was used to assign pigs into one of four experimental groups. One treatment block of pigs received 150 mEq of sodium acetate intravenously during 90 minutes of en bloc occlusion of the renal hilum (herein noted as 'cross clamping'). Another block received 0.75 g/kg of oral sodium acetate for three days prior to cross clamping. A third block received no acetate and underwent hilar dissection without cross clamping (negative control). The final block received no acetate and underwent cross clamping (positive control). Serum creatinine was used to estimate renal function post-nephrectomy. RESULTS A total of 16 animals (4 pigs in each group), completed the study protocol. Median pig weight was 34.6 kg. One pig receiving IV acetate was excluded from the final analysis due to unrecoverable renal failure following cross-clamping. There was a significantly lower mean serum creatinine for the IV acetate group compared to the positive control group 72 hours after cross clamp (p=0.012). The same effect was not observed for the pigs receiving oral acetate. By day 7, renal function recovered without significant difference in all groups. CONCLUSIONS We observed that the administration of intravenous acetate conferred a significant renoprotective benefit in our single kidney ischemia-reperfusion porcine model 72 hours following hilar occlusion. This work is hypothesis-generating and further work in human subjects undergoing renal hilar occlusion during partial nephrectomy is warrante.

Clinical Significance of Elevated Xanthine Dehydrogenase Levels and Hyperuricemia in Patients with Sepsis

Patient outcomes for severe sepsis and septic shock remain poor. Excessive oxidative stress accelerates organ dysfunction in severe acute illnesses. Uric acid (UA) is the most abundant antioxidant. We hypothesized that UA and related molecules, which play a critical role in antioxidant activity, might be markers of oxidative stress in sepsis. The study aimed to clarify the clinical significance of UA and the relationship between UA, molecules related to UA, and outcomes by measuring blood UA, xanthine dehydrogenase (XDH), and 8-hydroxy-2-deoxyguanosine (8-OHdG) levels over time. Blood UA levels in septic patients were correlated with the SOFA score (ρ = 0.36, p < 0.0001) and blood XDH levels (ρ = 0.27, p < 0.0001). Blood XDH levels were correlated with the SOFA score (ρ = 0.59, p < 0.0001) and blood 8-OHdG levels (ρ = -0.32, p < 0.0001). Blood XDH levels were persistently high in fatal cases. Blood XDH level (OR 8.84, 95% CI: 1.42-91.2, p = 0.018) was an independent factor of poor outcomes. The cutoff of blood XDH level was 1.38 ng/mL (sensitivity 92.8%, specificity 61.9%), and those 1.38 ng/mL or higher were associated with a significantly reduced survival rate (blood XDH level > 1.38 ng/mL: 23.7%, blood XDH level < 1.38 ng/mL: 96.3%, respectively, p = 0.0007). Elevated UA levels due to elevated blood XDH levels in sepsis cases may reduce oxidative stress. Countermeasures against increased oxidative stress in sepsis may provide new therapeutic strategies.

Mannitol for prevention of acute kidney injury after liver transplantation: a randomized controlled trial

BACKGROUND

Acute kidney injury (AKI) is a common complication after liver transplantation, which is associated with increased morbidity and mortality. Therefore, this study investigated mannitol as an oxygen-free radical scavenger and its role in the prevention of early AKI after living donor liver transplantation (LDLT).

METHODS

A total of 84 adult patients who underwent LDLT were randomly assigned to two equal groups: the M group, where patients received 1 g/kg mannitol 20%, or the S group, where patients received an equal volume of saline. The primary outcome was the incidence of early AKI, defined as a 0.3 mg/dl increase in the serum creatinine 48 h postoperatively. Laboratory assessments of the graft and creatinine were recorded until 3 months after transplantation besides the post-reperfusion syndrome and the intraoperative hemodynamic measurements.

RESULTS

The AKI incidence was comparable between groups (relative risk ratio of 1.285, 95% CI 0.598-2.759, P = 0.518). Moreover, AKI stages and serum creatinine 3 months after transplantation, P = 0.23 and P = 0.25, respectively. The incidence of the post-reperfusion syndrome was comparable in both groups, 29/39 (74.4%) and 31/41 (75.6%) in M and S groups, respectively, P = 0.897. The intraoperative hemodynamic parameters showed no significant difference between groups using the area under the curve.

CONCLUSION

The current LDLT recipient sample was insufficient to demonstrate that pre-reperfusion 1 g/kg mannitol infusion would reduce the risk of early AKI or post-reperfusion syndrome.

CLINICAL TRIAL REGISTRATION NUMBER

Pan African Clinical Trials Registry (PACTR202203622900599); https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=21511 .

Intraoperative Intravenous Mannitol Administration Failed to Provide Added Value on Renal Functional Preservation After Partial Nephrectomy in Patients with Chronic Kidney Disease: A Matched Cohort Study

Background: Previous randomized-controlled trials have demonstrated that intraoperative intravenous mannitol administration shows no added value on renal functional preservation after partial nephrectomy (PN) in patients with normal renal function. However, the renoprotective effect of mannitol has not been fully evaluated in patients with preoperative chronic kidney disease (CKD). Materials and Methods: This was a retrospective cohort study with propensity score matching. Patients with a preoperative estimated glomerular filtration rate (eGFR) of <60 mL/minute/1.73 m² undergoing PN were enrolled in the study between January 2012 and December 2019 in Peking University First Hospital. Participants were divided into two groups: patients who received 25 g of mannitol (group M+) or not (group M-). The primary endpoint was the decreased rate of eGFR at the 6-month follow-up. Results: A total of 244 patients were included in the analysis. After propensity score matching, 80 patients remained in each group. The percentage of decrease from baseline eGFR at postoperative 6-month follow-up showed no difference between the two patient groups (median 11.1 [interquartile range 5.3-25.3] in group M+ vs 12.2 [4.7-21.3] in group M-, median difference -0.7 [95% confidence interval -4.6 to 3.1]; p = 0.704). Postoperative acute kidney injury, renal replacement therapy during hospitalization, postoperative complications, incidence of >20% decrease from baseline eGFR at 6 months, and dialysis at 6 months showed no difference between the two patient groups. Conclusions: A 25 g dose of mannitol administration during PN failed to provide added value on renal functional preservation in CKD patients.

Mannitol for the Prevention of Peri-Operative Acute Kidney Injury: A Systematic Review

OBJECTIVE/BACKGROUND

Post-operative acute kidney injury (AKI) is a frequent peri-operative complication that negatively affects morbidity and mortality. Mannitol is frequently used peri-operatively for renal protection, although evidence for its use is ambiguous. A systematic review was conducted to clarify whether there is evidence supporting peri-operative mannitol administration for the prevention of post-operative AKI.

METHODS

A systematic literature search was performed in MEDLINE/Pubmed, Embase, the Cochrane Library, Clinical Trials registry, and the Cochrane Central Register of Controlled Trials (CENTRAL). Eligibility criteria were (i) population (studies involving adult patients undergoing surgery or a related intervention); (ii) intervention (intravenous mannitol administered in either the pre- or intra-operative period with comparison to controls); and (iii) predefined outcomes (post-operative AKI or respective renal end points/surrogates).

RESULTS

In total, 1,538 articles published between January 1990 and October 2018 were identified. After checking for eligibility, 22 studies, including 17 prospective and/or randomised controlled trials and five retrospective studies, were included. The investigations involved various fields of surgery, such as aortic surgery, cardiac surgery with cardiopulmonary bypass, and urological procedures, including partial nephrectomy. Significant heterogeneity, limited sample size, and mostly short follow up periods were noted.

CONCLUSION

Given the available evidence, the peri-operative use of mannitol to prevent AKI cannot be considered an evidence based intervention in cardiac surgery, partial nephrectomy, and/or other major surgery. Further research is required with a focus on patients at high risk of post-operative AKI.

Antioxidants as Renoprotective Agents for Ischemia during Partial Nephrectomy

Small renal masses have been diagnosed increasingly in recent decades, allowing surgical treatment by partial nephrectomy. This treatment option is associated with better renal function preservation, in comparison with radical nephrectomy. However, for obtaining a bloodless field during surgery, occlusion of renal artery and veins is often required, which results in transitory ischemia. The renal ischemia-reperfusion injury is associated with increased reactive oxygen species production leading to renal tissue damage. Thus, the use of antioxidants has been advocated in the partial nephrectomy perioperative period. Several antioxidants were investigated in regard to renal ischemia-reperfusion injury. The present manuscript aims to present the literature on the most commonly studied antioxidants used during partial nephrectomy. The results of experimental and clinical studies using antioxidants during partial nephrectomy are reported. Further, alimentary sources of some antioxidants are presented, stimulating future studies focusing on perioperative antioxidant-rich diets.

Effect of intraoperative mannitol administration on acute kidney injury after robot-assisted laparoscopic radical prostatectomy: A propensity score matching analysis

Mannitol, an osmotic diuretic, has been used to prevent acute kidney injury (AKI). However, studies have found divergent effects of intraoperative mannitol administration on postoperative AKI. We therefore evaluated the effects of intraoperative mannitol administration on AKI after robot-assisted laparoscopic radical prostatectomy (RALP) in prostate cancer patients.A total of 864 patients who underwent RALP were divided into mannitol (administered at 0.5 g/kg) and no-mannitol groups. Demographics, cancer-related data, preoperative laboratory values, intraoperative data, and postoperative outcomes such as AKI, chronic kidney disease at 12 months postoperation, duration of hospital stay, and intensive care unit admission rate and duration of stay were compared between the 2 groups using propensity score matching analysis. To determine the risk factors for AKI after RALP, univariate and multivariate logistic regression analyses were performed. Postoperative AKI was defined according to the Kidney Disease: Improving Global Outcomes criteria.After performing 1:1 propensity score matching, the mannitol and no-mannitol groups included 234 patients each. The overall incidence of AKI after RALP was 5.1% and was not significantly different between the no-mannitol and mannitol groups in the propensity score-matched patients (13 [5.6%] vs. 11 [4.7%], P = .832). Univariate logistic regression analysis revealed that body mass index and operative time were associated with AKI in 864 patients who underwent RALP. However, intraoperative mannitol administration was not associated with AKI after RALP (P = .284). Multivariate logistic regression analysis revealed that operative time was significantly associated with AKI after RALP (odds ratio = 1.013, P = .001). The incidence of chronic kidney disease (13 [5.6%] vs. 12 [5.1%], P = 1.000) and other postoperative outcomes were not also significantly different between the no-mannitol and mannitol groups in the propensity score-matched patients.Intraoperative mannitol administration has no beneficial effect on the prevention of AKI after RALP in prostate cancer patients. This result provides useful information for clinical practice guidelines regarding intraoperative mannitol use.

Mannitol reduces nephron loss after warm renal ischemia in a porcine model

BACKGROUND

Mannitol has been employed to ameliorate renal warm ischemia damage during partial nephrectomy, however, there is limited scientific evidence to support the use of mannitol during partial nephrectomy. The objective of the present study was to investigate the glomerular number after renal warm ischemia, with and without the use of mannitol in a Pig Model.

METHODS

Twenty-four male pigs were assigned into three groups. Eight animals were allocated to the sham group that was subjected to laparoscopic dissection of the left renal hilum, without renal ischemia. Eight animals were allocated to the ischemia group that had the left renal hilum clamped for 30 min through laparoscopic access. Eight animals received mannitol (250 mg/kg) before the occlusion of renal hilum for 30 min. The kidneys were collected after the euthanasia of the pigs 21 days post surgery. The right kidney was utilized as a self-control for each animal. Serum creatinine, urea levels, the weight and volume of the kidneys were measured. Glomerular volumetric density, volume-weighted glomerular volume, and cortical volume were quantified through stereological methods and employed to determine the number of nephrons per kidney. Student's t test and ANOVA were used for statistical analysis.

RESULTS

In the ischemia group, the left kidney recorded a reduction of 24.6% (290, 000 glomeruli) in the number of glomeruli in comparison to the right kidney. Kidneys subjected to ischemia also displayed decreased weight and volume in comparison to the sham and mannitol groups. No difference was observed between the left and right kidneys from the sham and mannitol groups. Further, no distinction in serum creatinine and urea among the groups was observed.

CONCLUSION

The use of mannitol significantly reduces nephron loss during warm ischemia in pigs.

Optimising renal cancer patients for nephron-sparing surgery: a review of pre-operative considerations and peri-operative techniques for partial nephrectomy

Nonmodifiable factors including pre-operative renal function and amount of healthy renal tissue preserved are the most important predictive factors that determine renal function after partial nephrectomy. Ischaemia time is an important modifiable risk factor and cold ischaemia time should be used if longer ischaemia time is anticipated. New techniques may have a role in maximising postoperative kidney function, but more robust studies are required to understand their potential benefits and risks.

A Randomized, Evaluator-Blinded, Split-Face Comparison Study of the Efficacy and Safety of a Novel Mannitol Containing Monophasic Hyaluronic Acid Dermal Filler for the Treatment of Moderate to Severe Nasolabial Folds

Background

Mannitol containing monophasic filler with higher crosslinking has not been well studied for moderate and severe nasolabial fold (NLF) correction.

Objective

To compare the efficacy and safety of a novel mannitol containing hyaluronic acid (HA) filler (HA-G) with biphasic HA filler (HA-P) for moderate and severe NLF correction.

Methods

Thirteen subjects with symmetric moderate to severe NLF received HA-G (in one NLF) and HA-P (in other NLF) and were evaluated for 24 weeks.

Results

At both 12 and 24 weeks, the mean improvement in Genzyme 6-point grading scale from baseline was significantly greater in the side of face that was treated with HA-G than HA-P (1.96±0.91 vs. 1.54±0.73 at week 12; p=0.044, 1.88±0.78 vs. 1.3±0.79 at week 24; p=0.027, respectively). At 12 weeks, the mean Global Aesthetic Improvement Scale score was 2.92±0.93 for HA-G and 2.31±0.95 for HA-P (p=0.008). Both fillers were well tolerated.

Conclusion

The HA filler HA-G provides better efficacy and similar local tolerability compared with HA-P in 6 months following treatment for moderate and severe NLF.

High Stroke Volume Variation Method by Mannitol Administration Can Decrease Blood Loss During Donor Hepatectomy

Optimal fluid management to reduce blood loss during donor hepatectomy is important for maximizing donor safety. Mannitol can induce osmotic diuresis, helping prevent increased intravascular volume status. We therefore evaluated the effect of high stroke volume variation (SVV) method by mannitol administration and fluid restriction on blood loss during donor hepatectomy.In this prospective study, 64 donors scheduled for donor right hepatectomy were included and allocated into 2 groups. In group A, the SVV value of each patient was maintained at 10% to 20% during hepatic resection with 0.5 g/kg mannitol administration and fluid restriction at a rate of 2 to 4 mL/kg/h. In group B, the SVV value was maintained at <10% by fluid administration at a rate of 6 to 10 mL/kg/h without diuretic administration during surgery. Intraoperative blood loss was estimated by the loss of red cell mass. Surgeon satisfaction scores and postoperative outcomes, including acute kidney injury, abnormal chest radiographic findings, and hospital stay duration, were also assessed.SVV during hepatectomy was significantly higher in group A than in group B (11.0 ± 1.7 vs 6.5 ± 1.1, P < 0.001). The red cell mass loss was significantly lower in group A than in group B (145.4 ± 107.6 vs 307.9 ± 110.7 mL, P < 0.001). Surgeon satisfaction scores were higher in group A than in group B (2.8 ± 0.5 vs 2.0 ± 0.6, P < 0.001). The incidence of acute kidney injury, abnormal chest radiographic findings, and duration of hospital stay did not significantly differ between the 2 groups.Maintenance of high SVV by mannitol administration is effective and safe for reducing blood loss during donor hepatectomy.

Pancreatic Injury Secondary to Renal Ischemia/Reperfusion (I/R) Injury: Possible Role of Oxidative Stress

Recent studies demonstrated remote effects of renal ischemia/reperfusion (I/R) injury on some organs such as brain, liver, and lungs. We investigated the effects of renal I-R injury on function, histology and oxidative stress state of pancreas. Twenty -four male adult Sprague-Dawley rats were divided equally into 2 groups; sham group: rats underwent midline laparotomy and dissection of renal pedicles without renal ischemia, and ischemic group: rats underwent bilateral renal ischemia for 45 min. Renal functions (serum creatinine and BUN), pancreatic functions (serum amylase, lipase and insulin) and fasting blood glucose were measured at 2 h, 1 day, 3 days and 7 days after ischemia. Also, pancreatic histology and malondialdehyde (MDA), catalase and reduced glutathione (GSH) were examined at 2 h and 7 days after ischemia. The ischemic rats showed significant increase in serum creatinine and BUN with significant increase in serum amylase and lipase at 2 h, 1 day and 3 days after ischemia. Blood glucose and fasting insulin showed no significant change apart from significant increase in insulin in sham group at 1 day after ischemia. Pancreas isolated from ischemic rats showed significant increase in histopathological damage score and significant increase in MDA and catalase enzyme with decrease in GSH. In conclusion, bilateral renal ischemia for 45 min caused significant impairment of pancreatic functions and histology. This might be due to deficiency of antioxidant and increased lipid peroxidations in pancreatic tissues.

Intravascular administration of mannitol for acute kidney injury prevention: a systematic review and meta-analysis

BACKGROUND

The effects of mannitol administration on acute kidney injury (AKI) prevention remain uncertain, as the results from clinical studies were conflicting. Due to the lack of strong evidence, the KDIGO Guideline for AKI did not propose completely evidence-based recommendations on this issue.

METHODS

We searched PubMed, EMBASE, clinicaltrials.gov and Cochrane Controlled Trials Register. Randomized controlled trials on adult patients at increased risk of AKI were considered on the condition that they compared the effects of intravascular administration of mannitol plus expansion of intravascular volume with expansion of intravascular volume alone. We calculated pooled risk ratios, numbers needed to treat and mean differences with 95% confidence intervals for dichotomous data and continuous data, respectively.

RESULTS

Nine trials involving 626 patients were identified. Compared with expansion of intravascular volume alone, mannitol infusion for AKI prevention in high-risk patients can not reduce the serum creatinine level (MD 1.63, 95% CI -6.02 to 9.28). Subgroup analyses demonstrated that serum creatinine level is negatively affected by the use of mannitol in patients undergoing an injection of radiocontrast agents (MD 17.90, 95% CI 8.56 to 27.24). Mannitol administration may reduce the incidence of acute renal failure or the need of dialysis in recipients of renal transplantation (RR 0.34, 95% CI 0.21 to 0.57, NNT 3.03, 95% CI 2.17 to 5.00). But similar effects were not found in patients at high AKI risk, without receiving renal transplantation (RR 0.29, 95% CI 0.01 to 6.60).

CONCLUSIONS

Intravascular administration of mannitol does not convey additional beneficial effects beyond adequate hydration in the patients at increased risk of AKI. For contrast-induced nephropathy, the use of mannitol is even detrimental. Further research evaluating the efficiency of mannitol infusions in the recipients of renal allograft should be undertaken.

Effects of intravenous administration of pentoxifylline in pancreatic ischaemia-reperfusion injury

BACKGROUND

Therapeutic strategies to reduce the occurrence of pancreatic ischaemia-reperfusion (I-R) injury might improve outcomes in human pancreas and kidney transplantation. In addition to its haemorrheologic effects, pentoxifylline has an anti-inflammatory effect by inhibiting NF-κB activation. This group has previously demonstrated that pentoxifylline induces an anti-inflammatory response in acute pancreatitis and liver I-R models. This led to the hypothesis that pentoxifylline might reduce pancreatic and renal lesions and the systemic inflammatory response in pancreatic I-R injury. The aim of this experimental study was to evaluate the effect of pentoxifylline administration in a rat model of pancreatic I-R injury.

METHODS

Pancreatic I-R was performed in Wistar rats over 1 h by clamping the splenic vessels. The animals submitted to I-R were divided into two groups: Group 1 (n = 20, control) rats received saline solution administered i.v. at 45 min after ischaemia, and Group 2 (n = 20) rats received pentoxifylline (25 mg/kg) administered i.v. at 45 min after ischaemia. Blood samples were collected to enable the determination of amylase, creatinine, tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-10. Pancreatic malondialdehyde (MDA) content, pancreas histology and pulmonary myeloperoxidase (MPO) were also assessed.

RESULTS

Significant reductions in serum TNF-α, IL-6 and IL-10 were observed in Group 2 compared with Group 1 (P < 0.05). No differences in pancreatic MDA content or serum amylase levels were observed between the two groups. The histologic score was significantly lower in pentoxifylline-treated animals, denoting less severe pancreatic histologic damage.

CONCLUSIONS

Pentoxifylline administration reduced the systemic inflammatory response, the pancreatic histological lesion and renal dysfunction in pancreatic I-R injury and may be a useful tool in pancreas and kidney transplantation.

Optimization of extraction of Eucommia ulmoides polysaccharides by response surface methodology

In this study, extraction yield of Eucommia ulmoides polysaccharides was optimized by the utilization of response surface methodology (RSM). Based on contour plots and variance analysis, optimum operational conditions for maximizing extraction yield were found to be extraction time 80 min, ratio of water to raw material 3, and extraction number 3. Then, we investigated the protective effect of the E. ulmoides polysaccharides on the tissue peroxidative damage and abnormal antioxidant levels in ischemia reperfusion (IR) induced renal toxicity in male albino rabbits. Decrease in all the enzymes (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR)) and non-enzymatic antioxidant (glutathione (GSH)), along with an increase in the lipid peroxidative index (malondialdehyde) was found in all the renal ischemia reperfusion (RIR) rabbits as compared with normal controls. The findings indicate that the extract of E. ulmoides polysaccharides can protect the kidney against IR induced oxidative damage in rabbits.

Altered cellular membrane fluidity levels and lipid peroxidation during experimental pancreas transplantation

Although the pathogenesis of ischemia reperfusion (IR) injury is based on complex mechanisms, free radicals play a central role. We evaluated membrane fluidity and lipid peroxidation during pancreas transplantation (PT) performed in 12 pigs (six donors and six recipients). Fluidity was measured by fluorescence spectroscopy, and malondialdehyde (MDA) and 4-hydroxyalkenals (4-HDA) concentrations were used as an index of lipid oxidation. Pancreatic tissues were collected as follows: (A) donor, immediately before vascular clamping; (B) graft, following perfusion lavage with University of Wisconsin preservation fluid; (C) graft, after 16 h of cold ischemia; and (D) recipient, 30 min vascular postreperfusion. Fluidity and MDA and 4-HDA concentrations were similar in cases A, B, and C. However, there was significant membrane rigidity and increased lipid peroxidation after reperfusion (D). These findings suggest that reperfusion exaggerates oxidative damage and may account for the rigidity in the membranes of allografts during PT.

The effect of phlebotomy and mannitol on acute renal injury induced by ischemia/reperfusion of lower limbs in rats

BACKGROUND

Abdominal aortic surgery can cause ischemic/reperfusion (I/R) injury not only in the lower limbs but also in remote organs such as kidneys. Venous blood volume exclusion from the inferior vena cava (phlebotomy) or/and mannitol are used as a treatment for I/R injury of kidney in humans, despite the fact that the effectiveness of these treatments is still debated. The aim of this study was to evaluate the effects of phlebotomy or/and mannitol on rat kidneys in a model of lower limbs I/R-induced acute renal injury (ARI).

MATERIAL AND METHODS

Thirty male Wistar albino rats were used and divided into five groups: (I) sham-operated group, laparotomy without I/R injury (group [S], n = 6); (II) I/R group, infrarenal aortic cross-clamp was used for lower limbs I/R, 3 hours of ischemia followed by 2 hours of reperfusion (group [I/R], n = 6); (III) I/R + phlebotomy group, identical to group [I/R] except for 1 mL of blood aspiration from the inferior caval vein just after ischemia (group [P], n = 6); (IV) I/R + mannitol-treated group, these rats were subjected to I/R and received a bolus injection of mannitol (group [M], n = 6); and (V) I/R + phlebotomy + mannitol-treated group (group [P + M], n = 6), the same procedures were performed as those described for previous groups. At the end of 2-hour reperfusion, all rats were sacrificed. Both kidneys were harvested for biochemical assay (myeloperoxidase [MPO] and superoxide dismutase [SOD] activities, and malondialdehyde [MDA] and reduced glutathione levels) and for histopathological examination (tubular necrosis and acute inflammation on kidney [ARI score]).

RESULTS

Aortic I/R significantly increased the level of MDA (reflecting lipid peroxidation), SOD (enzymatic endogenous antioxidant), and MPO (reflecting neutrophil infiltration) activity (p < 0.05). Phlebotomy or/and mannitol treatments significantly decreased the level of MDA, SOD, and MPO activity and increased glutathione level (nonenzymatic antioxidant in the kidney tissues) (p < 0.05). Histological evaluation of ARI score showed that aortic I/R significantly increased (p value for group [S] versus group [I/R] was 0.012), whereas phlebotomy or/and mannitol treatments significantly decreased tubular necrosis and inflammatory infiltration (p values for group [I/R] versus group [P], [M], and [P + M] were 0.043, 0.043, and 0.003, respectively).

CONCLUSION

This experiment clearly indicated that the lower limbs I/R-induced ARI attenuated significantly by phlebotomy or/and mannitol treatments. Phlebotomy plus mannitol is more effective treatment than phlebotomy or mannitol alone in preventing lower limbs I/R-induced ARI in rats. Further clinical studies are required to clarify whether phlebotomy or/and mannitol treatments are beneficial in alleviating of ARI during abdominal aortic surgery.

Oxidants as important determinants of renal apoptosis during pneumoperitoneum: a study in an isolated perfused rat kidney model

INTRODUCTION

Pneumoperitoneum-associated ischemia-reperfusion (IR) may initiate renal dysfunction. Whether oxidants are responsible for renal structural damage, such as cell apoptosis, has not yet been evaluated. We investigated such eventuality in an isolated rat kidney model.

METHODS

Thirty-five rat kidneys with their vessels and ureter were harvested and perfused within a closed environment at flow of 15 ml min(-1). After stabilization, kidneys were assigned to one of five groups (n = 7 per group): CO(2)-induced intrachamber pressure of 8, 12, or 0 mmHg (control), and 8 or 12 mmHg pressure applied to kidneys from rats treated pre-experimentally with tungsten for 14 days. Pressurization lasted 60 min.

RESULTS

Organ perfusion pressure raised as intrachamber pressure increased. Urinary output decreased in the two pressurized nonpretreated groups. Intrachamber pressure was directly associated with an increase in postexperimental xanthine oxidase tissue levels. Twofold apoptosis was documented (p < 0.05) in cortex of nonpretreated kidney in the 12 mmHg group compared with the 8 or 0 mmHg groups. Tungsten pretreatment significantly (p < 0.05) attenuated the abnormalities documented in the 12 mmHg group, but less so in the 8 mmHg pressurized nontreated counterparts.

CONCLUSIONS

Pneumoperitoneal pressure applied to isolated perfused kidney is associated with renal apoptosis. This rapidly induced structural renal damage is oxidant dependent and can be attenuated by antioxidants. Further studies may shed more light on the role of antioxidants in preventing pneumoperitoneum-induced kidney dysfunction.

Beneficial effects of N-acetyl cysteine on pancreas and kidney following experimental pancreatic ischemia-reperfusion in rats

OBJECTIVE

To evaluate the protective effects of N-acetyl cysteine on the pancreas and kidney after pancreatic ischemia reperfusion injury in a rat model.

METHODS AND MATERIALS

Pancreatic ischemia reperfusion was performed in Wistar rats for 1 hour. Revascularization was achieved followed by 4 h of reperfusion. A total of 24 animals were divided into four groups: Group 1: sham; Group 2: pancreatic ischemia reperfusion without treatment; Group 3: pancreatic ischemia reperfusion plus N-acetyl cysteine intravenously; and Group 4: pancreatic ischemia reperfusion plus N-acetyl cysteine per os. Blood and tissue samples were collected after reperfusion.

RESULTS

There were significant differences in amylase levels between Group 1 (6.11+/-0.55) and Group 2 (10.30+/-0.50) [p=0.0002] as well as between Group 2 (10.30+/-0.50) and Group 4 (7.82+/-0.38) [p=0.003]; creatinine levels between Group 1 (0.52 +/- 0.07) and Group 2 (0.77+/-0.18) [p=0.035] as well as between Group 2 (0.77+/-0.18) and Group 3 (0.48+/-0.13) [p=0.012]; and pancreatic tissue thiobarbituric acid reactive substance levels between Group 1 (1.27+/-0.96) and Group 2 (2.60+/-3.01) [p=0.026] as well as between Group 2 (2.60+/-3.01) and Group 4 (0.52+/-0.56) [p=0.002]. A decrease in pancreatic tissue GST-alpha3 gene expression was observed in Group 2 in comparison to Group 1 (p =0.006), and an increase was observed in Groups 3 and 4 when compared to Group 2 (p= 0.025 and p=0.010, respectively).

CONCLUSION

This study provides evidence that N-acetyl cysteine has a beneficial effect on pancreatic ischemia reperfusion injury and renal function in a rat model.