Effects of carbon dioxide pneumoretroperitoneum on free radical formation in remote organs and use of verapamil as an antioxidant

Verapamil attenuates oxidative stress and inflammatory responses in cigarette smoke (CS)-induced murine models of acute lung injury and CSE-stimulated RAW 264.7 macrophages via inhibiting the NF-κB pathway

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), severe form of ALI, are characterized by overwhelming of lung inflammation, and no treatment is currently available to treat ALI/ARDS. Cigarette smoke (CS) is one of the prime causes to induce ALI/ARDS via oxidative stress. Despite extensive research, no appropriate therapy is currently available to treat ALI/ARDS. Hence, new potential approaches are needed to treat ALI/ARDS. Consequently, this project was designed to explore the protective effects of verapamil against CS-induced ALI by in vivo and in vitro method. In vivo data obtained from respiratory mechanics, pulmonary morphometric analyses and lung histopathology revealed that verapamil dose-dependently and strikingly decreased the lung weight coefficient, attenuated the albumin exudation into lungs, minimized the infiltration of macrophages and neutrophils into lungs, reduced the pro-inflammatory cytokines (tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6) and keratinocyte chemoattractant (KC)) production, and improved the hypoxemia and lung histopathological changes. Similarly, verapamil also reduced the production of TNF-α, IL-6 and KC from cigarette smoke extract (CSE)-stimulated RAW 264.7 macrophage. Importantly, verapamil dose-dependently and remarkably suppressed the CS-induced oxidative stress via not only reducing the myeloperoxidase (MPO) activity of lungs, total oxidative stress (TOS) and malondialdehyde (MDA) content in the lungs and supernatant of RAW 264.7 macrophage but also improving total antioxidant capacity (TAC) and superoxide dismutase (SOD) production. Finally, verapamil strikingly decreased the NF-κB expression both in in vivo and in vitro models. Hence, verapamil has positive therapeutic effects against CS-induced ALI via suppressing uncontrolled inflammatory response, oxidative stress and NF-κB p65 signaling.

Hydromorphone Protects against CO2 Pneumoperitoneum-Induced Lung Injury via Heme Oxygenase-1-Regulated Mitochondrial Dynamics

Various pharmacological agents and protective methods have been shown to reverse pneumoperitoneum-related lung injury, but identifying the best strategy is challenging. Herein, we employed lung tissues and blood samples from C57BL/6 mice with pneumoperitoneum-induced lung injury and blood samples from patients who received laparoscopic gynecological surgery to investigate the therapeutic role of hydromorphone in pneumoperitoneum-induced lung injury along with the underlying mechanism. We found that pretreatment with hydromorphone alleviated lung injury in mice that underwent CO₂ insufflation, decreased the levels of myeloperoxidase (MPO), total oxidant status (TOS), and oxidative stress index (OSI), and increased total antioxidant status (TAS). In addition, after pretreatment with hydromorphone, upregulated HO-1 protein expression, reduced mitochondrial DNA content, and improved mitochondrial morphology and dynamics were observed in mice subjected to pneumoperitoneum. Immunohistochemical staining also verified that hydromorphone could increase the expression of HO-1 in lung tissues in mice subjected to CO₂ pneumoperitoneum. Notably, in mice treated with HO-1-siRNA, the protective effects of hydromorphone against pneumoperitoneum-induced lung injury were abolished, and hydromorphone did not have additional protective effects on mitochondria. Additionally, in clinical patients who received laparoscopic gynecological surgery, pretreatment with hydromorphone resulted in lower serum levels of club cell secretory protein-16 (CC-16) and intercellular adhesion molecule-1 (ICAM-1), a lower prooxidant-antioxidant balance (PAB), and higher heme oxygenase-1 (HO-1) activity than morphine pretreatment. Collectively, our results suggest that hydromorphone protects against CO₂ pneumoperitoneum-induced lung injury via HO-1-regulated mitochondrial dynamics and may be a promising strategy to treat CO₂ pneumoperitoneum-induced lung injury.

Low-pressure Pneumoperitoneum in Laparoscopic Cholecystectomy: A Randomized Controlled Trial

BACKGROUND/PURPOSE

To compare the changes in hepatic enzymes and comfort level of the surgeon in low-pressure pneumoperitoneum laparoscopic cholecystectomy (LPPLC, 7 mm Hg) with that of normal pressure pneumoperitoneum laparoscopic cholecystectomy (NPPLC, 14 mm Hg).

METHODS

Eighty-two patients were randomly divided into 2 groups (LPPLC and NPPLC). Serum levels of bilirubin, serum glutamic-oxaloacetic transaminase, serum glutamic-pyruvic transaminase, alkaline phosphatase, and lactate dehydrogenase were measured before the operation, at the time of reversal from anesthesia, 24 hours after the operation, and on day 7. Serious adverse events, intra-operative complications, surgeon's comfort level of dissection, operative time, conversion rates to an open procedure, or normal pressure pneumoperitoneum were recorded.

RESULTS

Of the 41 patients randomized for LPPLC, 8 patients were converted to NPPLC due to difficulty in dissection and 1 converted to open in each group. There was statistically significant fall in mean serum bilirubin level in both the groups in the immediate postoperative period (P<0.05). Statistically significant increase in its level was observed after 24 hours in the NPPLC group only (P<0.05). Levels of mean serum serum glutamic-oxaloacetic transaminase, serum glutamic-pyruvic transaminase, and lactate dehydrogenase increased significantly (P<0.05) in immediate postoperative period and a further increase was observed after 24 hours (P<0.05) in the NPPLC group only. The comfort level of surgeon was found to be significantly better in the NPPLC group.

CONCLUSIONS

LPPLC is a safe procedure, especially in the hands of an experienced surgeon with clinically insignificant systemic effects. But the comfort level of surgeon is better in normal pressure when compared with low pressure. In patients with deranged hepatic functions undergoing advanced laparoscopic procedures, it is advisable to start the surgery with low-pressure pneumoperitoneum. Pressure may be escalated further as per the surgeon's comfort.

Nephroprotective effect of calcium channel blockers against toxicity of lead exposure in mice

Exposure to lead (Pb) can induce kidney damage, which is related to induction of oxidative damage and disturbance of intracellular calcium homeostasis. Pb can readily permeate through dihydropyridine-sensitive L-type calcium channels and accumulate within cells. The objective of this study was to investigate protective effects of calcium channel blockers (CCBs) verapamil and nimodipine on nephrotoxicity induced by Pb acetate in mice. One hundred and twenty male mice were randomly divided into 6 groups: control, Pb, low-dose verapamil, high-dose verapamil, low-dose nimodipine and high-dose nimodipine (n=20 per group). Pb acetate was injected intraperitoneally (i.p.) at 40 mg/kg body weight/day for 10 days to establish the Pb toxicity model. While control mice received saline, mice of the treated groups simultaneously received i.p. injections of verapamil or nimodipine daily for 10 days. Both verapamil and nimodipine showed protection against Pb-induced kidney injury, including alleviation of renal pathological damage and decreasing the level of Pb in kidney homogenate and extent of apoptosis in nephrocytes. Moreover, verapamil and nimodipine significantly down-regulated levels of blood urea nitrogen and creatinine in the serum. In addition, verapamil and nimodipine administration decreased malondialdehyde content and increased activities of super oxide dismutase activity and glutathione peroxidase in the kidney homogenate. The findings in the present study implicate the therapeutic potential of CCBs for Pb-induced nephrotoxicity, which were at least partly due to the decrease of Pb uptake and inhibition of lipid peroxidation.

Neuroprotective effect of gadolinium: a stretch-activated calcium channel blocker in mouse model of ischemia-reperfusion injury

The present study was designed to investigate the potential of gadolinium, a stretch-activated calcium channel blocker in ischemic reperfusion (I/R)-induced brain injury in mice. Bilateral carotid artery occlusion of 12 min followed by reperfusion for 24 h was given to induce cerebral injury in male Swiss mice. Cerebral infarct size was measured using triphenyltetrazolium chloride staining. Memory was assessed using Morris water maze test and motor incoordination was evaluated using rota-rod, lateral push, and inclined beam walking tests. In addition, total calcium, thiobarbituric acid reactive substance (TBARS), reduced glutathione (GSH), and acetylcholinesterase (AChE) activity were also estimated in brain tissue. I/R injury produced a significant increase in cerebral infarct size. A significant loss of memory along with impairment of motor performance was also noted. Furthermore, I/R injury also produced a significant increase in levels of TBARS, total calcium, AChE activity, and a decrease in GSH levels. Pretreatment of gadolinium significantly attenuated I/R-induced infarct size, behavioral and biochemical changes. On the basis of the present findings, we can suggest that opening of stretch-activated calcium channel may play a critical role in ischemic reperfusion-induced brain injury and that gadolinium has neuroprotective potential in I/R-induced injury.

Pharmacological modulation of oxidative stress response in minimally invasive surgery: systematic review

This systematic review aims to synthesize the data on the effectiveness of pharmacological modulation of stress response in minimally invasive surgery. Eligible trials were clinical trials randomized or not or experimental trials that investigated the effect of pharmacological agents on modulation of surgical stress response to minimally invasive surgery. No clinical trials were identified. Eight experimental trials met the inclusion criteria and were obtained in full text. Experimental models were rats or rabbits subjected to pneumoperitoneum, or pneumoretroperitoneum, not to a whole operation. Pharmacological modulation of surgical stress response was attempted with erythromycin, melatonin, mesna, verapamil, pentoxifylline, N-acetylcysteine, and zinc. All the pharmacological agents, except pentoxifylline, seemed to reduce oxidative stress markers. However, only mesna pretreatment prevented oxidative stress, because oxidative stress markers remained in the sham levels. Contrasting data were obtained for pentoxyphilline. In conclusion, available data suggest that pharmacological modulation of surgical stress response to minimally invasive surgery might be feasible.

Carbon dioxide pneumoperitoneum induces anti-inflammatory response and hepatic oxidative stress in young rats with bacterial peritonitis

PURPOSE

The aim of this study was to investigate the effects of carbon dioxide (CO(2)) pneumoperitoneum on the intra-abdominal spread of bacteria, the local and systemic cytokine expression, and oxidant/antioxidant status in young rats with bacterial peritonitis.

METHODS

Young Sprague-Dawley rats, aging 20-27 days and weighing around 50 g, were allocated to six groups of six to nine animals in each. Intra-abdominal infection model was developed by intraperitoneal injection with 1 cc of Escherichia coli (E. coli) (10(8) CFU/mL, ATCC25922 strain) via right lower abdominal wall. Carbon dioxide (CO(2)) pneumoperitoneum was applied to the rats via umbilical pit insufflation with 20 cc CO(2) for 30 min. All survived rats underwent laparotomy and were killed 24 h or 3 days later. Serum levels of CO(2) and CRP were measured. Left lower abdomen peritoneum, peritoneal fluid, mesenteric lymph node of terminal ileum, and liver were taken for bacterial culture. Liver and plasma levels of TNF-α, IL-1β, and IL-6 were examined for the level of local and systemic immunologic response. Oxidant/antioxidant status in liver and plasma were assessed by measuring malondialdehyde (MDA), and reduced to oxidized glutathione ratio (GSH/GSSG).

RESULTS

Carbon dioxide (CO(2)) pneumoperitoneum does not facilitate E. coli dissemination to other intra-abdominal organs in rats with localized E. coli peritonitis. Peritonitis rats that underwent abdominal CO(2) insufflation have insignificantly higher CRP or lower CO(2) levels. Plasma and liver TNF-α, IL-1β concentrations were not significantly different among the four groups, but plasma IL-6 was significantly increased in rats with E. coli peritonitis and CO(2) pneumoperitoneum that were killed 3 days later as compared with that of rats that were killed 24 h later. In rats with E. coli peritonitis, CO(2) pneumoperitoneum was significantly associated with decreased hepatic GSH/GSSG ratio. However, plasma and liver MDA levels were not altered after CO(2) pneumoperitoneum.

CONCLUSIONS

Carbon dioxide (CO(2)) pneumoperitoneum is not associated with E. coli dissemination in the presence of local intra-abdominal infection. CO(2) pneumoperitoneum elicited systemic anti-inflammatory response at a specific time period and decreased hepatic antioxidant status in young rats with E. coli peritonitis.

Comparison of the protective effects of papaverine, lidocaine and verapamil on the sperm quality of the testis after induced torsion-detorsion in rats

OBJECTIVE

Spermatic cord torsion is a true urological emergency. Significant subfertility exists in patients following unilateral testicular torsion. Several studies have tested several agents such as vasodilators and antioxidants to inhibit or temper testicular damage.

MATERIAL AND METHODS

Sprague-Dawley rats were divided into five groups; in group 1 (control) no operation or drug injection was done. In groups 2-5 the left testis was subjected to 270 torsions. Two hours after induced torsion, drugs were injected intraperitoneally. Rats in group 2 received no drug, whereas those in groups 3, 4 and 5 were administered a single dose of papaverine (35 mg/kg), lidocaine (4 mg/kg) and verapamil (0.1 mg/kg), respectively. Thirty minutes after drug injection (2.5 h after torsion), testis detorsion was performed in all groups. The drug injections continued for 1 week. After 20 days, bilateral orchiectomy was carried out and semen from both testes was evaluated.

RESULTS

In animals treated with verapamil, left testis sperm count and the percentage of motile sperm were increased significantly in comparison with the sham-operated animals. Sperm morphology in all groups was in the normal range. Mean sperm count and motility in the right testes were not significantly different in different groups.

CONCLUSIONS

Verapamil can induce beneficial effects on semen analysis parameters after testicular torsion in rats.

Systematic review of oxidative stress associated with pneumoperitoneum

Background

There have been several reports of ischaemic complications after routine laparoscopy. The aim of this review was to investigate the relationship between this oxidative stress and pneumoperitoneum.

Methods

Medline, Medline in-process, The Cochrane Library, PubMed and EMBASE were searched for papers on oxidative stress and pneumoperitoneum, from 1947 to March 2008 with no language restriction or restriction on trial design. Papers that did not investigate pneumoperitoneum as a causative factor, or did not report outcome measures related to oxidative stress, were excluded.

Results

A total of 73 relevant papers were identified: 36 animal studies, 21 human clinical trials, nine case reports, five review articles and two comments. Pneumoperitoneum causes a reduction in splanchnic blood flow, resulting in biochemical evidence of oxidative stress in a pressure- and time-dependent manner. There is evidence that the use of carbon dioxide for insufflation is contributory. Several measures proposed to minimize the oxidative stress have shown promise in animal studies, but few have been evaluated in the clinical setting.

Conclusion

There is an increasing body of evidence, mainly from animal studies, that pneumoperitoneum decreases splanchnic perfusion with resulting oxidative stress. It is now appropriate to investigate the clinical significance of pneumoperitoneum-associated oxidative stress.

Validation and reduction of the oxidative stress following laparoscopic operations: a prospective randomized controlled study

OBJECTIVE

To validate ischemia-reperfusion mechanism during laparoscopic cholecystectomy, and to assess the reduction of oxidative stress by an intermittent sequential pneumatic compression (ISPC) device.

SUMMARY BACKGROUND

Increased intraperitoneal pressure during laparoscopic operations may lead to decreased cardiac output and visceral perfusion, and possible ischemia-reperfusion effects. Using the ISPC device was shown to improve cardiac output and visceral perfusion during pneumoperitoneum (PP).

METHODS

Twenty patients undergoing elective laparoscopic cholecystectomy were enrolled in a randomized prospective controlled study and divided into 2 groups: 1) study group (10 patients), activation of ISPC together with creation of PP; and 2) control group, without ISPC. Lipid peroxidation and glutathione levels (as indicators of oxidative stress) as well as liver and renal function tests, were measured before and at the end of PP, and again at 30 minutes, 4 hours, and 24 hours afterward, together with hemodynamic and respiratory parameters.

RESULTS

There was no significant difference between both groups concerning liver enzymes and bilirubin, nor in hemodynamic parameters. In the control group, increased lipid peroxide levels were noted 4 hours after PP termination, in comparison to pre-PP levels (590.4-649.2 mmol/L, P = 0.002). In the study group (ISPC), such changes were not inspected. Decreased total glutathione levels were noted in the control group, 30 minutes following CO2 evacuation.

CONCLUSIONS

Our study validates the ischemia-reperfusion mechanism following laparoscopic surgery. The use of an ISPC device decreased the oxidative stress (secondary to relative ischemia-reperfusion insult) following PP, probably due to improved cardiac output and visceral perfusion.

Effect of Carbon Dioxide Pneumoretroperitoneum on Bacterial Translocation in an Experimental Retroperitoneoscopy Model

PURPOSE

To evaluate the effect of artificial CO2 pneumoretroperitoneum on bacterial translocation in an experimental retroperitoneoscopy model.

MATERIALS AND METHODS

Eighteen adult male New Zealand White rabbits weighing 2.5 to 3 kg were divided into two groups. Group 1 (control group) consisted of 6 rabbits, while the remaining 12 served as the pneumoretroperitoneum group (group 2). In group 1, the left retroperitoneal space was dissected with a 50-mL balloon without CO2 insufflation, and the animals were kept under anesthesia for 3 hours with the balloons inflated. In group 2, after balloon dissection as in group 1, CO2 insufflation was applied at 1 L/min to achieve a pressure of 10 to 12 mm Hg for 3 hours. Afterward, all animals were sacrificed, and samples were taken from the blood, retroperitoneal area, lungs, liver, mesentery, heart, kidneys, ureters, bladder, colon, small intestine, and spleen and carried to the microbiology laboratory in Carry-Blair medium. Bacterial growth was evaluated using standard techniques.

RESULTS

All animals survived the experimental procedures. None of the rabbits in the control group demonstrated any bacterial translocation in the sampled tissues. In the pneumoretroperitoneum group, one rabbit was found to have 10(2) colony-forming units of E. coli in the kidney, but this was considered to be the result of contamination, not translocation.

CONCLUSION

Carbon dioxide pneumoretroperitoneum does not seem to cause bacteremia or bacterial translocation in this experimental model. Retroperitoneoscopy probably does not create any additional risk of septic complications.

Zinc may protect remote ocular injury caused by intestinal ischemia reperfusion in rats

Remote organ injury represents the oxidative damage, which occurs in various organs away from the tissues exposed to ischemia-reperfusion insult. Hypothesizing that the eye may be susceptible to this type of tissue damage, we investigated the effect of splanchnic ischemia-reperfusion on the chorio-retinal tissue in Sprague-Dawley rats. Four groups, each consisting of 10 male rats, were designed for the study. Ischemia-reperfusion was introduced by clamping superior mesenteric artery for 1 hour, followed by reperfusion for 90 min (IR group). In another group, the same operation was performed except that zinc aspartate (50 mg/kg) was given intra-peritoneally 15 min before the opening of the clamp (Zn-IR group). As control (sham group), the abdomen was opened without any intervention on superior mesenteric artery. The other group was given Zn after opening of abdomen without any intervention on superior mesenteric artery (Zn-sham group). After the choroid and the retina were dissected from the eye, malondialdehyde, superoxide dismutase, catalase and nitric oxide (NO) were measured in the collected eye tissues. We found that the levels of malondialdehyde, an indicator for lipid peroxidation, were higher in the chorio-retinal tissue of IR group compared to Zn-IR, Zn-sham or sham group (p < 0.05). The oxidative stress in Zn-IR group was not higher than that of sham group. Treatment with zinc decreased NO levels but had no noticeable effect on the level of antioxidant enzymes. Our study indicates that remote organ injury is induced in the eye during splanchnic ischemia-reperfusion and that zinc may be beneficial to ameliorate remote ocular injury.

Calcium channel blocker and renal mitochondrial function in warm renal ischemia

OBJECTIVE

Ions, particularly calcium ions, play an important role in ischemia-reperfusion cell injury. In this study, we investigated the action of verapamil on the mitochondrial function of kidneys submitted to ischemia without blood reperfusion in order to study isolated early and late ischemic effects.

MATERIALS AND METHODS

44 rats were submitted to bilateral warm renal ischemia for 30 minutes. The kidneys were then immediately reperfused with saline or Euro-Collins (EC) solution, with and without previous administration of 0.35 mg/kg of verapamil. Mitochondrial function was assessed at the end of renal perfusion and after 24 hours of cold preservation.

RESULTS

In kidneys perfused with saline, verapamil allowed a significant early preservation of state III mitochondrial respiration, a result that was no longer evident after 24 hours. In kidneys perfused with EC solution, verapamil did not change state III for either early or late evaluations. Comparison of the groups showed that the results obtained for kidneys perfused with EC were always superior to those obtained for the saline group, except for the initial analysis of kidneys treated with saline and verapamil, which showed results similar to those obtained with EC perfusion alone.

CONCLUSION

Administration of verapamil before warm ischemia provides partial and short-lasting functional protection of the mitochondrial function in kidneys perfused with sodium rich saline. With Euro-Collins solution, verapamil did not show any additional beneficial effect. This fact permits us to conclude that protective action is effective only under conditions that facilitate increased sodium uptake and/or potassium loss.