PORTAL: pilot study on the safety and tolerance of preoperative melatonin application in patients undergoing major liver resection: a double-blind randomized placebo-controlled trial

Melatonin for preoperative and postoperative anxiety in adults

BACKGROUND

Anxiety in relation to surgery is a well-known problem. Melatonin offers an alternative treatment to benzodiazepines for ameliorating this condition in the preoperative and postoperative periods.

OBJECTIVES

To assess the effects of melatonin on preoperative and postoperative anxiety compared to placebo or benzodiazepines.

SEARCH METHODS

We searched the following databases on 10 July 2020: CENTRAL, MEDLINE, Embase, CINAHL, and Web of Science. For ongoing trials and protocols, we searched clinicaltrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform.

SELECTION CRITERIA

We included randomized, placebo-controlled or standard treatment-controlled (or both) studies that evaluated the effects of preoperatively administered melatonin on preoperative or postoperative anxiety. We included adult patients of both sexes (15 to 90 years of age) undergoing any kind of surgical procedure for which it was necessary to use general, regional, or topical anaesthesia.

DATA COLLECTION AND ANALYSIS

One review author conducted data extraction in duplicate. Data extracted included information about study design, country of origin, number of participants and demographic details, type of surgery, type of anaesthesia, intervention and dosing regimens, preoperative anxiety outcome measures, and postoperative anxiety outcome measures.

MAIN RESULTS

We included 27 randomized controlled trials (RCTs), involving 2319 participants, that assessed melatonin for treating preoperative anxiety, postoperative anxiety, or both. Twenty-four studies compared melatonin with placebo. Eleven studies compared melatonin to a benzodiazepine (seven studies with midazolam, three studies with alprazolam, and one study with oxazepam). Other comparators in a small number of studies were gabapentin, clonidine, and pregabalin. No studies were judged to be at low risk of bias for all domains. Most studies were judged to be at unclear risk of bias overall. Eight studies were judged to be at high risk of bias in one or more domain, and thus, to be at high risk of bias overall. Melatonin versus placebo Melatonin probably results in a reduction in preoperative anxiety measured by a visual analogue scale (VAS, 0 to 100 mm) compared to placebo (mean difference (MD) -11.69, 95% confidence interval (CI) -13.80 to -9.59; 18 studies, 1264 participants; moderate-certainty evidence), based on a meta-analysis of 18 studies. Melatonin may reduce immediate postoperative anxiety measured on a 0 to 100 mm VAS compared to placebo (MD -5.04, 95% CI -9.52 to -0.55; 7 studies, 524 participants; low-certainty evidence), and may reduce delayed postoperative anxiety measured six hours after surgery using the State-Trait Anxiety Inventory (STAI) (MD -5.31, 95% CI -8.78 to -1.84; 2 studies; 73 participants; low-certainty evidence). Melatonin versus benzodiazepines (midazolam and alprazolam) Melatonin probably results in little or no difference in preoperative anxiety measured on a 0 to 100 mm VAS (MD 0.78, 95% CI -2.02 to 3.58; 7 studies, 409 participants; moderate-certainty evidence) and there may be little or no difference in immediate postoperative anxiety (MD -2.12, 95% CI -4.61 to 0.36; 3 studies, 176 participants; low-certainty evidence). Adverse events Fourteen studies did not report on adverse events. Six studies specifically reported that no side effects were observed, and the remaining seven studies reported cases of nausea, sleepiness, dizziness, and headache; however, no serious adverse events were reported. Eleven studies measured psychomotor and cognitive function, or both, and in general, these studies found that benzodiazepines impaired psychomotor and cognitive function more than placebo and melatonin. Fourteen studies evaluated sedation and generally found that benzodiazepine caused the highest degree of sedation, but melatonin also showed sedative properties compared to placebo. Several studies did not report on adverse events; therefore, it is not possible to conclude with certainty, from the data on adverse effects collected in this review, that melatonin is better tolerated than benzodiazepines.

AUTHORS' CONCLUSIONS

When compared with placebo, melatonin given as premedication (as tablets or sublingually) probably reduces preoperative anxiety in adults (measured 50 to 120 minutes after administration), which is potentially clinically relevant. The effect of melatonin on postoperative anxiety compared to placebo (measured in the recovery room and six hours after surgery) was also evident but was much smaller, and the clinical relevance of this finding is uncertain. There was little or no difference in anxiety when melatonin was compared with benzodiazepines. Thus, melatonin may have a similar effect to benzodiazepines in reducing preoperative and postoperative anxiety in adults.

The role of melatonin in colorectal cancer treatment: a comprehensive review

Colorectal cancer (CRC) is one of the most common types of cancer worldwide, known as the second leading cause of cancer-related deaths annually. Currently, multimodal treatment strategies, including surgical resection, combined with chemotherapy and radiotherapy, have been used as conventional treatments in patients with CRC. However, clinical outcome of advanced stage disease remains relatively discouraging, due mainly to appearance of CRC chemoresistance, toxicity, and other detrimental side effects. New strategies to overcome these limitations are essential. During the last decades, melatonin (MLT) has been shown to be a potent antiproliferative, anti-metastatic agent with cytotoxic effects on different types of human malignancies, including CRC. Hence, this comprehensive review compiles the available experimental and clinical data analyzing the effects of MLT treatment in CRC patients and its underlying molecular mechanisms.

The Effects of Melatonin on Elevated Liver Enzymes during Statin Treatment

Taking statins can cause increase in the level of aspartate and alanine aminotransferase. The aim of this study was to assess the usefulness of melatonin in counteracting the adverse hepatic events from statins. Methods. The research program included 60 patients (aged 47–65 years, 41 women and 19 men) with hyperlipidemia taking atorvastatin or rosuvastatin at a dose of 20–40 mg daily. The patients were randomly allocated in two groups. Group I (n = 30) was recommended to take the same statin at a standardized daily dose of 20 mg together with melatonin at a dose of 2 × 5 mg. Group II (n = 30) patients took statin with placebo at the same dose and time of the day. Follow-up laboratory tests (AST, ALT, GGT, and ALP) were evaluated after 2, 4, and 6 months of treatment. Results. In Group I the levels of all enzymes decreased after 6 months, particularly AST, 97,2 ± 19,1 U/L versus 52,8 ± 12,3 U/L (p < 0,001); ALT, 87,4 ± 15,6 U/L versus 49,8 ± 14,5 U/L (p < 0,001); and GGT, 84,1 ± 14,8 U/L versus 59,6 U/L (p < 0,001). Conclusion. Melatonin exerts a hepatoprotective effect in patients taking statins.

ROS homeostasis, a key determinant in liver ischemic-preconditioning

Reactive Oxygen Species (ROS) are key mediators of ischemia-reperfusion injury but also required for the induction of the stress response that limits tissue injury and underlies the protection provided by ischemic-preconditioning protocols. Liver steatosis is an important risk factor for liver transplant failure. Liver steatosis is associated with mitochondrial dysfunction and excessive mitochondrial ROS production. Studies aiming at decreasing the sensibility of the steatotic liver to ischemia-reperfusion injury using pre-conditioning protocols, have shown that the steatotic liver has a reduced capacity to respond to these protocols. Recent studies indicate that these effects are related to a reduced capacity of the steatotic liver to respond to elevated ROS levels following reperfusion by inducing a compensatory response. This failure to respond to ROS is associated with reduced levels of antioxidants, mitochondrial damage, hepatocyte cell death, activation of the immune system and induction of pro-fibrotic mediators.

Pharmacological strategy designed to limit ischemia-reperfusion injury in brain dead donor kidneys

Ischemia-reperfusion injury is a complex physiological process responsible for delayed renal function or primary graft non-function, explicitly when kidney allograft are issued from expanded criteria donor. The purpose of this review is to detail the detrimental phenomenons altering kidney allograft's integrity in brain dead donor, therefore suggesting pharmacological interventions aiming to reduce ischemia-reperfusion injuries and improving transplantation outcome. This ischemia-reperfusion phenomenon must therefore be anticipated through the whole procedure starting at the stage of conditioning of the potential donor. Hormonal and haemodynamic consequences of brain death modify perfusion and oxygenation conditions of the organs Thus, after describing the autonomic, metabolic, endocrine and chemokine storm occurring during brain death, the authors focus on strategies to prevent hemodynamic instability in the donor and to limit the consequences of hormonal and immunological changes on organs that will eventually be transplanted.

A review of melatonin in hepatic ischemia/reperfusion injury and clinical liver disease

Ischemia/reperfusion injury (IRI) can lead to cellular and, eventually, organ dysfunction, with the liver being one of the most frequently affected organs. Melatonin, a molecule that has notable antioxidant and anti-inflammatory properties, has been shown to protect against hepatic IRI. The purpose of this review is to summarize the protective effects of melatonin on hepatic IRI. The review initially summarizes the antioxidant properties of melatonin. We then discuss the protective effects of melatonin against endothelial and mitochondrial dysfunction. Thereafter, we introduce some information covering melatonin-related signaling pathways, including heme oxygenase-1 (HO-1), toll-like receptor (TLR), c-Jun N-terminal kinase (JNK), and so on. Furthermore, the clinical application of melatonin to hepatic diseases is considered. Finally, the safety of melatonin is evaluated. Taken together, the information compiled in this review will serve as a comprehensive reference regarding the pharmacological benefits of melatonin on hepatic IRI, aid in the design of future experimental research, and promote melatonin as a new therapeutic target.

Effects of a preconditioning oral nutritional supplement on pig livers after warm ischemia

Background. Several approaches have been proposed to pharmacologically ameliorate hepatic ischemia/reperfusion injury (IRI). This study was designed to evaluate the effects of a preconditioning oral nutritional supplement (pONS) containing glutamine, antioxidants, and green tea extract on hepatic warm IRI in pigs. Methods. pONS (70 g per serving, Fresenius Kabi, Germany) was dissolved in 250 mL tap water and given to pigs 24, 12, and 2 hrs before warm ischemia of the liver. A fourth dose was given 3 hrs after reperfusion. Controls were given the same amount of cellulose with the same volume of water. Two hours after the third dose of pONS, both the portal vein and the hepatic artery were clamped for 40 min. 0.5, 3, 6, and 8 hrs after reperfusion, heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), portal venous flow (PVF), hepatic arterial flow (HAF), bile flow, and transaminases were measured. Liver tissue was taken 8 hrs after reperfusion for histology and immunohistochemistry. Results. HR, MAP, CVP, HAF, and PVF were comparable between the two groups. pONS significantly increased bile flow 8 hrs after reperfusion. ALT and AST were significantly lower after pONS. Histology showed significantly more severe necrosis and neutrophil infiltration in controls. pONS significantly decreased the index of immunohistochemical expression for TNF-α, MPO, and cleaved caspase-3 (P < 0.001). Conclusion. Administration of pONS before and after tissue damage protects the liver from warm IRI via mechanisms including decreasing oxidative stress, lipid peroxidation, apoptosis, and necrosis.

Age-related differences in hepatic ischemia/reperfusion: gene activation, liver injury, and protective effect of melatonin

BACKGROUND

Ischemia/reperfusion (I/R) causes functional and structural damage to liver cells, this being more pronounced with increasing age of the tissue. Melatonin is a pineal indole that has been shown to play an important role as a free radical scavenger and anti-inflammatory molecule.

MATERIAL AND METHODS

The age-dependent responses to I/R were compared in 2-mo-old and 14-mo-old male Wistar rats. After 35 min of hepatic ischemia followed by 36 h of reperfusion, rats were sacrificed. Sham-operated control rats underwent the same protocol without real vascular occlusion. Animals were intraperitoneally injected with 10 mg/kg melatonin 24 h before the operation, at the time of surgery, and 12 and 24 h after it. The tissues were submitted to histopathologic evaluation. The levels of ALT and AST were analyzed in plasma. The expression of TNF-α, IL-1β, IL-10, MCP-1, IFN-γ, iNOS, eNOS, Bad, Bax, Bcl2, AIF, PCNA, and NFKB1 genes were detected by RT-PCR in hepatic tissue.

RESULTS

I/R was associated with significant increases in the expression of pro-inflammatory and pro-apoptotic genes in liver. Older rats submitted to I/R were found to respond with increased liver damage as compared with young rats, with serum ALT and AST levels significantly higher than in young animals. Mature rats also showed more evident increases in expression of pro-inflammatory cytokines (IL-1β, MCP-1, and IFN-γ) as well as a decrease in the mRNA expression of IL-10 as compared with young animals. Pro-apoptotic genes (Bax, Bad, and AIF) were significantly enhanced in liver after I/R, without differences between young and mature animals. However, the expression of Bcl2 gene did not show any change. Melatonin treatment was able to lower the expression of pro-inflammatory cytokines and pro-apoptotic genes and to improve liver function, as indicated by normalization of plasma AST and ALT levels and by reduction of necrosis and microsteatosis areas.

CONCLUSIONS

Melatonin treatment was able to reduce the I/R-stimulated pro-inflammatory and pro-apoptotic genes in the rat liver. Since older animals showed a more marked increase in inflammation and in liver injury, the treatment was more effective in those subjects.

Green tea extract ameliorates reperfusion injury to rat livers after warm ischemia in a dose-dependent manner

SCOPE

Polyphenolic constituents of green tea (Camellia sinensis) have been shown to be potent scavengers of reactive oxygen species (ROS). Thus, this study was designed to assess its effects after liver ischemia-reperfusion.

METHODS AND RESULTS

Fasted Sprague-Dawley rats were gavaged with different concentrations of green tea extract (GTE) 2 h before 90 min of warm ischemia of the left lateral liver lobe (30% of liver). Controls were given the same volume of Ringer's solution. A preparation of pentobarbital sodium (intraperitoneal) and ketamine (intramuscular) was used for anesthesia. After reperfusion, transaminases, liver histology, hepatic microcirculation, and both phagocytosis of latex bead particles as well as the expression of tumor necrosis alpha (TNF-α) to index cellular activation were investigated. Furthermore, the expression of superoxide dismutase (Mn-SOD) was assessed. After 90 min of warm ischemia aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) increased dramatically to 1946 ± 272/3244 ± 757 U/L, 1680 ± 134/2080 ± 379 U/L, and 7857 ± 1851/2036 ± 1193 U/L at 2/6 h, respectively. GTE (200 mg/kgbody weight) significantly prevented this increase in a dose-dependent manner by 21-51% at 2 h and 29-34% at 6 h, respectively. Histology confirmed the protective effects while both TNF-α expression and phagocytosis of latex beads by Kupffer cells (KCs) were significantly reduced. GTE intake significantly increased the expression of manganese superoxide dismutase. In vivo microscopy revealed improved acinar and sinusoidal perfusion after GTE.

CONCLUSION

Preconditioning with a single oral dose of GTE ameliorates ischemia-reperfusion injury in liver. Decreased cellular activation and improved microcirculation are the proposed mechanisms.

The use of high-dose melatonin in liver resection is safe: first clinical experience

Experimental data suggest that melatonin decreases inflammatory changes after major liver resection, thus positively influencing the postoperative course. To assess the safety of a preoperative single dose of melatonin in patients undergoing major liver resection, a randomized controlled double-blind pilot clinical trial with two parallel study arms was designed at the Department of General and Transplantation Surgery, Ruprecht-Karls-University, Heidelberg. A total of 307 patients, who were referred for liver surgery, were screened. One hundred and thirteen patients, for whom a major liver resection (≥3 segments) was scheduled, were eligible. Sixty-three eligible patients refused to participate, and therefore, 50 patients were randomized. A preoperative single dose of melatonin (50 mg/kg BW) dissolved in 250 mL of milk was administered through the gastric tube after the intubation for general anesthesia. Controls were given the same amount of microcrystalline cellulose. Primary endpoint was safety. Secondary endpoints were postoperative complications. Melatonin was effectively absorbed with serum concentrations of 1142.8 ± 7.2 ng/mL (mean ± S.E.M.) versus 0.3 ± 7.8 ng/mL in controls (P < 0.0001). Melatonin treatment resulted in lower postoperative transaminases over the study period (P = 0.6). There was no serious adverse event in patients after melatonin treatment. A total of three infectious complications occurred in either group. A total of eight noninfectious complications occurred in five control patients, whereas three noninfectious complications occurred in three patients receiving preoperative melatonin (P = 0.3). There was a trend toward shorter ICU stay and total hospital stay after melatonin treatment. Therefore, a single preoperative enteral dose of melatonin is effectively absorbed and is safe and well tolerated in patients undergoing major liver surgery.

Hepatoprotective actions of melatonin: Possible mediation by melatonin receptors

Melatonin, the hormone of darkness and messenger of the photoperiod, is also well known to exhibit strong direct and indirect antioxidant properties. Melatonin has previously been demonstrated to be a powerful organ protective substance in numerous models of injury; these beneficial effects have been attributed to the hormone’s intense radical scavenging capacity. The present report reviews the hepatoprotective potential of the pineal hormone in various models of oxidative stress in vivo, and summarizes the extensive literature showing that melatonin may be a suitable experimental substance to reduce liver damage after sepsis, hemorrhagic shock, ischemia/reperfusion, and in numerous models of toxic liver injury. Melatonin’s influence on hepatic antioxidant enzymes and other potentially relevant pathways, such as nitric oxide signaling, hepatic cytokine and heat shock protein expression, are evaluated. Based on recent literature demonstrating the functional relevance of melatonin receptor activation for hepatic organ protection, this article finally suggests that melatonin receptors could mediate the hepatoprotective actions of melatonin therapy.

Hepatoprotective actions of melatonin: possible mediation by melatonin receptors

Melatonin, the hormone of darkness and messenger of the photoperiod, is also well known to exhibit strong direct and indirect antioxidant properties. Melatonin has previously been demonstrated to be a powerful organ protective substance in numerous models of injury; these beneficial effects have been attributed to the hormone's intense radical scavenging capacity. The present report reviews the hepatoprotective potential of the pineal hormone in various models of oxidative stress in vivo, and summarizes the extensive literature showing that melatonin may be a suitable experimental substance to reduce liver damage after sepsis, hemorrhagic shock, ischemia/reperfusion, and in numerous models of toxic liver injury. Melatonin's influence on hepatic antioxidant enzymes and other potentially relevant pathways, such as nitric oxide signaling, hepatic cytokine and heat shock protein expression, are evaluated. Based on recent literature demonstrating the functional relevance of melatonin receptor activation for hepatic organ protection, this article finally suggests that melatonin receptors could mediate the hepatoprotective actions of melatonin therapy.

Systematic review of randomized controlled trials of pharmacological interventions to reduce ischaemia-reperfusion injury in elective liver resection with vascular occlusion

BACKGROUND

Vascular occlusion during liver resection results in ischaemia-reperfusion (IR) injury, which can lead to liver dysfunction. We performed a systematic review and meta-analysis to assess the benefits and harms of using various pharmacological agents to decrease IR injury during liver resection with vascular occlusion.

METHODS

Randomized clinical trials (RCTs) evaluating pharmacological agents in liver resections conducted under vascular occlusion were identified. Two independent reviewers extracted data on population characteristics and risk of bias in the trials, and on outcomes such as postoperative morbidity, hospital stay and liver function.

RESULTS

A total of 18 RCTs evaluating 17 different pharmacological interventions were identified. There was no significant difference in perioperative mortality, liver failure or postoperative morbidity between the intervention and control groups in any of the comparisons. A significant improvement in liver function was seen with methylprednisolone use. Hospital and intensive therapy unit stay were significantly shortened with trimetazidine and vitamin E use, respectively. Markers of liver parenchymal injury were significantly lower in the methylprednisolone, trimetazidine, dextrose and ulinastatin groups compared with their respective controls (placebo or no intervention).

DISCUSSION

Methylprednisolone, trimetazidine, dextrose and ulinastatin may have protective roles against IR injury in liver resection. However, based on the current evidence, they cannot be recommended for routine use and their application should be restricted to RCTs.

Pharmacological interventions versus no pharmacological intervention for ischaemia reperfusion injury in liver resection surgery performed under vascular control

BACKGROUND

Vascular occlusion to reduce blood loss is used during elective liver resection but results in significant ischaemia reperfusion injury. This, in turn, might lead to significant postoperative liver dysfunction and morbidity. Various pharmacological drugs have been used with an intention to ameliorate the ischaemia reperfusion injury in liver resections.

OBJECTIVES

To assess the benefits and harms of different pharmacological agents versus no pharmacological interventions to decrease ischaemia reperfusion injury during liver resections where vascular occlusion was performed during the surgery.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until January 2009.

SELECTION CRITERIA

We included randomised clinical trials, irrespective of language or publication status, comparing any pharmacological agent versus placebo or no pharmacological agent during elective liver resections with vascular occlusion.

DATA COLLECTION AND ANALYSIS

Two authors independently identified trials for inclusion and independently extracted the data. We analysed the data with both the fixed-effect and the random-effects models using RevMan Analysis. We calculated the risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI) based on intention-to-treat analysis or available case analysis.

MAIN RESULTS

We identified a total of 15 randomised trials evaluating 11 different pharmacological interventions (methylprednisolone, multivitamin antioxidant infusion, vitamin E infusion, amrinone, prostaglandin E1, pentoxifylline, mannitol, trimetazidine, dextrose, allopurinol, and OKY 046 (a thromboxane A2 synthetase inhibitor)). All trials had high risk of bias. There were no significant differences between the groups in mortality, liver failure, or perioperative morbidity. The trimetazidine group had a significantly shorter hospital stay than control (MD -3.00 days; 95% CI -3.57 to -2.43). There were no significant differences in any of the clinically relevant outcomes in the remaining comparisons. Methylprednisolone improved the enzyme markers of liver function and trimetazidine, methylprednisolone, and dextrose reduced the enzyme markers of liver injury compared with controls. However, there is a high risk of type I and type II errors because of the few trials included, the small sample size in each trial, and the risk of bias.

AUTHORS' CONCLUSIONS

Trimetazidine, methylprednisolone, and dextrose may protect against ischaemia reperfusion injury in elective liver resections performed under vascular occlusion, but this is shown in trials with small sample sizes and high risk of bias. The use of these drugs should be restricted to well-designed randomised clinical trials before implementing them in clinical practice.

Pharmacological interventions for ischaemia reperfusion injury in liver resection surgery performed under vascular control

BACKGROUND

Vascular occlusion used during elective liver resection to reduce blood loss results in significant ischaemia reperfusion (IR) injury. This in turn leads to significant postoperative liver dysfunction and morbidity. Various pharmacological drugs have been used in experimental settings to ameliorate the ischaemia reperfusion injury in liver resections.

OBJECTIVES

To assess the relative benefits and harms of using one pharmacological intervention versus another pharmacological intervention to decrease ischaemia reperfusion injury during liver resections where vascular occlusion was performed during the surgery.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until January 2009.

SELECTION CRITERIA

We included randomised clinical trials, irrespective of language or publication status, comparing one pharmacological agent versus another pharmacological agent during elective liver resections with vascular occlusion.

DATA COLLECTION AND ANALYSIS

Two authors independently identified trials for inclusion and independently extracted data. We analysed the data with both the fixed-effect and the random-effects models using RevMan Analysis. We planned to calculate the risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI) based on intention-to-treat analysis or available case analysis. However, all outcomes were only reported on by single trials, and meta-analysis could not be performed. Therefore, we performed Fisher's exact test on dichotomous outcomes.

MAIN RESULTS

We identified a total of five randomised trials evaluating nine different pharmacological interventions (amrinone, prostaglandin E1, pentoxifylline, dopexamine, dopamine, ulinastatin, gantaile, sevoflurane, and propofol). All trials had high risk of bias. There was no significant difference between the groups in mortality, liver failure, or perioperative morbidity. The ulinastatin group had significantly lower postoperative enzyme markers of liver injury compared with the gantaile group. None of the other comparisons showed any difference in any of the other outcomes. However, there is a high risk of type I and type II errors because of the few trials included, the small sample size in each trial, and the risk of bias.

AUTHORS' CONCLUSIONS

Ulinastatin may have a protective effect against ischaemia reperfusion injury relative to gantaile in elective liver resections performed under vascular occlusion. The absolute benefit of this drug agent remains unknown. None of the drugs can be recommended for routine clinical practice. Considering that none of the drugs have proven to be useful to decrease ischaemia reperfusion injury, such trials should include a group of patients who do not receive any active intervention whenever possible to determine the pharmacological drug's absolute effects on ischaemia reperfusion injury in liver resections.

Melatonin protects kidney grafts from ischemia/reperfusion injury through inhibition of NF-kB and apoptosis after experimental kidney transplantation

Free radicals are involved in pathophysiology of ischemia/reperfusion injury (IRI). Melatonin is a potent scavenger of reactive oxygen and nitrogen species. Thus, this study was designed to elucidate its effects in a model of rat kidney transplantation. Twenty Lewis rats were randomly divided into 2 groups (n = 10 animals each). Melatonin (50 mg/kg BW) dissolved in 5 mL milk was given to one group via gavage 2 hr before left donor nephrectomy. Controls were given the same volume of milk only. Kidney grafts were then transplanted into bilaterally nephrectomized syngeneic recipients after 24 hr of cold storage in Histidine-Tryptophan-Ketoglutarate solution. Both graft function and injury were assessed after transplantation through serum levels of blood urea nitrogen (BUN), creatinine, transaminases, and lactate dehydrogenase (LDH). Biopsies were taken to evaluate tubular damage, the enzymatic activity of superoxide dismutase (SOD) and lipid hydroperoxide (LPO), and the expression of NF-kBp65, inducible nitric oxide synthase (iNOS), caspase-3 as indices of oxidative stress, necrosis, and apoptosis, respectively. Melatonin improved survival (P < 0.01) while decreasing BUN, creatinine, transaminases, and LDH values up to 39-71% (P < 0.05). Melatonin significantly reduced the histological index for tubular damage, induced tissue enzymatic activity of SOD while reducing LPO. At the same time, melatonin down-regulated the expression of NF-kBp65, iNOS, and caspase-3. In conclusion, donor preconditioning with melatonin protected kidney donor grafts from IRI-induced renal dysfunction and tubular injury most likely through its anti-oxidative, anti-apoptotic and NF-kB inhibitory capacity.