Comparison of histopathologic effects of carnitine and ascorbic acid on reperfusion injury

The Effect of High-Dose Vitamin C on Biochemical Markers of Myocardial Injury in Coronary Artery Bypass Surgery

OBJECTIVE

To evaluate the effect of high-dose vitamin C on cardiac reperfusion injury and plasma levels of creatine kinase-muscle/brain (CK-MB), troponin I, and lactate dehydrogenase (LDH) in patients undergoing coronary artery bypass grafting (CABG).

METHODS

This is a double-blind randomized clinical trial study. Fifty patients (50-80 years old) who had CABG surgery were selected. The intervention group received 5 g of intravenous vitamin C before anesthesia induction and 5 g of vitamin C in cardioplegic solution. The control group received the same amount of placebo (normal saline). Arterial blood samples were taken to determine the serum levels of CK-MB, troponin I, and LDH enzymes. Left ventricular ejection fraction was measured and hemodynamic parameters were recorded at intervals.

RESULTS

High doses of vitamin C in the treatment group led to improvement of ventricular function (ejection fraction [EF]) and low Intensive Care Unit (ICU) stay. The cardiac enzymes level in the vitamin C group was lower than in the control group. These changes were not significant between the groups in different time intervals (anesthesia induction, end of bypass, 6 h after surgery, and 24 h after surgery) for CK-MB, LDH, and troponin I. Hemodynamic parameters, hematocrit, potassium, urinary output, blood transfusion, arrhythmia, and inotropic support showed no significant difference between the groups.

CONCLUSION

Vitamin C has significantly improved the patients' ventricular function (EF) 72 h after surgery and reduced the length of ICU stay. No significant changes in cardiac biomarkers, including CK-MB, troponin I, and LDH, were seen over time in each group.

IRCT CODE

IRCT2016053019470N33.

Curcumin and dexmedetomidine prevents oxidative stress and renal injury in hind limb ischemia/reperfusion injury in a rat model

Curcumin and dexmedetomidine have been shown to have protective effects in ischemia-reperfusion injury on various organs. However, their protective effects on kidney tissue against ischemia-reperfusion injury remain unclear. We aimed to determine whether curcumin or dexmedetomidine prevents renal tissue from injury that was induced by hind limb ischemia-reperfusion in rats. Fifty rats were divided into five groups: sham, control, curcumin (CUR) group (200 mg/kg curcumin, n = 10), dexmedetomidine (DEX) group (25 μg/kg dexmedetomidine, n = 10), and curcumin-dexmedetomidine (CUR-DEX) group (200 mg/kg curcumin and 25 μg/kg dexmedetomidine). Curcumin and dexmedetomidine were administered intraperitoneally immediately after the end of 4 h ischemia, just 5 min before reperfusion. The extremity re-perfused for 2 h and then blood samples were taken and total antioxidant capacity (TAC), total oxidative status (TOS) levels, and oxidative stress index (OSI) were measured, and renal tissue samples were histopathologically examined. The TAC activity levels in blood samples were significantly lower in the control than the other groups (p < 0.01 for all comparisons). The TOS activity levels in blood samples were significantly higher in Control group and than the other groups (p <  0.01 for all comparison). The OSI were found to be significantly increased in the control group compared to others groups (p < 0.001 for all comparisons). Histopathological examination revealed less severe lesions in the sham, CUR, DEX, and CUR-DEX groups, compared with the control group (p < 0.01). Rat hind limb ischemia-reperfusion causes histopathological changes in the kidneys. Curcumin and dexmedetomidine administered intraperitoneally was effective in reducing oxidative stress and renal histopathologic injury in an acute hind limb I/R rat model.

Potential protective effects of l-carnitine against neuromuscular ischemia-reperfusion injury: From experimental data to potential clinical applications

BACKGROUND & AIM

Ischemia-reperfusion (I/R) injury plays important role in morbidity and mortality in several pathologies, including myocardial infarction, ischemic stroke, acute kidney injury, trauma, and circulatory arrest. An imbalance in metabolic supply and tissue's demand during ischemia results in profound tissue hypoxia and microvascular dysfunction. Subsequently, reperfusion further results in activation of immune responses and cell death programs. l-carnitine and its derivatives have been administered to improve tolerance against I/R injury in various tissues. Anti-ischemic properties of l-carnitine and its derivative in neuromuscular organs will be reviewed here at the light of pertinent results from basic and clinical researches.

METHOD

All available in vitro and in vivo studies, patents, clinical trials, and meeting abstracts in English language that examined the protective effects of l-carnitine against I/R induced injury in neuromuscular organs were reviewed. Materials were obtained by searching ELSEVIER, web of knowledge, PubMed, Scopus, clinical trials, and Cochrane database of systematic reviews.

CONCLUSION

Although animal studies on central nervous system and some human studies on muscular system were in favors of effects of l-carnitine against I/R injury, however, more clinical trials are needed to clarify the clinical importance of l-carnitine as a treatment option to manage I/R-induced injury of neuromuscular system.

The effects of exogenous l-carnitine on lipid peroxidation and tissue damage in an experimental warm hepatic ischemia-reperfusion injury model

BACKGROUND

l-Carnitine is the essential endogenous factor for the transport of long-chain fatty acids from the cytoplasm to within the mitochondrion where the β-oxidation process takes place. l-Carnitine is a superoxide scavenger and an antioxidant that possesses an anti-ischemic action and a stabilizing effect on cell membranes. It may be of help in liver ischemia reperfusion injury. RESULTS regarding the effects of l-carnitine on liver ischemia and reperfusion injury are few and conflicting.

OBJECTIVE

The aim of this study was to investigate the efficacy of exogenous l-carnitine on lipid peroxidation and protecting liver at different stages of experimental total warm hepatic ischemia-reperfusion (TWHIR) procedure in rats.

METHODS

This experimental study in healthy, weanling, male Wistar rats (weighing 180-200 g) was conducted at the Experimental Animal Research Laboratory of the Faculty of Medicine of Mersin University, Mersin, Turkey. Rats were randomly divided into 5 groups: (A) Control group; (B) TWHIR procedure only; (C) l-carnitine administered 2 hours before the TWHIR procedure; (D) l-carnitine administered just before the TWHIR procedure; and (E) l-carnitine administered after total warm hepatic ischemia but just before the reperfusion procedure. Total warm hepatic ischemia (via the Pringle maneuver) and reperfusion were performed for 45 and 30 minutes, respectively. l-Carnitine (200 mg/kg) was administered intravenously. At the end of each procedure a blood sample was drawn and total hepatectomy was performed following reperfusion. Malondialdehyde (MDA) and myeloperoxidase (MPO) levels of both plasma and liver tissue, total antioxidant capacity (TAOC), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in plasma, and histopathologic examination were analyzed to assess lipid peroxidation and damage in liver tissue.

RESULTS

Thirty-four rats (mean [SD]age, 59.26 [1.2]days; mean [SD] weight, 194.1 [5.1] g) were used in the study. There was a significant difference observed between groups A (n = 5) and B (n = 5) for all evaluation parameters. The TWHIR procedure performed in group B was associated with significant increases versus baseline in ALT, AST, MDA, and MPO in plasma, and MDA and MPO in liver tissue, but a significant decrease of TAOC in plasma. ALT, AST, serum and liver MDA, and MPO levels of group B were significantly higher than all groups administered l-carnitine. l-Carnitine administration between total warm hepatic ischemia and reperfusion was associated with a significant attenuation in all parameters. The liver MDA levels of groups C (n = 8) and D (n = 8) were significantly lower than that of group E (n = 8) (mean [SD]: C, 16.53 [3.32] and D, 18.28 [1.67] vs E, 23.05 [3.52]; P = 0.001 and P = 0.016, respectively). The mean (SD) liver MPO level of group C (1.09 [0.16]) was significantly lower than that of groups D (2.12 [0.25]) and E (2.11 [0.28]) (both, P = 0.001). The TAOC of group B (0.77 [0.12]) was significantly lower than that of groups C (1.34 [0.19]) and D (1.08 [0.20]) (P = 0.001 and P = 0.015, respectively). The TAOC of group C was significantly higher than that of the other l-carnitine groups (E, 0.94 [0.13]) (P = 0.023 vs group D; and P = 0.001 vs group E). Histopathologic scores of groups A, C, and E were significantly lower than that of group B, but the difference between groups B and D was not statistically significant.

CONCLUSIONS

In this experimental study, administration of exogenous l-carnitine was associated with significantly decreased lipid peroxidation in plasma and liver tissue when administered prior to a TWHIR procedure. In addition, l-carnitine seemed to be more effective with regard to decreasing lipid peroxidation in liver tissue when administered before warm hepatic ischemia. l-Carnitine was associated with significantly decreased leukocyte sequestration in plasma and liver tissue. A significant increase in TAOC was associated with l-carnitine administered prior to ischemia. These observations suggest that l-carnitine might have a protective effect against ischemia-reperfusion injury in rat liver tissue.

Protective effect of N-acetylcysteine on kidney as a remote organ after skeletal muscle ischemia-reperfusion

PURPOSE: To investigate whether N-acetylcysteine has a protective effect against renal injury as a remote organ after skeletal muscle ischemia-reperfusion in rats. METHODS: Twenty Wistar male rats were divided randomly into two experimental groups: group ischemia-reperfusion (group I) and group ischemia-reperfusion + N-acetylcysteine (group II). After ketamine and xylazine anesthesia, femoral artery was exposed. All animals were undergone 2h of ischemia by occlusion femoral artery and 24h of reperfusion. Rats that were treated with N-acetylcysteine given IV at a dose of 150 mg/kg-¹, immediately before reperfusion. After 24h of reperfusion, the blood samples were collected and submitted for evaluation of plasmatic urea, creatinine values and then rats were euthanized and left kidney harvested for histopathological analysis under light microscopy. RESULTS: The urea (35±7.84 mg.dL-1), creatinine (1.46±0.47 mg.dL-1) values were significantly lower in group II (P=0.000). Renal histopathologic study in group I showed extensive distal and proximal tubular cells necrosis and sloughing of epithelial cells into the tubular lumen, cast formation in tubule and glomerul, glomerul fibrosis and hemorrhage. Histopathologically, there was a significant difference (p=0.037) between two groups. CONCLUSION: The N-acetylcysteine was able to decrease renal injury induced by skeletal muscle ischemia reperfusion in rats.

Effect of high-dose vitamin C on oxygen free radical production and myocardial enzyme after tourniquet ischaemia-reperfusion injury during bilateral total knee replacement

This study investigated the effects of high-dose vitamin C on oxygen free radical production and cardiac enzymes after tourniquet application and ischaemia-reperfusion injury during bilateral total knee replacement (TKR) in elderly patients. In the vitamin C (VC) group (VC group, n = 16), during surgery, patients received a priming bolus of 0.06 g/kg vitamin C with 100 ml saline followed by 0.02 g/kg vitamin C mixed with 30 ml saline, intravenously. The control group (n = 16) received no intra-operative vitamin C. In the VC group, malondialdehyde levels were lower, and arterial oxygen tension and mean blood pressure were higher, than in controls after post-operative deflation of both knee tourniquets. Troponin I levels were lower in the VC group than in controls 8 h post-operation. Administering high-dose vitamin C during bilateral TKR could prevent oxygen free radical production and a decline in arterial oxygen tension and mean blood pressure induced by ischaemia-reperfusion injury, thereby protecting the myocardium.

Iloprost, a prostacyclin (PGI2) analogue, reduces liver injury in hepatic ischemiareperfusion in rats

PURPOSE: To evaluate the effects of iloprost a prostacyclin analogue on the hepatic IR injury in rats. METHODS: Forty male Sprague-Dawley rats (250-300 g) were divided into four groups each containing 10 rats;(1)- controls: data from unmanipulated animals; (2) sham group: rats subjected to the surgical procedure, except for liver I/R, and given saline; (3) I/R group: rats that underwent liver ischemia for 45 min followed by reperfusion for 45 min; (4) IR/ Iloprost group: rats pretreated with iloprost (10 µg kg-1, i.v). Liver tissues were taken to determine SOD, CAT, GSH, and MDA levels and for biochemical and histological evaluation. RESULTS: The plasma ALT and AST levels were increased in group 3 than in group 4. MDA values and the liver injury score decreased, while the SOD, CAT, and GSH values increased in group 4 compared to group 3. In group 3, hepatocytes were swollen with marked vacuolization. In group 4, there were regular sinusoidal structures with normal morphology without any signs of congestion. CONCLUSION: We demonstrated hepatoprotective effects of iloprost against severe ischemia and reperfusion injury in rat liver.

Perioperative thrombotic occlusion of left external iliac artery during anterior lumbar interbody fusion

We report a case of thrombotic occlusion of left external iliac artery during the procedure of anterior lumbar interbody fusion. The diagnosis was confirmed by computed tomography angiography. The patient also developed severe rhabdomyolysis postoperatively. In spite of receiving emergent thromboendarterectomy, the patient expired on postoperative day 3. This report attempts to remind spinal surgeons and anesthesiologists of this rare but potentially fatal complication, and discuss the possible mechanism, management, and prevention.

The effects of iloprost and vitamin C on kidney as a remote organ after ischemia/reperfusion of lower extremities

BACKGROUND

Abdominal aortic surgery can cause ischemic/reperfusion (I/R) injury in not only the lower extremities, but also in the remote organs and tissues such as lungs, kidneys, heart, and liver during abdominal aortic surgery. It can result in mortality and morbidity because of the remote organ injury in early postoperative period. In this study, we investigate the effects of iloprost and vitamin C on the kidney remote organ damage after I/R following abdominal aortic surgery.

MATERIAL AND METHODS

Thirty-four adult male Wistar rats were used and divided into five groups. I/R was studied infrarenally in the abdominal aorta following a median laparotomy. The left kidney was excised immediately following the laparotomy in group I (n = 6, normal group). Group II (n = 6) was the sham group. Group III (n = 6, control group) was subjected to 3 h of ischemia followed by an hour of reperfusion. Group IV (n = 8) was given iloprost 20 ng/kg/min during I/R period before aortic-clamping. Group V (n = 8) was given vitamin C 100 mg/kg during I/R period before aortic-clamping. Arterial blood samples were obtained to determine the levels of blood pH, pO(2) (mmHg), pCO2 (mmHg), HCO(3) (mmol/L), and plasma malondialdehyde (MDA, nmol/mL) at the end of reperfusion period in all groups. The left kidneys were used for remote measurements of tissue MDA (nmol/g.w.t) and scored by histopathological examination for acute inflammation.

RESULTS

While the arterial blood pO(2) and HCO(3) levels significantly increased, the plasma and renal parenchymal MDA levels significantly decreased in both group IV and group V when compared to group III (P < 0.05). Histopathological and acute inflammation scores statistically decreased in both group IV and V compared with group III (P < 0.05). Although MDA levels, histopathologic and acute inflammation scores in group V were lower than group IV, the differences were not statistically significant (P > 0.05).

CONCLUSION

Both iloprost and vitamin C decreased remote organ damage on the kidney after I/R of lower extremities in the rat model. However, vitamin C is more effective than iloprost in preventing postoperative renal dysfunction.

Cardioprotective effect of aprotinin on myocardial ischemia/reperfusion injury during cardiopulmonary bypass

BACKGROUND

Aprotinin is a serine protease inhibitor used extensively in cardiac operations to reduce postoperative bleeding. It also has cardioprotective effects in ischemia/reperfusion injury. In this study, the effects of aprotinin on the release of cardiac markers were evaluated in patients who had good ventricular function and were undergoing coronary artery bypass grafting with cardiopulmonary bypass (CPB).

METHODS AND RESULTS

Eighty male patients with an ejection fraction >or=40%, were randomized into either an aprotinin (Group-I; n=40) or control (Group-II; n=40) group. Patients in the aprotinin group received the full Hammersmith doses of aprotinin (2 x 10(6) KIU pre-CPB, 2 x 10(6) KIU at pump prime, 500,000 KIU/h during CPB), whereas the patients in the control group received only saline solutions. Cardiac troponin-I (cTnI) levels were measured before surgery, immediately after surgery, and at postoperative 6(th), 12(th), 24(th) h and 5(th) day. Creatine kinase (CK)-MB measurements were performed at the same time except for the postoperative 5(th) day. Cardiac index (CI), mixed venous oxygen saturation and lactate dehydrogenase (LDH) measurements were also performed.

CONCLUSION

Although all patients were in reasonable condition, less myocardial enzyme leakage occurred on the aprotinin group, suggesting that aprotinin has a protective effect on the myocardium beyond that achieved with blood cardioplegia and systemic hypothermia. Because of aprotinin's effects on multiple targets of metabolism, its protective value might increase in more complicated cases.

Ascorbic acid (vitamin C) and iloprost attenuate the lung injury caused by ischemia/reperfusion of the lower extremities of rats

The objectives of this study were to compare the protective effects of ascorbic acid and iloprost on lung injury caused by ischemia reperfusion (I/R) of the lower extremities of rats. Wistar albino rats (n = 34) were divided into five groups. In the I/R group (n = 6), the aorta was cross-clamped for 3 hr, followed by 1 hr of reperfusion. In the vitamin C group (n = 8), animals were pretreated with 100 mg/kg ascorbic acid via the left jugular vein before aortic cross-clamping. In the iloprost group (n = 8), animals were pretreated with 20 ng/(kg x min) iloprost by constant intravenous infusion via the left jugular venous cannula. In the sham group (n = 6), the abdomen was left open at the same period and a juguler venous line was established. In the control group (n = 6), lungs were removed and blood samples taken immediately after sternotomy. No treatment was given in this group. After both lungs were removed, biochemical parameters were measured and histopathological evaluation was made. Although the arterial blood pO2 and HCO3 levels were statistically significantly high in both the vitamin C and iloprost groups compared to the I/R group, plasma malondialdehyde (MDA) levels were significantly low. Meanwhile, the MDA levels in the lung tissue were significantly low in the vitamin C group compared to the I/R group. The MDA level in the lung tissue in the iloprost group was also low compared to the I/R group, but it was not statistically significant. The lungs of the I/R group displayed intense interstitial leukocytic infiltration in histopathological examination compared to the other groups. Pretreatment of animals with iloprost and vitamin C significantly decreased the pulmonary injury characterized by decreased plasma leukocyte sequestration. The results suggest that both vitamin C and iloprost are useful agents for attenuating the lung injury caused by increased oxidative stress and neutrophil accumulation after a period of I/R of the lower extremities.

Differential healing activities of CD34+ and CD14+ endothelial cell progenitors

OBJECTIVE

Peripheral blood contains primitive (stem cell-like) and monocytic-like endothelial cell progenitors. Diabetes apparently converts these primitive progenitors, from a pro-angiogenic to anti-angiogenic phenotype. Monocytic progenitors seem to be less affected by diabetes, but potential pro-angiogenic activities of freshly isolated monocytic progenitors remain unexplored. We compared the ability of primitive and monocytic endothelial cell progenitors to stimulate vascular growth and healing in diabetes and investigated potential molecular mechanisms through which the cells mediate their in vivo effects.

METHODS AND RESULTS

Human CD34+ primitive progenitors and CD14+ monocytic progenitors were injected locally into the ischemic limbs of diabetic mice. CD14+ cell therapy improved healing and vessel growth, although not as rapidly or effectively as CD34+ cell treatment. Western blot analysis revealed that cell therapy modulated expression of molecules in the VEGF, MCP-1, and angiopoietin pathways.

CONCLUSIONS

Injection of freshly isolated circulating CD14+ cells improves healing and vascular growth indicating their potential for use in acute clinical settings. Importantly, CD14+ cells could provide a therapeutic option for people with diabetes, the function of whose CD34+ cells may be compromised. At least some progenitor-induced healing probably is mediated through increased sensitivity to VEGF and increases in MCP-1, and possibly modulation of angiopoietins.

PROTECTIVE EFFECTS OF l-CARNITINE ON MYOGLOBINURIC ACUTE RENAL FAILURE IN RATS

1. Muscle injury (rhabdomyolysis) is one of the causes of acute renal failure (ARF). Iron, free radicals and nitric oxide (NO) play a critical role in the pathogenesis of glycerol-induced myoglobinuric ARF. L-Carnitine is an anti-oxidant and prevents the accumulation of end-products of lipid peroxidation. Therefore, the aim of the present study was to investigate the effects of L-carnitine on myoglobinuric ARF induced by intramuscular (i.m.) hypertonic glycerol injection. 2. Sprague-Dawley rats were divided into three groups. Rats in group 1 (n = 8) were given saline, whereas those in groups 2 (n = 10) and 3 (n = 10) were injected with glycerol (10 mL/kg, i.m.). Concomitant with and 24 h after glycerol injection, L-carnitine (200 mg/kg, i.p.) was administered to group 3 rats. Forty-eight hours after glycerol injection, blood samples and kidney tissues were taken from anaesthetised rats. 3. Plasma creatine kinase (CK) activity, urea, creatinine and NO levels, as well as kidney tissue superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) enzyme activity and malondialdehyde (MDA) and glutathione (GSH) levels, were determined. In the kidney tissue, histopathological changes and iron accumulation in the tubular epithelium were also investigated. 4. Glycerol treatment caused severe ARF: a marked renal oxidative stress, significantly increased CK activity, urea and creatinine levels and decreased plasma NO levels. Histopathological findings in group 2 rats confirmed that there was renal impairment by cast formation and tubular necrosis and a marked increase in iron accumulation in the tubular epithelium. All these factors were significantly improved by L-carnitine supplementation. 5. These results may indicate that L-carnitine treatment protects against functional, biochemical and morphological damage and iron accumulation in glycerol-induced myoglobinuric ARF in rats. In this model, the protective effect of L-carnitine treatment may provide a new insight into the treatment of rhabdomyolysis-related ARF.

Effects of propionyl-carnitine in patients with type 2 diabetes and peripheral vascular disease: results of a pilot trial

OBJECTIVE

To assess the efficacy of propionyl-carnitine (PC) in patients with type 2 diabetes and peripheral arterial disease (PAD).

PATIENTS AND METHODS

This was an open pharmacodynamic study. Twenty-four obese patients with type 2 diabetes and PAD (stage IIb) were enrolled in the study. After an initial run-in period of 7 days on a low-calorie diet (1600 +/- 150 kcal/day), patients received intravenous PC (600mg in 100mL saline solution Na/K 0.9%) twice daily for 10 days (T1).

RESULTS

Treatment with PC produced statistically significant increases in maximal walking distance (30%; p < 0.05) and initial claudication distance (15%; p < 0.05) in 15 and eight patients, respectively. In addition, a decrease in dosage of oral antihyperglycaemic agents was observed in 21 patients at T1. No PC-related adverse effects were reported.

CONCLUSIONS

This study showed that acute intravenous administration of PC in patients with type 2 diabetes with PAD improved PAD-related symptoms as well as glycaemic control.

The Effect of Melatonin on Plasma Oxidant-Antioxidant Skeletal Muscle Reperfusion Injury in Rats

We investigated the effects of melatonin administration on skeletal muscle ischaemia-reperfusion injury (IRI) by assessing plasma malondialdehyde (MDA), superoxide dismutase (SOD), total glutathione (GSSH), glutathione peroxidase (GPX) and myeloperoxidase (MPO) concentrations. Male Sprague-Dawley rats ( n = 32) were randomized into four groups: group 1 served as time controls; group 2 were the test animals; group 3 received melatonin (30 mg/kg) intraperitoneally prior to the induction of ischaemia; and group 4 received melatonin (30 mg/kg) intraperitoneally prior to the reperfusion period. Administration of melatonin prior to reperfusion significantly decreased the elevated MDA concentration caused by IRI, and significantly elevated GSSH concentrations, which had been reduced by IRI. Ischaemia-reperfusion injury significantly increased activities of GPX, SOD and MPO, and melatonin administration reversed this effect. In conclusion, a pharmacological dose of melatonin showed significant protective effects against IRI by decreasing lipid peroxidation, MPO, SOD and GPX enzyme activities and regulating glutathione content.