Evaluation of DNA damage after tourniquet-induced ischaemia/reperfusion injury during lower extremity surgery

Mechanisms and Interventions on Acute Lower Limb Ischemia/Reperfusion Injury: A Review and Insights from Cell to Clinical Investigations

AIM

This review aims to highlight mechanistic insights on skeletal muscle ischemia/reperfusion injury (IRI), a potentially life-threatening complication after acute lower limb ischemia. Lower limb IRI produces a wide spectrum of manifestations, ranging from local skeletal muscle necrosis to multi-organ failure. There is increasing evidence from both in vitro and in vivo reports to demonstrate several promising interventions that have successfully reduced IRI in skeletal muscle ischemic models. However, clinical studies to confirm their benefits are still lacking.

METHOD

We conducted a comprehensive search of English literature listed in the PubMed database (All related published articles shown in PubMed until September 2020 have been included in this review), using the following keywords: acute limb ischemia, acute arterial occlusion, compartment syndrome, ischemic reperfusion injury, revascularization and hypoxic reoxygenation.

RESULT

58 articles pertinent to acute limb ischemia models were identified. The underlying mechanisms associated with IRI in skeletal muscle are due to excessive mitochondrial production of reactive oxygen species (ROS), cellular apoptosis and activation of inflammatory cascades. Several therapeutic interventions including both pharmacological and non-pharmacological treatments have been investigated and some showed promising results. These interventions include antioxidation, anti-inflammation, anti-hypertension, controlled-reperfusion and ischemic preconditioning. Further clinical studies are needed to warrant their use in a clinical setting for lower limb IRI treatment.

CONCLUSION

This review comprehensively summarizes the mechanisms underlying IRI in lower limb ischemia. The reports currently available regarding the potential therapeutic interventions against lower limb IRI from in vitro, in vivo and clinical studies are presented and discussed. These findings may provide mechanistic insights for devising the strategies to improve the clinical outcomes in IRI patients in the near future. Further clinical studies are needed to warrant their use in a clinical setting for lower limb IRI treatment.

Low-molecular-weight heparin calcium attenuates the tourniquet-induced ischemia-reperfusion injury in rats

Ischemia-reperfusion injury (IRI) is a common postoperative complication of the tourniquet used surgery; low-molecular-weight heparin calcium (LMWH) is frequently used postoperatively to prevent the formation of deep venous thrombosis. However, subcutaneous hemorrhage can usually be seen in patients who underwent lower limb surgery, especially in total knee arthroplasty, the influence of LMWH on IRI remains controversial. In this experiment, we designed an animal model to observe the influence of LMWH on the skeletal muscle injury induced by tourniquets. Sprague-Dawley (SD) rats underwent either 2 h of unilateral hindlimb ischemia or anesthesia alone, at different time points of reperfusion interval, animals received either 4mg/kg LMWH or normal saline subcutaneously twice a day. The levels of inflammatory markers in serum, the expression of apoptosis proteins, as well as histological examination of skeletal muscles, were detected at 48-h reperfusion. We found that the injury of skeletal muscle and the systemic inflammatory response was less severe in LMWH-treated animals, indicating that LMWH could attenuate the tourniquet-induced IRI. In conclusion, LMWH given postoperatively after limb surgery may be clinically beneficial.

The renoprotective effects of mannitol and udenafil in renal ischemia-reperfusion injury model

Purpose

The aim of this study was to investigate and compare the effects of udenafil and mannitol in an experimental renal ischemia-reperfusion (I/R) injury model.

Materials and Methods

A total of 64 female Wister Albino rats were used. Right nephrectomy was performed in all groups. In the control group; I/R injury was not performed. In the I/R group; left renal pedicle was clamped for 45 minutes and then underwent 60 minutes and 24 hours of reperfusion. In the mannitol group; 1 mL 20% mannitol was given intravenously 15 minutes before clamping. In the udenafil group; 10-mg/kg udenafil was given orally 1 hour before clamping. Creatinine (Cr), blood urea nitrogen (BUN), Cr clearance, malondialdehyde, neutrophil gelatinase associated lipocalin (NGAL), histological examination and DNA damage (Comet Assay method) levels were compared in tissue, serum and urine samples.

Results

Udenafil had a better protective effect than mannitol according to biochemical parameters (Cr, BUN, Cr clearance, and NGAL levels) and histopathological findings when compared with the I/R group. In the Comet sampling analysis no significant difference was detected.

Conclusions

Udenafil has a better renoprotective effect than mannitol against I/R injury and this effect supports more functional improvements. Further clinical trials are needed to demonstrate those effects and clinical utility of udenafil for that purpose in humans.

Comet assay in evaluating deoxyribonucleic acid damage after out-of-hospital cardiac arrest

Objective:

This study aimed to investigate whether out-of-hospital cardiac arrest (OHCA) may induce severe DNA damage measured using comet assay in successfully resuscitated humans and to evaluate a short-term prognostic role.

Methods:

In this prospective, controlled, blinded study (1/2013–1/2014), 41 patients (age, 63±14 years) successfully resuscitated from non-traumatic OHCA and 10 healthy controls (age, 53±17 years) were enrolled. DNA damage [double-strand breaks (DSBs) and single-strand breaks (SSBs)] was measured using comet assay in peripheral lymphocytes sampled at admission. Clinical data were recorded (according to Utstein style). A good short-term prognosis was defined as survival for 30 days.

Results:

Among the patients, there were 71% (29/41) short-term survivors. After OHCA, DNA damage (DSBs and SSBs) was higher (11.0±7.6% and 0.79±2.41% in tail) among patients than among controls (1.96±1.63% and 0.02±0.03% in tail), and it was more apparent for DSBs (p<0.001 and p=0.085). There was no difference in the DNA damage between patients with cardiac and non-cardiac etiology, or between survivors and nonsurvivors. Among Utstein style parameters, ventricular fibrillation, asystole, and early electrical defibrillation influenced DSB; none of the factors influenced SSBs. Factors influencing survival were SSBs, ventricular fibrillation, length of cardiopulmonary resuscitation by professionals ≤15 min, cardiogenic shock, and postanoxic encephalopathy. In contrast to DSBs [area under the curve (AUC)=0.520], SSBs seem to have a potential in prognostication (AUC=0.639).

Conclusion:

This study for the first time demonstrates revelation of DNA damage using comet assay in patients successfully resuscitated from OHCA. Whether DNA damage measured using comet assay may be a prognostic marker remains unknown, although our data may encourage some suggestions.

Comparisons of the effects of the sevoflurane and propofol on acute ischemia reperfusion and DNA damages in rabbits

BACKGROUND AND OBJECTIVES

The aim of this study was to compare the effects of sevoflurane and propofol anesthesia on oxidative DNA damage that occurs in low-extremity ischemia and is caused by tourniquet application.

METHODS

Fourteen New Zealand rabbits were randomly allocated into two equal groups. Group S (n=7) received sevoflurane (2.5-4 percent) inhalation and Group P (n=7) received a propofol infusion (1-2mg·kg^-1·min^-1), after which a pneumatic tourniquet was placed on the right lower extremity. Blood samples were collected prior to tourniquet placement (baseline), 120min after ischemia, 15min after ischemia and 120minutes (min) after ischemia. Malondialdehyde (MDA) levels were analyzed to determine lipid peroxidation, and single cell gel electrophoresis (SCGE) was used to determine DNA damage.

RESULTS

At 15min after ischemia, the MDA levels in Group P (8.15±2.61μM) were higher than baseline (6.26±3.19μM, p=0.026) and Group S (4.98±0.77μM, p=0.01). DNA damage was similar in both groups, although DNA damage was higher than baseline (tail moment 0.63±0.27, tail intensity 3.76±1.26) in Group P at the 15th minute of reperfusion (tail moment 1.05±0.45, p=0.06; tail intensity 5.33±1.56, p=0.01). The increase in tail moment and tail intensity returned to normal levels in both groups 2hours after the termination of ischemia.

CONCLUSION

Given that oxidative stress and genotoxic effect disappear in the late stages of reperfusion, we conclude that neither sevoflurane nor propofol can be considered superior to the other in anesthesia practices for extremity surgeries involving the use of a tourniquet.

Different oxidative stress marker levels in blood from the operated knee or the antecubital vein in patients undergoing knee surgery: a tourniquet-induced ischemia-reperfusion model

BACKGROUND

In knee surgery a tourniquet is usually applied in order to provide a bloodless surgical field. This study aims to compare, in a tourniquet-induced ischemia-reperfusion model, the glutathione oxidation and lipid peroxidation in two different blood sources: an operated knee drainage tube or the antecubital vein.

METHODS

Thirty-two patients undergoing total knee replacement were studied. We measured reduced glutathione (GSH), oxidized glutathione (GSSG), malondialdehyde (MDA) and other metabolic parameters in the blood from the operated knee (17 patients), or from the antecubital vein (15 patients) before tourniquet inflation (T(0)) and after tourniquet release at different times: 3, 10, and 60 minutes (T(1), T(2), and T(3), respectively).

RESULTS

We have found an early increase of approximately 100% in GSSG and MDA blood levels coinciding with a decrease in GSH levels at T(1)-T(3) in blood from the operated knee. These changes were also observed in blood from the antecubital vein at T(1) and T(2), but at lower levels than in blood from the operated knee.

CONCLUSIONS

There is an intense glutathione oxidation and lipid peroxidation in the operated knee after tourniquet deflation. The surgical drainage is a good source of blood for the determination of biomarkers in a tourniquet-induced ischemia-reperfusion model, because changes are observed more early and it is more direct than another source of systemic blood.

What is the effect of compartment syndrome and fasciotomies on fracture healing in tibial fractures?

Acute compartment syndrome (ACS) in tibial diaphyseal fractures has been associated with such complications as infection, delayed fracture healing or non-union, sensory and motor deficits, deformities, and poor functional outcome. Essential condition of an uncomplicated recovery is early diagnosis with prompt decompression. A comprehensive review of the literature was performed to evaluate the impact of compartment syndrome and leg fasciotomies on the time to fracture union and the incidence of delayed union and non-union in tibial diaphyseal fractures. A total of 16 articles, which included 245 tibial fractures complicated with compartment syndrome were analysed. There were statistically significant differences in the time to healing, being longer by 4.90 weeks (p<0.001), and in the rates of delayed union or non-union (55% versus 17.8%) (p<0.001) when these fractures were compared to tibial fractures without compartment syndrome. Patients with ACS of the tibia undergoing leg fasciotomies should be informed about the increased risk of impaired fracture healing and longer time to union.