Assessment of endothelium and inflammatory response at the onset of reperfusion injury in hand surgery

A randomized controlled trial: Comparison of one-per-mil tumescent technique and tourniquet in surgery for burn hand contracture in creating clear operative field and assessment of functional outcome

BACKGROUND

This study aims to compare the use of one-per-mil tumescent solution (a mixture of epinephrine and 0.2% lidocaine in a ratio of 1:1,000,000 in normal saline solution) and tourniquet to create clear operative fields and to evaluate the functional outcomes after post burn hand contracture surgery.

METHODS

The subjects of this randomized controlled trial were divided into one-permil tumescent technique and tourniquet group for a similar surgical procedure. Three independent assessors evaluated the clarity of the operative fields through recorded videos for the first 15 min and the first 10-minute of each hour of the surgery. Functional outcome was evaluated at least three months postoperatively using total active and passive motion (TAM and TPM) of each digit. Malondialdehyde (MDA) and tumor necrosis factor alpha (TNF-α) were tested during baseline (5 min before the procedures), ischemia phase, and reperfusion phase (a phase when the blood flow returned to the tissue).

RESULTS

35 subjects were included in this study: 17 in the tumescent group and 18 in the tourniquet group. We found a significant difference in the clarity of operative field between tumescent and tourniquet groups, 5 vs 35 bloodless operative fields, respectively (p < 0.05). TAM and TPM of each digit before surgery and 3 months postoperatively showed no significant difference between both groups (p > 0.05). Furthermore, we found no difference in MDA and TNF-α levels between both groups at their respective phases.

CONCLUSIONS

The use of one-per-mil tumescent technique does not replace tourniquet use to create bloodless operative fields in burned hand contracture surgery. However, the postoperative functional results were similar in both groups showing that tumescent technique can be used as an alternative to tourniquet without compromising outcomes. The MDA and TNF-α examinations do not provide conclusive outcomes regarding ischemia and reperfusion injury.

Evaluation of Early Markers of Ischemia-reperfusion Injury and Preservation Solutions in a Modified Hindlimb Model of Vascularized Composite Allotransplantation

Background.

Ischemia-reperfusion injury plays an important role in vascularized composite allotransplantation (VCA). Currently, there is no ideal preservation solution for VCA. In this study, we investigated the effects of 4 different preservation solutions on different tissues within an allogeneic hindlimb rat model.

Methods.

Sprague Dawley rat hindlimbs were flushed and placed at 4°C for 6 h in heparinized saline, histidine-tryptophan-ketoglutarate, University of Wisconsin (UW), and Perfadex and heterotopically transplanted for ease of ambulation. Apoptosis, necrosis, and the extracellular matrix of the tissues within the allograft were analyzed 2 h posttransplantation using immunohistochemistry, terminal deoxynucleotidyl transferase 2'-deoxyuridine 5'-triphosphate nick-end labeling (TUNEL) assay, and enzyme-linked immunoassay.

Results.

Higher expression of cleaved caspase 3, a significant increase of high-mobility group box 1 and TUNEL-positive apoptotic cells were observed in the muscle and vessels preserved with heparinized saline compared with UW and Perfadex following reperfusion. Higher expression of TUNEL-positive apoptotic cells was observed in the skin at 12 h of ischemia and in the nerve following reperfusion with histidine-tryptophan-ketoglutarate as a preservation solution.

Conclusions.

Our data suggest that UW and Perfadex are preferred solutions in VCA. The vessels within the allografts appear to be very susceptible, with laminins and CD31 playing a role in ischemia-reperfusion injury.

The Comparison of Inflammatory Cytokines between Spinal and General Anesthesia following Changes in Ischemic Reperfusion due to Tourniquet during Lower Limb Surgery

Methods

In this randomized controlled clinical trial, 34 patients with lower limb surgery admitted at the orthopedic ward of Imam Reza Hospital, Birjand, Iran, were selected by the available sampling method. They were randomly divided into two groups as follows: general anesthesia (n = 17) and spinal anesthesia (n = 17). Venous blood samples were taken from the patients of both groups at baseline (before the use of tourniquet) and 12 and 24 hours after reperfusion. Interleukin-6 (IL-6), tumor necrotizing factor-α (TNF-α), high-sensitivity C-reactive protein (hs-CRP), and ferritin were measured and recorded. The data were analyzed using independent t-test, chi-square, and repeated measure at the significant level of 0.05.

Results

The results showed that hs-CRP and IL-6 significantly increased during the study (p < 0.001); however, the mean changes of TNF-α and ferritin were not significant during the study. Moreover, none of the inflammatory cytokines indicated significant differences between these two study groups (p < 0.05).

Conclusion

According to the results, the use of tourniquet can lead to inflammation, and the inflammation is similar in both groups.

A preliminary study to assess neutrophil and endothelial response to knee arthroplasty with the use of a tourniquet : effects of spinal or sevoflurane anesthesia

Background : During orthopedic surgery, the use of a pneumatic tourniquet results in side effects secondary to ischemia-reperfusion phenomena. We tested the hypothesis that total knee arthroplasty with a tourniquet is associated with increase in plasma concentrations of biomarkers of neutrophil activation and endothelial injury. The second aim was to compare these changes during spinal or general inhalational anesthesia. Methods : 40 adult ASA I-II patients scheduled for total knee arthroplasty with a tourniquet under spinal or sevoflurane anesthesia were included. Venous blood samples were collected before surgery, 1 h, 3 h, and 24 h after tourniquet deflation. To assess neutrophil activation, plasma concentrations of total and active fractions of myeloperoxidase, as well as elastase concentrations and proteolytic activity were measured. Endothelial injury was assessed by measurement of plasma concentrations of syndecan-1, soluble thrombomodulin, soluble E-selectin, and vascular endothelial growth factor. Results were analyzed with a two-way analysis of variance. P< 0.05 was considered statistically significant. Results : Plasma concentrations of active but not total myeloperoxidase and elastase significantly increased following tourniquet deflation. The level of syndecan-1, soluble thrombomodulin, soluble E-selectin, but not vascular endothelial growth factor, significantly decreased postoperatively. These changes of biomarkers were similar during spinal and sevoflurane anesthesia. Conclusions : Total knee arthroplasty with pneumatic tourniquet is associated with systemic release of markers of neutrophil activation which was comparable during spinal or sevoflurane anesthesia. Systemic expression of endothelial injury was not detected in our clinical conditions.

MicroRNA-579-3p Exerts Neuroprotective Effects Against Ischemic Stroke via Anti-Inflammation and Anti-Apoptosis

BACKGROUND/AIMS

Multiple studies have found that microRNAs (miRNAs) are involved in the development of cerebral ischemia. MiR-579-3p can inhibit inflammatory responses and apoptosis, leading to ischemia/reperfusion (I/R) damage. However, the mechanism of how miR-579-3p actions in brain I/R injury remains unclear. This study aimed to investigate the mechanism of the role of miR-579-3p in brain I/R injury.

METHODS

A rat model of cerebral ischemia-reperfusion injury was established by suture method. The effects of miR-579-3p on cerebral infarction size, brain water content, and neurological symptoms were evaluated. Flow cytometry was used to detect apoptosis. ELISA was used to detect the level of inflammatory factors. Western blot was used to detect the expression of P65, NCOA1, Bcl-2 and Bax. The relationship between miR-579-3p and NCOA1 was analyzed by bioinformatics analysis and luciferase assay.

RESULTS

Overexpression of miR-579-3p reduced infarct volume, brain water content and neurological deficits. Overexpression of miR-579-3p inhibited the expression level of the inflammatory cytokines, such as TNF-α, IL-6, COX-2 and iNOS, and increased the expression level of IL-10. MiR-579-3p overexpression inhibited NF-кB activity by reducing NRIP1. In addition, miR-579-3p could reduce the apoptotic rate of cortical neurons. Overexpression of miR-579-3p inhibited the activity of caspase-3, increased the expression level of anti-apoptotic gene Bcl-2 in neurons, and decreased the expression level of apoptotic gene Bax.

CONCLUSION

miR-579-3p can be used to treat brain I/R injury, and its neuroprotective effect may be ascribed to the reduction of inflammation and apoptosis.

Revascularization and muscle adaptation to limb demand ischemia in diet-induced obese mice

BACKGROUND

Obesity and type 2 diabetes are major risk factors for peripheral arterial disease in humans, which can result in lower limb demand ischemia and exercise intolerance. Exercise triggers skeletal muscle adaptation including increased vasculogenesis. The goal of this study was to determine whether demand ischemia modulates revascularization, fiber size, and signaling pathways in the ischemic hind limb muscles of mice with diet-induced obesity (DIO).

MATERIALS AND METHODS

DIO mice (n = 7) underwent unilateral femoral artery ligation and recovered for 2 wks followed by 4 wks with daily treadmill exercise to induce demand ischemia. A parallel sedentary ischemia (SI) group (n = 7) had femoral artery ligation without exercise. The contralateral limb muscles of SI served as control. Muscles were examined for capillary density, myofiber cross-sectional area, cytokine levels, and phosphorylation of STAT3 and ERK1/2.

RESULTS

Exercise significantly enhanced capillary density (P < 0.01) and markedly lowered cross-sectional area (P < 0.001) in demand ischemia compared with SI. These findings coincided with a significant increase in granulocyte colony-stimulating factor (P < 0.001) and interleukin-7 (P < 0.01) levels. In addition, phosphorylation levels of STAT3 and ERK1/2 (P < 0.01) were increased, whereas UCP1 and monocyte chemoattractant protein-1 protein levels were lower (P < 0.05) without altering vascular endothelial growth factor and tumor necrosis factor alpha protein levels. Demand ischemia increased the PGC1α messenger RNA (P < 0.001) without augmenting PGC1α protein levels.

CONCLUSIONS

Exercise-induced limb demand ischemia in the setting of DIO causes myofiber atrophy despite an increase in muscle capillary density. The combination of persistent increase in tumor necrosis factor alpha, lower vascular endothelial growth factor, and failure to increase PGC1α protein may reflect a deficient adaption to demand ischemia in DIO.

Refinement of tourniquet-induced peripheral ischemia/reperfusion injury in rats: comparison of 2 h vs 24 h reperfusion

Prolonged ischemia of skeletal muscle tissue, followed by reperfusion, leads to ischemia/reperfusion injury (IRI), which is a feared local and systemic inflammatory reaction. With respect to the 3Rs, we wanted to determine which parameters for assessment of IRI require a reperfusion time of 24 h and for which 2 h of reperfusion are sufficient. Rats were subjected to 3 h of hind limb ischemia and 2 h or 24 h of reperfusion. Human plasma derived C1 inhibitor was used as a drug to prevent reperfusion injury. For 2 h of reperfusion the rats stayed under anesthesia throughout (severity grade 1), whereas for 24 h they were awake under analgesia during reperfusion (grade 2). The femoral artery was clamped and a tourniquet was placed, under maintenance of venous return. C1 esterase inhibitor was systemically administered 5 min before the induction of ischemia. No differences in local muscle edema formation and depositions of immunoglobulin G and immunoglobulin M were observed between 2 h and 24 h (P > 0.05), whereas lung edema was only observed after 24 h. Muscle viability was significantly lower after 24 h vs 2 h reperfusion (P < 0.05). Increased plasma creatine kinase (CK)-MM and platelet-derived growth factor (PDGF)-bb could be detected after 2 h, but not after 24 h of reperfusion. By contrast, depositions of C3b/c and fibrin in muscle were only detected after 24 h (P < 0.001). In conclusion, for a first screening of drug candidates to reduce IRI, 2 h reperfusions are sufficient, and these reduce the severity of the animal experiment. Twenty-four-hour reperfusions are only needed for in-depth analysis of the mechanisms of IRI, including lung damage.

Tourniquet-induced ischemia-reperfusion injuries during extremity surgery at children's age: impact of anesthetic chemical structure

OBJECTIVES

The aim of this study was to determine the relationship between the antioxidant profile of anesthetics and its relation to total antioxidant capacity (TAC) of plasma in children who underwent tourniquet-induced ischemia-reperfusion (IR) injury during extremity operations.

METHODS

Children were randomized into three groups: general inhalational anesthesia with sevoflurane (group S), total intravenous anesthesia (TIVA) with propofol (group T), and regional anesthesia (group R). Venous blood samples were obtained before peripheral nerve block and induction of general anesthesia (baseline), 1 minute before tourniquet release (BTR), and 5 and 20 minutes after tourniquet release (ATR). Plasma TAC as well as antioxidant potential of propofol, thiopental, and bupivacaine were measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay.

RESULTS

Plasma TAC in group T was increased significantly at 20 minutes ATR in comparison with basal and BTR values, and also was significantly higher in comparison with plasma TAC in groups S and R measured at the same time point. The radical scavenging activity of anesthetics in vitro indicated that only propofol possessed a significant antioxidative activity in the reaction with DPPH radical in comparison with thiopental and bupivacaine.

DISCUSSION

These data confirm that TIVA with propofol attenuates oxidative stress related to tourniquet-induced ischaemia-reperfusion injury in children.