[Tourniquet-induced ischaemia-reperfusion injury: the comparison of antioxidative effects of small-dose propofol and ketamine]

Effects of Kynurenic Acid on the Rat Aorta Ischemia-Reperfusion Model: Pharmacological Characterization and Proteomic Profiling

Kynurenic acid (KYNA) is derived from tryptophan, formed by the kynurenic pathway. KYNA is being widely studied as a biomarker for neurological and cardiovascular diseases, as it is found in ischemic conditions as a protective agent; however, little is known about its effect after ischemia-reperfusion in the vascular system. We induced ischemia for 30 min followed by 5 min reperfusion (I/R) in the rat aorta for KYNA evaluation using functional assays combined with proteomics. KYNA recovered the exacerbated contraction induced by phenylephrine and relaxation induced by acetylcholine or sodium nitroprussiate in the I/R aorta, with vessel responses returning to values observed without I/R. The functional recovery can be related to the antioxidant activity of KYNA, which may be acting on the endothelium-injury prevention, especially during reperfusion, and to proteins that regulate neurotransmission and cell repair/growth, expressed after the KYNA treatment. These proteins interacted in a network, confirming a protein profile expression for endothelium and neuron repair after I/R. Thus, the KYNA treatment had the ability to recover the functionality of injured ischemic-reperfusion aorta, by tissue repairing and control of neurotransmitter release, which reinforces its role in the post-ischemic condition, and can be useful in the treatment of such disease.

The effect of pregabalin on tourniquet-induced ischemia-reperfusion injury: a prospective randomized study

Background/aim

The aim of this study was to investigate the efficacy of pregabalin on ischemia-reperfusion injuries.

Materials and methods

Fifty-four patients were randomly assigned into 2 groups. A 150-mg tablet of pregabalin was given the night before and then 1 h before the operation for patients in Group P (pregabalin group, n = 27). A placebo was given to patients in Group C (control group, n = 27) at the same times. After combined spinal-epidural anesthesia was performed, venous blood samples were taken before tourniquet inflation (t₁), just before tourniquet deflation (t₂), and 20 min after tourniquet deflation (t₃) for the analysis of total antioxidant status (TAS), total oxidant status (TOS), catalase (CAT), and ischemia-modified albumin (IMA).

Results

There was no significant difference in TAS levels between the groups for the t₃ period. However, the TAS in Group P was significantly higher in the t₃ period than the t₂ period (mean ± SD, 0.46 ± 0.1 vs. 0.38 ± 0.2 mmol of Trolox equivalent/L, respectively; P < 0.05). The CAT level in the t₃ period was significantly higher in Group P than Group C (mean ± SD, 53.04 ± 32.1 vs. 35.46 ± 17.2 µmol/formaldehyde, respectively; P < 0.05). In the t₃ period, the TOS was significantly lower in Group P than Group C (mean ± SD, 11.97 ± 5 vs. 18.29 ± 9.9 pg/mL, respectively; P < 0.05). The TOS in Group P was significantly lower in the t₃ period than the t₂ period (mean ± SD, 11.97 ± 5 vs. 18.98 ± 10.7 pg/mL, respectively; P < 0.0001).

Conclusion

Pregabalin has no marked antioxidant activity, but it contributes to the antioxidant defense system of an organism.

Acute responses of hemodynamic and oxidative stress parameters to aerobic exercise with blood flow restriction in hypertensive elderly women

Systemic arterial hypertension has been associated with the majority deaths from cardiovascular disease, especially among the elderly population, and the imbalance between antioxidant and pro-oxidants has been associated with hypertension. This study analyzed the acute responses of cardiorespiratory and oxidative stress parameters to low intensity aerobic exercise (LIAE) with blood flow restriction (BFR) in hypertensive elderly women. The experimental group consisted of 16 hypertensive women (67.2 ± 3.7 years) who underwent a progressive treadmill test and performed three exercise protocols in random order: high intensity (HIAE), low intensity aerobic exercise (LIAE) and low intensity aerobic exercise with blood flow restriction (LIAE + BFR). Data analysis showed that blood pressure and heart rate augmented from rest to post effort (p < 0.05) and reduced from post effort to recovery (p < 0.05) in all protocols. The values of lipid peroxidation were higher after 30 min of recovery when compared to the moment at rest in the LILIAE + BFR (p < 0.05). The same occurred with glutathione-S-transferase and superoxide dismutase activity. However, non-protein thiols levels (NPSH) reduced after 30 min of recovery when compared to the moment at rest in the LILIAE + BFR protocol (p < 0.05). In the HIAE and LIAE + BFR protocols, the levels of NPSH were lower at 30 min of recovery when compared to the same moment in the LIAE protocol (p < 0.05). LIAE + RBF produces an oxidative status and hemodynamic stimulus similar to HIAE. Taken together, these results support the indication of LIAE with BFR in chronic intervention protocols, with potential benefits for the hypertensive elderly population.