Marvin D. Atkins

Postischemic Treatment With Ethyl Pyruvate Prevents Adenosine Triphosphate Depletion, Ameliorates Inflammation, and Decreases Thrombosis in a Murine Model of Hind-Limb Ischemia and Reperfusion

INTRODUCTION Experiments were designed to investigate the effects of ethyl pyruvate (EP) in a murine model of hind-limb ischemia-reperfusion (IR) injury. METHODS C57BL6 mice underwent 90 minutes of unilateral ischemia followed by 24 hours of reperfusion using two treatment protocols. For the preischemic treatment (pre-I) protocol, mice (n=6) were given 300 mg/kg EP before ischemia, followed by 150 mg/kg of EP just before reperfusion and at 6 hours and 12 hours after reperfusion. In a postischemic treatment (post-I) protocol, mice (n=7) were treated with 300 mg/kg EP at the end of the ischemic period, then 15 minutes later, and 2 hours after reperfusion and 150 mg/kg of EP at 4 hours, 6 hours, 10 hours, 16 hours, and 22 hours after reperfusion. Controls mice for both protocols were treated with lactated Ringers alone at time intervals identical to EP. Skeletal muscle levels of adenosine triphosphate (ATP), interleukin-1β, keratinocyte chemoattractant protein, and thrombin antithrombin-3 complex were measured. Skeletal muscle architectural integrity was assessed microscopically. RESULTS ATP levels were higher in mice treated with EP compared with controls under the both treatment protocols (p=0.02). Interleukin-1β, keratinocyte chemoattractant protein, thrombin antithrombin-3 complex (p<0.05), and the percentage of injured fibers (p<0.0001) were significantly decreased in treated versus control mice under the both protocols. CONCLUSION Muscle fiber injury and markers of tissue thrombosis and inflammation were reduced, and ATP was preserved with EP in pre-I and post-I protocols. Further investigation of the efficacy of EP to modulate IR injury in a larger animal model of IR injury is warranted.

Postischemic poly (ADP-ribose) polymerase (PARP) inhibition reduces ischemia reperfusion injury in a hind-limb ischemia model

BACKGROUND Several experiments were designed to determine whether the systemic, postischemic administration of PJ34,which is a poly-adenosine diphosphate (ADP)-ribose polymerase inhibitor, decreased tissue injury and inflammation after hind-limb ischemia reperfusion (I/R). METHODS C57BL6 mouse limbs were subjected to 1.5 h ischemia followed by 24-h reperfusion. The treatment group (PJ) received intraperitoneal PJ34 (30 mg/kg) immediately before reperfusion, as well as 15 min and 2 h into reperfusion. The control group (CG) received lactated Ringers alone at the same time intervals as PJ34 administration. The skeletal muscle levels of adenosine triphosphate (ATP), macrophage inflammatory protein-2 (MIP-2), keratinocyte derived chemokine (KC), and myeloperoxidase (MPO) were measured. Quantitative measurement of skeletal muscle tissue injury was assessed by microscopic analysis of fiber injury. RESULTS ATP levels were higher in limbs of PJ versus CG mice (absolute ATP: 4.7 +/- 0.35 vs 2.3 +/- 0.15-ng/mg tissue, P = .002). The levels of MIP-2, KC, and MPO were lower in PJ versus CG mice (MIP-2: 1.4 +/- 0.34 vs 3.67 +/- 0.67-pg/mg protein, P = .014; KC: 4.97 +/- 0.97 vs 12.65 +/- 3.05-pg/mg protein, P = .037; MPO: 46.27 +/- 10.53 vs 107.34 +/- 13.58-ng/mg protein, P = .008). Muscle fiber injury was markedly reduced in PJ versus CG mice (4.25 +/- 1.9% vs 22.68 +/- 3.0% total fibers, P = .0004). CONCLUSION Systemic postischemic administration of PJ34 preserved skeletal muscle energy levels, decreased inflammatory markers, and preserved tissue viability post-I/R. These results support PARP inhibition as a viable treatment for skeletal muscle I/R in a clinically relevant post hoc scenario.

Surgical management of carotid body tumors: a 15-year single institution experience employing an interdisciplinary approach.

Cervical paragangliomas are rare neoplasms that arise from extraadrenal paraganglia in close association with the cranial nerves and extracranial arterial system of the head and neck, and therefore surgical extirpation can be challenging. A retrospective study was conducted of all patients undergoing surgical excision of a cervical paraganglioma between 2000 and 2015. The demographic characteristics, clinical features, surgical approach, and outcomes were reviewed. A total of 20 cervical paragangliomas were excised in 17 patients. There were 14 female and 3 male patients with a mean age of 56.6 ± 17.0 at the time of operation. Twelve patients had unilateral tumors and 5 patients had bilateral tumors. Familial involvement was confirmed by history or direct genetic analysis in 8 (47%) of the 17 patients. There were no malignant paragangliomas, and only 3 patients had tumors that were determined to be functional. Tumor size ranged from 1.3 to 6.0 cm. Two patients required combined arterial resection as part of complete excision of the tumor. There were no permanent operative cranial nerve injuries, no recurrences, minimal morbidity, and no mortality. In conclusion, optimal management of cervical paragangliomas should include a thorough preoperative evaluation, accurate definition of the surgical anatomy, and exclusion of synchronous paragangliomas. A combined therapeutic approach by a multidisciplinary team including surgeons and interventional radiologists provides safe and effective management of cervical paragangliomas with very low morbidity and excellent outcomes.

Role of poly(ADP-ribose) polymerase during vascular reconstruction.

Open vascular repair of ischemic myocardium and aortic aneurysms results in a systemic inflammatory response that influences the mortality and morbidity of these procedures. Recent studies in animal models of complex vascular reconstruction indicate that the activity of poly(ADP-ribose) polymerase (PARP) may influence the mortality and morbidity of these kinds of reconstructions. PARPs activity, localized to nuclei and mitochondria, is stimulated by deoxyribonucleic acid (DNA) strand breaks. Activation of PARP results in synthesis of poly(ADP-ribose) sugar moieties, whose primary role is to protect DNA from degradation during cytotoxic stress. Paradoxically, when stressful conditions similar to those experienced during vascular reconstructions result in overactivation of PARP, depletion of cellular levels of adenosine triphosphate and nicotinamide adenine dinucleotide can result in exacerbation of tissue injury. Herein we review the role of PARP in inflammation and its relevance to cardiovascular reconstructions.