Taurine-mediated cardioprotection is greater when administered upon reperfusion than prior to ischemia.

UNLABELLED: Taurine (TA) administered exogenously before the induction of myocardial ischemia decreases lactic acid production and increases pyruvic acid production during ischemia. It also preserves the activity of GOT, GPT, LDH and CPK during ischemia and enhances recovery of CKMB synthesis as early as 5 minutes after onset of reperfusion. The aim of the study was to determine the optimal conditions for administering TA in order to reduce myocardial ischemia-reperfusion injury. Left ventricular (LV) function, creatine kinase (CK) and lipid peroxide products (LPOP = oxidant stress), as well as the area at risk (AAR), and infarct size (IS) after reperfusion were studied in 3 groups of isolated rat hearts perfused with Krebs Henseleit Buffer (KHB)-stabilized isolated rat hearts that were subjected to 20 minutes(') of global ischemia at 37 degrees C followed by 60' of reperfusion with KHB: Hearts were perfused with TA containing KHB for 10' just prior to ischemia or during the first 10' of reperfusion. CONCLUSION: Taurine before ischemia or during reperfusion was equally effective in preventing infarction; however, when administered at reperfusion, taurine reduced lipid peroxidation and myocardial injury more, thereby providing improved early recovery of function.

Taurine at early reperfusion significantly reduces myocardial damage and preserves cardiac function in the isolated rat heart.

OBJECTIVE: The Myocardial protective effects of taurine (TA) are well known. We investigated the optimal phase of giving taurine to reduce myocardial ischaemia-reperfusion injury in isolated rat hearts. METHODS: Isolated rat hearts were subjected to 20 min of global ischaemia followed by 60 min of reperfusion under three different conditions: global ischaemia alone (control group; n=8); pre-ischaemic administration of taurine (pre-TA group; n=8), perfusion with 10 mmol/L taurine for 10 min just before ischaemia; post-ischaemic administration of taurine (post-TA group; n=8), perfusion with 10 mmol/L taurine for the first 10 min of reperfusion. Ventricular functional and biochemical variables, the area at risk (AAR), and infarct size (IS) after reperfusion were compared between groups. RESULTS: Recovery of ventricular function in the post-TA group was significantly greater than that in the control and pre-TA groups in terms of left ventricular pressure and rate-pressure product. Lipid peroxide product as a marker of oxidant stress in the post-TA group was significantly less than that in the control and pre-TA groups. AAR relative to left ventricular area in the post-TA group was significantly less than that in the control and pre-TA groups. IS relative to AAR in the post-TA group was significantly less than that in the control group. CONCLUSION: Taurine administered before or after ischaemia prevents infarction; being a potent free radical scavenging antioxidant, it reduced myocardial injury and provided significantly better functional recovery when given immediately after reperfusion.

Pathological analyses of long-term intracoronary Palmaz-Schatz stenting; Is its efficacy permanent?

BACKGROUND: Angiographic regression of luminal narrowing occurs 6 months to 3 years poststenting. However, after 4 years lesions progressed gradually and late restenosis was observed in 28% of 179 Palmaz-Schatz-stented lesions during the past 10 years. Elucidating its pathogenesis is pivotal to developing preventive strategies. METHODS AND RESULTS: Histopathological and immunohistochemical studies were performed in 19 stented coronary arteries obtained from 19 patients autopsied after noncardiac death 2-7 years poststenting. The quality/severity of chronic inflammatory cells (T lymphocytes, macrophages and multinucleated giant cells) infiltration around the stent struts that is observed even in the absence of restenosis depended on the time elapsed from stenting: a) 2 years postprocedure, in spite of angiographic regression during the first year and pathologically expressed as maturation of the neointimal scar, there was chronic inflammatory response evidence: neovascularization and lymphocyte infiltration, b) > or = 3 years: the neointimal smooth muscle cells were sparse with abundant proliferation of collagen fibers. Presence of slight helper/inducer T lymphocytes and mild macrophage infiltration around the stent struts was evident immunohistochemically, c) > or = 4 years: prominent infiltration by lipid-laden macrophages with strong collagen-degrading matrix metalloproteinase immunoreactivity was observed around the struts. In two of these arteries, the surface contacting the stent was focally disrupted and covered by nonocclusive mural thrombi. CONCLUSIONS: Stainless steel stents evoke a remarkable foreign-body inflammatory reaction to the metal. These persistent peri-strut chronic inflammatory cells may accelerate new indolent atherosclerotic changes and consequent plaque vulnerability.

Up to 8-year follow-up of valve replacement with carbomedics valve.

BACKGROUND: The aim of this study was to report midterm valve replacement (VR) results with the Carbo-Medics valve (Sulzer Carbomedics, Austin, TX). METHODS: From 1991 to 1999, 468 patients aged 13 to 76 years (mean 56 years) underwent VR with CarboMedics valve: 239 aortic (A), 167 mitral (M), and 62 A+M or double valve replacement (DVR). Mean follow-up time was 4.4 years; follow-up was 99.1% complete for 2,016 patient-years (PY). The anticoagulation level was targeted to an international normalized ratio of 1.47 to 2.8. RESULTS: The hospital mortality rate was 1.2%. Actuarial analysis for the entire group at 7 years for survival was 87%+/-2.3%. Freedom from valve-related death was 94%+/-1.9%. Freedom from thromboembolic and bleeding events, respectively, were as follows: for AVR, 82%+/-4.9% (2.4%/PY) and 88%+/-2.9% (1.6%/PY); for MVR, 95%+/-2.1% (0.8%/PY) and 91%+/-3.1% (1.3%/PY); and for DVR, 96%+/-3.2% (0.7%/PY) and 85%+/-9.7% (1.0%/PY). Actuarial freedom from reoperation was 98%+/-1.4%. CONCLUSIONS: The CarboMedics valve can be implanted with satisfactory early mortality and a low incidence of valve-related events even under low-intensity anticoagulation, as shown in a Japanese population.

Objective assessment of CNS function within 6 hours of spinal cord ischemia in rabbits.

PURPOSE: To develop a neurologic scoring (NS) system to objectively assess CNS function shortly after spinal cord ischemia. METHODS: Spinal cord ischemia was induced by temporarily clamping the infrarenal aorta in 27 rabbits anesthetized with isoflurane/N2O/O2 without muscle relaxants. Animals were divided ito group I, normothermic ischemia [I-a, 11 min (n=8); I-b, 12 min (n=8)], and group II, 60 min hypothermic ischemia targeted to II-a, 29.5°C (n=5), and II-i, 30.0°C (n=6). Postischemic neurologic function was scored from 0 to 6. RESULTS: Seventy-five percent of each group I subgroup ended with paraplegia. Function in the I-b group tended to be worse than in I-a (NS=1.7vs 1.9P>0.05). Hypothermia of 29.9±0.1°C protected partially (NS=2.8), whereas 29.4±0.1°C resulted in significantly higher NS, starting at 150 min (P<0.05vs IIi) with total recovery 5.5 hours (P<0.0001) post re-perfusion. CONCLUSIONS: Protection of the spinal cord from ischemia can be objectively quantitated by our system. Protection strategies can be compared within 6 h of the ischemia-insult.