Cardioprotective actions of pentoxifylline in an animal model of acute myocardial ischaemia

Abstract

1The action of pentoxifylline on some of the consequences of acute myocardial ischaemia was studied in cats in vivo. 2 Occlusion of the left anterior descending coronary artery (LAD) for 5 h resulted in a significant elevation in the ST-segment of the ECG, a reduction in free platelet count in right atrial blood and a loss of creatine phosphokinase (CK) and cathepsin D activities in homogenates of the severely ischaemic myocardium as compared to non-ischaemic myocardium. 3 Intravenous infusions of pentoxifylline (0.30mgkg-min1 for 1 h and 0.15 mgkg-min-1 for the remainder of the 5 h observation period, starting 0.5 h after LAD occlusion) significantly reduced the loss of enzymes from the ischaemic myocardium, prevented any further increase in the ST-segment and restored the platelet count to its control level.4 There were no significant changes in plasma immunoreactive 6-oxo-prostaglandin Fl, (6-oxoPGF1c,) and thromboxane B2 (TXB2), although a tendency for a reduction in TXB2 levels was observed. 5 Pentoxifylline seems to affect, beneficially, the myocardium in this animal model of acute myocardial ischaemia. The reason for this cardioprotective action remains to be elucidated. It is, however, noteworthy that the overall profile of action of pentoxifylline resembles that of PGI2 administration in this model.

Pentoxifylline: cerebral blood flow and glucose utilization in conscious spontaneously hypertensive rats.

“…Pentoxiphylline has been reported to have a beneficial effect on cardiac ischemia in the cat in the dose used in the present study. 27 In a preliminary report, the drug was also claimed to maintain energy stores in ischemic brain tissue. 28 Further studies are needed to establish if in fact pentoxiphylline has a protective effect on brain tissue during ischemia and, if so, to reveal the mechanism.…”

Treatment of acute myocardial ischaemia with a selective antagonist of thromboxane receptors (BM 13.177)

“…The cells were separated by centrifugation at 12,000 g for 10 min at 4'C. The supernatant was subjected to radioimmunoassay ofTXB2 using specific and highly selective TXB2 antibodies prepared in our laboratory (see Gallenkamper et al, 1984, for details). …”

Pentoxifylline does not reduce infarct size in a canine model of acute myocardial infarction

“…The results of the pre pentoxifylline does not as a function of the are acute myocardial infar previous study has inv ifylline on anatomical ii *pentoxifylline on heart rate, in anaesthetized cats subjected to coronary artery blood pressure in dogs ligation (Gallenkemper et al, 1984), pentoxifylline did not significantly affect the loss of creatine kinase from 0 0.5 1.5 6 left ventricles, although, there was a significant reduction in the standard limb lead ST segment elevation. In the present study, pentoxifylline had no effect on 1± 6 144 ± 7 149 ± 7 145 10 heart rate or arterial blood pressure; this is in 5 ± 5 149 ± 6 143 ± 5 127 ± 7 agreement with other studies.…”

“…15 mg kg-' min-' for 4.5 h; volume of 27.2 ml h') or a control infusion of distilled water (27.2 ml h-') intravenously. This dose of pentoxifylline has been shown previously to reduce ischaemically induced ST segment elevation without affecting heart rate or blood pressure (Gallenkemper et al, 1984). The volume ofthe infusion did not change the haematocrit.…”