CLINICAL PRESENTATION AND INTERVENTION: A 41-year-old man with previous bilateral pheochromocytoma presented with chest pain. He was suffering from cardiac failure and persistent hypotension requiring an inotrope. Cardiac markers, an electrocardiogram and an echocardiogram confirmed acute myocardial infarct with poor ejection fraction and global hypokinesia. An (18)F-fluorodeoxyglucose PET/CT scan showed progressive left suprarenal and organ of Zuckerkandl pheochromocytomas. Blood pressure stabilisation proved challenging but was achieved by titrating an incremental dose of α-blocker against a tapering inotropic dose.
CONCLUSION: This case showed the efficacy of an α-blocker despite persistent hypotension in a patient with pheochromocytoma-induced cardiomyopathy.
METHODS: Twelve Sprague-Dawley rats received either 20% fructose solution [FFR] or tap water [C] to drink ad libitum for 8 weeks. The renal vasoconstrictor response to noradrenaline (NA), phenylephrine (PE), methoxamine (ME) and Ang II was determined in the presence and absence of 5-methylurapidil (5-MU) (α1A-adrenoceptor antagonist) in a three-phase experiment (pre-drug, low- and high-dose 5-MU). Data, mean ± SEM were analysed by ANOVA or Student's unpaired t-test with significance at P < 0.05.
RESULTS: FFR exhibited insulin resistance (HOMA index), hypertension and significant increases in plasma levels of glucose and insulin. All agonists caused dose-related reductions in cortical blood perfusion that were larger in C than in FFR while the magnitudes of the responses were progressively reduced with increasing doses of 5-MU in both C and FFR. The degree of 5-MU attenuation of the renal cortical vasoconstriction due to NA, ME and Ang II was significantly greater in the FFR compared to C.
CONCLUSIONS: Fructose intake for 8 weeks results in smaller vascular response to adrenergic agonists and Ang II. The α1A-adrenoceptor subtype is the functional subtype that mediates renal cortical vasoconstriction in control rats, and this contribution becomes higher due to fructose feeding.