Adrenomedullin mRNA is Highly Expressed in PBMC of Acute Kawasaki Syndrome

Abstract

Introduction; Dilation of coronary arteries is a common finding in acute phase Kawasaki Syndrome (KS). The cause of this phenomenon remains unknown. Macrophages and lymphocytes are known to infiltrate into the arterial wall of KS patients. These cells are producers of vasodilatory agents such as nitric oxide synthetase (NOS), calcitonin-related gene protein and adrenomedullin (ADM). The purpose of the current study was to examine the expression of three vasodi lators in acute and convalescent KS. Patients and Methods; Twenty-two KS patients were enrolled in this study. Blood drawing was performed on around 4th disease day for acute KS and around 20th disease day for convalescent KS patients. Five microgram of RNA from PBMC of each sample was processed to make cRNA and Genechip cDNA microarray (Affymetrix) was performed in four patients. Semi-quantitative RT-PCR was also done with another six KS patients also in acu te and convalescent phase. Plasma levels of ADM were assayed in twelve KS patients with RIA kit (Peninsula Labs.). All statistics were performed using Students' paired-t test. Results; No differences were observed in mRNA expression by microarray analysis of the vasodilatory agents, NOS and calcitonin-like gene protein between acute vs convalescent phases of 4 patients with KS initially studied. In contrast, ADM showed high-level mRNA expression in acute KS which w as 7 fold-higher and showed statistically significant difference (p<0.05) from mRNA expression in convalescent KS. In RT-PCR of 6 additional patients, the same results were obtained. All six patients had high expression of ADM mRNA in acute p hase a nd showed statistically significant difference from convalescent phase (p<0.05). Plasma levels of ADM protein were also high in acute phase and normalized in convalescent phase. Conclusion; ADM may contribute to the coronary artery dilation found in acute Kawasaki Syndrome.