Heterogeneous expression of nonmuscle myosin heavy chain-B in mesangial cells of patients with Gitelman's syndrome

Aims. It has been suggested that angiotensin II (Ang II) promotes hypertrop hy and hyperplasia of mesangial cells. Nonmuscle myosin heavy chain-B (NMHC -B) and alpha -smooth muscle (SM) actin are considered to be molecular mark ers for phenotypic change of proliferative mesangial cells. One Of the clin ical characteristics in Gitelman's syndrome (GS) is the elevation of plasma Ang IL However, little is known about the relation between Ang II and phen otypic change of mesangial cells in patients with GS. In this report, we ex amined the expression of NMHC-B and alpha -SM actin in mesangial cells of t wo GS patients. Materials and methods. Plasma renin activity, and the conce ntrations of Ang II, 6-keto-prostaglandin F-1 alpha (6-keto-PGF(1 alpha)), urinary kallikrein, and 6-keto-PGF(1 alpha) were measured. Immunchistochemi cal staining of NMHC-B and alpha -SM actin in mesangial cells of GS patient s was also performed. Results. Both cases of GS showed normal glomerular fu nction, few histological abnormalities, and higher than normal plasma conce ntrations of renin and Ang II. Furthermore, one case showed a high urinary concentration of kallikrein and the expression of both NMHC-B and alpha -SM actin in mesangial cells. The other case showed a high urinary concentrati on of 6-keto-PGF(1 alpha) but not kallikrein and without the expression of NMHC-B and alpha -SM actin. Conclusion. Not only plasma kinin-kallikrein an d prostaglandins, but the renal expression ofNMHC-B and alpha -SM actin may be variable in different patients with GS.