Localization of sulphonylurea receptor proteins SUR2A and SUR2B and/or SUR1 in rat kidney

To further explore precise expression and localization of sulphonylurea receptor isoforms SUR2A and SUR2B [SUR1] in rat kidney, total RNA was isolated from the kidney tissue using the TRIzol kit. Three different primer sets designed against SUR isoforms were used in reverse transcriptase reactions. Western blotting was done on membrane fractions obtained from kidney tissues using the primary antisera for SUR2A and SUR2B [SUR1]. Paraformaldehyde fixed kidney sections were immunostained with SUR2A and SUR2B [SUR1] primary antisera. Sections were developed with DAB as a chromogen. RT-PCR results demonstrated mRNA consistent with SUR1 isoform to be the only identifiable transcript. Western blotting could not identify any protein consistent with SUR2A or SUR2B [SUR1] but recognized instead a smaller 55kD protein of unknown identity. Immunohistochemistry demonstrated a differential staining pattern whereby SUR2A was localized to the mesangial cells, intra- and extrarenal blood vessels and smooth muscles. In contrast, SUR2B [SUR1] was localized only to distal nephron epithelia. Intense immunoreactivity was localized to the thick ascending limb and as well as in the outer and inner medullary collecting ducts, both. Our results demonstrate differential and highly localized expression pattern of sulphonylurea receptor proteins SUR2A and 2B [SUR1] in rat kidney with implications for drug design

Angiotensin converting enzyme inhibitors impair recombinant human erythropoietin induced erythropoiesis in patients with chronic renal failure

To investigate the effects of angiotensin converting enzyme [ACE] inhibitors/angiotensin receptor blockers [ARBs] and other anti-hypertensive agents on recombinant human erythropoietin [rHuEPO] in chronic renal failure [CRF] patients. The present study was conducted at the Nephrology Department, Khan Research Laboratories Hospital and Quaid-i-Azam University, Islamabad, Pakistan during March 2004 to February 2005. One hundred patients, 55 males and 45 females [age range 13-78 years] were divided into 2 groups. Group-I patients received rHuEPO and ACE inhibitors/ARBs while Group-II patients received rHuEPO with other antihypertensives such as calcium channel blockers or beta-adrenergic receptor blockers. Monthly increment in hematocrit [HCT%] was monitored in both groups for 4 continuous months. One-way ANOVA on Dunn's, univariate and multivariate analyses were carried out to determine any significant improvement in erythropoiesis between the 2 treatment groups. Monthly increase in HCT% was significantly greater in the group that was treated with rHuEPO and antihypertensives other than ACE inhibitors/ARBs compared with that treated with ACE inhibitors/ARBs, an effect observed even at a higher dose of rHuEPO, and the patients were iron replete. The present data from our population confirms that ACE inhibitors/ARBs interfere with rHuEPO therapy for treatment of anemia in CRF. The ACE inhibitors/ARBs inhibit erythropoiesis induced by rHuEPO in CRF patients, therefore, simultaneous use of ACE inhibitors/ARBs and rHuEPO should be carried out with caution