Expression analysis and clinical correlation of aquaporin 1 and 4 genes in human hippocampal sclerosis.

Mesial temporal sclerosis (MTS) is the most frequent cause of drug resistant symptomatic partial epilepsy. The mechanism and genetic background of this unique pathology are not well understood. Aquaporins (AQP) are regulators of water homeostasis in the brain and are expressed in the human hippocampus. We explored the role of AQP genes in the pathogenetic mechanisms of MTS through an evaluation of gene expression in surgically removed human brain tissue. We analyzed AQP1 and 4 mRNA levels by quantitative real-time polymerase chain reaction and normalized to ABL and cyclophilin genes, followed by immunohistochemistry for AQP4. Relative expressions were calculated according to the delta Ct method and the results were compared using the Mann-Whitney U test. Brain specimens of 23 patients with epilepsy who had undergone surgery for MTS and seven control autopsy specimens were investigated. Clinical findings were concordant with previous studies and 61% of the patients were seizure-free in the postoperative period. AQP1 and 4 gene expression levels did not differ between MTS patients and control groups. Immunofluorescence analysis of AQP4 supported the expression results, showing no difference. Previous studies have reported contradictory results about the expression levels of AQP in MTS. To our knowledge, only one study has suggested upregulation whereas the other indicated downregulation of perivascular AQP4. Our study did not support these findings and may rule out the involvement of AQP in human MTS.

Effects of imatinib mesylate on renin-angiotensin system (RAS) activity during the clinical course of chronic myeloid leukaemia.

The renin-angiotensin system (RAS) is involved in cell growth, proliferation and differentiation in bone marrow in an autocrine-paracrine manner, and it modulates normal and neoplastic haematopoietic cell proliferation. This study aimed to assess expressions of the RAS components, renin, angiotensinogen and angiotensin-converting enzyme (ACE), during imatinib mesylate treatment of patients with chronic myeloid leukaemia (CML). Expressions of RAS components were studied in patients with CML at the time of diagnosis (n = 83) and at 3, 6 and 12 months after diagnosis (n = 35) by quantitative real-time polymerase chain reaction. De novo CML patients had increased ACE, angiotensinogen and renin mRNA levels and these expression levels decreased following administration of imatinib. The RAS activities were significantly different among Sokal risk groups of CML, highlighting the altered biological activity of RAS in neoplastic disorders. The results of this study confirm that haematopoietic RAS affects neoplastic cell production, which may be altered via administration of tyrosine kinase inhibitors such as imatinib mesylate.