title: The interstitial expression of alpha-smooth muscle actin in glomerulonephritis is associated with renal function.
abstract: BACKGROUND
  In a healthy kidney, contractile protein alpha-smooth muscle actin (ASMA) is immunohistochemically strongly expressed only in the blood vessels, while in pathological conditions it can be visualized in glomerular mesangial cells and interstitial myofibroblasts. The aim of this study was to explore the possible correlation between expression of ASMA in glomerulonephritis (GN) and indicators of renal function.
  
  
  METHODS
  We analyzed expression of ASMA in percutaneous renal biopsy of 142 adult and pediatric patients with GN and its correlation with blood pressure, serum creatinine, creatinine clearance and 24-hour urine protein at the time of biopsy. Immunoexpression of ASMA was analyzed quantitatively using computer-assisted morphometric analysis. Relative surface of ASMA expression in all glomeruli and interstitium was calculated for each patient.
  
  
  RESULTS
  In adults and children, greater expression of ASMA in interstitium was associated with higher serum creatinine and reduced creatinine clearance. Conversely, greater ASMA expression in glomeruli was associated with normal or decreased serum creatinine in adults and increased creatinine clearance in children. In children, correlation was found between high blood pressure and ASMA expression in interstitium.
  
  
  CONCLUSIONS
  We confirmed that interstitial expression of ASMA is associated with reduced renal function at time of biopsy. The connection of ASMA expression in glomeruli with lower serum creatinine and normal or increased creatinine clearance suggests a favorable role of this phenotypic change in glomerular filtration rate; further investigation is needed.
authors.affiliation: Department of Urology, University Hospital Split, School of Medicine in Split, Split, Croatia.
authors.forename: Zana
authors.initials: Z
authors.lastname: Saratlija Novakovic
authors.forename: Merica
authors.initials: M
authors.lastname: Glavina Durdov
authors.forename: Livia
authors.initials: L
authors.lastname: Puljak
authors.forename: Marijan
authors.initials: M
authors.lastname: Saraga
authors.forename: Dragan
authors.initials: D
authors.lastname: Ljutic
authors.forename: Tomislav
authors.initials: T
authors.lastname: Filipovic
authors.forename: Zvonimir
authors.initials: Z
authors.lastname: Pastar
authors.forename: Antonia
authors.initials: A
authors.lastname: Bendic
authors.forename: Katarina
authors.initials: K
authors.lastname: Vukojevic
mesh_terms: D000199:Actins / Q000378:metabolism*; D000293:Adolescent; D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D003404:Creatinine / Q000097:blood; D045604:Extracellular Fluid / Q000378:metabolism*; D005921:Glomerulonephritis / Q000097:blood / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D007223:Infant; D007677:Kidney Function Tests; D008875:Middle Aged; D011507:Proteinuria / Q000097:blood / Q000150:complications / Q000503:physiopathology; D055815:Young Adult
chemical_list: C541116:ACTA2 protein, human; D000199:Actins; D003404:Creatinine