title: Microalbuminuria, indicated by total versus immunoreactive urinary albumins, in acute ischemic stroke patients.
abstract: Microalbuminuria, assessed by measuring immunoreactive albumin, is common in patients with cerebrovascular disease and is associated with increased risk of stroke. Total urinary albumin (t-uAlb) comprises both immunoreactive albumin (ir-uAlb) and nonimmunoreactive albumin (nir-uAlb). We hypothesized that t-uAlb is a more sensitive indicator of microalbuminuria than ir-uAlb, and that measurement of t-uAlb will increase the prevalence of microalbuminuria in ischemic stroke patients compared with measurement of ir-uAlb and will show a stronger correlation with the severity of stroke and oxidative stress. In urine samples from 98 patients with ischemic stroke, the albumin-to-creatinine ratios t-uAlb/uCreat and ir-uAlb/uCreat were measured by high-performance liquid chromatography (HPLC) and immunoturbidimetry (IT), and the nir-uAlb/uCreat ratio was calculated. Urinary ortho-tyrosine (o-Tyr/uCreat), an indicator of oxidative stress, was measured by HPLC. The severity of stroke was scored based on the National Institutes of Health Stroke Scale (NIHSS). The prevalence of microalbuminuria detected by HPLC was significantly higher than that detetcted by IT (66.3 vs 36.7%). Although all forms of albumin showed significant correlation with stroke severity (t-uAlb: r = 0.24, P < .05 ir-uAlb: r = 0.25, P < .05 nir-uAlb: r = 0.29, P < .05), only nir-uAlb was found to be an independent predictor of stroke severity (B = 0.20, β = 0.35, P < .05). In addition, t-uAlb/uCreat and nir-uAlb/uCreat had a significant correlation with o-Tyr/uCreat (r = 0.336, P < .05 and r = 0.358, P < .05 respectively), whereas ir-uAlb/uCreat did not (r = 0.22, P > .05). Our data suggest that in acute ischemic stroke patients, t-uAlb is a more sensitive indicator of microalbuminuria than the presently used ir-uAlb. Future studies should aim to elucidate the underlying mechanisms for the relationship among urinary albumins and cerebrovascular diseases and the role of urinary albumins in risk stratification for stroke.
authors.affiliation: Department of Physiology, New York Medical College, Valhalla, New York, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Toth
authors.forename: Akos
authors.initials: A
authors.lastname: Koller
authors.forename: Gabriella
authors.initials: G
authors.lastname: Pusch
authors.forename: Edit
authors.initials: E
authors.lastname: Bosnyak
authors.forename: Laszlo
authors.initials: L
authors.lastname: Szapary
authors.forename: Samuel
authors.initials: S
authors.lastname: Komoly
authors.forename: Lajos
authors.initials: L
authors.lastname: Marko
authors.forename: Judit
authors.initials: J
authors.lastname: Nagy
authors.forename: Istvan
authors.initials: I
authors.lastname: Wittmann
mesh_terms: D000368:Aged; D000419:Albuminuria / Q000175:diagnosis* / Q000453:epidemiology / Q000652:urine; D015415:Biomarkers / Q000652:urine; D002545:Brain Ischemia / Q000175:diagnosis* / Q000453:epidemiology / Q000652:urine; D016009:Chi-Square Distribution; D002851:Chromatography, High Pressure Liquid; D003404:Creatinine / Q000652:urine; D006801:Humans; D006814:Hungary / Q000453:epidemiology; D007118:Immunoassay; D016014:Linear Models; D009391:Nephelometry and Turbidimetry; D011237:Predictive Value of Tests; D015995:Prevalence; D011379:Prognosis; D012720:Severity of Illness Index; D020521:Stroke / Q000175:diagnosis* / Q000453:epidemiology / Q000652:urine; D014443:Tyrosine / Q000652:urine
chemical_list: D015415:Biomarkers; D014443:Tyrosine; D003404:Creatinine