alpha-1-Antichymotrypsin gene A1252G variant (ACT Isehara-1) is associated with a lacunar type of ischemic cerebrovascular disease

Transcriptional analysis of the molecular basis of human kidney aging using cDNA microarray profiling

BACKGROUND

The molecular basis of renal aging is not completely understood.

METHODS

We used global gene expression monitoring by cDNA microarrays to identify age associated genes in human kidney samples. Our samples included young (8 weeks-8 years, N= 4), adult (31-46 years, N= 7), and old kidneys (71-88 years, N= 9).

RESULTS

Old kidneys had more glomerulosclerosis, tubular atrophy, interstitial fibrosis, and fibrous intimal thickening in small arteries. We identified approximately 500 genes that were differentially expressed among the three age groups. Old kidneys appeared to have increased extracellular matrix turnover and a nonspecific inflammatory response, combined with a reduction in processes dependent on energy metabolism and mitochondrial function. Quantitative supervised bioinformatics analyses of adult and old kidney expression data correlated the expression of 255 gene profiles with renal pathology scores. Microarray class prediction analysis (PAM) identified 50 unique genes that segregated old kidneys into two distinct clusters: those more similar within age class (OO, N= 5) versus old kidneys more similar to adult kidneys (OA, N= 4). The expression of six functionally significant genes was further validated by quantitative reverse transcription-polymerase chain reaction (RT-PCR) (FN1, MMP7, TNC, SERPIN3A, BPHL, CSPG2) in the experiment group and, subsequently, confirmed independently in 17 additional old and adult age-stratified test kidney samples. The p53 inducible gene, CSPG2, performed best in separating OO kidneys from adults and OA samples in this analysis.

CONCLUSION

The method described in this study using independent validation samples can be envisioned to test utility of the identified genes in assessing age-related changes that contribute to decline in renal function.

Addressing the heterogeneity of the ischemic stroke phenotype in human genetics research

BACKGROUND AND PURPOSE

Many investigators have approached ischemic stroke as a complex phenotype by dividing the ischemic stroke population into distinct subtypes. The purpose of this study was to review systematically the methods used to subtype ischemic stroke in recent genetic studies.

METHODS

The MEDLINE database was searched for articles pertaining to research on the genetics of human ischemic stroke published from January 2000 through January 2002. Abstracts and full-length reports were then sequentially screened to select articles pertaining to original case-control or cohort studies.

RESULTS

The initial search yielded 153 publications. Of 41 relevant articles, ischemic stroke was subtyped in 25 (61%). The most common standard subtyping system was the Cerebrovascular Classification of Diseases III system (9 articles). Of the subtyping systems used, 3 had previously published interrater reliability. The subtyping system was reported to have been prespecified in 1 study. Four articles reported using central adjudication. Two articles reported that the person doing the subtyping was blinded to genotype, and 2 reported that the person doing the genotyping was blinded to the patient's subtype status.

CONCLUSIONS

When investigators subtyped ischemic stroke, they typically used either nonstandard classification systems or systems of undetermined reliability. Important methodological issues, including blinding and prespecification of the classification system, were rarely reported. Advances in methodology and scientific reporting standards would foster identification of subtype-specific genetic risk factors.