Age-dependent telomere attrition as a potential indicator of racial differences in renal growth patterns.
BACKGROUND
Racial differences in the predilection to salt sensitivity may arise from different renal growth patterns. To test this idea, we monitored age-dependent telomere attrition rate, reflecting largely the replicative history of somatic cells, in the outer renal cortex and the inner renal medulla of African Americans and Caucasians.


METHODS
Telomere length, determined by the mean length of the terminal restriction fragments (TRF), was measured in specimens from 58 African-American and 63 Caucasian males, ages 1 day to 71 years.


RESULTS
In the outer renal cortex, TRF length attrition rate was significantly slower in African Americans (-0.021 +/- 0.0064 kb/year) than in Caucasians (-0.060 +/- 0.0094 kb/year) (p = 0.0007). In both ethnic groups the TRF length attrition rate was slower in the inner medulla than in the outer renal cortex, but without significant racial differences.


CONCLUSIONS
The proximal tubule is the most abundant nephron structure in the outer renal cortex. Less proliferative growth of proximal tubular cells in kidneys from African Americans may be one factor explaining the slower age-dependent telomere attrition rate in the outer renal cortex of African Americans than in Caucasians.
Tchakmakjian
L
L
Hypertension Research Center, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, NJ 07103, USA.
Gardner
J P
JP
Wilson
P D
PD
Kimura
M
M
Skurnick
J
J
Zielke
H R
HR
Aviv
A
A
D000293:Adolescent; D000328:Adult; D001741:Black or African American; D000368:Aged; D000375:Aging / Q000502:physiology*; D001344:Autopsy; D049109:Cell Proliferation; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007668:Kidney / Q000254:growth & development*; D007672:Kidney Cortex / Q000502:physiology; D007687:Kidney Tubules, Proximal; D008297:Male; D008875:Middle Aged; D012982:Sodium, Dietary / Q000378:metabolism; D016615:Telomere / Q000648:ultrastructure*; D044465:White People
D012982:Sodium, Dietary