Changes in Conjunctival Hemodynamics Predict Albuminuria in Sickle Cell Nephropathy.
BACKGROUND
Albuminuria is an early manifestation of deterioration in renal function in subjects with sickle cell disease (SCD). Hyperfiltration may be an early mechanism for kidney damage in SCD. The purpose of the current study was to determine the association between conjunctival hemodynamics and albuminuria in SCD subjects with preserved glomerular filtration rate.


METHODS
Conjunctival microcirculation imaging was performed to measure conjunctival diameter and axial blood velocity (V) in 35 SCD and 10 healthy control subjects. Albuminuria, defined as albumin excretion ratio (AER), was obtained from the medical charts. Based on the 95% CI of conjunctival V in control subjects (0.40-0.60 mm/s), SCD subjects were allocated to 3 groups: V1 <0.40 mm/s (n = 7), V2 of 0.40-0.60 mm/s (n = 18) and V3 ≥0.60 mm/s (n = 10).


RESULTS
Mean log(AER) measurements in the V1, V2 and V3 groups were 1.08 ± 0.67, 1.39 ± 0.59 and 2.00 ± 0.91 mg/g creatinine, respectively, and followed a positive linear trend from the V1 to V3 groups (p = 0.01). By multivariate linear regression analysis, conjunctival V significantly correlated with albuminuria (p = 0.01) independent of age, blood pressure, α-thalassemia, hematocrit, white blood cell count and lactate dehydrogenase concentration.


CONCLUSIONS
Increased conjunctival V is associated with albuminuria in SCD subjects. Assessment of conjunctival microvascular hemodynamics may improve our understanding of the pathophysiology and clinical management of sickle cell nephropathy.
Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Ill., USA.
Ali
A
Kord Valeshabad
Justin
J
Wanek
Santosh L
SL
Saraf
Bruce I
BI
Gaynes
Victor R
VR
Gordeuk
Robert E
RE
Molokie
Mahnaz
M
Shahidi
D000328:Adult; D000419:Albuminuria / Q000209:etiology / Q000503:physiopathology*; D000755:Anemia, Sickle Cell / Q000150:complications*; D001783:Blood Flow Velocity; D016022:Case-Control Studies; D003228:Conjunctiva / Q000098:blood supply / Q000503:physiopathology*; D003404:Creatinine / Q000097:blood; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D051437:Renal Insufficiency / Q000209:etiology / Q000503:physiopathology*
D003404:Creatinine