Urinary hydroxyproline: relationship to growth, bone mineral content, and serum alkaline phosphatase level in premature infants.
There is little information on urinary hydroxyproline (UHP) excretion in premature infants. We hypothesized that UHP excretion would positively correlate with growth in premature infants, and that there would be correlations between UHP excretion and serum alkaline phosphatase concentration as well as bone mineral content (BMC). Twenty-six premature infants (birth weight, less than 1,300 g; gestational age, less than or equal to 32 weeks) received one of four oral feedings. Seven received mother's own milk (HM), and eight received mothers own milk fortified with 0.85 g/dl of bovine whey, 90 mg/dl of Ca, and 45 mg/dl of P. Six and five infants received Similac, 20 cal/oz (SIM) and Similac Special Care, 20 cal/oz, respectively. Measurements of UHP, serum alkaline phosphatase, BMC (photon absorptiometry), and growth were made during the 1st 7 weeks of life. The lowest UHP excretion was in the HM group. For all infants, there was a significant correlation between UHP excretion (mg/day) and absolute weight (r = 0.64, p less than 0.001), as well as rate of weight gain (r = 0.50, p less than 0.01). The UHP excretion (milligrams per day) also correlated with absolute length (r = 0.41, p less than 0.01) and rate of gain in length (centimeters per week) (r = 0.70, p less than 0.001). The UHP excretion did not correlate significantly with BMC or serum alkaline phosphatase concentration. We conclude that UHP excretion is increased in the growing premature infant compared to older infants and adults and is a good marker for somatic growth in this population.(ABSTRACT TRUNCATED AT 250 WORDS)
Greer
F R
FR
Department of Pediatrics, Center for Health Sciences, University of Winconsin, Madison.
Chen
X R
XR
McCormick
A
A
D000469:Alkaline Phosphatase / Q000097:blood*; D001842:Bone and Bones / Q000737:chemistry*; D006801:Humans; D006909:Hydroxyproline / Q000652:urine*; D007225:Infant Food; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood / Q000254:growth & development / Q000652:urine*; D008895:Milk, Human; D008903:Minerals / Q000032:analysis*; D015430:Weight Gain
D008903:Minerals; D000469:Alkaline Phosphatase; D006909:Hydroxyproline