Kandasamy Yogavijayan, Smith Roger, Wright Ian M R, Lumbers Eugenie R
Department of Neonatology, The Townsville Hospital, Douglas, Queensland - Australia.
J Nephrol. 2013 Sep-Oct;26(5):894-8. doi: 10.5301/jn.5000220. Epub 2012 Oct 3.
Low birth weight (LBW), defined as birth weight below 2,500 g, is an important risk factor for the development of hypertension and renal disease in adult life. LBW is associated with a reduced nephron number, which results in hyperfiltration. The objective of this study was to compare the glomerular filtration rates (GFRs) of LBW and normal-birth-weight (NBW) term infants relative to their kidney volumes.
Term infants (born after 37 weeks of gestation) who had been admitted to Townsville Hospital's neonatal unit were recruited for this study. Serum cystatin C was used to calculate gfr. a kidney ultrasound was used to measure renal volume. all assessments were performed during the first week of life.
Data from 39 infants (17 male, 22 female; 13 LBW, 26 NBW) were analyzed. There were no significant differences in the median cystatin C (1.36 mg/L, inter quartile range [IQR] = 1.12 - 1.41, vs. 1.17 mg/L, IQR = 1.10 - 1.39; p = 0.39) and gestational age. There was no significant difference in the median GFR (53.0 ml/min per 1.73 m2, IQR = 50.8-66.9, vs. 63.2 ml/min per m2, IQR = 51.8-69.5; p = 0.39) between LBW and NBW infants, but LBW infants had smaller total renal volume compared with NBW infants (18.0 ± 4.7 mL vs. 24.4 ± 6.2 mL; p = 0.002).
Within 6 days, LBW infants achieved a similar GFR to NBW infants, despite 25% smaller kidney volumes. Thus, the single-nephron glomerular filtration rate must be increased in LBW infants. Prior to this study, it was unclear when hyperfiltration begins, but our results demonstrate that hyperfiltration begins in early life.
低出生体重（LBW）定义为出生体重低于2500克，是成年后发生高血压和肾脏疾病的重要危险因素。低出生体重与肾单位数量减少有关，这会导致肾小球高滤过。本研究的目的是比较低出生体重和正常出生体重（NBW）足月儿的肾小球滤过率（GFR）与其肾脏体积的关系。
招募入住汤斯维尔医院新生儿科的足月儿（妊娠37周后出生）进行本研究。使用血清胱抑素C计算肾小球滤过率。通过肾脏超声测量肾脏体积。所有评估均在出生后第一周内进行。
分析了39名婴儿（17名男性，22名女性；13名低出生体重儿，26名正常出生体重儿）的数据。胱抑素C中位数（1.36毫克/升，四分位间距[IQR]=1.12-1.41，与1.17毫克/升，IQR=1.10-1.39；p=0.39）和胎龄无显著差异。低出生体重儿和正常出生体重儿的肾小球滤过率中位数无显著差异（53.0毫升/分钟/1.73平方米，IQR=50.8-66.9，与63.2毫升/分钟/平方米，IQR=51.8-69.5；p=0.39），但低出生体重儿的总肾体积比正常出生体重儿小（18.0±4.7毫升对24.4±6.2毫升；p=0.002）。
在6天内，低出生体重儿的肾小球滤过率与正常出生体重儿相似，尽管其肾脏体积小25%。因此，低出生体重儿的单个肾单位肾小球滤过率必定增加。在本研究之前，尚不清楚高滤过何时开始，但我们的结果表明高滤过在生命早期就开始了。
