Division of Metabolism and Nutrition, University Hospital, Federal University of Rio de Janeiro, RJ, Brazil.
J Hum Nutr Diet. 2010 Dec;23(6):583-9. doi: 10.1111/j.1365-277X.2010.01072.x.
The liver is the main organ involved in homeostasis, metabolism and the storage of retinol. During the fibrotic process, hepatic stellate cells lose their lipid drops, and retinol reserves may deplete. Thus, the present study aimed to evaluate serum retinol levels (RL), hepatic retinol storage and dietary vitamin A intake in cirrhotic patients.
RL were measured by high-performance liquid chromatography in fifty-eight cirrhotic patients. Fasting RL <1.05 μmol L⁻¹ indicates vitamin A deficiency (VAD). A relative dose response (RDR) to oral retinol ≥20% indicates an inadequate hepatic retinol reserve (positive test). Severe malnutrition was defined as a mid-arm muscle circumference (MAMC) and/or triceps skinfold thickness (TSF) below the 5th percentile and moderate malnutrition as MAMC and/or TSF below the 10th percentile. Vitamin A daily intake was estimated by a specific questionnaire. The Child-Pugh classification of liver disease severity and the Model for End-Stage Liver Disease were used.
Low RL were found in 60% of the patients. Twenty-three cirrhotic patients had adequate fasting RL (RL = 1.34; 1.05-2.12 μmol L⁻¹) and negative RDR, indicating efficient liver stores. Among thirty-five cirrhotic patients with low RL, 43% had negative RDR (RL = 0.42; 0.06-0.82 μmol L⁻¹) and 57% had positive RDR (RL = 0.45; 0.09-0.93 μmol L⁻¹). Malnutrition (36%) and inadequate vitamin A intake (55%) were not associated with fasting RL or RDR.
VAD was highly prevalent in cirrhotic patients. However, in those with low serum RL and negative RDR, factors other than inadequate vitamin A intake, such as impaired hepatic vitamin A mobilization and intestinal vitamin A malabsorption, which were not examined in the present study, could have influenced the negative results obtained by the RDR method.
肝脏是参与内稳态、代谢和视黄醇储存的主要器官。在纤维化过程中，肝星状细胞失去脂滴，视黄醇储备可能耗尽。因此，本研究旨在评估肝硬化患者的血清视黄醇水平（RL）、肝视黄醇储存和膳食维生素 A 摄入量。
通过高效液相色谱法测量 58 例肝硬化患者的 RL。空腹 RL<1.05μmol L⁻¹表示维生素 A 缺乏（VAD）。口服视黄醇的相对剂量反应（RDR）≥20%表示肝内视黄醇储备不足（阳性试验）。严重营养不良定义为中臂肌围（MAMC）和/或三头肌皮褶厚度（TSF）低于第 5 百分位，中度营养不良定义为 MAMC 和/或 TSF 低于第 10 百分位。维生素 A 的日摄入量通过特定的问卷来估计。采用肝脏疾病严重程度的 Child-Pugh 分类和终末期肝病模型。
发现 60%的患者 RL 较低。23 例肝硬化患者空腹 RL 充足（RL=1.34；1.05-2.12μmol L⁻¹）且 RDR 阴性，表明肝脏储存效率高。在 35 例 RL 较低的肝硬化患者中，43%的患者 RDR 阴性（RL=0.42；0.06-0.82μmol L⁻¹），57%的患者 RDR 阳性（RL=0.45；0.09-0.93μmol L⁻¹）。营养不良（36%）和维生素 A 摄入不足（55%）与空腹 RL 或 RDR 无关。
肝硬化患者 VAD 患病率很高。然而，在那些血清 RL 较低且 RDR 阴性的患者中，除了维生素 A 摄入不足外，其他因素可能影响 RDR 方法的阴性结果，如肝内维生素 A 动员受损和肠道维生素 A 吸收不良，但这些因素在本研究中未进行检查。
