Prevalence of vitamin D insufficiency in early pregnancies- a Singapore study.

Vitamin D plays an essential role in bone and mineral metabolism. There is increased interest in understanding prevalence of Vitamin D deficiency in pregnancy as many studies report association of low vitamin D levels with obstetric complications and neonatal sequelae. There is a paucity of studies in Singapore evaluating levels of vitamin D levels during the first trimester of pregnancies. We aim to study the prevalence of vitamin D insufficiency in this population. Our study assessed vitamin D levels in these women. Vitamin D (Plasma 25(OH)D concentration) levels in multiracial women during the first trimester were collected via venepuncture at their booking antenatal visit. They were stratified into sufficient ≥30ng/ml, insufficient ≥20ng/ml and <30ng/ml, moderately deficient ≥10ng/ml and <20ng/ml and severely deficient <10ng/ml. 93 women were included in this study. Only 2.2% of our study population had sufficient vitamin D levels. In women who had insufficient levels, the heavier the weight, the more likely to be vitamin D deficient. Interestingly, we also note that the older the patient, the less likely they are to be deficient. In women with periconceptual multivitamin supplementation, the average vitamin D level for those with supplementation was 2.10ng/ml higher than those without. Majority of patients were recruited from a single study member's patient pool who were mostly Chinese. Prevalence of Vitamin D deficiency in general obstetric patients with higher BMI and darker skinned patients may be even lower in Singapore. The high prevalence of Vitamin D insufficiency in our patients prove that it is a prominent problem in our population. We aim to implement screening of vitamin D levels as part of antenatal investigations in the first trimester and recommend supplementation as required. We also hope to evaluate the association of low vitamin D levels with obstetric or neonatal complications further understanding its implications.

Delineation of Natural Killer Cell Differentiation from Myeloid Progenitors in Human.

Understanding of natural killer (NK) cell development in human is incomplete partly because of limited access to appropriate human tissues. We have developed a cytokine-enhanced humanized mouse model with greatly improved reconstitution and function of human NK cells. Here we report the presence of a cell population in the bone marrow of the cytokine-treated humanized mice that express both NK cell marker CD56 and myeloid markers such as CD36 and CD33. The CD56(+)CD33(+)CD36(+) cells are also found in human cord blood, fetal and adult bone marrow. Although the CD56(+)CD33(+)CD36(+) cells do not express the common NK cell functional receptors and exhibit little cytotoxic and cytokine-producing activities, they readily differentiate into mature NK cells by acquiring expression of NK cell receptors and losing expression of the myeloid markers. Further studies show that CD33(+)CD36(+) myeloid NK precursors are derived from granulo-myelomonocytic progenitors. These results delineate the pathway of human NK cell differentiation from myeloid progenitors in the bone marrow and suggest the utility of humanized mice for studying human hematopoiesis.