Michiko Kido

Comparison of mesenchymal stem cells derived from arterial, venous, and Wharton's jelly explants of human umbilical cord.

We isolated mesenchymal stem cells (MSC) from arteries (UCA), veins (UCV), and Wharton’s jelly (UCWJ) of human umbilical cords (UC) and determined their relative capacities for sustained proliferation and multilineage differentiation. Individual UC components were dissected, diced into 1–2 mm³ fragments, and aligned in explant cultures from which migrating cells were isolated using trypsinization. Preparations from 13 UCs produced 13 UCWJ, 11 UCV, and 10 UCA cultures of fibroblast-like, spindle-shaped cells negative for CD31, CD34, CD45, CD271, and HLA-class II, but positive for CD13, CD29, CD44, CD73, CD90, CD105, and HLA-class I. UCV cells exhibited a significantly higher frequency of colony-forming units fibroblasts than did UCWJ and UCA cells. Individual MSCs could be selectively differentiated into osteoblasts, chondrocytes, and adipocytes. When compared for osteogenic potential, UCWJ cells were the least effective precursors, whereas UCA-derived cells developed alkaline phosphatase activity with or without an osteogenic stimulus. UC components, especially blood vessels, could provide a promising source of MSCs with important clinical applications.

Investigation of optimal weight gain during pregnancy for Japanese Women

This study aims to compare the US Institute of Medicine (IOM) and Japanese guidelines proposed by the Ministry and the Japan Society for the Study of Obesity on gestational weight gain (GWG), and to explore the optimal GWG range in Japanese women. We investigated 8,152 Japanese women who had full-term singleton babies between 2010 and 2013 at a single center in Tokyo. Logistic regression models showed that GWG below the recommendation of the IOM and Japanese guidelines was similarly associated with an increased risk of light-for-date (LFD), whereas GWG above these guidelines was similarly associated with an increased risk of heavy-for-date (HFD) in pre-pregnancy body mass index categories of underweight (<18.5 kg/m2, n = 1559), normal-weight (18.5–24.9 kg/m2, n = 4998), overweight (25.0–29.9 kg/m2, n = 270), and obese (30 ≤ kg/m2, n = 60). The receiver-operating characteristic curve demonstrated that the optimal cutoffs for LFD and HFD were 9.7 and 10.4 kg, respectively in normal-weight mothers. The IOM and Japanese guidelines identified the risk of LFD or HFD equally well. The optimal GWG range in normal-weight women observed in this study was more close to Japanese guideline (i.e., 7–12 kg) compared to the IOM guideline (i.e., 11.5–16 kg).

Pre-pregnancy body mass index as a predictor of low birth weight infants in Japan

BACKGROUND AND OBJECTIVES The prevalence of low birth weight (LBW) infants in Japan has doubled in the last several decades. The objective of this study was to examine the effects of pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) on LBW infants of Japanese women. METHODS AND STUDY DESIGN This retrospective study was conducted using data on 1,336 mothers (mean age, 34.0 years)whose pre-pregnancy BMI was less than 23 kg/m2 and their singleton infants were born at full term between January and December in 2011. The outcome of interest was LBW infants (less than 2,500 g). The main exposure variables were pre-pregnancy BMI and GWG. The effects of these two variables on LBW were determined after adjusting for confounder variables such as maternal age, smoking, drinking, parity, gestational week at birth and infant gender. RESULTS The proportion of LBW infants was 4.2% in total, 6.1% among underweight mothers (<18.5 kg/m2) and 3.5% among normal weight mothers (18.5-22.9 kg/m2).A stepwise multivariable logistic regression model showed that underweight mother were more likely [odds ratio (OR) 1.86, 95% confidence interval (CI), 1.04-3.31] than normal weight mother to deliver a LBW infant. Mothers with inadequate GWG <8.5 kg were more likely to deliver a LBW infant (OR 1.66, 95% CI: 0.80-3.45) compared with mothers who gained 10.5-12.4 kg (the third lowest quartile) but this did not reach statistical significance. CONCLUSIONS This study demonstrated that mothers who were underweight before pregnancy were independently associated with the delivery of LBW infants.

Combination of parity and pre-pregnancy BMI and low birth weight infants among Japanese women of reproductive age

This study aimed to examine the effects of parity and pre-pregnancy body mass index (BMI) on low birth weight (LBW) infants among Japanese women. Participants included 1,518 mothers (mean age 34.0 years) of singleton full-term infants in 2011. The incidence of LBW infants was 7.5% in primiparous women with BMI<18.5 (Group A; n=239), 4.0% in multiparous women with BMI<18.5 (Group B; n=124), 6.0% in primiparous women with 18.5≤BMI<25 (Group C; n=715), and 1.8% in multiparous women with 18.5≤BMI<25 (Group D; n=440). A multivariable logistic regression model revealed that mothers in Group A were more likely to deliver a LBW infant [odds ratio (OR) 6.41, 95% confidence interval (CI), 2.65–15.49] than were mothers in Group D. Being both underweight (OR 1.8, 95% CI: 1.05–3.11) and primiparous (OR 3.41, 95% CI: 1.82–6.44) were independently associated with LBW infants. This study demonstrated that the characteristics of primiparous and underweight in mothers are additively associated with LBW infants.

Nutritional Status of Japanese Women of Childbearing Age and the Ideal Weight Range for Pregnancy

According to the recent 2015 Nutrition Survey, the prevalence of being underweight (Body Mass Index, BMI <18.5 kg/m2) among women in their 20s is 22.3%. Women of childbearing age tend to have a lower intake of protein and their total energy intake is lower than the requirements established by the 2015 Dietary Reference Intakes for Japanese. There is a growing body of evidence showing that underweight women tend to bear small babies and that these babies have an increased risk of diabetes or cancer in their adulthood. In order to prevent Japanese women from bearing small babies, the literature has suggested that women of childbearing age should be encouraged to remain at a normal weight before pregnancy. For optimal weight gain during pregnancy, existing guidelines recommend different ranges of weight gain based on prepregnancy BMI. Owing to the absence of official GWG recommendations in Asian countries, including China and Taiwan, the US Institute of Medicine (IOM) guidelines are generally followed. However, Asian women are smaller and experience lower weight gains; therefore, excessive weight gain may lead to harmful events including macrosomia, preterm birth, preeclampsia, gestational diabetes, pregnancy-induced hypertension, and short- and long-term postpartum weight retention. Thus, an accurate GWG range should be determined for Asian women. We introduce one epidemiological study in which the optimal weight gain range was investigated by analyzing receiver-operating characteristic curves together with potential research ideas in this field with the aim of encouraging young researchers to solve this public health problem affecting mothers and children.