Mark D. Kilby

Normal human pregnancy is associated with an elevation in the immune suppressive CD25+ CD4+ regulatory T-cell subset

CD4+ CD25+ T regulatory cells (TReg), suppress antigen‐specific immune responses and are important for allograft tolerance. During pregnancy the mother tolerates an allograft expressing paternal antigens (the fetus) requiring substantial changes in immune regulation over a programmed period of time. We analysed whether immune‐suppressive TReg cells were altered during pregnancy and therefore might play a part in this tolerant state. The presence of TReg cells was assessed in the blood of 25 non‐pregnant, 63 pregnant and seven postnatal healthy women by flow cytometry. We observed an increase in circulating TReg cells during early pregnancy, peaking during the second trimester and then a decline postpartum. Isolated CD25+ CD4+ cells expressed FoxP3 messenger RNA, a marker of TReg cells, and suppressed proliferative responses of autologous CD4+ CD25– T cells to allogeneic dendritic cells. These data support the concept that normal pregnancy is associated with an elevation in the number of TReg cells which may be important in maintaining materno‐fetal tolerance.

Differential regulation of vitamin D receptor and its ligand in human monocyte-derived dendritic cells

The functions of dendritic cells (DCs) are tightly regulated such that protective immune responses are elicited and unwanted immune responses are prevented. 1α25-dihydroxyvitamin D3 (1α25(OH)2D3) has been identified as a major factor that inhibits the differentiation and maturation of DCs, an effect dependent upon its binding to the nuclear vitamin D receptor (VDR). Physiological control of 1α25(OH)2D3 levels is critically dependent upon 25-hydroxyvitamin D3-1α-hydroxylase (1αOHase), a mitochondrial cytochrome P450 enzyme that catalyzes the conversion of inactive precursor 25-hydroxyvitamin D3 (25(OH)D3) to the active metabolite 1α25(OH)2D3. Using a human monocyte-derived DC (moDC) model, we have examined the relationship between DC VDR expression and the impact of exposure to its ligand, 1α25(OH)2D3. We show for the first time that moDCs are able to synthesize 1α25(OH)2D3 in vitro as a consequence of increased 1αOHase expression. Following terminal differentiation induced by a diverse set of maturation stimuli, there is marked transcriptional up-regulation of 1αOHase leading to increased 1αOHase enzyme activity. Consistent with this finding is the observation that the development and function of moDCs is inhibited at physiological concentrations of the inactive metabolite 25(OH)D3. In contrast to 1αOHase, VDR expression is down-regulated as monocytes differentiate into immature DCs. Addition of 1α25(OH)2D3 to moDC cultures at different time points indicates that its inhibitory effects are greater in monocyte precursors than in immature DCs. In conclusion, differential regulation of endogenous 1α25(OH)2D3 ligand and its nuclear receptor appear to be important regulators of DC biology and represent potential targets for the manipulation of DC function.

Vitamin D and Placental-Decidual Function:

The active form of vitamin D (1,25-dihydroxyvitamin D3, 1,25[OH]2D3) has well-established effects on bone metabolism and mineral homeostasis. However, recently it has become clear that 1,25(OH)2D3 has potent antiproliferative and immunomodulatory actions that are not immediately linked to its role as a skeletal regulator. Both the nuclear receptor for 1,25(OH)2D3 (vitamin D receptor, VDR) and the vitamin D-activating enzyme 1α-hydroxylase are expressed in a wide variety of nonclassic tissues, highlighting the potential for local autocrine-paracrine responses rather than traditional endocrine effects. Prominent among the tissues that express 1α-hydroxylase is the placenta-decidua, and this has raised important questions concerning the potential role of locally generated 1,25(OH)2D3 as a modulator of fetal-placental development and function. When bound to the VDR, 1,25(OH)2D3 regulates key target genes associated with implantation, such as HOXA10, whereas the potent immunosuppressive effects of 1,25(OH)2D3 suggest a role in implantation tolerance. These observations are further supported by data from our group showing increased expression of 1αhydroxylase and VDR in first-trimester trophoblast and decidua from human pregnancies. Studies by other groups have reported abnormal expression of 1α-hydroxylase in preeclamptic pregnancies, revealing a poential role for 1,25(OH)2D3 as a regulator of placentation. The effect of vitamin D on reproduction has been further endorsed by murine gene knockout models for 1α-hydroxylase and VDR, both of which are infertile. These observations and other are discussed in this article in which we postulate an active role for 1,25(OH)2D3 in placenta-decidua. In particular, we describe how induction of the vitamin D—activating enzyme 1α-hydroxylase in early gestation might provide a mechanism by which environmental or dietary vitamin D can influence fetal-placental development.

Association between thyroid autoantibodies and miscarriage and preterm birth: meta-analysis of evidence

Objectives To evaluate the association between thyroid autoantibodies and miscarriage and preterm birth in women with normal thyroid function. To assess the effect of treatment with levothyroxine on pregnancy outcomes in this group of women. Design Systematic review and meta-analysis. Data sources Medline, Embase, Cochrane Library, and SCISEARCH (inception-2011) without any language restrictions. We used a combination of key words to generate two subsets of citations, one indexing thyroid autoantibodies and the other indexing the outcomes of miscarriage and preterm birth. Study selection Studies that evaluated the association between thyroid autoantibodies and pregnancy outcomes were selected in a two stage process. Two reviewers selected studies that met the predefined and explicit criteria regarding population, tests, and outcomes. Data synthesis Odds ratios from individual studies were pooled separately for cohort and case-control studies with the random effects model. Results 30 articles with 31 studies (19 cohort and 12 case-control) involving 12 126 women assessed the association between thyroid autoantibodies and miscarriage. Five studies with 12 566 women evaluated the association with preterm birth. Of the 31 studies evaluating miscarriage, 28 showed a positive association between thyroid autoantibodies and miscarriage. Meta-analysis of the cohort studies showed more than tripling in the odds of miscarriage with the presence of thyroid autoantibodies (odds ratio 3.90, 95% confidence interval 2.48 to 6.12; P<0.001). For case-control studies the odds ratio for miscarriage was 1.80, 1.25 to 2.60; P=0.002). There was a significant doubling in the odds of preterm birth with the presence of thyroid autoantibodies (2.07, 1.17 to 3.68; P=0.01). Two randomised studies evaluated the effect of treatment with levothyroxine on miscarriage. Both showed a fall in miscarriage rates, and meta-analysis showed a significant 52% relative risk reduction in miscarriages with levothyroxine (relative risk 0.48, 0.25 to 0.92; P=0.03). One study reported on the effect of levothyroxine on the rate of preterm birth, and noted a 69% relative risk reduction (0.31, 0.11 to 0.90). Conclusion The presence of maternal thyroid autoantibodies is strongly associated with miscarriage and preterm delivery. There is evidence that treatment with levothyroxine can attenuate the risks.

Effects of 25-Hydroxyvitamin D3 and 1,25-Dihydroxyvitamin D3 on Cytokine Production by Human Decidual Cells

Abstract The active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25[OH]2D3) is a potent immunomodulatory seco-steroid. We have demonstrated that several components of vitamin D metabolism and signaling are strongly expressed in human uterine decidua from first trimester pregnancies, suggesting that locally produced 1,25(OH)2D3 may exert immunosuppressive effects during early stages of gestation. To investigate this further, we used primary cultures of human decidual cells from first and third trimester pregnancies to demonstrate expression and activity of the enzyme that catalyzes synthesis of 1,25(OH)2D3, 1alpha-hydroxylase (CYP27B1). Synthesis of 1,25(OH)2D3 was higher in first trimester decidual cells (41 ± 11.8 fmoles/h/mg protein) than in third trimester cells (8 ± 4.4 fmoles/h/mg protein; P < 0.05). Purification of decidual cells followed by quantitative RT-PCR analysis showed that CYP27B1 was expressed by both CD10+VE stromal-enriched and CD10−VE stromal-depleted cells, with higher levels of mRNA in first trimester pregnancies. Expression of CYP27B1 correlated with TLR4 and IDO. Functional responses to 1,25(OH)2D3 were studied using CD56+ve natural killer (NK) cells isolated from first trimester decidua. Decidual NK cells treated with 1,25(OH)2D3 or precursor 25-hydroxyvitamin D3 (25OHD3) for 28 h showed decreased synthesis of cytokines, such as granulocyte-macrophage colony stimulating factor 2 (CSF2), tumor necrosis factor, and interleukin 6, but increased expression of mRNA for the antimicrobial peptide cathelicidin antimicrobial peptide. These data indicate that human decidual cells are able to synthesize active 1,25(OH)2D3, particularly in early gestation, and this may act in an autocrine/paracrine fashion to regulate both acquired and innate immune responses at the fetal-maternal interface.

The Ontogeny of 25-Hydroxyvitamin D3 1α-Hydroxylase Expression in Human Placenta and Decidua

In addition to its classical calciotropic effects, the active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) is a potent anti-proliferative/immunomodulatory secosteroid. The enzyme that catalyzes the synthesis of 1,25(OH)2D3, 1α-hydroxylase (1α-OHase), is expressed in many human tissues, highlighting its possible role as an autocrine/paracrine activator of vitamin D. Immunohistochemical and RNA analyses were used to characterize the ontogeny of 1α-OHase expression in human placenta and decidua. Protein for 1α-OHase was detectable in trophoblast and decidua; the latter being stronger in decidualized stromal cells than macrophages, with no staining of lymphocytes. Quantitative reverse transcriptase-polymerase chain reaction was used to assess changes in mRNA expression for 1α-OHase at different gestations: first (mean, 9.1 ± 1.5 weeks); second (mean, 14 ± 1.8 weeks), and third trimester (mean, 39.3 ± 2.5 weeks). 1α-OHase expression in decidua was ∼1000-fold higher in first (95% confidence limits, 611 to 1376) and second (95% confidence limits, 633 to 1623) trimester biopsies when compared with the third trimester (95% confidence limits, 0.36 to 2.81) (both P < 0.001). In placenta, 1α-OHase expression was 80-fold higher in the first (range, 42 to 137) and second (range, 30 to 199) trimester when compared with third trimester biopsies (0.6 to 1.6) (both P < 0.001). Similar results were obtained by semiquantitative IHC. Parallel analysis of the receptor for 1,25(OH)2D3 (vitamin D receptor) indicated that, as with 1α-OHase, highest levels of expression occurred in first trimester decidua. However, changes in vitamin D receptor mRNA expression across gestation were less pronounced than 1α-OHase. These spatiotemporal data emphasize the potential importance of 1α-OHase during early fetoplacental life and, in particular, suggest an autocrine/paracrine immunomodulatory function for the enzyme.

Additional information from array comparative genomic hybridization technology over conventional karyotyping in prenatal diagnosis: a systematic review and meta‐analysis

Array comparative genomic hybridization (CGH) is transforming clinical cytogenetics with its ability to interrogate the human genome at increasingly high resolution. The aim of this study was to determine whether array CGH testing in the prenatal population provides diagnostic information over conventional karyotyping.

Hypoplastic left heart syndrome

Hypoplastic left heart syndrome is a rare congenital heart defect in which the left side of the heart is underdeveloped. Surgical management of hypoplastic left heart syndrome has changed the prognosis of the condition that was previously regarded as fatal. We discuss surgical strategies based on staged procedures, with the right ventricle supporting both systemic and pulmonary circulation. We also discuss other management options, such as neonatal transplantation and the recent innovation of hybrid techniques. Surgical techniques and the understanding of the pathophysiology of this condition have been at the forefront of neonatal cardiac surgery and intensive care. The management of the syndrome remains a challenge because affected children grow into adolescence and adulthood posing various new problems and demands.

Congenital anterior abdominal wall defects in England and Wales 1987–93: retrospective analysis of OPCS data

Abstract Objectives: Analysis of incidence and characteristics of congenital abdominal wall defects, with special reference to the differences between the incidence of gastroschisis and exomphalos (omphalocele). Design: Retrospective analysis using data from the Office of Population Censuses and Surveys (recoded to differentiate exomphalos and gastroschisis) and the National Congenital Malformation Notification Scheme. Setting: England and Wales, 1987 to 1993. Results: 1043 congenital anterior abdominal wall defects were notified within the seven year study period. Of these, 539 were classified as gastroschisis, 448 as exomphalos, 19 as “prune belly syndrome,” and 37 as “unclassified.” Gastroschisis doubled in incidence from 0.65 in 1987 to 1.35 per 10 000 total births in 1991, with little further change; the incidence of exomphalos decreased from 1.13 to 0.77 per 10 000 births. The overall incidence of notified congenital abdominal wall defects was 2.15 per 10 000 total births. Gastroschisis was associated with a lower overall maternal age than exomphalos and with a significantly lower proportion of additional reported congenital malformations (5.0%) than in the cohort with exomphalos (27.4%) (odds ratio 0.14, 95% confidence interval 0.09 to 0.22; P<0.001). The sex ratio of the two cohorts was the same. The incidence of gastroschisis and exomphalos was higher in the northern regions of England than in the south east of the country. Conclusions: The national congenital malformation notification system showed an increasing trend in the incidence of fetuses born with gastroschisis and a progressive decreasing incidence of exomphalos in England and Wales between 1987 and 1993. Although the reasons for this are likely to be multifactorial, a true differential change seems likely. The observed increase in incidence of gastroschisis relative to exomphalos and the differentiation in maternal age have implications for resource management within the NHS and warrant further epidemiological monitoring. Regional differences may be due to a dietary or environmental factor, which requires further study. Key messages Gastroschisis was also associated with a significantly lower proportion of additional reported congenital malformations Younger mothers are significantly more likely than older mothers to have a child with gastroschisis The incidence of congenital abdominal wall defects seemed to be higher in the regions in the north than in the south east of England

Prenatal bladder drainage in the management of fetal lower urinary tract obstruction: a systematic review and meta-analysis

OBJECTIVE To estimate the effect of prenatal bladder drainage on perinatal survival in fetuses with lower urinary tract obstruction. DATA SOURCES Relevant articles were identified by searching the databases MEDLINE (1966–2002), EMBASE (1988–2002), and the Cochrane library (2000;4). METHODS OF STUDY SELECTION Studies were selected if the effect of prenatal bladder drainage (vesicocentesis, vesicoamniotic shunt, or open fetal bladder surgery) on perinatal survival was reported in fetuses with ultrasonic evidence of lower urinary tract obstruction. Study selection, quality assessment, and data abstraction were performed independently and in duplicate. TABULATION, INTEGRATION, AND RESULTS Sixteen observational studies that included nine case series (147 fetuses) and seven controlled series (195 fetuses) were identified. Study characteristics and quality were recorded for each study. Data on the effect of bladder drainage on perinatal survival were abstracted. Where controlled data were available, 2 × 2 tables were generated to compare the effects of bladder drainage versus no bladder drainage on perinatal survival. Pooled odds ratios (ORs) were used as summary measures of effect, and the results were stratified according to predicted fetal prognoses (based on ultrasound features and fetal urinary electrolytes). Among controlled studies, bladder drainage appeared to improve perinatal survival relative to no drainage (OR 2.5; 95% confidence interval [CI] 1.1, 5.9; P = .03). However, this observation was largely because among the subgroup of fetuses with a poor prognosis there was a marked improvement (OR 8.1; 95% CI 1.2, 52.9; P = .03). Improved perinatal outcome was also suggested in those fetuses considered to have a good prognosis (OR 2.8; 95% CI 0.7, 10.8; P = .13). CONCLUSION There is a lack of high quality evidence to reliably inform clinical practice regarding prenatal bladder drainage in fetuses with ultrasonic evidence of lower urinary tract obstruction. The limited available evidence suggests that prenatal bladder drainage may improve perinatal survival in these fetuses, particularly those with poor predicted prognoses. Further research in the form of a multicenter randomized controlled trial is required to assess the short- and long-term effects of this intervention.