Joaquin Santolaya-Forgas

A primate subfamily of galectins expressed at the maternal–fetal interface that promote immune cell death

Galectins are proteins that regulate immune responses through the recognition of cell-surface glycans. We present evidence that 16 human galectin genes are expressed at the maternal–fetal interface and demonstrate that a cluster of 5 galectin genes on human chromosome 19 emerged during primate evolution as a result of duplication and rearrangement of genes and pseudogenes via a birth and death process primarily mediated by transposable long interspersed nuclear elements (LINEs). Genes in the cluster are found only in anthropoids, a group of primate species that differ from their strepsirrhine counterparts by having relatively large brains and long gestations. Three of the human cluster genes (LGALS13, -14, and -16) were found to be placenta-specific. Homology modeling revealed conserved three-dimensional structures of galectins in the human cluster; however, analyses of 24 newly derived and 69 publicly available sequences in 10 anthropoid species indicate functional diversification by evidence of positive selection and amino acid replacements in carbohydrate-recognition domains. Moreover, we demonstrate altered sugar-binding capacities of 6 recombinant galectins in the cluster. We show that human placenta-specific galectins are predominantly expressed by the syncytiotrophoblast, a primary site of metabolic exchange where, early during pregnancy, the fetus comes in contact with immune cells circulating in maternal blood. Because ex vivo functional assays demonstrate that placenta-specific galectins induce the apoptosis of T lymphocytes, we propose that these galectins reduce the danger of maternal immune attacks on the fetal semiallograft, presumably conferring additional immune tolerance mechanisms and in turn sustaining hemochorial placentation during the long gestation of anthropoid primates.

Middle cerebral artery peak systolic velocity: a new Doppler parameter in the assessment of growth-restricted fetuses.

The aims of this study were to determine if there is a relationship between middle cerebral artery (MCA) peak systolic velocity (PSV) and perinatal mortality in preterm intrauterine growth‐restricted (IUGR) fetuses, to compare the performance of MCA pulsatility index (PI), MCA‐PSV and umbilical artery (UA) absent/reversed end‐diastolic velocity (ARED) in predicting perinatal mortality, to determine the longitudinal changes that occur in MCA‐PI and MCA‐PSV in these fetuses, and to test the hypothesis that MCA‐PSV can provide additional information on the prognosis of hypoxemic IUGR fetuses.

A New Approach to Fetal Echocardiography Digital Casts of the Fetal Cardiac Chambers and Great Vessels for Detection of Congenital Heart Disease

The purpose of this study was to describe a method of 4‐dimensional (4D) reconstruction of the cardiac chambers and outflow tracts using a combination of spatiotemporal image correlation, “inversion mode,” and “B‐flow” imaging.

Human β-defensin-2: A natural antimicrobial peptide present in amniotic fluid participates in the host response to microbial invasion of the amniotic cavity

Objective. Human β-defensin-2 (HBD-2) is a potent antimicrobial peptide that is part of the innate immune response. The purpose of this study was to determine whether HBD-2 is present in amniotic fluid and if its concentration changes with microbial invasion of the amniotic cavity (MIAC) and labor. Study design. Amniotic fluid was retrieved by amniocentesis from 318 patients in the following groups: (1) mid-trimester (n = 75); (2) term not in labor (n = 28) and in labor (n = 51); (3) preterm labor and intact membranes without MIAC who delivered at term (n = 36), who delivered preterm without MIAC (n = 52), and preterm labor with MIAC who delivered preterm (n = 25); and (4) preterm premature rupture of membranes (preterm PROM) with (n = 25) and without MIAC (n = 26). MIAC was defined as a positive amniotic fluid culture for microorganisms. Amniotic fluid HBD-2 concentrations were determined using a sensitive and specific ELISA. Non-parametric statistics were used for analysis. Results. (1) HBD-2 was detected in all amniotic fluid samples; (2) the concentration of HBD-2 did not change with gestational age from mid-trimester to term (p = 0.8); (3) intra-amniotic infection was associated with a significant increase in amniotic fluid concentrations of HBD-2 in both women with preterm labor and intact membranes, and women with preterm PROM (p < 0.05 for each comparison); (4) patients with preterm labor and a negative amniotic fluid culture who delivered preterm had a higher median amniotic fluid HBD-2 concentration than those with preterm labor who delivered at term (p=0.001); and (5) among patients with preterm labor without MIAC, those who had intra-amniotic inflammation (amniotic fluid white blood cell count >100 cells per mL) had a higher median amniotic fluid concentration of HBD-2 than those without this condition (p < 0.002). Conclusion. (1) Amniotic fluid contains HBD-2, a natural antimicrobial peptide, and this may account for some of the antimicrobial activity of amniotic fluid; (2) amniotic fluid HBD-2 concentrations are increased in women with MIAC, regardless of the membrane status (intact membranes or PROM); and (3) we propose that amniotic fluid HBD-2 is part of the innate immune system within the amniotic cavity.

Emergence of hormonal and redox regulation of galectin-1 in placental mammals: Implication in maternal-fetal immune tolerance

Galectin-1 is an anti-inflammatory lectin with pleiotropic regulatory functions at the crossroads of innate and adaptive immunity. It is expressed in immune privileged sites and is implicated in establishing maternal–fetal immune tolerance, which is essential for successful pregnancy in eutherian mammals. Here, we show conserved placental localization of galectin-1 in primates and its predominant expression in maternal decidua. Phylogenetic footprinting and shadowing unveil conserved cis motifs, including an estrogen responsive element in the 5′ promoter of LGALS1, that were gained during the emergence of placental mammals and could account for sex steroid regulation of LGALS1 expression, thus providing additional evidence for the role of galectin-1 in immune–endocrine cross-talk. Maximum parsimony and maximum likelihood analyses of 27 publicly available vertebrate and seven newly sequenced primate LGALS1 coding sequences reveal that intense purifying selection has been acting on residues in the carbohydrate recognition domain and dimerization interface that are involved in immune functions. Parsimony- and codon model-based phylogenetic analysis of coding sequences show that amino acid replacements occurred in early mammalian evolution on key residues, including gain of cysteines, which regulate immune functions by redox status-mediated conformational changes that disable sugar binding and dimerization, and that the acquired immunoregulatory functions of galectin-1 then became highly conserved in eutherian lineages, suggesting the emergence of hormonal and redox regulation of galectin-1 in placental mammals may be implicated in maternal–fetal immune tolerance.

Anaphylatoxins in preterm and term labor.

Abstract Objective: The complement system plays a central role in the first line of defense against invading pathogens, and its activation involves the release of potent pro-inflammatory mediators such as anaphylatoxins C3a, C4a and C5a. The aim of this study was to determine whether differences existed in maternal plasma anaphylatoxin concentrations between patients with term and preterm parturition. Study design: A cross-sectional study was designed to determine the plasma anaphylatoxin concentrations in 296 pregnant women in the following groups: 1) normal pregnancy between 20–36 6/7 weeks (n=64); 2) term not in labor (n=70); 3) term in labor (n=60); and 4) preterm labor with intact membranes (n=102). Women with preterm labor were classified into: a) term delivery (n=24); b) preterm delivery without intra-amniotic infection (IAI) (n=62); and c) preterm delivery with IAI (n=16). Concentrations of C3a, C4a and C5a were determined by ELISAs. Statistical analysis was conducted with non-parametric methods. Results: 1) The median plasma C5a concentration was lower in women at term in labor than in those not in labor (P<0.001). In contrast, there were no differences in plasma C3a and C4a concentrations between the two groups (P>0.05). 2) Among patients with preterm labor, those with IAI had a higher median plasma C5a concentration than those without IAI and those who delivered at term (post-hoc tests P<0.001 and P=0.01, respectively). When comparing the preterm labor subgroups with normal pregnancy, only women with preterm delivery and IAI had a median plasma C5a concentration higher than that of normal pregnant women (Kruskal-Wallis P<0.001, post hoc test P<0.001). There was no difference in the plasma C4a concentration among patients with preterm labor. The median plasma C3a concentration in patients with preterm labor with IAI was higher than in those without IAI (Kruskal-Wallis P=0.01, and post-hoc test P=0.005). There was no difference in the plasma C3a concentrations between women with preterm labor who delivered at term and those with preterm delivery, with or without IAI. In addition, no differences were observed in the median plasma C3a concentration between women with normal pregnancy and those in each of the preterm labor subgroups. Conclusions: The maternal plasma concentration of anaphylatoxin C5a is increased in women with preterm labor and IAI, but not in spontaneous labor at term.

Applications of 2-dimensional matrix array for 3- and 4-dimensional examination of the fetus: a pictorial essay.

Objectives. Two‐dimensional (2D) matrix array is a new technology for the performance of 3‐dimensional and 4‐dimensional (4D) ultrasonography. In this study, we report the use of a 2D matrix array transducer for examination of fetal structures including the fetal heart. Methods. Thirty‐four fetuses without abnormalities and 19 fetuses with congenital anomalies were examined with a 2D matrix array transducer (x3‐1, IE‐33; Philips Medical Systems, Bothell, WA). Median gestational age was 25 6/7 weeks (range, 13 0/7–40 1/7 weeks). Results. (1) A 360° rotation and examination of selected structures was possible in the second trimester. (2) Structures were examined by maintaining the transducer in a fixed position and rotating the volume using the system trackball. (3) Dorsal and ventral parts of the hands and feet were visualized in a single volume data set, in real time, without moving the transducer. (4) Real‐time en face visualization of atrioventricular valves was possible from the ventricular or atrial chambers. (5) Four‐dimensional images of bones were obtained by decreasing gain settings only, with no need for cropping. (6) Four‐dimensional reconstruction of vascular structures was possible with color Doppler imaging. Two limitations were identified: (1) lower resolution than mechanical volumetric transducers, and (2) narrow volume display. Conclusions. Real‐time direct 4D imaging with 360° rotation for examination of fetal anatomic structures is feasible. This technology allows examination of fetal structures from multiple perspectives, in real time, without the need to move the transducer in the maternal abdomen. Further technological developments may overcome the limitations identified in this study.

Unexplained intrauterine fetal death is accompanied by activation of complement

Abstract Objective: Activation of the complement system has recently been implicated in the mechanisms of fetal loss in the antiphospholipid syndrome. It is, however, possible that complement activation is also involved in other causes of fetal death in the second and third trimesters of pregnancy. We therefore conducted a study to determine whether fetal death is associated with changes in the maternal plasma concentrations of complement split products or anaphylatoxins (C3a, C4a and C5a). Study design: A cross-sectional study was designed to include normal pregnant women (n=60) and patients with fetal death (n=60). Patients with fetal death were classified according to the cause of fetal demise into: a) unexplained (n=44); b) associated with preeclampsia (n=8); and c) associated with chromosomal abnormalities or major congenital fetal anomalies (n=8). The plasma concentrations of C3a, C4a and C5a were measured using sensitive and specific ELISAs. Non-parametric statistics were used for analysis. A P value of <0.05 was considered significant. Results: 1) The median plasma concentration of C5a was higher in patients with fetal death than in normal pregnant women [median 16 ng/mL (range 4.5–402.5) vs. median 11.6 ng/mL (range 1.2–87.1), respectively; P<0.001]; 2) patients with an unexplained fetal death and those associated with preeclampsia had a higher median plasma C5a concentration than normal pregnant women (P=0.002 and P<0.001, respectively); 3) no differences were observed in the maternal plasma concentrations of C3a and C4a among the study groups. Conclusions: Unexplained fetal death is associated with evidence of complement activation.

The human progesterone receptor shows evidence of adaptive evolution associated with its ability to act as a transcription factor

The gene encoding the progesterone receptor (PGR) acts as a transcription factor, and participates in the regulation of reproductive processes including menstruation, implantation, pregnancy maintenance, parturition, mammary development, and lactation. Unlike other mammals, primates do not exhibit progesterone withdrawal at the time of parturition. Because progesterone-mediated reproductive features vary among mammals, PGR is an attractive candidate gene for studies of adaptive evolution. Thus, we sequenced the progesterone receptor coding regions in a diverse range of species including apes, Old World monkeys, New World monkeys, prosimian primates, and other mammals. Adaptive evolution occurred on the human and chimpanzee lineages as evidenced by statistically significant increases in nonsynonymous substitution rates compared to synonymous substitution rates. Positive selection was rarely observed in other lineages. In humans, amino acid replacements occurred mostly in a region of the gene that has been shown to have an inhibitory function (IF) on the ability of the progesterone receptor to act as a transcription factor. Moreover, many of the nonsynonymous substitutions in primates occurred in the N-terminus. This suggests that cofactor interaction surfaces might have been altered, resulting in altered progesterone-regulated gene transcriptional effects. Further evidence that the changes conferred an adaptive advantage comes from SNP analysis indicating only one of the IF changes is polymorphic in humans. In chimpanzees, amino acid changes occurred in both the inhibitory and transactivation domains. Positive selection provides the basis for the hypothesis that changes in structure and function of the progesterone receptor during evolution contribute to the diversity of primate reproductive biology, especially in parturition.

Ancient origin of placental expression in the growth hormone genes of anthropoid primates

In anthropoid primates, growth hormone (GH) genes have undergone at least 2 independent locus expansions, one in platyrrhines (New World monkeys) and another in catarrhines (Old World monkeys and apes). In catarrhines, the GH cluster has a pituitary-expressed gene called GH1; the remaining GH genes include placental GHs and placental lactogens. Here, we provide cDNA sequence evidence that the platyrrhine GH cluster also includes at least 3 placenta expressed genes and phylogenetic evidence that placenta expressed anthropoid GH genes have undergone strong adaptive evolution, whereas pituitary-expressed GH genes have faced strict functional constraint. Our phylogenetic evidence also points to lineage-specific gene gain and loss in early placental mammalian evolution, with at least three copies of the GH gene present at the time of the last common ancestor (LCA) of primates, rodents, and laurasiatherians. Anthropoid primates and laurasiatherians share gene descendants of one of these three copies, whereas rodents and strepsirrhine primates each maintain a separate copy. Eight of the amino-acid replacements that occurred on the lineage leading to the LCA of extant anthropoids have been implicated in GH signaling at the maternal-fetal interface. Thus, placental expression of GH may have preceded the separate series of GH gene duplications that occurred in catarrhines and platyrrhines (i.e., the roles played by placenta-expressed GHs in human pregnancy may have a longer evolutionary history than previously appreciated).