Aneuploidy, a chromosomal numerical abnormality in the conceptus or fetus, occurs in at least 5% of all pregnancies and is the leading cause of early pregnancy loss in humans. Accumulating evidence now suggests that the correct segregation of chromosomes is affected by events occurring in prophase during meiosis I. These events include homologous chromosome pairing, sister-chromatid cohesion, and meiotic recombination. In our current study, we show that mutations in SYCP3, a gene encoding an essential component of the synaptonemal complex that is central to the interaction of homologous chromosomes, are associated with recurrent pregnancy loss. Two out of 26 women with recurrent pregnancy loss of unknown cause were found to carry independent heterozygous nucleotide alterations in this gene, neither of which was present among a group of 150 fertile women. Analysis of transcripts from minigenes harboring each of these two mutations revealed that both affected normal splicing, possibly resulting in the production of C-terminally mutated proteins. The mutant proteins were found to interact with their wild-type counterpart in vitro and inhibit the normal fiber formation of the SYCP3 protein when coexpressed in a heterologous system. These data suggest that these mutations are likely to generate an aberrant synaptonemal complex in a dominant-negative manner and contribute to abnormal chromosomal behavior that might lead to recurrent miscarriage. Combined with the fact that similar mutations have been previously identified in two males with azoospermia, our current data suggest that sexual dimorphism in response to meiotic disruption occurs even in humans.

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SummaryThe objective of this study was to determine whether (β2-glycoprotein I (β2GPI) has procoagulant activity by inhibiting the anticoagulant activity of activated protein C (APC). β2GPI inhibited significantly the APC-catalyzed inactivation of factor Va in an assay using factor V-deficient plasma and physiological levels of protein S and factor Va. This inhibitory effect was diminished by the addition of increasing concentrations of phospholipids, suggesting that β2GPI competitively inhibits the binding of APC to the phospholipid surface. β2GPI inhibited weakly factor Va- and phospholipid-dependent prothrombinase activity at concentrations similar to those to inhibit APC activity. The depletion of β2GPI from plasma led to only a slight shortening of the diluted Russell’s viper venom-dependent clotting time, but to a strong and significant potentiation of the anticoagulant activity of APC. These results suggest that under certain physiological conditions β2GPI has procoagulant property by inhibiting the phospholipid-dependent APC anticoagulant activity.

Because of a worldwide shortage of renal grafts, kidneys procured from donors after cardiac death (DCD) have recently become an important source of renal transplants. However, DCD kidneys often have complications with delayed graft function (DGF) and recipients require hemodialysis (HD) in the early period after kidney transplantation (KTx). This study evaluated serum NGAL as a potential specific parameter to predict early functional recovery of transplanted DCD kidneys. The average serum neutrophil gelatinase-associated lipocalin (NGAL) level in normal samples was 53 +/- 30 ng/ml, while that in patients with chronic renal failure requiring HD was markedly raised at 963 +/- 33 ng/ml. In patients undergoing a living-related KTx from a living donor (n=11), serum NGAL level decreased rapidly after KTx, and only in two cases, with serum NGAL levels over 400 ng/ml on postoperative day 1 (POD1), was HD required due to DGF. In contrast, all patients undergoing a KTx from a DCD (n=5) required HD due to DGF. Even in these cases, serum NGAL levels decreased rapidly several days after a KTx prior to the recovery of urine output and preceding the decrease in serum creatinine level. The pattern of decline in serum NGAL was biphasic, the decrease after the second peak indicating a functional recovery within the next several days. These data suggest that monitoring of serum NGAL levels may allow us to predict graft recovery and the need for HD after a KTx from a DCD.

Urinary NGAL may be a potential noninvasive diagnostic biomarker of renal scarring.