Synthesis of coagulation proteins in the fetus and neonate

Massive thrombosis in an infant with suspected nephrocalcinosis: case report and literature review

Introduction

Perinatal period is characterized by an increased risk of thrombosis due to low resources and limited compensatory capacity of the coagulation system in early stages of life.

Case report

We report a case of a second pregnancy female infant born at 39 weeks by caesarean section, due to pre-labor rupture of membranes, with body weight of 3,570 γ and Apgar score 10. The pregnancy was complicated by hypothyroidism, uterine myoma, urinary tract infections, and mother's appendectomy at 16 Hbd. At 3 months, the girl was admitted to our hospital due to kidney calcifications, which were incidentally found during ultrasound scan. In laboratory workup, no abnormalities in calcium and phosphate homeostasis were detected. However, in ultrasound scan, linear calcifications along pyramids were visualized in both kidneys. Due to atypical location of nephrocalcinosis, Doppler scan was performed, showing lack of visible blood flow from renal veins to inferior vena cava (IVC), with compensatory flow from renal veins to paravertebral plexuses, and IVC obliteration with a massive calcification in the hepatic section. Magnetic resonance confirmed obliteration of IVC and common iliac veins, segmental dilatation of IVC, and compensatory blood flow from kidneys and lower limbs to paravertebral plexuses. Clinical picture and formation of collateral circulation suggested intrauterine thrombosis. Congenital thrombophilia was excluded in laboratory examination.

Conclusions

The differential diagnosis of calcifications in renal parenchyma (nephrocalcinosis) should include renal vein thrombosis. Massive fetal and perinatal thrombosis can be asymptomatic due to high ability to form collateral circulation at the early stage of life.

The hemostatic status of pediatric recipients of adult liver grafts suggests that plasma levels of hemostatic proteins are not regulated by the liver

Plasma levels of coagulation factors differ profoundly between adults and children, but are remarkably stable throughout adulthood. It is unknown which factors determine plasma levels of coagulation factors in a given individual. We hypothesized that the liver, which synthesizes coagulation factors, also controls plasma levels. We measured a panel of coagulation factors in samples taken from either adults or young children who underwent a liver transplantation with adult donor livers. Samples were taken 1-3 months after transplantation, when the patients were clinically stable with adequate graft function. After liver transplantation, the hemostatic profile of the pediatric group was remarkably different from that of the adult group, and resembled the hemostatic profile of normal children. Thus, children transplanted with an adult liver graft maintain a pediatric hemostatic profile after transplantation despite receiving an adult liver graft. These findings suggest that plasma levels of hemostatic proteins are not controlled by the liver.

Development of coagulation regulatory proteins in the fetal and neonatal lamb

To investigate the development of coagulation regulatory proteins-protein C (PC), protein S (PS), and antithrombin (AT)-in relationship to the procoagulant protein factor X (FX), a chronically catheterized fetal ovine model was used. Infusion and sampling catheters were placed into pregnant ewes and their fetuses and maintained from mid-gestation. From a total of 110 fetuses, 17 lambs, and 63 ewes that were studied on one to 15 occasions, 212 fetal, 88 neonatal, and 157 maternal samples were obtained. Liver tissue was obtained from 31 fetuses and 15 ewes. Plasma levels of all proteins studied were higher in the ewe than in the fetus (p < 0.0001). Plasma levels of FX, PC, and PS achieved neonatal levels by mid-gestation with mild but significant decreases during mid- and late gestation. Fetal and early neonatal plasma concentrations of these vitamin K-dependent proteins fit a model with both quadratic (p < 0.01) and linear (p < 0.01) components. The discrepant levels in mRNA relative to plasma concentration were consistent with regulatory control beyond the level of transcription. In contrast, a simple linear increase in plasma protein levels was determined for the vitamin K-independent coagulation regulatory protein, AT (p for quadratic component > 0.05). This study suggests that fetal regulation of coagulation proteins follows characteristic patterns relative to the vitamin K dependence of the protein rather than its role as a procoagulant versus regulatory protein.

The neonatal liver, Part 1: embryology, anatomy, and physiology

The liver is the largest organ in the body and is critical to a number of metabolic, regulatory, and detoxification processes. These include the production of bile, metabolic processing of nutrients, synthesis and regulation of plasma proteins and glucose, and biotransformation of drugs and toxins.