Chlamydia trachomatis Is Responsible for Lipid Vacuolation in the Amniotic Epithelium of Fetal Gastroschisis

In vitro extracellular replication of Wolbachia endobacteria

Obligate intracellular endobacteria of the genus Wolbachia are widespread in arthropods and several filarial nematodes. Control programs for vector-borne diseases (dengue, Zika, malaria) and anti-filarial therapy with antibiotics are based on this important endosymbiont. Investigating Wolbachia, however, is impeded by the need for host cells. In this study, the requirements for Wolbachia wAlbB growth in a host cell-free in vitro culture system were characterized via qPCRs. A cell lysate fraction from Aedes albopictus C6/36 insect cells containing cell membranes and medium with fetal bovine serum were identified as requisite for cell-free replication of Wolbachia. Supplementation with the membrane fraction of insect cell lysate increased extracellular Wolbachia replication by 4.2-fold. Replication rates in the insect cell-free culture were lower compared to Wolbachia grown inside insect cells. However, the endobacteria were able to replicate for up to 12 days and to infect uninfected C6/36 cells. Cell-free Wolbachia treated with the lipid II biosynthesis inhibitor fosfomycin had an enlarged phenotype, seen previously for intracellular Wolbachia in C6/36 cells, indicating that the bacteria were unable to divide. In conclusion, we have developed a cell-free culture system in which Wolbachia replicate for up to 12 days, providing an in vitro tool to elucidate the biology of these endobacteria, e.g., cell division by using compounds that may not enter the C6/36 cells. A better understanding of Wolbachia biology, and in particular host-symbiont interactions, is key to the use of Wolbachia in vector control programs and to future drug development against filarial diseases.

Risk of gastroschisis with maternal genitourinary infections: the US National birth defects prevention study 1997-2011

OBJECTIVE

To assess the association between occurrence and timing of maternal self-reported genitourinary tract infection (urinary tract infections [UTIs] and/or sexually transmitted infection [STI]) and risk for gastroschisis in the offspring.

DESIGN

Population-based case-control study.

SETTING

National Birth Defects Prevention Study, a multisite study in the USA.

PARTICIPANTS

Mothers of 1366 gastroschisis cases and 11 238 healthy controls.

MAIN OUTCOME MEASURES

Crude and adjusted ORs (aORs) with 95% CIs.

RESULTS

Genitourinary infections were frequent in case (19.3%) and control women (9.9%) during the periconceptional period (defined as 3 months prior to 3 months after conception). UTI and/or STI in the periconceptional period were associated with similarly increased risks for gastroschisis (aOR 1.5, 95% CI 1.3 to 1.8; aOR 1.6, 95% CI 1.2 to 2.3, respectively). The risk was increased with a UTI before (aOR 2.5; 95% CI 1.4 to 4.5) or after (aOR 1.7; 95% CI 1.1 to 2.6) conception only among women ≥25 years of age. The risk was highest among women <20 years of age with an STI before conception (aOR 3.6; 95% CI 1.5 to 8.4) and in women ≥25 years of age, the risk was similar for before (aOR 2.9; 95% CI 1.0 to 8.5) and after (aOR 2.8; 95% CI 1.3 to 6.1) conception. A specific STI pathogen was reported in 89.3% (50/56) of cases and 84.3% (162/191) of controls with Chlamydia trachomatis the most common (25/50 cases, 50%; 58/162 controls, 36%) and highest among women <20 years of age (16/25 cases, 64%; 22/33 controls, 67%).

CONCLUSIONS

UTI and/or STI were associated with an increased risk for gastroschisis, with the strength of the association varying by maternal age and timing of infection.

Insights into the etiology and embryology of gastroschisis

The development of gastroschisis has long remained an area of interest and controversy. Successive theories about its pathogenesis are herein reviewed and discussed. Two historical assumptions, that omphalocele results from a persistent umbilical hernia, and that gastroschisis does not involve the umbilical cord, are dismissed. Therefore, one can envision gastroschisis for what it is, i.e. a ruptured physiological hernia. The causal agents for this intrauterine accident to occur are yet to be determined. Further bowel damage and complications can be explained by the mesenteric insult.