A rare complication of monochorionic twin pregnancy: Twin-reversed arterial perfusion (TRAP) sequence

Antiviral responses versus virus-induced cellular shutoff: a game of thrones between influenza A virus NS1 and SARS-CoV-2 Nsp1

Following virus recognition of host cell receptors and viral particle/genome internalization, viruses replicate in the host via hijacking essential host cell machinery components to evade the provoked antiviral innate immunity against the invading pathogen. Respiratory viral infections are usually acute with the ability to activate pattern recognition receptors (PRRs) in/on host cells, resulting in the production and release of interferons (IFNs), proinflammatory cytokines, chemokines, and IFN-stimulated genes (ISGs) to reduce virus fitness and mitigate infection. Nevertheless, the game between viruses and the host is a complicated and dynamic process, in which they restrict each other via specific factors to maintain their own advantages and win this game. The primary role of the non-structural protein 1 (NS1 and Nsp1) of influenza A viruses (IAV) and the pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), respectively, is to control antiviral host-induced innate immune responses. This review provides a comprehensive overview of the genesis, spatial structure, viral and cellular interactors, and the mechanisms underlying the unique biological functions of IAV NS1 and SARS-CoV-2 Nsp1 in infected host cells. We also highlight the role of both non-structural proteins in modulating viral replication and pathogenicity. Eventually, and because of their important role during viral infection, we also describe their promising potential as targets for antiviral therapy and the development of live attenuated vaccines (LAV). Conclusively, both IAV NS1 and SARS-CoV-2 Nsp1 play an important role in virus-host interactions, viral replication, and pathogenesis, and pave the way to develop novel prophylactic and/or therapeutic interventions for the treatment of these important human respiratory viral pathogens.

Twin reversed arterial perfusion sequence-a rare and dangerous complication form of monochorionic twins: A case report

BACKGROUND

Twin reversed arterial perfusion (TRAP) sequence is an extremely rare congenital anomaly in monochorionic (MC) twins. The condition is characterized by a malformed fetus (acardiac twin) without cardiac activities being perfused by a structurally normal one (pump twin) via an artery-to-artery anastomosis in a reverse direction.

CASE SUMMARY

We described the first case of TRAP to receive laser surgery in Vietnam. The 26-wk pregnancy was originally misdiagnosed in another hospital as MC twins with single intrauterine fetal death. Following admission to our center, the diagnosis was amended to a 26-wk TRAP sequence stage IIb. The acardiac twin was 7.5 cm at the longest length, the ratio of the weight of the acardiac twin to the weight of the pump twin was more than 90%, the pump twin showed fetal distress with absent diastolic flow in umbilical artery of pump twin, and the peak systolic velocity in the middle cerebral artery = 1.6 MoM. We performed emergency laser photocoagulation of the acardiac twin’s umbilical cord. After surgery, we successfully maintained the pregnancy for 8 wk and ended it electively by cesarean section at 34 wk of gestation due to rupture of membranes.

CONCLUSION

TRAP should be appropriately diagnosed and treated early to avoid complications of the pump twin. Fetoscopic laser photocoagulation is a new and effective treatment for this condition.

Monochorionic-Triamniotic Triplet Pregnancy Complicated by Twin Reversed Arterial Perfusion Sequence: Case Report and Literature Review

Background  Monochorionic-triamniotic pregnancies are rare and fraught with complications. Case  A case of monochorionic-triamniotic triplet pregnancy complicated by twin reversed arterial perfusion (TRAP) sequence is presented. The patient declined termination or selective fetal reduction. Triplet C was acardiac. At 24 weeks, triplet B developed polyhydramnios. At 30 weeks, polyhydramnios was seen in all three amniotic sacs, but without signs of fetal hydrops and with normal Doppler velocimetry measurements in the umbilical artery, middle cerebral artery, and ductus arteriosus of triplets A and B. At 32 ^2/7 weeks, the patient presented with preterm premature rupture of membranes and preterm labor. Two live male infants were delivered by cesarean delivery weighing 1,350 and 1,390 g, respectively; the acardiac fetus weighed 1,460 g. Pathology examination revealed a single placenta weighing1,250 g, with evidence of direct vascular connections between triplets A and C as well as between triplets A and B. Conclusion  Monochorionic-triamniotic triplet pregnancy with TRAP sequence is rare. Although the risk of complications is high, such pregnancies can be managed conservatively in select cases.

A new method for selective reduction in TRAP sequence with a contraindication to fetoscopic surgery: A case report

RATIONALE

The preferred method for multifetal pregnancy reduction (MFPR) is a transabdominal intrathoracic or intracranial injection of potassium chloride (KCl). However, in monochorionic multiple pregnancies (MMPs), especially in monoamnionic multifetal pregnancies, selective feticide by this method is often associated with miscarriage of the remaining fetuses. Selective fetal reduction in MMPs by blood flow ablation using radiofrequency ablation or fetoscopic laser surgery may improve survival of the remaining fetus. Although often successful, MFPR by these methods is contraindicated in cases of twin reversed arterial perfusion (TRAP) sequence in triplet pregnancies complicated by polyhydramnios or anterior placenta, as it is difficult to locate the ablation target.

PATIENT CONCERNS

2 cases were admitted to Xiangya Hospital, Central South University with triplet pregnancies at 23 or 21weeks of gestation.

DIAGNOSES

Case 1 was a 29-year-old woman with a triplet pregnancy in 2 distinct amniotic sacs and 1 fetus with multiple malformations. Case 2 was a 32-year-old woman who was identified as a triplet pregnancy with TRAP sequence with an acardiac/acephalic twin and anterior placenta.

INTERVENTIONS

Both of the 2 cases were underwent a new method for MFPR involving fine needle amniotic fluid aspiration and injection of hypertonic sodium chloride (10% NaCl) into the Wharton jelly of the umbilical cord.

OUTCOMES

The 2 cases resulted in selective feticide and the birth of the remaining infants from the triplet pregnancies. All infants were healthy at birth and the 2-year follow-up.

LESSONS

The new approach provided a safer, more accessible, and more cost-effective method for MFPR in MMPs with a contraindication to fetoscopic surgery compared to radiofrequency ablation and fetoscopic laser surgery.

[A rare complication of monochorionic twin pregnancy: Twin Reversed Arterial Perfusion Sequence (TRAP)]

La séquence TRAP est une forme majeure et rare du syndrome transfuseur transfusé, caractérisée par l'absence de développement des structures cardiaques avec un spectre de malformations chez le fœtus transfusé qui n'est jamais viable et d'importantes complications touchant le jumeau transfuseur. Nous rapportons le cas d'une multipare admise avec expulsion en cours d'une présentation de siège, puis l'examen a trouvé une présentation irrégulière. Et à l’échographie une image hétérogène sans aire cardiaque ni organes fœtaux individualisables avec une seule masse placentaire sont visible, évoquant en premier un jumeau acardiaque. La voie basse a été acceptée, mais elle a présenté une hypercinésie évoquant un syndrome de prérupture. La césarienne a permis l'extraction d'une masse acardiaque. A travers ce cas, nous insistons sur l'intérêt du diagnostic prénatal de cette entité dans l'adaptation de la prise en charge, l'amélioration du pronostic du jumeau transfuseur ainsi que l’évitement du retard diagnostic et de ces conséquences.