Polymorphism analyses and protein modelling inform on functional specialization of Piwi clade genes in the arboviral vector Aedes albopictus.

Current knowledge of the piRNA pathway is based mainly on studies on Drosophila melanogaster where three proteins of the Piwi subclade of the Argonaute family interact with PIWI-interacting RNAs to silence transposable elements in gonadal tissues. In mosquito species that transmit epidemic arboviruses such as dengue and chikungunya viruses, Piwi clade genes underwent expansion, are also expressed in the soma and cross-talk with proteins of recognized antiviral function cannot be excluded for some Piwi proteins. These observations underscore the importance of expanding our knowledge of the piRNA pathway beyond the model organism D. melanogaster. Here we focus on the emerging arboviral vector Aedes albopictus and we couple traditional approaches of expression and adaptive evolution analyses with most current computational predictions of protein structure to study evolutionary divergence among Piwi clade proteins. Superposition of protein homology models indicate possible high structure similarity among all Piwi proteins, with high levels of amino acid conservation in the inner regions devoted to RNA binding. On the contrary, solvent-exposed surfaces showed low conservation, with several sites under positive selection. Analysis of the expression profiles of Piwi transcripts during mosquito development and following infection with dengue serotype 1 or chikungunya viruses showed a concerted elicitation of all Piwi transcripts during viral dissemination of dengue viruses while maintenance of infection relied on expression of primarily Piwi5. Opposite, establishment of persistent infection by chikungunya virus is accompanied by increased expression of all Piwi genes, particularly Piwi4 and, again, Piwi5. Overall these results are consistent with functional specialization and a general antiviral role for Piwi5. Experimental evidences of sites under positive selection in Piwi1/3, Piwi4 and Piwi6, that have complex expression profiles, provide useful knowledge to design tailored functional experiments.

Conversion from laparoscopic adjustable gastric banding (LAGB) and laparoscopic sleeve gastrectomy (LSG) to one anastomosis gastric bypass (OAGB): preliminary data from a multicenter retrospective study.

BACKGROUND: Laparoscopic sleeve gastrectomy (LSG) is the most commonly performed bariatric procedure, while laparoscopic adjustable gastric banding (LAGB) has been for a decade one of the most popular interventions for weight loss. After LSG and LAGB, some patients may require a second surgery due to weight regain or late complications. One anastomosis gastric bypass (OAGB) is a promising bariatric procedure, which provides effective long-term weight loss and has a favorable effect on type 2 diabetes. OBJECTIVES: To retrospectively analyze data from 10 Italian centers on conversion from LAGB and LSG to OAGB. SETTING: High-volume centers for bariatric surgery. METHODS: Prospectively collected data from 10 high-volume centers were retrospectively reviewed. Body mass index (BMI), percentage of excess BMI loss, reasons for redo, remission from co-morbidities (hypertension, diabetes, gastroesophageal reflux, and dyslipidemia), and major complications were recorded. RESULTS: Three hundred patients were included in the study; 196 patients underwent conversion from LAGB to OAGB and 104 were converted from LSG. BMI was 45.1 ± 7 kg/m2 at the time of first intervention, 41.8 ± 6.3 kg/m2 at redo time, and 30.5 ± 5.5 kg/m2 at last follow-up appointment. Mean percentage of excess BMI loss was 13.2 ± 28.2 at conversion and 73.4 ± 27.5 after OAGB. Remission rates from hypertension, diabetes, gastroesophageal reflux, and dyslipidemia were 40%, 62.5%, 58.7% and 52%, respectively. Mean follow-up was 20.8 (range, 6-156) months and overall complications rate was 8.6%. CONCLUSION: Our data show that OAGB is a safe and effective revisional procedure after failed restrictive bariatric surgery.