Epigenetic mechanisms may play a central role in mediating phenotypic plasticity, especially during range expansions, when populations face a suite of novel environmental conditions. Individuals may differ in their epigenetic potential (EP; their capacity for epigenetic modifications of gene expression), which may affect their ability to colonize new areas. One form of EP, the number of CpG sites, is higher in introduced house sparrows (Passer domesticus) than in native birds in the promoter region of a microbial surveillance gene, Toll-like Receptor 4 (TLR4), which may allow invading birds to fine-tune their immune responses to unfamiliar parasites. Here, we compared TLR4 gene expression from whole blood, liver and spleen in house sparrows with different EP, first challenging some birds with lipopolysaccharide (LPS), to increase gene expression by simulating a natural infection. We expected that high EP would predict high inducibility and reversibility of TLR4 expression in the blood of birds treated with LPS, but we did not make directional predictions regarding organs, as we could not repeatedly sample these tissues. We found that EP was predictive of TLR4 expression in all tissues. Birds with high EP expressed more TLR4 in the blood than individuals with low EP, regardless of treatment with LPS. Only females with high EP exhibited reversibility in gene expression. Further, the effect of EP varied between sexes and among tissues. Together, these data support EP as one regulator of TLR4 expression.

Animals encounter many novel and unpredictable challenges when moving into new areas including pathogen exposure. Because effective immune defenses against such threats can be costly, plastic immune responses could be particularly advantageous, as such defenses can be engaged only when context warrants activation. DNA methylation is a key regulator of plasticity via its effects on gene expression. In vertebrates, DNA methylation occurs exclusively at CpG dinucleotides, and typically, high DNA methylation decreases gene expression, particularly when it occurs in promoters. The CpG content of gene regulatory regions may therefore represent one form of epigenetic potential (EP), a genomic means to capacitate gene expression and hence adaptive phenotypic plasticity. Non-native populations of house sparrows (Passer domesticus) - one of the world's most cosmopolitan species – have high EP in the promoter of a key microbial surveillance gene, Toll-like receptor 4 (TLR4), compared to native populations. We previously hypothesized that high EP may enable sparrows to balance the costs and benefits of inflammatory immune responses well, a trait critical to success in novel environments. In the present study, we found support for this hypothesis: house sparrows with high EP in TLR4 promoter were better able to resist a pathogenic Salmonella enterica infection than sparrows with low EP. These results support the idea that high EP contributes to invasion and perhaps adaptation in novel environments, but the mechanistic details whereby these organismal effects arise remain obscure.

Synopsis Epigenetic potential, defined as the capacity for epigenetically-mediated phenotypic plasticity, may play an important role during range expansions. During range expansions, populations may encounter relatively novel challenges while experiencing lower genetic diversity. Phenotypic plasticity via epigenetic potential might be selectively advantageous at the time of initial introduction or during spread into new areas, enabling introduced organisms to cope rapidly with novel challenges. Here, we asked whether one form of epigenetic potential (i.e., the abundance of CpG sites) in three microbial surveillance genes: Toll-like receptors (TLRs) 1B (TLR1B), 2A (TLR2A), and 4 (TLR4) varied between native and introduced house sparrows (Passer domesticus). Using an opportunistic approach based on samples collected from sparrow populations around the world, we found that introduced birds had more CpG sites in TLR2A and TLR4, but not TLR1B, than native ones. Introduced birds also lost more CpG sites in TLR1B, gained more CpG sites in TLR2A, and lost fewer CpG sites in TLR4 compared to native birds. These results were not driven by differences in genetic diversity or population genetic structure, and many CpG sites fell within predicted transcription factor binding sites (TFBS), with losses and gains of CpG sites altering predicted TFBS. Although we lacked statistical power to conduct the most rigorous possible analyses, these results suggest that epigenetic potential may play a role in house sparrow range expansions, but additional work will be critical to elucidating how epigenetic potential affects gene expression and hence phenotypic plasticity at the individual, population, and species levels.

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A rare complication of sleeve gastrectomy surgery is gastropleural fistulas (GPF), where a fistula develops between the stomach and the pleural cavity. This complication can be debilitating and present with many nonspecific symptoms making it hard to diagnose. This is a case report of a 45-year-old female who underwent robotic-assisted gastric sleeve revision after developing a GPF as a complication of her gastric sleeve six years later. This led to the development of a recurrent subdiaphragmatic abscess in the left upper quadrant. Before presenting to us, she underwent multiple hospitalizations and received numerous endoscopic stent treatments. However, the abscess continued to recur. Given her recurrent abscess, she consented to gastric sleeve revision. GPFs are amongst the rarest complications, with only 76 reported cases. Since this complication can cause shock, early diagnosis and treatment are necessary to improve patient outcomes and reduce morbidity.

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Leaks and bleeding are major acute postoperative complications following laparoscopic sleeve gastrectomy (LSG). Various staple line reinforcement (SLR) methods have been invented such as oversewing, omentopexy/gastropexy, gluing, and buttressing. However, many surgeons don’t use any type of reinforcement. On the other hand, surgeons who use a reinforcement method are often confused of what kind of reinforcement they should use. No robust and high-quality data supports the use of one reinforcement over the other, or even supports the use of reinforcement over no reinforcement. Therefore, SLR is a controversial topic that is worth our focus. The aim of this study is to compare the outcomes of LSG with versus without Seamguard buttressing of the staple line during LSG.

Animals encounter many novel and unpredictable challenges when moving into new areas including pathogen exposure. Because effective immune defenses against such threats can be costly, plastic immune responses could be particularly advantageous, as such defenses can be engaged only when context warrants activation. DNA methylation is a key regulator of plasticity via its effects on gene expression. In vertebrates, DNA methylation occurs exclusively at CpG dinucleotides, and typically, high DNA methylation decreases gene expression. The CpG content of gene regulatory regions may therefore represent one form of epigenetic potential (EP), a genomic means to capacitate gene expression. Non-native populations of house sparrows (Passer domesticus) - one of the world’s most cosmopolitan species – have high EP in the promoter of a key microbial surveillance gene, Toll-like receptor 4 (TLR4), compared to native populations. We previously hypothesized that high EP may enable sparrows to balance the costs and benefits of immune responses well, a trait critical to success in novel environments. In the present study, we found support for this hypothesis. House sparrows with high EP in TLR4 were better able to resist a pathogenic Salmonella enterica infection than sparrows with low EP. These results support the premise that high EP contributes to adaptation in novel environments.