Extracellular matrix remodeling derangement in ex-obese patients

Histological Skin Assessment of Patients Submitted to Bariatric Surgery: A Prospective Longitudinal Cohort Study

BACKGROUND

Obesity is a stigmatizing disease that can cause dermatological aberrations, such as sagging after rapid weight loss.

OBJECTIVE

This study is to evaluate the effects of obesity and massive weight loss following bariatric surgery on collagen and elastic fibers of the extracellular matrix of the skin.

METHODS

Thirty-three skin biopsies were collected from patients prior to bariatric surgery and one year after surgery. Histological analyses were performed using hematoxylin-eosin and Weigert's resorcin-fuchsin staining for collagen and elastic and elaunin fibers, respectively. Differences between means were submitted to the Student's t-test or Mann-Whitney U test, with p < 0.05 significant.

RESULTS

The study demonstrated an architectural alteration of the skin 1 year after bariatric surgery. In the histological analysis of the skin samples, a significant difference in the thickness of the epidermis was found 1 year after surgery in all age groups as well as in the 38-to-68-kg weight loss group (p < 0.0001). In addition to laxity, disorganization of collagen was found, with an apparent decrease in quantity and an increase in elastic fibers, although fragmented (p < 0.0001).

CONCLUSION

Obesity and massive weight loss following bariatric surgery cause the disorganization of collagen fibers and the fragmentation of elastic fibers of the extracellular matrix of the skin.

M1 Polarized Macrophages Persist in Skin of Post-Bariatric Patients after 2 Years

BACKGROUND

Obesity is considered a condition of systemic chronic inflammation. Under this condition, adipose tissue macrophages switch from an M2 (anti-inflammatory) activation pattern to an M1 (proinflammatory) activation pattern.

OBJECTIVE

The study aimed to verify the profile of skin macrophage activation after bariatric surgery as well as the role of MMP-1 in extracellular tissue remodeling.

METHODS

This is a prospective, controlled and comparative study with 20 individuals split into two groups according to their skin condition: post-bariatric and eutrophic patients. Histological and morphometric analyses based on hematoxylin-eosin, picrosirius red (collagen), orcein (elastic fiber systems), and alcian blue (mast cells)-stained sections and immunohistochemical analysis (CD68, iNOS, and mannose receptor) for macrophages and metalloproteinase-1 were performed.

RESULTS

Post-bariatric skin showed an increase in inflammation, angiogenesis, CD68, M1 macrophages (P< 0.001), and mast cells (P< 0.01); a decrease in M2 macrophages (P< 0.01); and a significant decrease in the collagen fiber network (P< 0.001). MMP-1 was increased in the papillary dermis of post-bariatric skin and decreased in the epidermis compared to eutrophic skin (P< 0.05).

CONCLUSION

This study shows that post-bariatric skin maintains inflammatory characteristics for two years. Mast cells and M1 macrophages maintain and enhance the remodeling of the dermal extracellular matrix initiated during obesity in part due to the presence of MMP-1 in the papillary dermis.

EBM LEVEL IV

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Histological and molecular biological analysis on the reaction of absorbable thread; Polydioxanone and polycaprolactone in rat model

INTRODUCTION

One of the most frequently performed anti-aging surgical procedures is thread facelift. Since the 2010s, thread lifts using absorbable polydioxanone (PDO) thread were developed and have become increasingly popular. This research aims to identify the changes in and the mechanisms of absorbable thread-lifting components, namely, PDO (polydioxanone) and PCL (polycaprolactone), with varied absorption periods in the body.

METHODS

Four different types of threads, namely, single-stranded thread, 4-stranded thread, 12-stranded thread, and barbed Cog thread, were used for each component. Histological changes in the thread and neighboring tissue of rat model were investigated for 2-week interval, and PCR was conducted for genes related to fibroblast proliferation including type 1α1 collagen, type 3α1 collagen, transforming growth factor beta 1 (TGF-β1).

RESULTS

An increase in the collagen formation in all types of PDO and PCL groups was observed during the first 12 weeks and decreased afterward. Collagen formation decreased later in the PCL thread group significantly than the POD group. PCL thread remained logner in the tissue for over a year regarding POD requiring around 24 weeks of absorption-degradation. A larger surface area between the thread and the tissue induces a greater response in the tissue, resulting in an increase in inflammatory cells, myofibroblasts, and fibroblasts. Results showed a similar pattern of increase in type 1α1 collagen and TGF-β in the PDO thread group. This suggests that TGF-β signal transduction leads to fibroblast proliferation that stimulates collagen formation and tissue re-formation. In contrast, only type 3α1 collagen increased in the PCL thread group.

CONCLUSION

More collagen formation and tissue responses are induced by PCL thread, remaining longer in the tissue than PDO, leading to more tissue tightening effects that is one of the most important points of face lifting. Morphological comparison of threads shows that not only an increase in surface area between thread and tissue but also multi-strand increase tissue response, which in turn increases tissue maintenance effects.

PCV2 inhibits the Wnt signalling pathway in vivo and in vitro

Porcine circovirus type 2 (PCV2) is an important pathogen of the current pig industry. The Wnt signalling pathway plays an important role in the growth of young animals. In this study, we mainly elucidated the relationship between PCV2 and the Wnt signalling pathway. In an in vivo experiment in mice, we demonstrated the downregulatory effects of PCV2 infection on expression levels of downstream components of the Wnt signalling pathway. Weight loss in mice was reversed by activating the Wnt signalling pathway, and the body weight was still significantly higher than that in mice infected with PCV2. We detected levels of growth hormone (GH) in the liver and sera, which showed that GH was also downregulated in mice challenged with PCV2. Lithium chloride, the activator of Wnt signalling, upregulated GH, albeit to a significantly lesser degree than that in corresponding non-stimulated mock mice. In vitro studies showed that PCV2 infection downregulated protein expression of β-catenin and mRNA expression of matrix metallopeptidase-2 (Mmp2), downregulated protein expression of β-catenin in the cytoplasm and nucleus, and reduced the activity of the TCF/LEF promoter, demonstrating that PCV2 inhibited activation of the Wnt signalling pathway in vitro. Finally, we found that Rep protein of PCV2 might be responsible for the inhibitory effect.

Neurosurgical issues of bariatric surgery: A systematic review of the literature and principles of diagnosis and treatment

Bariatric surgery is gaining popularity as the treatment of choice of morbid obesity since this condition is constantly increasing over the last decades. Several complications have emerged as the number of surgeries and follow-up data increase. No systematic review of the neurosurgery-related potential complications has been performed to date. Objective of this work is to fill this gap. We reviewed the literature for bariatric surgery-related complications involving the neurosurgical practice. Moreover, we present explicative cases dealing with peri- and post-operative therapeutic precautions. Three pathological mechanisms emerged. The first is related to intracranial pressure alterations and may imply either intracranial hypertension or hypotension syndromes in the operative or post-operative periods. The second is the deficiency of macro- and micro-nutrients which are potential risk factors for neuro- or myelo-encephalopathies, fetal malformations and spine disorders. The third is a dysregulation of both autonomic and endocrine / pituitary control. Neurosurgeons must be aware of the several, multifactorial neurosurgery-related complications of bariatric surgery as their prevalence is likely to be higher in the next few years.

Porcine Circovirus-Like Virus P1 Inhibits Wnt Signaling Pathway in Vivo and in Vitro

Porcine circovirus-like virus P1 is an important pathogen of the current pig industry, the infection mechanism is not entirely clear. Wnt signaling pathway plays an important role in the growth of young animals and infection of some viruses. This study was designed to demonstrate the effects of P1 infection on the Wnt signaling pathway. In vivo experiments, we demonstrated the down-regulatory effects of P1 infection in piglets and mice on the downstream components expression levels of Wnt signaling pathway, and the effects of Wnt signaling pathway activation on the pathogenesis of P1. In vitro studies, we found P1 infection down-regulated protein level of β-catenin and mRNA level of mmp2, prevented the β-catenin from entering into nucleus, abolished the TCF/LEF promoter activity, proved that P1 could inhibit the activation of Wnt signaling pathway in vitro. Finally, we found that VP1 of P1 virus also had the inhibitory effects on Wnt signaling pathway in vitro, elucidated the mechanism of P1’s inhibitory effects on the Wnt signaling pathway and offered the possibility that the suppression of Wnt signaling pathway was involved in the post-weaning multisystemic wasting syndrome (PMWS), laying a foundation for elucidating the pathogenesis of P1.