Proliferation Patterns of MCF-7 Breast Cancer Cells in Lipoaspirate Conditioned Media.

INTRODUCTION: Autologous fat grafting (AFG) is a common technique used to enhance aesthetic outcomes in postmastectomy breast reconstruction patients. Adipokines are hormones secreted by adipose tissue that play a critical role in regulating metabolic processes and the immune system. However, dysregulated adipokine secretion and signaling can contribute to the development and progression of cancer by promoting angiogenesis, altering the immune response, and inducing the epithelial mesenchymal transition. We aimed to assess how breast cancer cells behave in conditioned media derived from fat grafting lipoaspirates and gain a better understanding of the potential interactions that may occur within the tumor microenvironment. METHODS: Patients who were undergoing AFG as a part of breast reconstruction at NY-Presbyterian/Weill Cornell Medical Center between March 2021 and July 2023 were consented and enrolled in the study. This study was approved by the Weill Cornell Medicine Institutional Review Board (#20-10022850-14). Conditioned media is created using 20% of patient lipoaspirate secretome and 80% starving media. The growth of MCF-7, a human ER/PR+ breast cancer cell line, in conditioned media is assessed using CyQUANT. RESULTS: The breast cancer cells incubated in conditioned media displayed similar growth trends as those in complete media, which is enriched for cell growth (P > 0.05). MCF-7 cell behavior in conditioned media differed significantly from their proliferation patterns when serum starved in 100% starving media (P < 0.05). DISCUSSION: Our results suggest that there may be inherent factors within the lipoaspirate that may promote MCF-7 proliferation. One potential implication is that AFG used for breast reconstruction should be delayed until local-regional disease control has been established. In addition, based on the in vitro proliferation patterns of breast cancer cells in conditioned media, the safety profile of AFG may be enhanced if the procedure is performed after attaining negative margins and the completion breast cancer treatment.

Assessing Long-Term Volume Retention in Breast Fat Grafting: A Comparative Study of Lipoaspirate Processing Techniques.

INTRODUCTION: Autologous fat grafting is a method of improving aesthetic outcomes after both breast reconstruction and aesthetic surgery through volume enhancement and tissue contouring. Long-lasting effects are linked to greater patient satisfaction and more optimal augmentation results. Harvesting, processing, and injection techniques may all affect the longevity of deformity filling. Our objective is to evaluate the effect of lipoaspirate processing modality on longitudinal volume retention after surgery. METHODS: A prospective, single-institution, randomized control trial placed consented postmastectomy fat grafting patients into 1 of 3 treatment arms (active filtration, low-pressure decantation, and standard decantation) in a 1:1:1 ratio. A preoperative 3-dimensional scan of the upper torso was taken as baseline. At the 3-month postoperative visit, another 3D scan was taken. Audodesk Meshmixer was used to evaluate the volume change. RESULTS: The volume of fat injected during the initial procedure did not differ significantly between the treatment arms (P > 0.05). Both active filtration and low-pressure decantation resulted in higher percentage volume retention than traditional decantation (P < 0.05). Active filtration and low-pressure decantation exhibited comparable degrees of fat maintenance at 3 months (P > 0.05). DISCUSSION: Compared with using traditional decantation as the lipoaspirate purification technique, active filtration and low-pressure decantation may have led to higher levels of cell viability by way of reduced cellular debris and other inflammatory components that may contribute to tissue resorption and necrosis. Further immunohistochemistry studies are needed to examine whether active filtration and low-pressure decantation lead to lipoaspirates with more concentrated viable adipocytes, progenitor cells, and factors for angiogenesis.

A Machine Learning Approach to Predicting Donor Site Complications Following DIEP Flap Harvest.

BACKGROUND: The additional donor site incisions in autologous breast reconstruction can predispose to abdominal complications. The purpose of this study is to delineate predictors of donor site morbidity following deep inferior epigastric perforator (DIEP) flap harvest and use those predictors to develop a machine learning model that can identify high-risk patients. METHODS: This is a retrospective study of women who underwent DIEP flap reconstruction from 2011 to 2020. Donor site complications included abdominal wound dehiscence, necrosis, infection, seroma, hematoma, and hernia within 90 days postoperatively. Multivariate regression analysis was used to identify predictors for donor site complications. Variables found significant were used to construct machine learning models to predict donor site complications. RESULTS: Of 258 patients, 39 patients (15%) developed abdominal donor site complications, which included 19 cases of dehiscence, 12 cases of partial necrosis, 27 cases of infection, and 6 cases of seroma. On univariate regression analysis, age (p = 0.026), body mass index (p = 0.003), mean flap weight (p = 0.006), and surgery time (p = 0.035) were predictors of donor site complications. On multivariate regression analysis, age (p = 0.025), body mass index (p = 0.010), and surgery duration (p = 0.048) remained significant. Radiographic features of obesity, such as abdominal wall thickness and total fascial diastasis, were not significant predictors of complications (p > 0.05). In our machine learning algorithm, the logistic regression model was the most accurate at predicting donor site complications with the accuracy of 82%, specificity of 0.93, and negative predictive value of 0.87. CONCLUSION: This study demonstrates that body mass index is superior to radiographic features of obesity in predicting donor site complications following DIEP flap harvest. Other predictors include older age and longer surgery duration. Our logistic regression machine learning model has the potential to quantify the risk of donor site complications.

Augmenting Breast Implant Research: Accessible Methods for Fabricating Miniature Smooth and Textured Breast Implants in a Laboratory Setting.

BACKGROUND: Because of the association of textured breast implants with breast implant-associated anaplastic large cell lymphoma, anatomically shaped breast implants, which rely on a textured surface to maintain rotational stability, have been recalled from the market. The dearth of anatomically shaped implants on the market reflects a need for novel breast implant technology, which has been traditionally developed by commercial breast implant manufacturers due to the complexities of implant manufacturing. To increase the accessibility of preclinical breast implant research, miniature breast implants made from polydimethylsiloxane were designed and fabricated for high throughput and low-cost prototyping and in vivo testing of both smooth and textured implants in a laboratory setting. METHODS: Two-piece negative molds measuring 2 × 1 cm were constructed in Fusion360 and 3D printed in Polysmooth filament. Textured molds were painted with a mixture of an epoxy and fine sugar or granular salt to create textured surfaces, while molds for smooth implants were smoothed using ethanol spray. Molds were injected with polydimethylsiloxane and cured for 12 hours at 37°C. The surface topography of laboratory-made implants and commercial textured and smooth implant shells was analyzed using scanning electron microscopy and implants were evaluated in vivo in an immunocompetent rodent model. RESULTS: Implants retained the original dome shape of the 3D-printed molds. Qualitative assessment of scanning electron microscopy images demonstrated similar surface topography between laboratory-made and commercial smooth and textured implants. There was no statistical difference in the diameter or density of the surface indentations of the Allergan's textured implant compared with laboratory-made textured implants ( P > 0.05). Finally, the surface topography and thickness of laboratory-made implant capsules were similar to previously published data using industry made miniature silicone devices implanted in rats. CONCLUSIONS: This study demonstrates a low-cost, highly customizable approach to fabricate miniature smooth and textured breast implant prototypes for in vivo studies. The accessibility of this implant fabrication strategy allows nonindustry investigators to develop novel implant designs more rapidly for preclinical investigation.

Using Clinical Measurements to Predict Breast Skin Necrosis: A Quantitative Analysis.

BACKGROUND: Breast skin necrosis can lead to poor healing, reoperation, and unaesthetic reconstructive outcomes after mastectomy. Furthermore, the prolonged recovery can delay adjuvant oncologic regimens. This study aims to explore the role of breast surface area as a risk factor for mastectomy skin flap necrosis and to identify predictive clinical measurements. METHODS: The authors retrospectively identified patients who underwent immediate breast reconstruction (N = 926 breasts) by 2 surgeons at a single institution between 2011 and 2021. Preoperative breast measurements such as nipple-notch (NN) distance, nipple-inframammary fold (NF) distance, chest width (CW), breast circumference (BC), and breast height (BH) were used to estimate breast surface area. Univariate analysis and receiver operating characteristic curves were used to determine predictive measurements and optimal cutoff values. RESULTS: When approximated using either a cone without base or a half ellipsoid, larger surface area was a significant risk factor for mastectomy skin flap necrosis (P = 0.027 and P = 0.022, respectively). Larger NN, NF, CW, BC, and BH measurements were significant predictors of necrosis (P < 0.05). Surface area (cone without base) greater than 212 cm2, surface area (half ellipsoid) greater than 308 cm2, NN distance greater than 27 cm, NF greater than 8.5 cm, CW greater than 15 cm, BC greater than 29 cm, and BH greater than 10.5 cm are all values shown to increase the incidence of necrosis. CONCLUSIONS: Larger breast surface area is an independent risk factor for breast skin necrosis. Preoperative breast measurements can be a useful adjunct for predicting necrosis in postmastectomy patients.

Streamlining the Fat: A Systematic Review of Active Closed Wash and Filtration in Autologous Fat Grafting After Breast Reconstruction.

Although fat grafting in breast reconstruction continues to grow in popularity, the optimal technique remains elusive and outcomes are varied. This systematic review of available controlled studies utilizing active closed wash and filtration (ACWF) systems sought to examine differences in fat processing efficiency, aesthetic outcomes, and revision rates. A literature search was performed from inception to February 2022 following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) in Ovid MEDLINE (Wolters Kluwer, Alphen aan den Rijn, the Netherlands), Ovid Embase (Wolters Kluwer), and Cochrane Library (Wiley, Hoboken, NJ). Two independent reviewers screened the studies for eligibility with Covidence software. Bibliographies and citing references from selected articles were screened from Scopus (Elsevier, Amsterdam, the Netherlands). The search identified 3476 citations, with 6 studies included. Three studies demonstrated a significantly higher volume of graftable fat harvested in a significantly lower mean grafting time with ACWF than with their respective controls. With respect to adverse events, 3 studies reported significantly lower incidences of nodule or cyst formation with ACWF with respect to control. Two studies reported a significantly lower incidence of fat necrosis with ACWF vs control, with this trend upheld in 2 additional studies. Three studies reported significantly lower revision rates with ACWF with respect to control. No study reported inferiority with ACWF for any outcome of interest. These data suggest that ACWF systems yield higher fat volumes in less time than other common techniques, with decreased rates of suboptimal outcomes and revisions, thereby supporting active filtration as a safe and efficacious means of fat processing that may reduce operative times. Further large-scale, randomized trials are needed to definitively demonstrate the above trends.

The great vessel freeze-out: A meta-analysis of conventional versus frozen elephant trunks in aortic arch surgery.

BACKGROUND: The optimal treatment strategy for complex aortic arch and proximal descending aortic pathologies remains controversial. Despite the frozen elephant trunk (FET) technique's increasing popularity, its use over the conventional elephant trunk (CET) remains a matter of physician preference and outcomes are varied. METHODS: This meta-analysis of available comparative studies of FET versus CET sought to examine differences in survival, reintervention, and adverse events. The following databases were searched from inception-May 2020: Ovid MEDLINE, Ovid EMBASE, and The Cochrane Library. Studies retrieved were then screened for eligibility against predefined inclusion/exclusion criteria with a protocol registered on Open Science Framework at https://osf.io/hrfze/. RESULTS: The search identified 1911 citations, with five studies included. The resultant meta-analysis included 313 CET and 292 FET cases. FET had lower perioperative mortality (risk ratio [RR]: 0.50, 95% confidence interval [CI]: [0.42; 0.60], p < .001) and improved 1-year survival compared to CET (hazard ratio: 0.63, 95% CI: [0.42; 0.95], p = .03). There were no significant differences in rates of overall or open reinterventions following FET versus CET, but FET did yield a significantly higher rate of endovascular reintervention (RR: 2.32, 95% CI: [1.17; 4.61], p = .03). No significant differences were observed in the incidences of postoperative stroke, spinal cord injury, or renal failure between groups. CONCLUSIONS: The FET technique yields superior rates of perioperative and medium-term survival with no significant increase in overall reinterventions. There was no significant difference in the rate of spinal cord injury between groups, providing further large-scale evidence that the FET is an acceptable, safe alternative to the CET.

Production of a Low-Cost, Off-the-Shelf, Decellularized Cartilage Xenograft for Tissue Regeneration.

BACKGROUND: Reconstruction of cartilaginous deformities is a well-established surgical challenge with high levels of unpredictability and complication. Because of the morbidity associated with autologous cartilage grafting, combined with its limited supply and the significant expense of commercially decellularized allografts, increasing efforts have sought to produce an acellular, nonimmunogenic cartilage xenograft. We have developed and validated a novel protocol for high throughput decellularization of ovine costal cartilage with immediate translational potential for preclinical investigation of novel strategies for cartilaginous reconstruction. METHODS: Floating ribs were isolated from freshly slaughtered rack of lamb and after cleaning, the ribs were either minced into 2-mm cubes or zested into 1-mm flakes. Tissue was then decellularized via a protocol consisting of 4 freeze/thaw cycles, digestion with trypsin, incubation in hyperosmolar and hypoosmolar salt solutions, with incubation in 1% Tween following both the hyperosmolar and hypoosmolar steps, a 48-hour incubation in nucleases, DNA elution via EDTA, and 2 terminal sterilization steps. Protocol success was evaluated via histologic analysis with hematoxylin and eosin, DAPI, and safranin-O staining, as well as DNA quantification. RESULTS: Histologic analysis of the decellularized tissue revealed a significant reduction in nuclei as evidenced by hematoxylin and eosin and DAPI staining (P < 0.01). Safranin-O staining demonstrated a depletion of glycosaminoglycan content in the decellularized cartilage but with preservation of tissue architecture. Unprocessed lamb cartilage contained 421 ± 60 ng DNA/mg of lyophilized tissue, whereas decellularized zested and minced costal cartilage contained 27 ± 2 ng DNA/mg lyophilized tissue (P < 0.0001) and 24 ± 2.3 ng DNA/mg lyophilized tissue (p < 0.0001), respectively, well below the threshold of 50 ng accepted as evidence of suitable decellularization. In comparison, commercial allograft cartilage contained 17 ± 5 ng DNA/mg of lyophilized tissue. CONCLUSIONS: We have developed a novel protocol for the decellularization of xenogeneic cartilage graft. This structurally stable, low immunogenicity decellularized cartilage can be produced at low cost in large quantities for use in preclinical investigation.

Off-the-Shelf Nipple Engineering: Neonipple Formation via Implantation of Scaffolded Decellularized Ovine Xenograft.

BACKGROUND: Nipple reconstruction is widely regarded as the final step in postmastectomy breast reconstruction. While grafts, local flaps, or combination approaches have been used in nipple reconstruction, none has been able to achieve reliable long-term projection preservation. In response, we have sought to bioengineer neonipples in situ via the implantation of processed, decellularized cartilage xenografts placed within 3-dimensional-printed polylactic acid (PLA) scaffolds. MATERIALS AND METHODS: External nipple scaffolds were designed in-house and 3-dimensional-printed with PLA filament. Decellularized ovine xenograft infill was prepared and processed by mincing or zesting. All nipple scaffolds were placed subcutaneously on the dorsa of Sprague-Dawley rats and explanted after 1, 3, and 6 months for analysis. RESULTS: Explanted nipple scaffolds demonstrated gross maintenance of scaffold shape, diameter, and projection with accompanying increases in tissue volume. Histologic analyses revealed preservation of native cartilage architecture after 6 months without evidence of degradation. Analysis of formed tissue within the scaffolds revealed a progressive invasion of fibrovascular tissue with identifiable vascular channels and adipose tissue after 6 months in vivo. Confined compression testing revealed equilibrium moduli of both minced and zested samples that were within the expected range of previously reported human nipple tissue, while these data revealed no differences in the mechanical properties of the neotissue between time points or processing techniques. CONCLUSIONS: These preliminary data support potential use of decellularized allograft to foster healthy tissue ingrowth within a PLA scaffold, thereby offering a novel solution to current limitations in nipple reconstruction.

Effect of oxytocin on lipid accumulation under inflammatory conditions in human macrophages.

INTRODUCTION AND AIMS: Oxytocin (OT) is a neuropeptide hormone secreted by the posterior pituitary gland. Deficits in OT action have been observed in patients with behavioral and mood disorders, some of which correlate with an increased risk of cardiovascular disease (CVD). Recent research has revealed a wider systemic role that OT plays in inflammatory modulation and development of atherosclerotic plaques. This study investigated the role that OT plays in cholesterol transport and foam cell formation in LPS-stimulated THP-1 human macrophages. METHODS: THP-1 differentiated macrophages were treated with media, LPS (100 ng/ml), LPS + OT (10 pM), or LPS + OT (100 pM). Changes in gene expression and protein levels of cholesterol transporters were analyzed by real time quantitative PCR (RT-qPCR) and Western blot, while oxLDL uptake and cholesterol efflux capacity were evaluated with fluorometric assays. RESULTS: RT-qPCR analysis revealed a significant increase in ABCG1 gene expression upon OT + LPS treatment, compared to LPS alone (p = 0.0081), with Western blotting supporting the increase in expression of the ABCG1 protein. Analysis of oxLDL uptake showed a significantly lower fluorescent value in LPS + OT (100pM) -treated cells when compared to LPS alone (p < 0.0001). While not statistically significant (p = 0.06), cholesterol efflux capacity increased with LPS + OT treatment. CONCLUSION: We demonstrate here that OT can attenuate LPS-mediated lipid accumulation in THP-1 macrophages. These findings support the hypothesis that OT could be used to reduce pro-inflammatory and potentially atherogenic changes observed in patients with heightened CVD risk. This study suggests further exploration of OT effects on monocyte and macrophage cholesterol handling in vivo.

An update on the use of hydroxychloroquine in cutaneous lupus erythematosus: A systematic review.

BACKGROUND: Hydroxychloroquine is widely used for the treatment of cutaneous lupus erythematosus (CLE). Although new recommendations exist for hydroxychloroquine dosing, there is still uncertainty about the dosage that will elicit a satisfactory response in CLE while limiting adverse effects, specifically retinopathy. OBJECTIVE: To summarize hydroxychloroquine dosages, outcomes, and adverse effects in the treatment of CLE, focusing on retinopathy. METHODS: A comprehensive literature search from inception to December 2018 was performed in Ovid MEDLINE, Ovid Embase, and The Cochrane Library (Wiley). Studies were screened against predefined inclusion and exclusion criteria. RESULTS: Twelve studies were selected and included 5 retrospective studies, 3 prospective studies, 2 case series, and 2 randomized controlled trials. These studies show that a hydroxychloroquine dosage up to 400 mg/d is effective for most CLE patients (range of effectiveness, 50%-97%), with few adverse effects. One incidence of retinopathy, after a very high cumulative dose, was reported across all 12 studies (852 total patients). LIMITATIONS: Because retinopathy and other serious adverse effects may not appear until much later, many of these studies are limited by short follow-up time. CONCLUSIONS: This evidence suggests that hydroxychloroquine for CLE is effective at 400 mg/d, with an exceedingly low incidence of retinopathy and other adverse effects.

Immunogenetic effects of low dose (CEM43 30) magnetic nanoparticle hyperthermia and radiation in melanoma cells.

Objective: In this in vitro study we have used an RNA quantification technique, nanoString, and a conventional protein analysis technique (Western Blot) to assess the genetic and protein expression of B16 murine melanoma cells following a modest magnetic nanoparticle hyperthermia (mNPH) dose equivalent to 30 minutes @ 43°C (CEM43 30) and/or a clinically relevant 8 Gy radiation dose.Methods: Melanoma cells with mNPs(2.5 µg Fe/106 cells) were pelleted and exposed to an alternating magnetic field (AMF) to generate the targeted thermal dose. Thermal dose was accurately monitored by a fiber optic probe and automatically maintained at CEM43 30. All cells were harvested 24 hours after treatment.Results: The mNPH dose demonstrated notable elevations in the thermotolerance/immunogenic HSP70 gene and a number of chemoattractant and toll-like receptor gene pathways. The 8 Gy dose also upregulated a number of important immune and cytotoxic genetic and protein pathways. However, the mNPH/radiation combination was the most effective stimulator of a wide variety of immune and cytotoxic genes including HSP70, cancer regulating chemokines CXCL10, CXCL11, the T-cell trafficking chemokine CXCR3, innate immune activators TLR3, TLR4, the MDM2 and mTOR negative regulator of p53, the pro-apoptotic protein PUMA, and the cell death receptor Fas. Importantly a number of the genetic changes were accurately validated by protein expression changes, i.e., HSP70, p-mTOR, p-MDM2.Conclusion: These results not only show that low dose mNPH and radiation independently increase the expression of important immune and cytotoxic genes but that the effect is greatly enhanced when they are used in combination.

Customizable, biocompatible implants for dorsal nasal augmentation: An in vivo pilot study of eight polylactic acid scaffold designs.

Augmentation of the nasal dorsum often requires implantation of structural material. Existing methods include autologous, cadaveric or alloplastic materials and injectable hydrogels. Each of these options is associated with considerable limitations. There is an ongoing need for precise and versatile implants that produce long-lasting craniofacial augmentation. Four separate polylactic acid (PLA) dorsal nasal implant designs were 3D-printed. Two implants had internal PLA rebar of differing porosities and two were designed as "shells" of differing porosities. Shell designs were implanted without infill or with either minced or zested processed decellularized ovine cartilage infill to serve as a "biologic rebar", yielding eight total treatment groups. Scaffolds were implanted heterotopically on rat dorsa (N = 4 implants per rat) for explant after 3, 6, and 12 months followed by volumetric, histopathologic, and biomechanical analysis. Low porosity implants with either minced cartilage or PLA rebar infill had superior volume retention across all timepoints. Overall, histopathologic and immunohistochemical analysis showed a resolving inflammatory response with an M1/M2 ratio consistently favoring tissue regeneration over the study course. However, xenograft cartilage showed areas of degradation and pro-inflammatory infiltrate contributing to volume and contour loss over time. Biomechanical analysis revealed all constructs had equilibrium and instantaneous moduli higher than human septal cartilage controls. Biocompatible, degradable polymer implants can induce healthy neotissue ingrowth resulting in guided soft tissue augmentation and offer a simple, customizable and clinically-translatable alternative to existing craniofacial soft tissue augmentation materials. PLA-only implants may be superior to combination PLA and xenograft implants due to contour irregularities associated with cartilage degradation.

Bioengineering Full-scale auricles using 3D-printed external scaffolds and decellularized cartilage xenograft.

Reconstruction of the human auricle remains a formidable challenge for plastic surgeons. Autologous costal cartilage grafts and alloplastic implants are technically challenging, and aesthetic and/or tactile outcomes are frequently suboptimal. Using a small animal "bioreactor", we have bioengineered full-scale ears utilizing decellularized cartilage xenograft placed within a 3D-printed external auricular scaffold that mimics the size, shape, and biomechanical properties of the native human auricle. The full-scale polylactic acid ear scaffolds were 3D-printed based upon data acquired from 3D photogrammetry of an adult ear. Ovine costal cartilage was processed either through mincing (1 mm3) or zesting (< 0.5 mm3), and then fully decellularized and sterilized. At explantation, both the minced and zested neoears maintained the size and contour complexities of the scaffold topography with steady tissue ingrowth through 6 months in vivo. A mild inflammatory infiltrate at 3 months was replaced by homogenous fibrovascular tissue ingrowth enveloping individual cartilage pieces at 6 months. All ear constructs were pliable, and the elasticity was confirmed by biomechanical analysis. Longer-term studies of the neoears with faster degrading biomaterials will be warranted for future clinical application. STATEMENT OF SIGNIFICANCE: Accurate reconstruction of the human auricle has always been a formidable challenge to plastic surgeons. In this article, we have bioengineered full-scale ears utilizing decellularized cartilage xenograft placed within a 3D-printed external auricular scaffold that mimic the size, shape, and biomechanical properties of the native human auricle. Longer-term studies of the neoears with faster degrading biomaterials will be warranted for future clinical application.

Sourcing and development of tissue for transplantation in reconstructive surgery: A narrative review.

The wealth of allogeneic and xenogeneic tissue products available to plastic and reconstructive surgeons has allowed for the development of novel surgical solutions to challenging clinical problems, often obviating the need to inflict donor site morbidity. Allogeneic tissue used for reconstructive surgery enters the tissue industry through whole body donation or reproductive tissue donation and has been regulated by the FDA as human cells, tissues, and cellular and tissue-based products (HCT/Ps) since 1997. Tissue banks offering allogeneic tissue can also undergo voluntary regulation by the American Association of Tissue Banks (AATB). Tissue prepared for transplantation is sterilized and can be processed into soft tissue or bone allografts for use in surgical reconstruction, whereas non-transplant tissue is prepared for clinical training and drug, medical device, and translational research. Xenogeneic tissue, which is most often derived from porcine or bovine sources, is also commercially available and is subject to strict regulations for animal breeding and screening for infectious diseases. Although xenogeneic products have historically been decellularized for use as non-immunogenic tissue products, recent advances in gene editing have opened the door to xenograft organ transplants into human patients. Herein, we describe an overview of the modern sourcing, regulation, processing, and applications of tissue products relevant to the field of plastic and reconstructive surgery.

Osseointegration for Lower-Extremity Amputees: Operative Considerations from the Plastic Surgeon's Perspective.

➢: Osseointegration for lower-extremity amputees, while increasing in frequency, remains in its relative infancy compared with traditional socket-based prostheses. ➢: Ideal candidates for osseointegration have documented failure of a traditional prosthesis and should be skeletally mature, have adequate bone stock, demonstrate an ability to adhere to a longitudinal rehabilitation protocol, and be in an otherwise good state of health. ➢: Lowering the reoperation rate for soft-tissue complications depends heavily on surgical technique and on the implant device itself; the current gold standard involves a smooth implant surface for dermal contact as well as maximal skin resection to prevent skin breakdown against the prosthesis. This may include the need for thighplasty to optimize skin reduction. ➢: Interdisciplinary peripheral nerve management, such as targeted muscle reinnervation, performed in tandem with a plastic surgery team can treat existing and prevent future symptomatic neuromas, ultimately improving pain outcomes.

Perfuse and Reuse: A Low-Cost Three-Dimensional-Printed Perfusion Bioreactor for Tissue Engineering.

This article describes fabrication of a customizable bioreactor, which comprises a perfusion system and coverslip-based tissue culture chamber that allow centimeter-scale vascularized or otherwise canalized tissue constructs to be maintained in weeks long static and/or perfusion culture at an exceptionally low cost, with intermittent live imaging and media sampling capabilities. The perfusion system includes a reusable polydimethylsiloxane (PDMS) lid generated from a three-dimensional (3D)-printed poly-lactic acid (PLA) mold and several lengths of perfusion tubing. The coverslip tissue culture chamber includes PDMS components built with 3D-printed PLA molds, as well as 3D-printed PLA frames and glass coverslips that house perfusable hydrogel constructs. As proof of concept, we fabricated a vascularized hydrogel construct, which was subjected to static and perfusion tissue culture, as well as flow studies using fluorescent beads and widefield fluorescent microscopy. This system can be readily reproduced, promoting the advancement of tissue engineering and regenerative medicine research.

Long-term spaceflight and the cardiovascular system.

While early investigations into the physiological effects of spaceflight suggest the body's ability to reversibly adapt, the corresponding effects of long-term spaceflight (>6 months) are much less conclusive. Prolonged exposure to microgravity and radiation yields profound effects on the cardiovascular system, including a massive cephalad fluid translocation and altered arterial pressure, which attenuate blood pressure regulatory mechanisms and increase cardiac output. Also, central venous pressure decreases as a result of the loss of venous compression. The stimulation of baroreceptors by the cephalad shift results in an approximately 10%-15% reduction in plasma volume, with fluid translocating from the vascular lumen to the interstitium. Despite possible increases in cardiac workload, myocyte atrophy and notable, yet unexplained, alterations in hematocrit have been observed. Atrophy is postulated to result from shunting of protein synthesis from the endoplasmic reticulum to the mitochondria via mortalin-mediated action. While data are scarce regarding their causative agents, arrhythmias have been frequently reported, albeit sublethal, during both Russian and American expeditions, with QT interval prolongation observed in long, but not short duration, spaceflight. Exposure of the heart to the proton and heavy ion radiation of deep space has also been shown to result in coronary artery degeneration, aortic stiffness, carotid intima thickening via collagen-mediated action, accelerated atherosclerosis, and induction of a pro-inflammatory state. Upon return, long-term spaceflight frequently results in orthostatic intolerance and altered sympathetic responses, which can prove hazardous should any rapid mobilization or evacuation be required, and indicates that these cardiac risks should be especially monitored for future missions.

The adverse health effects of punitive immigrant policies in the United States: A systematic review.

BACKGROUND: Immigrants in the United States (US) today are facing a dynamic policy landscape. The Trump administration has threatened or curtailed access to basic services for 10.5 million undocumented immigrants currently in the US. We sought to examine the historical effects that punitive laws have had on health outcomes in US immigrant communities. METHODS: In this systematic review, we searched the following databases from inception-May 2020 for original research articles with no language restrictions: Ovid MEDLINE, Ovid EMBASE, Cochrane Library (Wiley), Web of Science Core Collection (Clarivate), CINAHL (EBSCO), and Social Work Abstracts (Ovid). This study is registered with PROSPERO, CRD42019138817. Articles with cohort sizes >10 that directly evaluated the health-related effects of a punitive immigrant law or policy within the US were included. FINDINGS: 6,357 studies were screened for eligibility. Of these, 32 studies were selected for inclusion and qualitatively synthesized based upon four themes that appeared throughout our analysis: (1) impact on healthcare utilization, (2) impact on women's and children's health, (3) impact on mental health services, and (4) impact on public health. The impact of each law, policy, mandate, and directive since 1990 is briefly discussed, as are the limitations and risk of bias of each study. INTERPRETATION: Many punitive immigrant policies have decreased immigrant access to and utilization of basic healthcare services, while instilling fear, confusion, and anxiety in these communities. The federal government should preserve and expand access for undocumented individuals without threat of deportation to improve health outcomes for US citizens and noncitizens.

The gut microbiome and psycho-cognitive traits.

The idea that trillions of bacteria inhabit our gut is somewhat unnerving, yet these bacteria may have a greater influence on our behavior than previously thought. Accumulating data strongly suggest that these gut commensal organisms have a strong inter-relationship with our brain and behavior, including cognitive function, mood, and personality. In this chapter, we discuss the role of the gut microbiome in the development of human personality, mood and mood disorders, and cognition, with a particular emphasis on the current consensus and controversies in the literature surrounding the behavioral effects of bioactive metabolites, microbial ratio shifts, and neurotransmitter synthesis facilitated by the microbiome.