Comparing Outcomes in the Therapeutic and Prophylactic Breast for Bilateral Mastectomy With Implant-Based Breast Reconstruction.

BACKGROUND: Increasingly patients with unilateral breast cancer elect to undergo bilateral mastectomy with subsequent reconstruction. Studies have aimed to better identify the risks associated with performing mastectomy on the noncancerous breast. Our study aims to identify differences in complications between therapeutic and prophylactic mastectomy in patients undergoing implant-based breast reconstruction. METHODS: A retrospective analysis of implant-based breast reconstruction from 2015 to 2020 at our institution was completed. Patients with less than 6-month follow-up after final implant placement had reconstruction using autologous flaps, expander or implant rupture, metastatic disease requiring device removal, or death before completion of reconstruction were excluded. McNemar test identified differences in incidence of complications for therapeutic and prophylactic breasts. RESULTS: After analysis of 215 patients, we observed no significant difference in incidence of infection, ischemia, or hematoma between the therapeutic and prophylactic sides. Therapeutic mastectomies had higher odds of seroma formation ( P = 0.03; odds ratio, 3.500; 95% confidence interval, 1.099-14.603). Radiation treatment status was analyzed for patients with seroma; 14% of patients unilateral seroma of the therapeutic side underwent radiation (2 of 14), compared with 25% patients with unilateral seroma of the prophylactic side (1 of 4). CONCLUSIONS: For patients undergoing mastectomy with implant-based reconstruction, the therapeutic mastectomy side has an increased risk of seroma formation.

The Impact of Postoperative Antibiotic and Duration After Implant-Based Breast Reconstruction on Resistance Among Cultured Species.

BACKGROUND: There is a growing presence of literature within plastic surgery that establishes best practice for postoperative antibiotics after implant-based breast reconstruction (IBBR), although it has not been widely adopted or translated into clinical practice. This study aims to determine how antibiotic and duration affects patient outcomes. We hypothesize that IBBR patients who receive a longer duration of postoperative antibiotics will demonstrate higher rates of antibiotic resistance as compared with the institutional antibiogram. METHODS: A retrospective chart review included patients who underwent IBBR between 2015 and 2020 at a single institution. Variables of interest included patient demographics, comorbidities, surgical techniques, infectious complications, and antibiograms. Groups were classified by antibiotic (cephalexin, clindamycin, or trimethoprim/sulfamethoxazole) and duration (≤7 days, 8-14 days, and >14 days). RESULTS: There were a total of 70 patients who experienced infections included in this study. Onset of infection did not differ based on antibiotic during either device implantation (postexpander P = 0.391; postimplant P = 0.234). Antibiotic and duration did not have an established relationship with explantation rate either (P = 0.154). In patients who had Staphylococcus aureus isolated, there was significantly increased resistance to clindamycin when compared with the institutional antibiogram (sensitivities of 43% and 68%, respectively). CONCLUSIONS: Neither antibiotic nor duration displayed a difference in overall patient outcomes, including explantation rates. In this cohort, S. aureus strains isolated in association with IBBR infections demonstrated a higher level of resistance to clindamycin compared with strains isolated and tested within the broader institution.

Health Care Provider Bias in Estimating the Health Literacy of Caregivers in a Pediatric Emergency Department.

BACKGROUND: Health literacy is a growing concern because of its effects on communication and health outcomes. One aspect of this communication is the ability of the health care provider to estimate the health literacy of a patient or their caregiver. The objectives of this study are to quantify misestimation of caregiver health literacy by providers and identify potential descriptive or demographic factors that might be related to those misestimations. METHODS: Providers were asked to perceive descriptive factors and estimate the health literacy of caregivers in a pediatric Emergency Department. Then, the health literacy of the caregiver was tested using the Short Assessment of Health Literacy, and cross-tabulated with provider estimates. RESULTS: Providers correctly estimated the health literacy of the caregivers 60% of the time, and misestimates were often underestimates (27.7%) rather than overestimates (12.3%). Providers overestimated the health literacy of 24.1% of fathers and only 9.8% of mothers (P = 0.012). They correctly estimated the health literacy of 63.9% of English-speaking caregivers compared with 30.6% of Spanish-speaking caregivers, and underestimated the health literacy of 50% of Spanish-speaking caregivers and 24.8% of English-speaking caregivers (P < 0.001). Providers correctly estimated the health literacy of 34.4% of racially and ethnically diverse caregivers compared with 71.5% of White/non-Hispanic caregivers. They underestimated the health literacy of 52.1% of these racially and ethnically diverse caregivers and 16.8% of White/non-Hispanic caregivers (P < 0.001). CONCLUSIONS: Providers often overestimate and underestimate the health literacy of parents in the pediatric emergency department. Misestimates are related to race, caregiver role, and language spoken by the caregiver. When providers misestimate health literacy, they may use words or phrases that are above or below the health literacy level of the caregiver. These results suggest a need for further health literacy research and interventions in provider education and clinical practice.

Viewing stromal vascular fraction de novo vessel formation and association with host microvasculature using the rat mesentery culture model.

OBJECTIVE: The objective of the study is to demonstrate the innovation and utility of mesenteric tissue culture for discovering the microvascular growth dynamics associated with adipose-derived stromal vascular fraction (SVF) transplantation. Understanding how SVF cells contribute to de novo vessel growth (i.e., neovascularization) and host network angiogenesis motivates the need to make observations at single-cell and network levels within a tissue. METHODS: Stromal vascular fraction was isolated from the inguinal adipose of adult male Wistar rats, labeled with DiI, and seeded onto adult Wistar rat mesentery tissues. Tissues were then cultured in MEM + 10% FBS for 3 days and labeled for BSI-lectin to identify vessels. Alternatively, SVF and tissues from green fluorescent-positive (GFP) Sprague Dawley rats were used to track SVF derived versus host vasculature. RESULTS: Stromal vascular fraction-treated tissues displayed a dramatically increased vascularized area compared to untreated tissues. DiI and GFP+ tracking of SVF identified neovascularization involving initial segment formation, radial outgrowth from central hub-like structures, and connection of segments. Neovascularization was also supported by the formation of segments in previously avascular areas. New segments characteristic of SVF neovessels contained endothelial cells and pericytes. Additionally, a subset of SVF cells displayed the ability to associate with host vessels and the presence of SVF increased host network angiogenesis. CONCLUSIONS: The results showcase the use of the rat mesentery culture model as a novel tool for elucidating SVF cell transplant dynamics and highlight the impact of model selection for visualization.

Quantity of Acellular Dermal Matrix in Immediate Breast Reconstruction and Outcomes.

PURPOSE: This study aimed to determine the impact of the quantity of acellular dermal matrix (ADM), "ADM burden," used in implant-based breast reconstruction on infection, drain duration, and seroma formation. METHODS: A single-institution, retrospective review from 2015 to 2020 was conducted for patients who underwent immediate, implant-based breast reconstruction after mastectomy. Three cohorts were generated based on the amount of ADM used: (1) total ADM, (2) sling ADM, and (3) no ADM. RESULTS: In total, there were 374 patients who satisfied the inclusion criteria yielding 641 breasts with 143, 432, and 66 breasts in the total ADM, sling ADM, and no-ADM groups, respectively. The no-ADM group had higher mastectomy weights (788.4 g) than the sling (654.2 g) and total ADM (503.4 g) groups (F = 10.8, P < 0.001). Total ADM had higher rates of explantation secondary to infection compared with no ADM (P < 0.001). Linear regression analysis for drain duration was significant for body mass index (P < 0.0001) but not for ADM quantity (P = 0.52). Logistic regression analysis demonstrated a higher risk of infection in the total ADM group (odds ratio [OR], 5.4; P < 0.0001). Diabetes mellitus was a risk factor for both infection (OR, 3.6; P = 0.05) and seroma formation (OR, 0.04; P = 0.04). CONCLUSIONS: Higher ADM burden is associated with an increased risk of infections and device explantation secondary to those infections. Although ADM has created new avenues in breast reconstruction, these findings indicate a need to evolve the technique to minimize the ADM burden. By doing so, patients can minimize their risk of postoperative complications while reducing the financial impact on institutions.

A clinical perspective on adipose-derived cell therapy for enhancing microvascular health and function: Implications and applications for reconstructive surgery.

Restoration of form and function requires apposition of tissues in the form of flaps to reconstitute local perfusion. Successful reconstruction relies on flap survival and its integration with the recipient bed. The flap's precariously perfused hypoxic areas undergo adaptive microvascular changes both internally and in connection with the recipient bed. A cell-mediated, coordinated response to hypoxia drives these adaptive processes, restoring a tissue's normoxic homeostasis via de novo vasculogenesis, sprouting angiogenesis, and stabilizing arterialization. As cells exert prolonged and coordinated effects on site, their use as biological agents merit translational consideration of sourcing angio-competent cells and delivering them to territories enduring microcirculatory acclimatization. Angio-competent cells abound in adipose tissue: a reliable, accessible, and expendable source of adipose-derived cells (ADC). When subject to enzymatic digestion and centrifugation, adipose tissue separates its various ADC: A subset of buoyant oil-dense adipocytes (the tissue's parenchymal component) accumulates on a supra-natant layer, whereas the mesenchymal component remains in the infra-natant sediment, containing the tissue's stromal vascular fraction (SVF), where angio-component cells abound. The SVF can be further manipulated, selected, or culture expanded into more specific stromal subsets (herein defined as adipose stromal cells, ASC). While promising clinical applications for ADC await clinical proof and regulatory authorization, basic science investigation is needed to elucidate the specific ADC mechanisms that influence microvascular growth, remodeling, and function following flap surgery. The objective of this article is to share the clinical perspectives of reconstructive plastic surgeons regarding the use of ADC-based therapies to help with flap tissue integration, revascularization, and wound healing. Specifically, the focus will be on considering the potential for ADC as therapeutic agents and how their clinical application motivates basic science opportunities.

Describing advanced practice provider roles within critical care teams with Tele-ICUs: Exemplars from seven US health systems.

Telehealth is an acknowledged strategy to meet patient healthcare needs. In critical care settings, Tele-ICU's are expanding to deliver clinical services across a diverse spectrum of critically ill patients. The expansion of telehealth provides increased opportunities for advanced practice providers including advanced practice nurses and physician assistants; however, limited information on roles and models of care for advanced practice providers in telehealth exist. This article reviews current and evolving roles for advanced practice providers in telehealth in acute and critical care settings across 7 healthcare systems in the United States. The health system exemplars described in this article identify the important role of advanced practice providers in providing patient care oversight and in improving outcomes for acute and critically ill patients. As telehealth continues to expand, additional opportunities will lead to novel roles for advanced practice providers in the field of telehealth to assist with patient care management for subacute, acute, and critically ill patients.

Historical Roots of Modern Plastic Surgery: A Cited Reference Analysis.

BACKGROUND: Highly cited publications are referred to as citation classics and can signify important contributions to a discipline. Although citation classics in plastic surgery have been identified, none were published before 1960. Citation classics in earlier periods may contain the historical roots or intellectual origins of the field. We set out to identify such scholarly works and analyze their characteristics. METHODS: A novel technique of citation analysis, referred to as reference publication year spectroscopy, was used to analyze the literature. The spectrogram revealed distinct peaks before 1960, which corresponded to 20 citation classics. These 20 references were then analyzed with respect to historical context, topic of interest, anatomical region, originality, and if authors were named for their findings (eponyms). RESULTS: Twenty distinct citation classics (published from 1851 to 1959) were identified, accounting for 430 literature citations. Salmon's "Arteres de la Peau" was the most cited reference, followed by Gillies' "Principles of Plastic Surgery" and Neuber's "Fat Grafting." The theme of angiosomes was highly represented. Most citation classics dealt with reconstruction of acquired defects (37%) and primarily focused on the head and neck regions (45%). Thirty-five percent of clinical studies were noted for their originality, and 5 studies earned their authors' eponymous distinctions. CONCLUSION: The roots of modern plastic surgery began in the late 19th century with early efforts to describe cutaneous vasculature. Historical studies that either establish principles or lead to an advancement in our reconstructive methods have the best chance of achieving classical status.

A Glycovariant of Human CD44 is Characteristically Expressed on Human Mesenchymal Stem Cells.

The clinical effectiveness of systemically administered human mesenchymal stem cells (hMSCs) depends on their capacity to engage vascular endothelium. hMSCs derived from bone marrow (BM-hMSCs) natively lack endothelial binding capacity, but express a CD44 glycovariant containing N-linked sialyllactosamines that can be α(1,3)-fucosylated using fucosyltransferase-VI (FTVI) to enforce sLeX decorations, thereby creating hematopoietic cell E-/L-selectin ligand (HCELL). HCELL expression programs potent shear-resistant adhesion of circulating cells to endothelial beds expressing E-selectin. An alternative source of hMSCs is adipose tissue (A-hMSCs), and we assessed whether A-hMSCs bind E-selectin and/or possess sialyllactosamine-decorated CD44 accessible to α(1,3)-fucosylation. Similar to BM-hMSCs, we found that A-hMSCs natively lack E-selectin ligands, but FTVI-mediated cell surface α(1,3)-fucosylation induces sLeX expression and robust E-selectin binding secondary to conversion of CD44 into HCELL. Moreover, treatment with the α(1,3)-fucosyltransferase-FTVII also generated expression of HCELL on both BM-hMSCs and A-hMSCs, with sLeX decorations created on N-linked glycans of the "standard" CD44 (CD44s) isoform. The finding that hMSCs from both source tissues each lack native E-selectin ligand expression prompted examination of the expression of glycosyltransferases that direct lactosaminyl glycan synthesis. These studies reveal that both types of hMSCs conspicuously lack transcripts encoding α(1,3)-fucosyltransferases, but equally express glycosyltransferases critical to creation of sialyllactosamines. Collectively, these data indicate that assembly of a sialyllactosaminyl-decorated CD44s glycovariant is a conserved feature of hMSCs derived from adipose tissue and marrow, thus identifying a CD44 glycosignature of these cells and supporting the applicability of cell surface α(1,3)-fucosylation in programming migration of systemically administered A-hMSCs to sites of tissue injury/inflammation. Stem Cells 2017;35:1080-1092.

Fluorescein Isothiocyanate: A Novel Application for Lymphatic Surgery.

The Lymphatic Microsurgical Preventing Healing Approach (LYMPHA) procedure entails performing a lymphovenous bypass (LVB) at the time of axillary lymph node dissection to reduce lymphedema risk. The two most common fluorophores utilized in LVB are blue dye and indocyanine green. We developed a novel application of fluorescein isothiocyanate for intraoperative lymphatic mapping. Our goal is to demonstrate the safety and efficacy of fluorescein isothiocyanate for this application. We reviewed a prospectively collected database on breast cancer patients who underwent LYMPHA from March to September 2015. Fluorescein isothiocyanate was used to identify arm lymphatic channels after axillary lymph node dissection to perform an LVB between disrupted lymphatics and axillary vein tributaries. Data on preoperative and intraoperative variables were analyzed. Thirteen patients underwent LYMPHA with intraoperative fluorescein isothiocyanate lymphatic mapping from March to September 2015. Average patient age was 50 years with a mean body mass index of 28. On average, 3.4 lacerated lymphatic channels were identified at an average distance of 2.72 cm (range, 0.25-5 cm) caudal to the axillary vein. On average, 1.7 channels were bypassed per patient. Eleven anastomoses were performed to the accessory branch of the axillary vein and 1 to a lateral branch. In 1 patient, a bypass was not performed due to poor lymphatic caliber and inadequate length of the harvested vein tributary. No intraoperative adverse events were noted. Fluorescein isothiocyanate is a safe and effective method for intra-operative lymphatic mapping. Fluorescein isothiocyanate imaging allows for simultaneous dissection and lymphatic visualization, making it an ideal agent for lymphatic mapping and dissection in open surgical fields, such as in the LYMPHA procedure.

Irisin exerts dual effects on browning and adipogenesis of human white adipocytes.

To better understand the role of irisin in humans, we examined the effects of irisin in human primary adipocytes and fresh human subcutaneous white adipose tissue (scWAT). Human primary adipocytes derived from 28 female donors' fresh scWAT were used to examine the effects of irisin on browning and mitochondrial respiration, and preadipocytes were used to examine the effects of irisin on adipogenesis and osteogenesis. Cultured fragments of scWAT and perirenal brown fat were used for investigating signal transduction pathways that mediate irisin's browning effect by Western blotting to detect phosphorylated forms of p38, ERK, and STAT3 as well as uncoupling protein 1 (UCP1). Individual responses to irisin in scWAT were correlated with basal expression levels of brown/beige genes. Irisin upregulated the expression of browning-associated genes and UCP1 protein in both cultured primary mature adipocytes and fresh adipose tissues. It also significantly increased thermogenesis at 5 nmol/l by elevating cellular energy metabolism (OCR and ECAR). Treating human scWAT with irisin increased UCP1 expression by activating the ERK and p38 MAPK signaling. Blocking either pathway with specific inhibitors abolished irisin-induced UCP1 upregulation. However, our results showed that UCP1 in human perirenal adipose tissue was insensitive to irisin. Basal levels of brown/beige and FNDC5 genes correlated positively with the browning response of scWAT to irisin. In addition, irisin significantly inhibited adipogenic differentiation but promoted osteogenic differentiation. We conclude that irisin promotes "browning" of mature white adipocytes by increasing cellular thermogenesis, whereas it inhibits adipogenesis and promotes osteogenesis during lineage-specific differentiation. Our findings provide a rationale for further exploring the therapeutic use of irisin in obesity and exercise-associated bone formation.

Farnesol repurposing for prevention and treatment of Acinetobacter baumannii biofilms.

Acinetobacter baumannii has emerged as a multidrug-resistant (MDR) superbug by causing severe infections, with high mortality rates. The ability of A. baumannii to form biofilms significantly contributes to its persistence in diverse environmental and hospital settings. Here we report that farnesol, an FDA-approved commercial cosmetic and flavoring agent, demonstrates efficacy for both inhibition of biofilm formation, and disruption of established A. baumannii biofilms. Moreover, no resistance to farnesol was observed even after prolonged culture in the presence of sub-inhibitory farnesol doses. Farnesol combats A. baumannii biofilms by direct killing, while also facilitating biofilm detachment. Furthermore, farnesol was safe, and effective, for both prevention and treatment of A. baumannii biofilms in an ex vivo burned human skin model. Since current treatment options for A. baumannii biofilm infections were mainly counted on the combination therapy of last-resort antibiotics, and clearly non-sustainable due to robust MDR phenotype of A. baumannii, we propose that farnesol alone can be repurposed as a highly effective agent for both preventing and treating life-threating biofilm-associated infections of A. baumannii due to its proven safety, convenient topical delivery, and excellent efficiency, plus its superiority of evading resistance development.

Repurposing Farnesol for Combating Drug-Resistant and Persistent Single and Polymicrobial Biofilms.

Biofilm-associated infections caused by drug-resistant and persistent bacteria remain a significant clinical challenge. Here we report that farnesol, commercially available as a cosmetic and flavoring agent, shows significant anti-biofilm properties when dissolved in ethanol using a proprietary formulation emulsion technique. Farnesol in the new formulation inhibits biofilm formation and disrupts established biofilms for Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa, including their polymicrobial biofilms, and, moreover, kills S. aureus persister cells that have developed tolerance to antibiotics. No resistance to farnesol was observed for S. aureus after twenty continuous passages. Farnesol combats biofilms by direct killing, while also facilitating biofilm detachment. Furthermore, farnesol was safe and effective for preventing and treating biofilm-associated infections of both types of bacteria in an ex vivo burned human skin model. These data suggest that farnesol in the new formulation is an effective broad-spectrum anti-biofilm agent with promising clinical potential. Due to its established safety, low-cost, versatility, and excellent efficacy-including ability to reduce persistent and resistant microbial populations-farnesol in the proprietary formulation represents a compelling transformative, translational, and commercial platform for addressing many unsolved clinical challenges.

LTP induction translocates cortactin at distant synapses in wild-type but not Fmr1 knock-out mice.

Stabilization of long-term potentiation (LTP) depends on reorganization of the dendritic spine actin cytoskeleton. The present study tested whether this involves activity-driven effects on the actin-regulatory protein cortactin, and whether such effects are disturbed in the Fmr1 knock-out (KO) model of fragile X syndrome, in which stabilization of both actin filaments and LTP is impaired. LTP induced by theta burst stimulation (TBS) in hippocampal slices from wild-type mice was associated with rapid, broadly distributed, and NMDA receptor-dependent decreases in synapse-associated cortactin. The reduction in cortactin content was blocked by blebbistatin, while basal levels were reduced by nocodazole, indicating that cortactin's movements into and away from synapses are regulated by microtubule and actomyosin motors, respectively. These results further suggest that synapse-specific LTP influences cytoskeletal elements at distant connections. The rapid effects of TBS on synaptic cortactin content were absent in Fmr1 KOs as was evidence for activity-driven phosphorylation of the protein or its upstream kinase, ERK1/2. Phosphorylation regulates cortactin's interactions with actin, and coprecipitation of the two proteins was reduced in the KOs. We propose that, in the KOs, excessive basal phosphorylation of ERK1/2 disrupts its interactions with cortactin, thereby blocking the latter protein's use of actomyosin transport systems. These impairments are predicted to compromise the response of the subsynaptic cytoskeleton to learning-related afferent activity, both locally and at distant sites.

Reduced excitatory neurotransmission and mild autism-relevant phenotypes in adolescent Shank3 null mutant mice.

Mutations in the synaptic scaffolding protein gene SHANK3 are strongly implicated in autism and Phelan-McDermid 22q13 deletion syndrome. The precise location of the mutation within the Shank3 gene is key to its phenotypic outcomes. Here, we report the physiological and behavioral consequences of null and heterozygous mutations in the ankyrin repeat domain in Shank3 mice. Both homozygous and heterozygous mice showed reduced glutamatergic transmission and long-term potentiation in the hippocampus with more severe deficits detected in the homozygous mice. Three independent cohorts were evaluated for magnitude and replicability of behavioral endophenotypes relevant to autism and Phelan-McDermid syndrome. Mild social impairments were detected, primarily in juveniles during reciprocal interactions, while all genotypes displayed normal adult sociability on the three-chambered task. Impaired novel object recognition and rotarod performance were consistent across cohorts of null mutants. Repetitive self-grooming, reduced ultrasonic vocalizations, and deficits in reversal of water maze learning were detected only in some cohorts, emphasizing the importance of replication analyses. These results demonstrate the exquisite specificity of deletions in discrete domains within the Shank3 gene in determining severity of symptoms.

Stromal cells from the adipose tissue-derived stromal vascular fraction and culture expanded adipose tissue-derived stromal/stem cells: a joint statement of the International Federation for Adipose Therapeutics and Science (IFATS) and the International Society for Cellular Therapy (ISCT).

BACKGROUND AIMS: Adipose tissue is a rich and very convenient source of cells for regenerative medicine therapeutic approaches. However, a characterization of the population of adipose-derived stromal and stem cells (ASCs) with the greatest therapeutic potential remains unclear. Under the authority of International Federation of Adipose Therapeutics and International Society for Cellular Therapy, this paper sets out to establish minimal definitions of stromal cells both as uncultured stromal vascular fraction (SVF) and as an adherent stromal/stem cells population. METHODS: Phenotypic and functional criteria for the identification of adipose-derived cells were drawn from the literature. RESULTS: In the SVF, cells are identified phenotypically by the following markers: CD45-CD235a-CD31-CD34+. Added value may be provided by both a viability marker and the following surface antigens: CD13, CD73, CD90 and CD105. The fibroblastoid colony-forming unit assay permits the evaluation of progenitor frequency in the SVF population. In culture, ASCs retain markers in common with other mesenchymal stromal/stem cells (MSCs), including CD90, CD73, CD105, and CD44 and remain negative for CD45 and CD31. They can be distinguished from bone-marrow-derived MSCs by their positivity for CD36 and negativity for CD106. The CFU-F assay is recommended to calculate population doublings capacity of ASCs. The adipocytic, chondroblastic and osteoblastic differentiation assays serve to complete the cell identification and potency assessment in conjunction with a quantitative evaluation of the differentiation either biochemically or by reverse transcription polymerase chain reaction. CONCLUSIONS: The goal of this paper is to provide initial guidance for the scientific community working with adipose-derived cells and to facilitate development of international standards based on reproducible parameters.

Long-term in-vivo tumorigenic assessment of human culture-expanded adipose stromal/stem cells.

After more than a decade of extensive experimentation, the promise of stem cells to revolutionize the field of medicine has negotiated their entry into clinical trial. Adipose tissue specifically holds potential as an attainable and abundant source of stem cells. Currently undergoing investigation are adipose stem cell (ASC) therapies for diabetes and critical limb ischemia, among others. In the enthusiastic pursuit of regenerative therapies, however, questions remain regarding ASC persistence and migration, and, importantly, their safety and potential for neoplasia. To date, assays of in vivo ASC activity have been limited by early end points. We hypothesized that with time, ASCs injected subcutaneously undergo removal by normal tissue turnover and homeostasis, and by the host's immune system. In this study, a high dose of culture expanded ASCs was formulated and implanted as multicellular aggregates into immunocompromised mice, which were maintained for over one year. Animals were monitored for toxicity, and surviving cells quantified at study endpoint. No difference in growth/weight or lifespan was found between cell-treated and vehicle treated animals, and no malignancies were detected in treated animals. Moreover, real-time PCR for a human specific sequence, ERV-3, detected no persistent ASCs. With the advent of clinical application, clarification of currently enigmatic stem cell properties has become imperative. Our study represents the longest duration determination of stem cell activity in vivo, and contributes strong evidence in support of the safety of adipose derived stem cell applications.

The effects of prolonged intraoperative hypothermia on patient outcomes in immediate implant-based breast reconstruction.

BACKGROUND: The importance of thermoregulation in surgical procedures has become a recent focus for anesthesiologists and surgeons to improve patient outcomes. In breast surgery, maintenance of normothermia has been shown to reduce surgical-site infections. However, there is a paucity of information evaluating the relationship between intraoperative core body temperatures and reconstructive surgical outcomes. METHODS: A retrospective review of patients who underwent immediate breast reconstruction following mastectomy from 2015 to 2020 was performed. Patients were classified into a majority normothermic (NT) group if patients spent greater than half of the operative time ≥36 °C or a majority hypothermic (HT) group if patients spent greater than or equal to half of the operative time <36 °C. Patient demographics, comorbidities, surgical techniques, and postoperative complications were recorded. Complications were classified according to the Clavien-Dindo Classification. Univariate and multivariate statistics were used to assess significant relationships. RESULTS: A total of 329 patients met inclusion criteria, of which 174 were in the NT group and 155 were in the HT group, yielding 302 and 264 total breasts, respectively. There was no significant difference in rates of infection (p = 1.0), seroma (p = 0.27), hematoma (p = 0.61), or wound dehiscence (p = 1.0). However, patients in the HT group had significantly more overall ischemic complications (p = 0.009) and, specifically, grade IIIb ischemic complications (p = 0.04). After controlling for tobacco use, body mass index, mastectomy pattern, radiation, operating surgeon, and mastectomy weight, multivariate analysis showed increased ischemic complications in the HT group (p = 0.04). CONCLUSION: Prolonged intraoperative hypothermia can increase the risk for the development of ischemic wounds such as tissue necrosis or eschar formation that require operative intervention. This presents reconstructive complications that increase both patient and health system burdens that could be addressed through the maintenance of normothermia. Further studies using real-time flap temperature would provide more accurate insight into the relationship between temperature and implant-based breast reconstruction.

Extent of Tissue Washing Can Significantly Alter the Composition of Adipose-Derived Stromal Vascular Fraction Cell Preparations: Implications for Clinical Translation.

Stromal vascular fraction (SVF) cell preparations have recently attracted much interest as a form of autologous cell therapy. These heterogenous cell populations typically include some proportion of blood-derived cells (BDCs)-including both red blood cells (RBCs) and leukocytes (WBCs). The objectives of this paper were to evaluate the effects of tissue washing and hypotonic RBC lysis-separately and together-on BDC concentrations within SVF, and further to explore whether BDCs can confer detectable and modifiable effects on adipose-derived cell activity. Using various cell culture assays, flow cytometry and ELISA analysis of human-derived SVF preparations, we show that thorough washing of adipose tissue prior to enzymatic dissociation effectively removes RBCs from SVF preparations as well as standard lysis methods and significantly alters the type and relative quantities of WBCs. In addition, these studies demonstrate that potentially toxic RBC components are detectable for up to 1 week in cultures containing RBC lysate, but not those with intact RBCs, and, that culture-expanded cells proliferate significantly more in the presence of intact RBCs versus RBC lysis products or control media. Broadly, these data exemplify how different seemingly mundane tissue processing steps can significantly influence SVF identity/composition, purity, and potency. Based on the findings of this work, we propose that translational efforts in the field would benefit by a better understanding of the impact of RBCs, WBCs, and non-viable cells on the in vivo therapeutic activity of SVF therapies.

Realizations of vascularized tissues: From in vitro platforms to in vivo grafts.

Vascularization is essential for realizing thick and functional tissue constructs that can be utilized for in vitro study platforms and in vivo grafts. The vasculature enables the transport of nutrients, oxygen, and wastes and is also indispensable to organ functional units such as the nephron filtration unit, the blood-air barrier, and the blood-brain barrier. This review aims to discuss the latest progress of organ-like vascularized constructs with specific functionalities and realizations even though they are not yet ready to be used as organ substitutes. First, the human vascular system is briefly introduced and related design considerations for engineering vascularized tissues are discussed. Second, up-to-date creation technologies for vascularized tissues are summarized and classified into the engineering and cellular self-assembly approaches. Third, recent applications ranging from in vitro tissue models, including generic vessel models, tumor models, and different human organ models such as heart, kidneys, liver, lungs, and brain, to prevascularized in vivo grafts for implantation and anastomosis are discussed in detail. The specific design considerations for the aforementioned applications are summarized and future perspectives regarding future clinical applications and commercialization are provided.