Oxylipins in Breast Implant Associated Systemic Symptoms.

BACKGROUND: A subset of women with breast implants have reported a myriad of nonspecific systemic symptoms collectively termed systemic symptoms associated with breast implants (SSBI). SSBI symptoms are similar to manifestations associated with autoimmune and connective tissue disorders Breast tissue is rich in adipose cells, comprised of lipids. Insertion of an implant creates an oxidative environment leading to lipid oxidation. Oxylipins can influence immune responses and inflammatory processes. OBJECTIVES: This study explores the abundance of a spectrum of oxylipins in the peri-prosthetic tissue surrounding the breast implant. Since oxylipins are immunogenic, we sought to determine if they are associated with the SSBI subjects. We have also attempted to determine if the common manifestations exhibited by such subjects have any association with oxylipin abundance. METHODS: The study included 120 subjects divided in three cohorts. Forty-six subjects with breast implants exhibiting manifestation associated with SSBI, 29 in control cohort I subjects with breast implants not exhibiting manifestation associated with SSBI (non-SSBI) and 45 in control cohort II subjects without implants (normal tissue) were analyzed. Lipid extraction and oxylipin quantification was performed using LCMS. LC-MS/MS targeted analysis from the breast adipose tissue was performed. RESULTS: Of the fifteen oxylipins analyzed, four exhibited increased abundance in the SSBI cohort compared to the non-SSBI and normal cohorts. CONCLUSIONS: The study documents the association of the oxylipins with each manifestation reported by the subject. This study provides an objective assessment on the subjective questionnaire highlighting which symptoms could be more relevant than the others.

Quantification of Lymphangiogenesis in the Murine Lymphedema Tail Model Using Intravital Microscopy.

Background: Lymphedema is chronic limb swelling resulting from lymphatic dysfunction. It affects an estimated five million Americans. There is no cure for this disease. Assessing lymphatic growth is essential in developing novel therapeutics. Intravital microscopy (IVM) is a powerful imaging tool for investigating various biological processes in live animals. Tissue nanotransfection technology (TNT) facilitates a direct, transcutaneous nonviral vector gene delivery using a chip with nanochannel poration in a rapid (<100 ms) focused electric field. TNT was used in this study to deliver the genetic cargo in the murine tail lymphedema to assess the lymphangiogenesis. The purpose of this study is to experimentally evaluate the applicability of IVM to visualize and quantify lymphatics in the live mice model. Methods and Results: The murine tail model of lymphedema was utilized. TNT was applied to the murine tail (day 0) directly at the surgical site with genetic cargo loaded into the TNT reservoir: TNTpCMV6 group receives pCMV6 (expression vector backbone alone) (n = 6); TNTProx1 group receives pCMV6-Prox1 (n = 6). Lymphatic vessels (fluorescein isothiocyanate [FITC]-dextran stained) and lymphatic branch points (indicating lymphangiogenesis) were analyzed with the confocal/multiphoton microscope. The experimental group TNTProx1 exhibited reduced postsurgical tail lymphedema and increased lymphatic distribution compared to TNTpCMV6 group. More lymphatic branching points (>3-fold) were observed at the TNT site in TNTProx1 group. Conclusions: This study demonstrates a novel, powerful imaging tool for investigating lymphatic vessels in live murine tail model of lymphedema. IVM can be utilized for functional assessment of lymphatics and visualization of lymphangiogenesis following gene-based therapy.

The Lymphedematous Limb as a Donor Site for Breast Fat Grafting.

Breast cancer-related lymphedema results in chronic upper limb swelling with subcutaneous deposition of fluid and fibroadipose tissue. Morbidity includes psychosocial distress, infection, and difficulty using the extremity. Operative management includes excisional procedures such as suction-assisted lipectomy to reduce abnormal subcutaneous fibroadipose tissue to improve limb volume. Patients who have had postmastectomy breast reconstruction often benefit from fat grafting. This report introduces the concept of fat grafting the breast using the lymphedematous arm as a donor site. This technique improves the volume of the limb by removing the excess subcutaneous adipose, and at the same time reconstructs the breast without adding a donor site not related to the breast cancer-related lymphedema.

Topical tissue nanotransfection of Prox1 is effective in the prophylactic management of lymphedema.

Lymphedema is chronic limb swelling resulting from lymphatic dysfunction. There is no cure for the disease. Clinically, a preventive surgical approach called immediate lymphatic reconstruction (ILR) has gained traction. Experimental gene-based therapeutic approaches (e.g., using viral vectors) have had limited translational applicability. Tissue nanotransfection (TNT) technology uses a direct, transcutaneous nonviral vector, gene delivery using a chip with nanochannel poration in response to a rapid (<100 ms) focused electric field. The purpose of this study was to experimentally prevent lymphedema using focal delivery of a specific gene Prox1 (a master regulator of lymphangiogenesis). TNT was applied to the previously optimized lymphedematous mice tail (day 0) directly at the surgical site with genetic cargo loaded into the TNT reservoir: group I (sham) was given pCMV6 (expression vector backbone alone) and group II was treated with pCMV6-Prox1. Group II mice had decreased tail volume (47.8%) compared to sham and greater lymphatic clearance on lymphangiography. Immunohistochemistry showed greater lymphatic vessel density and RNA sequencing exhibited reduced inflammatory markers in group II compared to group I. Prox1 prophylactically delivered using TNT to the surgical site on the day of injury decreased the manifestations of lymphedema in the murine tail model compared to control.

CD30 Lateral Flow and Enzyme-Linked Immunosorbent Assays for Detection of BIA-ALCL: A Pilot Study.

INTRODUCTION: Breast Implant-Associated Anaplastic Large Cell Lymphoma (BIA-ALCL) commonly presents as a peri-implant effusion (seroma). CD30 (TNFRSF8) is a consistent marker of tumor cells but also can be expressed by activated lymphocytes in benign seromas. Diagnosis of BIA-ALCL currently includes cytology and detection of CD30 by immunohistochemistry or flow cytometry, but these studies require specialized equipment and pathologists' interpretation. We hypothesized that a CD30 lateral flow assay (LFA) could provide a less costly rapid test for soluble CD30 that eventually could be used by non-specialized personnel for point-of-care diagnosis of BIA-ALCL. METHODS: We performed LFA for CD30 and enzyme-linked immunosorbent assay (ELISA) for 15 patients with pathologically confirmed BIA-ALCL and 10 patients with benign seromas. To determine the dynamic range of CD30 detection by LFA, we added recombinant CD30 protein to universal buffer at seven different concentrations ranging from 125 pg/mL to 10,000 pg/mL. We then performed LFA for CD30 on cryopreserved seromas of 10 patients with pathologically confirmed BIA-ALCL and 10 patients with benign seromas. RESULTS: Recombinant CD30 protein added to universal buffer produced a distinct test line at concentrations higher than 1000 pg/mL and faint test lines at 250-500 pg/mL. LFA produced a positive test line for all BIA-ALCL seromas undiluted and for 8 of 10 malignant seromas at 1:10 dilution, whereas 3 of 10 benign seromas were positive undiluted but all were negative at 1:10 dilution. Undiluted CD30 LFA had a sensitivity of 100.00%, specificity of 70.00%, positive predictive value of 76.92%, and negative predictive value of 100.00% for BIA-ALCL. When specimens were diluted 1:10, sensitivity was reduced to 80.00% but specificity and positive predictive values increased to 100.00%, while negative predictive value was reduced to 88.33%. When measured by ELISA, CD30 was below 1200 pg/mL in each of six benign seromas, whereas seven BIA-ALCL seromas contained CD30 levels > 2300 pg/mL, in all but one case calculated from dilutions of 1:10 or 1:50. CONCLUSIONS: BIA-ALCL seromas can be distinguished from benign seromas by CD30 ELISA and LFA, but LFA requires less time (<20 min) and can be performed without special equipment by non-specialized personnel, suggesting future point-of-care testing for BIA-ALCL may be feasible.

Biofilm-derived oxylipin 10-HOME-mediated immune response in women with breast implants.

This study investigates a mechanistic link of bacterial biofilm-mediated host-pathogen interaction leading to immunological complications associated with breast implant illness (BII). Over 10 million women worldwide have breast implants. In recent years, women have described a constellation of immunological symptoms believed to be related to their breast implants. We report that periprosthetic breast tissue of participants with symptoms associated with BII had increased abundance of biofilm and biofilm-derived oxylipin 10-HOME compared with participants with implants who are without symptoms (non-BII) and participants without implants. S. epidermidis biofilm was observed to be higher in the BII group compared with the non-BII group and the normal tissue group. Oxylipin 10-HOME was found to be immunogenically capable of polarizing naive CD4+ T cells with a resulting Th1 subtype in vitro and in vivo. Consistently, an abundance of CD4+Th1 subtype was observed in the periprosthetic breast tissue and blood of people in the BII group. Mice injected with 10-HOME also had increased Th1 subtype in their blood, akin to patients with BII, and demonstrated fatigue-like symptoms. The identification of an oxylipin-mediated mechanism of immune activation induced by local bacterial biofilm provides insight into the possible pathogenesis of the implant-associated immune symptoms of BII.

Prophylactic Absorbable Antibiotic Beads for High-risk, Implant-based Prepectoral Reconstruction.

Infections are problematic in postmastectomy implant-based reconstruction with infection rates as high as 30%. Strategies to reduce the risk of infection have demonstrated various efficacies. A prolonged course of systemic, oral antibiotics has not shown evidence-based benefit. Although absorbable antibiotic beads have been described for orthopedic procedures and pressure wounds, their use has not been well studied during breast reconstruction, particularly for prepectoral implant placement. The purpose of this study was to evaluate the selective use of prophylactic absorbable calcium sulfate antibiotic beads during high-risk implant-based, prepectoral breast reconstruction after mastectomy. Patients who underwent implant-based, prepectoral breast reconstruction between 2019 and 2022 were reviewed. Groups were divided into those who received antibiotic beads and those who did not. Outcome variables included postoperative infection at 90 days. A total of 148 patients (256 implants) were included: 15 patients (31 implants) who received biodegradable antibiotic beads and 133 patients (225 implants) in the control group. Patients who received antibiotic beads were more likely to have a history of infection (66.7%) compared with the control group (0%) (P < 0.01). Surgical site infection occurred in 3.2% of implants in the antibiotic bead group compared with 7.6%, but this did not reach statistical significance. The incidence of infection in high-risk patients who have absorbable antibiotic beads placed during the time of reconstruction seems to be normalized to the control group in this pilot study. We present a novel use of prophylactic absorbable antibiotic beads in prepectoral breast implant reconstruction.

Human fetal dermal fibroblast-myeloid cell diversity is characterized by dominance of pro-healing Annexin1-FPR1 signaling.

Fetal skin achieves scarless wound repair. Dermal fibroblasts play a central role in extracellular matrix deposition and scarring outcomes. Both fetal and gingival wound repair share minimal scarring outcomes. We tested the hypothesis that compared to adult skin fibroblasts, human fetal skin fibroblast diversity is unique and partly overlaps with gingival skin fibroblasts. Human fetal skin (FS, n = 3), gingiva (HGG, n = 13), and mature skin (MS, n = 13) were compared at single-cell resolution. Dermal fibroblasts, the most abundant cluster, were examined to establish a connectome with other skin cells. Annexin1-FPR1 signaling pathway was dominant in both FS as well as HGG fibroblasts and related myeloid cells while scanty in MS fibroblasts. Myeloid-specific FPR1-ORF delivered in murine wound edge using tissue nanotransfection (TNT) technology significantly enhanced the quality of healing. Pseudotime analyses identified the co-existence of an HGG fibroblast subset with FPR1high myeloid cells of fetal origin indicating common underlying biological processes.

Diagnosis of breast implant associated anaplastic large cell lymphoma by analysis of cytokines in peri-implant seromas.

More than 1300 women with breast implants have developed an anaplastic large cell lymphoma (ALCL) in fluid (seroma) around their implant. More often, seromas are due to benign causes, for example, capsule contracture, leakage, or trauma. Our report in American Journal of Hematology identified several cytokines (IL-9, IL-10, IL-13) as significantly elevated only in seromas due to ALCL. We further showed that the most robust biomarker, IL-10, could be detected by a lateral flow assay (similar to COVID detection) within minutes allowing physicians to quickly plan management, eliminate or reduce costly testing and patient time away from family. Early detection of ALCL in seromas before infiltration may avoid need for cytotoxic or immunotherapy and is possibly life-saving.

Inducible miR-1224 silences cerebrovascular Serpine1 and restores blood flow to the stroke-affected site of the brain.

The α-tocotrienol (TCT) form of natural vitamin E is more potent than the better known α-tocopherol against stroke. Angiographic studies of canine stroke have revealed beneficial cerebrovascular effects of TCT. This work seeks to understand the molecular basis of such effect. In mice, TCT supplementation improved perfusion at the stroke-affected site by inducing miR-1224. miRNA profiling of a laser-capture-microdissected stroke-affected brain site identified miR-1224 as the only vascular miR induced. Lentiviral knockdown of miR-1224 significantly blunted the otherwise beneficial effects of TCT on stroke outcomes. Studies on primary brain microvascular endothelial cells revealed direct angiogenic properties of miR-1224. In mice not treated with TCT, advance stereotaxic delivery of an miR-1224 mimic to the stroke site markedly improved stroke outcomes. Mechanistic studies identified Serpine1 as a target of miR-1224. Downregulation of Serpine1 augmented the angiogenic response of the miR-1224 mimic in the brain endothelial cells. The inhibition of Serpine1, by dietary TCT and pharmacologically, increased cerebrovascular blood flow at the stroke-affected site and protected against stroke. This work assigns Serpine1, otherwise known to be of critical significance in stroke, a cerebrovascular function that worsens stroke outcomes. miR-1224-dependent inhibition of Serpine1 can be achieved by dietary TCT as well as by the small-molecule inhibitor TM5441.

Pseudomonas Aeruginosa Theft Biofilm Require Host Lipids of Cutaneous Wound.

OBJECTIVE: This work addressing complexities in wound infection, seeks to test the reliance of bacterial pathogen Pseudomonas aeruginosa (PA) on host skin lipids to form biofilm with pathological consequences. BACKGROUND: PA biofilm causes wound chronicity. Both CDC as well as NIH recognizes biofilm infection as a threat leading to wound chronicity. Chronic wounds on lower extremities often lead to surgical limb amputation. METHODS: An established preclinical porcine chronic wound biofilm model, infected with PA or Pseudomonas aeruginosa ceramidase mutant (PA ∆Cer ), was used. RESULTS: We observed that bacteria drew resource from host lipids to induce PA ceramidase expression by three orders of magnitude. PA utilized product of host ceramide catabolism to augment transcription of PA ceramidase. Biofilm formation was more robust in PA compared to PA ∆Cer . Downstream products of such metabolism such as sphingosine and sphingosine-1-phosphate were both directly implicated in the induction of ceramidase and inhibition of peroxisome proliferator-activated receptor (PPAR)δ, respectively. PA biofilm, in a ceram-idastin-sensitive manner, also silenced PPARδ via induction of miR-106b. Low PPARδ limited ABCA12 expression resulting in disruption of skin lipid homeostasis. Barrier function of the wound-site was thus compromised. CONCLUSIONS: This work demonstrates that microbial pathogens must co-opt host skin lipids to unleash biofilm pathogenicity. Anti-biofilm strategies must not necessarily always target the microbe and targeting host lipids at risk of infection could be productive. This work may be viewed as a first step, laying fundamental mechanistic groundwork, toward a paradigm change in biofilm management.

Adipose Tissue in Peripheral Obesity as an Assessment Factor for Pressure Ulcers.

Scope and Significance: Pressure ulcers are very difficult to treat and pose an economic burden, just below cancer and cardiovascular illness, at 4.82 billion U.S. dollars. It is important to understand the pathophysiology of the condition, risk stratification, and ways of preventing it. Prevention forms the most important aspect of their management. The authors systematically evaluated the existing risk prediction scales and explored the evidence from literature regarding the role of additional factors including body mass index, obesity, subcutaneous tissue thickness, and skin integrity in pressure ulcers. With this review it is hoped that the future management of pressure ulcers will concentrate on the preventable and alterable factors in its pathophysiology. Translational Relevance: The review focuses on how adipose tissue thickness can predict the occurrence of pressure ulcer. If adequately proved that a definite thickness of peripheral adipose tissue is efficient in prevention of pressure ulcers, then methods of maintaining the thickness of this tissue will be the next effective strategy in the management of this chronic issue. Clinical Relevance: The review addresses the management of pressure ulcers to wound care providers and emphasize on confounding parameters of obesity, subcutaneous tissue thickness, and skin integrity during the treatment regimen of pressure ulcers. Objectives: The main objective of this review is to draw a consensus concerning the role of adipose tissue in pressure ulcers, based on the published research. A review of the various preexisting predictive scales for pressure ulcers is a secondary objective to highlight the shortcomings in ulcer management. This review finally aims in the future at paving a way to refine our prognosticating scales for pressure sores based on these results. Accurate preventative injury risk scales are needed so that preventative resources can be directed to the patients for whom they are the most appropriate.

Comparison of Breast Reconstruction Outcomes Using Oxychlorosene versus Triple Antibiotic Solution for Pocket Irrigation.

Background: Breast pocket irrigation with antiseptic solutions is performed to reduce contamination with breast implants. The optimal antiseptic irrigation solution and the efficacy of individual practices are unclear. Oxychlorosene sodium is frequently used at our institution. Oxychlorosene is bactericidal with a mechanism of action of oxidation and hypochlorination. The purpose of our study was to compare the outcomes of oxychlorosene sodium irrigation with triple antibiotic solution (TAS) in implant-based breast reconstruction. Methods: All patients who underwent implant-based reconstruction after mastectomy were reviewed. The primary predictive variable was type of solution used for pocket irrigation (TAS or oxychlorosene). Outcome variables included surgical site infection, device removal, and wound complications. Results: Between 2013 and 2018, 331 implant-based breast reconstructions were performed. Of these, 62% (n = 206) received oxychlorosene for surgical pocket irrigation (group I), and 38% (n = 125) received TAS (group II). Group I had an 11.7% (n = 24) 90-day surgical site infection rate, with 4.9% (n = 10) requiring oral antibiotics, 2.4% (n = 5) requiring intravenous antibiotics without device removal, and 4.4% (n = 9) requiring prosthetic removal. Group II had an 11.2% (n = 14) 90-day infection rate, with 5.6% (n = 7) requiring oral antibiotics, 2.4% (n = 3) requiring intravenous antibiotics without device removal, and 3.2% (n = 4) requiring removal (P = 0.90). When comparing the cost of oxychlorosene irrigation with TAS irrigation, oxychlorosene was less expensive. Conclusions: Oxychlorosene and TAS have similar surgical site infection rates in prosthetic breast reconstruction. Ease of preparation and cost make oxychlorosene a more favorable option for antibiotic irrigation in reconstructive breast surgery with prosthetic devices.

Breast Implant-Associated Immunological Disorders.

Background: Breast implants are commonly placed postbreast cancer reconstruction, cosmetic augmentation, and gender-affirming surgery. Breast implant illness (BII) is a systemic complication associated with breast implants. Patients with BII may experience autoimmune symptoms including fatigue, difficulty concentrating, hair loss, weight change, and depression. BII is poorly understood, and the etiology is unknown. The purpose of this literature review is to characterize BII autoimmune disorders and determine possible causes for its etiology. Methods: The PubMed, Google Scholar, Embase, Web of Science, and OVID databases were interrogated from 2010 to 2020 using a query strategy including search term combinations of "implants," "breast implant illness," "autoimmune," and "systemic illness." Results: BII includes a spectrum of autoimmune symptoms such as fatigue, myalgias/arthralgias, dry eyes/mouth, and rash. A review of epidemiological studies in the past ten years exhibited evidence affirming an association between breast implants and autoimmune diseases. The most commonly recognized were Sjogren's syndrome, rheumatoid arthritis, systemic sclerosis, chronic fatigue syndrome, and Raynaud's syndrome. Explantation resulted in alleviation of symptoms in over 50% of patients, strengthening the hypothesis linking breast implants to BII. Studies have shown that silicone is a biologically inert material and unlikely to be the cause of these symptoms. This is supported by the fact that increased risk of autoimmune disease was also reported in patients with other implantable biomaterials such as orthopedic implants. Recent studies shed light on a possible role of bacterial biofilm and subsequent host-pathogen interactions as a confounding factor to this problem. Conclusion: BII could be dependent on biofilm infection and the microenvironment around the implants. The true pathophysiology behind these complaints must be further investigated so that alternative treatment regimens other than explantation can be developed. Translational significance of these studies is not limited to breast implants but extends to other implants as well.

Laser Capture Microdissection in the Spatial Analysis of Epigenetic Modifications in Skin: A Comprehensive Review.

Each cell in the body contains an intricate regulation for the expression of its relevant DNA. While every cell in a multicellular organism contains identical DNA, each tissue-specific cell expresses a different set of active genes. This organizational property exists in a paradigm that is largely controlled by forces external to the DNA sequence via epigenetic regulation. DNA methylation and chromatin modifications represent some of the classical epigenetic modifications that control gene expression. Complex tissues like skin consist of heterogeneous cell types that are spatially distributed and mixed. Furthermore, each individual skin cell has a unique response to physiological and pathological cues. As such, it is difficult to classify skin tissue as homogenous across all cell types and across different environmental exposures. Therefore, it would be prudent to isolate targeted tissue elements prior to any molecular analysis to avoid a possibility of confounding the sample with unwanted cell types. Laser capture microdissection (LCM) is a powerful technique used to isolate a targeted cell group with extreme microscopic precision. LCM presents itself as a solution to tackling the problem of tissue heterogeneity in molecular analysis. This review will cover an overview of LCM technology, the principals surrounding its application, and benefits of its application to the newly defined field of epigenomics, in particular of cutaneous pathology. This presents a comprehensive review about LCM and its use in the spatial analysis of skin epigenetics. Within the realm of skin pathology, this ability to isolate tissues under specific environmental stresses, such as oxidative stress, allows a far more focused investigation.

Do Patient Expectations of Discharge Affect Length of Stay after Deep Inferior Epigastric Perforator Flap for Breast Reconstruction?

BACKGROUND: Deep inferior epigastric artery perforator (DIEP) flap is a common method of breast reconstruction. Enhanced recovery after surgery (ERAS) postoperative protocols have been used to optimize patient outcomes and facilitate shorter hospital stays. The effect of patient expectations on length of stay (LOS) after DIEP has not been evaluated. The purpose of this study was to investigate whether patient expectations affect LOS. METHODS: A retrospective chart review was performed for patients undergoing DIEP flaps for breast reconstruction from 2017 to 2020. All patients were managed with the same ERAS protocol. Patients were divided in Group I (early expectations) and Group II (standard expectations). Group I patients had expectations set for discharge postoperative day (POD) 2 for unilateral DIEP and POD 3 for bilateral DIEP. Group II patients were given expectations for POD 3 to 4 for unilateral DIEP and POD 4 to 5 for bilateral. The primary outcome variable was LOS. RESULTS: The study included 215 DIEP flaps (45 unilateral and 85 bilateral). The average age was 49.8 years old, and the average body mass index (BMI) was 31.4. Group I (early expectations) included 56 patients (24 unilateral DIEPs, 32 bilateral). Group II (standard expectations) had 74 patients (21 unilateral, 53 bilateral). LOS for unilateral DIEP was 2.9 days for Group I compared with 3.7 days for Group II (p = 0.004). Group I bilateral DIEP patients had LOS of 3.5 days compared with 3.9 days for Group II (p = 0.02). Immediate timing of DIEP (Group I 42.9 vs. Group II 52.7%) and BMI (Group I 32.1 vs. Group II 30.8) were similar (p = 0.25). CONCLUSION: Our study found significantly shorter hospital stay after DIEP flap for patients who expected an earlier discharge date despite similar patient characteristics and uniform ERAS protocol. Patient expectations should be considered during patient counseling and as a confounding variable when analyzing ERAS protocols.

Immediate Lymphatic Reconstruction to Prevent Breast Cancer-Related Lymphedema: A Systematic Review.

Significance: Lymphedema is chronic limb swelling from lymphatic dysfunction. The condition affects up to 250 million people worldwide. In breast cancer patients, lymphedema occurs in 30% who undergo axillary lymph node dissection (ALND). Recent Advances: Immediate lymphatic reconstruction (ILR), also termed Lymphatic Microsurgical Preventing Healing Approach (LyMPHA), is a method to decrease the risk of lymphedema by performing prophylactic lymphovenous anastomoses at the time of ALND. The objective of this study is to assess the risk reduction of ILR in preventing lymphedema. Critical Issues: Lymphedema has significant effects on the quality of life and morbidity of patients. Several techniques have been described to manage lymphedema after development, but prophylactic treatment of lymphedema with ILR may decrease risk of development to 6.6%. Future Directions: Long-term studies that demonstrate efficacy of ILR may allow for prophylactic management of lymphedema in the patient undergoing lymph node dissection.

A Murine Tail Lymphedema Model.

Lymphedema is extremity swelling caused by lymphatic dysfunction. The affected limb enlarges because of accumulation of fluid, adipose, and fibrosis. There is no cure for this disease. A mouse tail model that uses a focal full thickness skin excision near the base of the tail, resulting in tail swelling, has been used to study lymphedema. However, this model may result in vascular comprise and consequent tail necrosis and early tail swelling resolution, limiting its clinical translatability. The chronic murine tail lymphedema model induces sustained lymphedema over 15 weeks and a reliable perfusion to the tail. Enhancements of the traditional murine tail lymphedema model include 1) precise full thickness excision and lymphatic clipping using a surgical microscope, 2) confirmation of post-operative arterial and venous perfusion using high resolution laser speckle, and 3) functional assessment using indocyanine green near infrared laser lymphangiography. We also use tissue nanotransfection technology (TNT) for novel non-viral, transcutaneous, focal delivery of genetic cargo to the mouse tail vasculature.

High resolution ultrasound imaging for repeated measure of wound tissue morphometry, biomechanics and hemodynamics under fetal, adult and diabetic conditions.

Non-invasive, repeated interrogation of the same wound is necessary to understand the tissue repair continuum. In this work, we sought to test the significance of non-invasive high-frequency high-resolution ultrasound technology for such interrogation. High-frequency high-resolution ultrasound imaging was employed to investigate wound healing under fetal and adult conditions. Quantitative tissue cellularity and elastic strain was obtained for visualization of unresolved inflammation using Vevo strain software. Hemodynamic properties of the blood flow in the artery supplying the wound-site were studied using color Doppler flow imaging. Non-invasive monitoring of fetal and adult wound healing provided unprecedented biomechanical and functional insight. Fetal wounds showed highly accelerated closure with transient perturbation of wound tissue cellularity. Fetal hemodynamics was unique in that sharp fall in arterial pulse pressure (APP) which was rapidly restored within 48h post-wounding. In adults, APP transiently increased post-wounding before returning to the pre-wounding levels by d10 post-wounding. The pattern of change in the elasticity of wound-edge tissue of diabetics was strikingly different. Severe strain acquired during the early inflammatory phase persisted with a slower recovery of elasticity compared to that of the non-diabetic group. Wound bed of adult diabetic mice (db/db) showed persistent hypercellularity compared to littermate controls (db/+) indicative of prolonged inflammation. Normal skin strain of db/+ and db/db were asynchronous. In db/db, severe strain acquired during the early inflammatory phase persisted with a slower recovery of elasticity compared to that of non-diabetics. This study showcases a versatile clinically relevant imaging platform suitable for real-time analyses of functional wound healing.