Protein profiling of mechanically processed lipoaspirates: discovering wound healing and anti-fibrotic biomarkers in nanofat

BACKGROUND: Nanofat is an injectable oily emulsion, rich in adipose derived stem cells (ADSCs) and growth factors. It is prepared from lipoaspirates through mechanical emulsification and filtration. Despite being successfully used in several procedures in regenerative medicine such as scar attenuation, skin rejuvenation and treatment of chronic wounds, little is known about exactly how nanofat induces regeneration in treated skin at the molecular level. METHODS: Microfat and nanofat samples were isolated from 18 healthy patients. Proteomic profiling was performed through untargeted mass spectrometry proteomics and multiplex antibody arrays. Pathway enrichment analysis of differentially expressed proteins between microfat and nanofat was performed using Gene Ontology, Reactome and KEGG as reference databases. RESULTS: Untargeted proteomics showed that upregulated genes in nanofat are involved in innate immunity responses, coagulation and wound healing, while downregulated genes were linked to cellular migration and extracellular matrix (ECM) production. Secretome array screening of microfat and nanofat samples showed no significantly different expression, which strongly suggests that the mechanical emulsification step does not affect the concentration of tissue regeneration biomarkers. The identified proteins are involved in wound healing, cellular migration, extracellular matrix remodelling, angiogenesis, stress response and immune response. CONCLUSIONS: Mechanical processing of lipoaspirates into nanofat significantly influences the proteome profile by enhancing inflammation, antimicrobial and wound healing pathways. Nanofat is extremely rich in tissue repair and tissue remodelling factors. CLINICAL RELEVANCE STATEMENT: This study shows that the effects of Micro- and Nanofat treatment are based on upregulated inflammation, antimicrobial and wound healing pathways. Mechanical emulsification does not alter the concentration of tissue regeneration biomarkers

Nanofat applications: from clinical esthetics to regenerative research

Nanofat grafting is a relatively new technique that has gained popularity in esthetic surgery in recent years. Since its discovery, it has emerged as an effective treatment to improve scar quality and attenuate wrinkles. Nanofat is produced through the mechanical shuffling and filtration of microfat, which is harvested by liposuction. It is easily injectable, rich in adipose-derived stem cells, microvascular fragments, and rich in growth factors that, put together, contribute to its pleasing clinical results. Compared with other stem cell–based therapies, harvesting and processing of nanofat is cost-effective as it requires no additional devices or culturing time. Moreover, the liquid consistency of nanofat allows for easy application in a broad range of clinical cases. Hence, we propose that nanofat should also be considered for use in translational research. Based on current techniques in biomaterial loading with stem cells and microvascular fragments, nanofat has the potential to be a valuable alternative to lengthy tissue regeneration protocols in translational research

High heparin content surface-modified polyurethane discs promote rapid and stable angiogenesis in full thickness skin defects through VEGF immobilization

Three-dimensional scaffolds have the capacity to serve as an architectural framework to guide and promote tissue regeneration. Parameters such as the type of material, growth factors, and pore dimensions are therefore critical in the scaffold's success. In this study, heparin has been covalently bound to the surface of macroporous polyurethane (PU) discs via two different loading methods to determine if the amount of heparin content had an influence on the therapeutic affinity loading and release of (VEGF165 ) in full thickness skin defects. PU discs (5.4 mm diameter, 300 µm thickness, and interconnected pore size of 150 µm) were produced with either a low (2.5 mg/g) or high (6.6 mg/g) heparin content (LC and HC respectively), and were implanted into the modified dorsal skin chamber (MDSC) of C57BL/6 J mice with and without VEGF. Both low- and high-content discs with immobilized VEGF165 (LCV and HCV, respectively) presented accelerated neovascularization and tissue repair in comparison to heparin discs alone. However, the highest angiogenetic peak was on day 7 with subsequent stabilization for HCV, whereas other groups displayed a delayed peak on day 14. We therefore attribute the superior performance of HCV due to its ability to hold more VEGF165, based on its increased heparin surface coverage, as also demonstrated in VEGF elution dynamics. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2543-2550, 2017

Adipose tissue and the vascularization of biomaterials: Stem cells, microvascular fragments and nanofat-a review

Tissue defects in the human body after trauma and injury require precise reconstruction to regain function. Hence, there is a great demand for clinically translatable approaches with materials that are both biocompatible and biodegradable. They should also be able to adequately integrate within the tissue through sufficient vascularization. Adipose tissue is abundant and easily accessible. It is a valuable tissue source in regenerative medicine and tissue engineering, especially with regard to its angiogenic potential. Derivatives of adipose tissue, such as microfat, nanofat, microvascular fragments, stromal vascular fraction and stem cells, are commonly used in research, but also clinically to enhance the vascularization of implants and grafts at defect sites. In plastic surgery, adipose tissue is harvested via liposuction and can be manipulated in three ways (macro-, micro- and nanofat) in the operating room, depending on its ultimate use. Whereas macro- and microfat are used as a filling material for soft tissue injuries, nanofat is an injectable viscous extract that primarily induces tissue remodeling because it is rich in growth factors and stem cells. In contrast to microfat that adds volume to a defect site, nanofat has the potential to be easily combined with scaffold materials due to its liquid and homogenous consistency and is particularly attractive for blood vessel formation. The same is true for microvascular fragments that are easily isolated from adipose tissue through collagenase digestion. In preclinical animal models, it has been convincingly shown that these vascular fragments inosculate with host vessels and subsequently accelerate scaffold perfusion and host tissue integration. Adipose tissue is also an ideal source of stem cells. It yields larger quantities of cells than any other source and is easier to access for both the patient and doctor compared with other sources such as bone marrow. They are often used for tissue regeneration in combination with biomaterials. Adipose-derived stem cells can be applied unmodified or as single cell suspensions. However, certain pretreatments, such as cultivation under hypoxic conditions or three-dimensional spheroids production, may provide substantial benefit with regard to subsequent vascularization in vivo due to induced growth factor production. In this narrative review, derivatives of adipose tissue and the vascularization of biomaterials are addressed in a comprehensive approach, including several sizes of derivatives, such as whole fat flaps for soft tissue engineering, nanofat or stem cells, their secretome and exosomes. Taken together, it can be concluded that adipose tissue and its fractions down to the molecular level promote, enhance and support vascularization of biomaterials. Therefore, there is a high potential of the individual fat component to be used in regenerative medicine

Lipoconstruct surface topography grating size influences vascularization onset in the dorsal skinfold chamber model

After skin tissue injury or pathological removal, vascularization timing is paramount in graft survival. As full thickness skin grafts often fail to become perfused over larger surfaces, split-thickness grafts are preferred and can be used together with biomaterials, which themselves are non-angiogenic. One way of promoting vascular ingrowth is to “pre-vascularize” an engineered substitute by introducing endothelial cells (ECs). Since it has been previously demonstrated that surface structured biomaterials have an effect on wound healing, skin regeneration, and fibrosis reduction, we proposed that a microvascular-rich lipoconstruct with anisotropic topographical cues could be a clinically translatable vascularization approach. Murine lipofragments were formed with three polydimethylsiloxane molds (flat, 5 µm, and 50 µm parallel gratings) and implanted into the dorsal skinfold chamber of male C57BL/6 mice. Vascular ingrowth was observed through intravital microscopy over 21 days and further assessed by histology and protein identification. Our investigation revealed that topographical feature size influenced the commencement of neovascular ingrowth, with 5 µm gratings exhibiting early construct perfusion at 3 days post-operation, and 50 µm being delayed until day 5. We therefore postulate that surface structured lipoconstructs may serve as an easily obtained and produced construct suitable for providing soft tissue and ECs to tissue defects

Healthcare experiences of patients with Down syndrome who are Black, African American, of African descent, or of mixed race.

Scant research has explored the healthcare experiences of people with Down syndrome (DS) in the United States who are Black, African American, of African descent, or of mixed race. The purpose of this study was to identify and describe the barriers and facilitators that such patients and their caregivers face when accessing healthcare. We gathered data in three ways: focus groups with caregivers, a national survey completed by caregivers, and in-depth interviews with primary care providers. Many caregivers and primary care physicians felt that patients with DS who are Black, African American, of African descent, or of mixed race receive a lower quality of medical care than their white counterparts with DS. Caregivers mentioned feeling tired of being reminded by the medical community about their race and wanting acknowledgment that raising a child with DS can be hard at times. Many felt that the medical communitys conscious and unconscious racial biases do negatively impact the care of their loved ones with DS. Caregivers desired more race concordant medical providers or, when not possible, medical providers who are willing to learn more about DS and build trusted, longitudinal relationships. Primary care providers discussed the need for funded resources and support services to effectively care for their patients with DS

A survey of the global impact of COVID‐19 on the practice of pediatric anesthesia: A study from the pediatric anesthesia COVID‐19 Collaborative Group

BackgroundPediatric anesthesiology has been greatly impacted by COVID-19 in the delivery of care to patients and to the individual providers. With this study, we sought to survey pediatric centers and highlight the variations in care related to perioperative medicine during the COVID-19 pandemic, including the availability of protective equipment, the practice of pediatric anesthesia, and economic impact.AimThe aim of the survey was to determine how COVID-19 directly impacted pediatric anesthesia practices during the study period.MethodsA survey concerning four major domains (testing, safety, clinical management/policy, economics) was developed. It was pilot tested for clarity and content by members of the Pediatric Anesthesia COVID-19 Collaborative. The survey was administered by email to all Pediatric Anesthesia COVID-19 Collaborative members on September 1, 2020. Respondents had six weeks to complete the survey and were instructed to answer the questions based on their institution's practice during September 1 - October 13, 2020.ResultsSixty-three institutions (100% response rate) participated in the COVID-19 Pediatric Anesthesia Survey. Forty-one hospitals (65%) were from the United States, and 35% included other countries. N95 masks were available to anesthesia teams at 91% of institutions (n = 57) (95% CI: 80%-96%). COVID-19 testing criteria of anesthesia staff and guidelines to return to work varied by institution. Structured simulation training aimed at improving COVID-19 safety and patient care occurred at 62% of institutions (n = 39). Pediatric anesthesiologists were economically affected by a reduction in their employer benefits and restriction of travel due to employer imposed quarantine regulations.ConclusionOur data indicate that the COVID-19 pandemic has impacted the testing, safety, clinical management, and economics of pediatric anesthesia practice. Further investigation into the long-term consequences for the specialty is indicated