Faculty Bibliography

OBJECTIVE:Rejection is common and pernicious following Vascularized Composite Allotransplantation (VCA). Current monitoring and diagnostic modalities include the clinical exam which is subjective and biopsy with dermatohistopathologic Banff grading, which is subjective and invasive. We reviewed literature exploring non- and minimally invasive modalities for diagnosing and monitoring rejection (NIMMs) in VCA. METHODS:PubMed, Cochrane, and Embase databases were queried, 3125 unique articles were reviewed, yielding 26 included studies exploring 17 distinct NIMMs. Broadly, NIMMs involved Imaging, Liquid Biomarkers, Epidermal Sampling, Clinical Grading Scales, and Introduction of Additional Donor Tissue. RESULTS:Serum biomarkers including MMP3 and donor-derived microparticles rose with rejection onset. Epidermal sampling non-invasively enabled measurement of cytokine & gene expression profiles implicated in rejection. Both hold promise for monitoring. Clinical grading scales were useful diagnostically as was reflection confocal microscopy. Introducing additional donor tissue showed promise for preemptively identifying rejection but requires additional allograft tissue burden for the recipient. CONCLUSION/CONCLUSIONS:NIMMs have the potential to dramatically improve monitoring and diagnosis in VCA. Many modalities show promise however, additional research is needed and a multimodal algorithmic approach should be explored.

Osteoarthritis (OA) pathogenesis is associated with reduced chondrocyte homeostasis and increased levels of cartilage cellular senescence. Chondrosenescence is the development of cartilage senescence that increases with aging joints and disrupts chondrocyte homeostasis and is associated with OA. Adenosine A2A receptor (A2AR) activation in cartilage via intra-articular injection of liposomal A2AR agonist, liposomal-CGS21680, leads to cartilage regeneration in vivo and chondrocyte homeostasis. A2AR knockout mice develop early OA isolated chondrocytes demonstrate upregulated expression of cellular senescence and aging-associated genes. Based on these observations, we hypothesized that A2AR activation would ameliorate cartilage senescence. We found that A2AR stimulation of chondrocytes reduced beta-galactosidase staining and regulated levels and cell localization of common senescence mediators p21 and p16 in vitro in the human TC28a2 chondrocyte cell line. In vivo analysis similarly showed A2AR activation reduced nuclear p21 and p16 in obesity-induced OA mice injected with liposomal-CGS21680 and increased nuclear p21 and p16 in A2AR knockout mouse chondrocytes compared to wild-type mice. A2AR agonism also increased activity of the chondrocyte Sirt1/AMPK energy-sensing pathway by enhancing nuclear Sirt1 localization and upregulating T172-phosphorylated (active) AMPK protein levels. Lastly, A2AR activation in TC28a2 and primary human chondrocytes reduced wild-type p53 and concomitantly increased p53 alternative splicing leading to increase in an anti-senescent p53 variant, Δ133p53α. The results reported here indicate that A2AR signaling promotes chondrocyte homeostasis in vitro and reduces OA cartilage development in vivo by reducing chondrocyte senescence.

Background: Early surgical exposure and research fellowships can influence medical students' specialty choice, increase academic productivity, and impact residency match. However, to our knowledge, there is no published guidance on the programmatic evaluation and quality enhancement necessary for the sustainability of formal plastic surgery summer research programs for first year medical students. We present seven years (2013-2020) of institutional experience in an effort to inform program development at other institutions. Methods: From 2013 to 2016, a sole basic science research arm existed. In 2017, a clinical research arm was introduced, with several supplemental activities, including surgical skills curriculum. A formalized selection process was instituted in 2014. Participant feedback was analyzed annually. Long-term outcomes included continued research commitment, productivity, and residency match. Results: The applicant pool reached 96 applicants in 2019, with 85% from outside institutions. Acceptance rate reached 7% in 2020. With adherence to a scoring rubric for applicant evaluation, good to excellent interrater reliability was achieved (intraclass correlation coefficient = 0.75). Long-term outcomes showed that on average per year, 28% of participants continued involvement in departmental research and 29% returned for dedicated research. Upon finishing medical school, participants had a mean of 7 ± 4 peer-reviewed publications. In total, 62% of participants matched into a surgical residency program, with 54% in integrated plastic surgery. Conclusions: A research program designed for first year medical students interested in plastic surgery can achieve academic goals. Students are provided with mentorship, networking opportunities, and tools for self-guided learning and career development.

SIGNIFICANCE/CONCLUSIONS:Skin wounds and disorders compromise the protective functions of skin and patient quality of life. Though accessible on the surface, they are challenging to address due to paucity of effective therapies. Exogenous extracellular vesicles (EVs), cell-free derivatives of adult multipotent stromal cells (MSCs), are developing as a treatment modality. Knowledge of origin MSCs, EV processing and mode of action is necessary for directed use of EVs in preclinical studies and methodical translation. Recent advances: Nano to microscale EVs, though from non-skin cells, induce functional responses in cutaneous wound cellular milieu. EVs allow a shift from cell-based to cell-free/derived modalities by carrying the MSC beneficial factors but eliminating risks associated with MSC transplantation. EVs have demonstrated striking efficacy in resolution of preclinical wound models, specifically within the complexity of skin structure and wound pathology. CRITICAL ISSUES/RESULTS:To facilitate comparison across studies, tissue sources and processing of MSCs, culture conditions, isolation and preparations of EVs, and vesicle sizes require standardization as these criteria influence EV types and contents, and potentially determine the induced biological responses. Procedural parameters for all steps preceding the actual therapeutic administration may be the key to generating EVs that demonstrate consistent efficacy through known mechanisms. We provide a comprehensive review of such parameters and the subsequent tissue, cellular and molecular impact of the derived EVs in different skin wounds/disorders. FUTURE DIRECTIONS/CONCLUSIONS:We will gain more complete knowledge of EV-induced effects in skin, and specificity for different wounds/conditions. The safety and efficacy of current preclinical xenogenic applications will favor translation into allogenic clinical applications of EVs as a biologic.

Objective: Compare short term surgical outcomes and trends in cleft lip repair with or without gingivoperiosteoplasty (GPP). Design: Retrospective review of the ACS NSQIP-Pediatric database from 2014 to 2019. Patients: Patients between 2 and 18 months of age undergoing any initial cleft lip repair, with or without GPP, were selected via relevant CPT^® codes. Main Outcome Measures: Patient demographics, comorbidities, 30-day readmissions and post-operative complications are assessed. Results: From 2014 to 2019, a total of 6269 patients were identified, of which 6.67% underwent GPP (n = 418). Patients undergoing GPP were significantly older with an average age of 9 months compared to 5 months in the non-GPP group (P <.001). Co-morbidities were similar amongst both cohorts, although patients undergoing GPP were more likely to have a higher ASA class (P =.006), cardiac risk factors (P =.012) and syndromic diagnosis (P <.001). There were no differences in 30-day short term surgical outcomes. GPP was associated with increased operative time by ~25 minutes when compared to cleft lip repair alone (P <.001). Conclusion: GPP was not associated with increased 30-day postoperative complications, readmission, reoperation, or total length of hospital stay, and was associated with an increased operative time of 25 minutes. Children undergoing GPP were significantly older in age and were more likely to have a higher ASA class/cardiac risk factors.

The current standard of care for an alveolar cleft defect is an autogenous bone graft, typically from the iliac crest. Given the limitations of alveolar bone graft surgery, such as limited supply, donor site morbidity, graft failure, and need for secondary surgery, there has been growing interest in regenerative medicine strategies to supplement and replace traditional alveolar bone grafts. Though there have been preliminary clinical studies investigating bone tissue engineering methods in human subjects, lack of consistent results as well as limitations in study design make it difficult to determine the efficacy of these interventions. As the field of bone tissue engineering is rapidly advancing, reconstructive surgeons should be aware of the preclinical studies informing these regenerative strategies. We review preclinical studies investigating bone tissue engineering strategies in large animal maxillary or mandibular defects and provide an overview of scaffolds, stem cells, and osteogenic agents applicable to tissue engineering of the alveolar cleft. An electronic search conducted in the PubMed database up to December 2021 resulted in 35 studies for inclusion in our review. Most studies showed increased bone growth with a tissue engineering construct compared to negative control. However, heterogeneity in the length of follow up, method of bone growth analysis, and inconsistent use of positive control groups make comparisons across studies difficult. Future studies should incorporate a pediatric study model specific to alveolar cleft with long-term follow up to fully characterize volumetric defect filling, cellular ingrowth, bone strength, tooth movement, and implant support.

[Figure: see text].

Purpose: Skin biopsies are currently the gold standard for evaluating the inflammatory status of face allografts. However, "tape stripping" is emerging as a noninvasive technique to monitor autoimmune/auto inflammatory skin diseases. This technique, highly suitable for serial sampling and combined with high sensitive PCR assays, could revolutionize molecular monitoring the face allograft status. Herein, we tested the hypothesis that isolation of total RNA and gene expression profiling are feasible using skin samples collected using tape strips.
Method(s): Tape strips (CuDerm Corporation, Texas) were used to obtain RNA from two face transplant recipients. Each tape strip is comprised of 10 discs. Allograft skin area was marked, cleaned with alcohol, and 8 samples (8 tape strips) were obtained. Each disc (10 discs from one sample) was immersed in 1ml RLT buffer with 100ul beta-mercaptoethanol. RNA was isolated from the tape strip skin samples using the RNeasy mini kit. We quantified total RNA using A260/A280 ratio, reverse transcribed RNA into cDNA and pre-amplified cDNA using oligonucleotide primer pairs for a custom panel of mRNAs. We measured absolute levels of mRNA for Keratin 15, MIP1alpha, and MIP1beta, as well as 18S rRNA by preamplification enhanced real time quantitative PCR assays (RT-qPCR assays) using Quant Studio 6. We designed gene specific Taqman primers and probes to amplify and detect gene of interest and a customized BAK amplicon to develop a standard curve for absolute quantification of transcript copies per microgram of total RNA.
Result(s): Median quantity of total RNA from the tape strips was 64.48ng. Individual and the median number of total RNA, individual and the median number of the reference gene 18S rRNA, and individual and median number of mRNA copies of Keratin 15, MIP1alpha, and MIP1beta are shown in Figure 1.
Conclusion(s): We have demonstrated the feasibility of isolating total RNA from tape strips and quantifying transcript abundance. Further refinement of this technology is ongoing in our laboratory. Tape strip based molecular monitoring of face transplant recipients may offer a noninvasive substitute for allograft biopsies

BACKGROUND:Cutaneous wounds in patients with diabetes exhibit impaired healing due to physiological impediments and conventional care options are severely limited. Multipotent stromal cells (MSCs) have been touted as a powerful new therapy for diabetic tissue repair owing to their trophic activity and low immunogenicity. However, variations in sources and access are limiting factors for broader adaptation and study of MSC-based therapies. Amniotic fluid presents a relatively unexplored source of MSCs and one with wide availability. Here, we investigate the potential of amniotic fluid-derived multipotent stromal cells (AFMSCs) to restore molecular integrity to diabetic wounds, amend pathology and promote wound healing. METHOD/METHODS:diabetic mouse skin, and splinted them open to allow for humanized wound modeling. Immediately after wounding, we applied AFMSCs topically to the sites of injuries on diabetic mice, while media application only, defined as vehicle, served as controls. Post-treatment, we compared healing time and molecular and cellular events of AFMSC-treated, vehicle-treated, untreated diabetic, and non-diabetic wounds. A priori statistical analyses measures determined significance of the data. RESULT/RESULTS:Average time to wound closure was approximately 19 days in AFMSC-treated diabetic wounds. This was significantly lower than the vehicle-treated diabetic wounds, which required on average 27.5 days to heal (p < 0.01), and most similar to time of closure in wild type untreated wounds (an average of around 18 days). In addition, AFMSC treatment induced changes in the profiles of macrophage polarizing cytokines, resulting in a change in macrophage composition in the diabetic wound bed. We found no evidence of AFMSC engraftment or biotherapy induced immune response. CONCLUSION/CONCLUSIONS:Treatment of diabetic wounds using amniotic fluid-derived MSCs encourages cutaneous tissue repair through affecting inflammatory cell behavior in the wound site. Since vehicle-treated diabetic wounds did not demonstrate accelerated healing, we determined that AFMSCs were therapeutic through their paracrine activities. Future studies should be aimed towards validating our observations through further examination of the paracrine potential of AFMSCs. In addition, investigations concerning safety and efficacy of this therapy in clinical trials should be pursued.