Faculty Bibliography

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.

Unveiling the molecular mechanisms underlying tissue regeneration provides new opportunities to develop treatments for diabetic ulcers and other chronic skin lesions. Here, we show that Ccl2 secretion by epidermal keratinocytes is directly orchestrated by Nrf2, a prominent transcriptional regulator of tissue regeneration that is activated early after cutaneous injury. Through a unique feedback mechanism, we find that Ccl2 from epidermal keratinocytes not only drives chemotaxis of macrophages into the wound but also triggers macrophage expression of EGF, which in turn activates basal epidermal keratinocyte proliferation. Notably, we find dysfunctional activation of Nrf2 in epidermal keratinocytes of diabetic mice after wounding, which partly explains regenerative impairments associated with diabetes. These findings provide mechanistic insight into the critical relationship between keratinocyte and macrophage signaling during tissue repair, providing the basis for continued investigation of the therapeutic value of Nrf2.

Chronic venous insufficiency (CVI) stems from venous hypertension, extravasation of blood, and iron-rich skin deposits. The latter is central to ulcer development through generating reactive oxygen species (ROS) that drive persistent local inflammation and the development of lipodermatosclerosis. The ability to study CVI cutaneous inflammation is fundamental to advancing therapies. To address this end, a novel protocol was adapted to investigate cutaneous wound healing in iron-induced inflammation.

Despite promising short- and long-term results to date in vascularized composite allotransplantation (VCA), acute rejection remains the most common major complication in recipients. Currently, diagnosis of acute rejection relies on clinical inspection correlated with histopathological analysis. However, disagreement exists regarding the value of full-thickness skin and mucosal biopsies and histopathology remains semiquantitative, subject to sampling bias, and prone to intra- and inter-observer variabilities. Additionally, biopsies may cause infection, scarring, and/or potentially incite rejection through immune activation after injury. Noninvasive methods to diagnose rejection represent a critical unmet need for the emerging field of VCA. Here, we propose a novel technique utilizing skin stripping of the epidermis and subsequent molecular analysis to detect known markers of acute rejection. Using a small animal VCA model, we sought to validate our epidermal sampling technique as a noninvasive diagnostic test for acute rejection.

The molecular and cellular level reaches of the metabolic dysregulations that characterize diabetes are yet to be fully discovered. As mechanisms underlying management of reactive oxygen species (ROS) gain interest as crucial factors in cell integrity, questions arise about the role of redox cues in regulation and maintenance of bone marrow-derived multipotent stromal cells (BMSCs) that contribute to wound healing, particularly in diabetes. Through comparison of BMSCs from wild type and diabetic mice, with a known redox and metabolic disorder, we found that the cytoprotective Nrf2/Keap1 pathway is dysregulated and functionally insufficient in diabetic BMSCs. Nrf2 is basally active, but in chronic ROS we found irregular inhibition of Nrf2 by Keap1, altered metabolism and limited BMSC multipotency. Forced upregulation of Nrf2-directed transcription, through knockdown of Keap1, restores redox homeostasis. Normalized Nrf2/Keap1 signaling restores multipotent cell properties in diabetic BMSCs through Sox2 expression. These restored BMSCs can resume their role in regenerative tissue repair and promote healing of diabetic wounds. Knowledge of diabetes and hyperglycemia-induced deficits in BMSC regulation, and strategies to reverse them offers translational promise. Our study establishes Nrf2/Keap1 as a cytoprotective pathway, as well as a metabolic rheostat that affects cell maintenance and differentiation switches in BMSCs.