Reza Jarrahy

Purpose: Bone morphogenic proteins (BMPs) are pivotal in craniomaxillofacial surgery for bone reconstruction. However, their side effects, such as severe edema and local inflammation, limit their use. Nanoscale peptide amphiphiles (PAs) self-assemble into nanofibers and can act as sustained-release carriers for biological molecules, supporting tissue regeneration. This study investigates the impact of PA gels on in vitro osteogenic differentiation and bone repair and inflammation in craniomaxillofacial bone defect models in vivo. Methods: BMP-2 release from PA gels was analyzed. Human bone marrow stromal cells (BMSCs) were treated with growth medium or medium containing BMP-2 and PAs. Osteogenic differentiation was assessed using quantitative RT-PCR for osteogenesis-specific genes. Bone defects were created in rabbit calvaria and rat maxilla and treated with collagen material containing BMP-2 with or without PA gels. Control groups included collagen material only. Bone tissue and surrounding soft tissue were harvested for radiographic and histologic analyses and inflammation-related gene expression. Immunohistochemical (IHC) staining was performed for inflammatory responses. Results: BMP-2 was released from PA gels in a sustained manner, significantly increasing osteogenic activity in BMSCs compared to controls. In bone defect models, collagen with low-dose BMP-2 incorporating PA gels showed robust bone regeneration, comparable to high-dose BMP-2 without PAs. Inflammatory markers, such as IL6, TNF-α, and Cox2, were elevated in high-dose BMP-2 groups but normalized in groups treated with BMP-2 incorporating PAs, consistent with IHC findings. Conclusions: PAs with low-dose BMP-2 may be a viable alternative to high-dose BMP-2 in craniofacial surgery, offering reduced inflammation and effective bone regeneration. Lay Summary: This study evaluates the potential of a hybrid material combining peptide amphiphile (PA) nanostructures and collagen particles as an alternative for bone reconstruction in craniomaxillofacial surgery. While bone morphogenetic proteins (BMPs) are effective for bone regeneration, their use is often limited by side effects like inflammation. PA gels mimic extracellular structures, enabling sustained BMP-2 release and promoting tissue regeneration. The study demonstrated that low-dose BMP-2 combined with PA gels supports robust bone regeneration while reducing inflammation, as compared to high-dose BMP-2, which elevated inflammation-related gene expression. These findings suggest that PA gels with low-dose BMP-2 offer a promising, less inflammatory alternative for bone reconstruction in craniomaxillofacial surgery.

Background: The core circadian gene Neuronal PAS domain 2 (NPAS2) is expressed in dermal fibroblasts and has been shown to play a critical role in regulating collagen synthesis during wound healing. We have performed high throughput drug screening to identify genes responsible for downregulation of Npas2 while maintaining cell viability. From this, five FDA-approved hit compounds were shown to suppress Npas2 expression in fibroblasts. In this study, we hypothesize that the therapeutic suppression of Npas2 by hit compounds will have two effects: (1) attenuated excessive collagen deposition and (2) accelerated dermal wound healing without hypertrophic scarring.Materials and methods: To test the effects of each hit compound (named Dwn1, 2, 3, 4, and 5), primary adult human dermal fibroblasts (HDFa) were treated with either 0, 0.1, 1, or 10 μM of a single hit compound. HDFa behaviors were assessed by picrosirius red staining and quantitative RT-PCR for in vitro collagen synthesis, cell viability assay, in vitro fibroblast-to-myofibroblast differentiation test, and cell migration assays.Results: Dwn1 and Dwn2 were found to significantly affect collagen synthesis and cell migration without any cytotoxicity. Dwn3, Dwn4, and Dwn5 did not affect collagen synthesis and were thereby eliminated from further consideration for their role in mitigation of gene expression or myofibroblast differentiation. Dwn1 also attenuated myofibroblast differentiation on HDFa.Conclusion: Dwn1 and Dwn2 may serve as possible therapeutic agents for future studies related to skin wound healing.

Attempts to minimize scarring remain among the most difficult challenges facing surgeons, despite the use of optimal wound closure techniques. Previously, we reported improved healing of dermal excisional wounds in circadian clock neuronal PAS domain 2 (Npas2)-null mice. In this study, we performed high-throughput drug screening to identify a compound that downregulates Npas2 activity. The hit compound (Dwn1) suppressed circadian Npas2 expression, increased murine dermal fibroblast cell migration, and decreased collagen synthesis in vitro. Based on the in vitro results, Dwn1 was topically applied to iatrogenic full-thickness dorsal cutaneous wounds in a murine model. The Dwn1-treated dermal wounds healed faster with favorable mechanical strength and developed less granulation tissue than the controls. The expression of type I collagen, Tgfβ1, and α-smooth muscle actin was significantly decreased in Dwn1-treated wounds, suggesting that hypertrophic scarring and myofibroblast differentiation are attenuated by Dwn1 treatment. NPAS2 may represent an important target for therapeutic approaches to optimal surgical wound management.

Background: Current common techniques for repairing calvarial defects by autologous bone grafting and alloplastic implants have significant limitations. In this study, we investigated a novel alternative approach to bone repair based on peptide amphiphile (PA) nanofiber gels that are engineered to control the release of vascular endothelial growth factor (VEGF) to recruit circulating stem cells to a site of bone regeneration and facilitate bone healing by bone morphogenetic protein-2 (BMP-2). Methods: VEGF release kinetics from PA gels were evaluated. Chemotactic functional scaffolds (CFS) were fabricated by combining collagen sponges with PA gels containing VEGF. The in vitro and in vivo chemotactic activities of CFS were evaluated by measuring mesenchymal stem cell (MSC) migration. and angiogenic capability of CFS was also evaluated. Large-scale rodent cranial bone defects were created to evaluate bone regeneration after implanting CFS and other control materials. Results: VEGF was released from PA in a controlled-release manner. In vitro migration of MSCs was significantly greater when exposed to CFS compared to control scaffolds. In vivo chemotaxis was evidenced by migration of tracer-labeled MSCs to the CFS. CFS showed significantly increased angiogenesis in vivo. Successful bone regeneration was noted in the defects treated with CFS and BMP-2. Conclusion: Our observations suggest that this bioengineered construct successfully acts as a chemo- attractant for circulating MSCs due to controlled release of VEGF from the PA gels. The CFS may play a role in the future design of clinically relevant bone graft substitutes for large-scale bone defects.

Natural killer cells are thought to represent more than 30 percent of all lymphocytes within the stromal vascular fraction of lipoaspirates. However, their physiologic interaction with adipocytes and their precursors has never been specifically examined. The authors hypothesized that natural killer cells, by means of cytokine secretion, are capable of promoting the differentiation of adipose-derived stem cells. Human natural killer cells purified from healthy donors' peripheral blood mononuclear cells were activated with a combination of interleukin-2 and anti-CD16 monoclonal antibody; natural killer cell supernatant was collected. Adipose-derived stem cells isolated from raw human lipoaspirates from healthy patients were treated with growth media, growth media with natural killer cell supernatant, adipogenic media, and adipogenic media with natural killer cells supernatant. Flow cytometric analysis was performed on cells using antibodies against B7H1, CD36, CD44, CD34, CD29, and MHC-1. Adipogenic-related gene expression (PPAR-γ, LPL, GPD-1, and aP2) was assessed. Oil Red O staining was performed as a functional assay of adipocyte differentiation and adipogenesis. Adipose-derived stem cells maintained in growth media with natural killer cell supernatant lost markers of "stemness," including CD44, CD34, and CD29; and expressed markers of differentiation, including B7H1 and MHC-1. Adipose-derived stem cells treated with natural killer cell supernatant accumulated small amounts of lipid after 10 days of natural killer cell supernatant treatment. Adipose-derived stem cells treated with natural killer cell supernatant showed altered expression of adipogenesis-associated genes compared with cells maintained in growth media. Adipose-derived stem cells maintained in adipogenic media with natural killer cell supernatant accumulated less lipid than those cells in adipogenic media alone. The authors demonstrate that, through secreted factors, natural killer cells are capable of differentiating adipose-derived stem cells. In cells maintained in adipogenic media, treatment with natural killer cell supernatant modulated adipogenic potential.

Current reconstructive techniques for complex craniofacial osseous defects are challenging and are associated with significant morbidity. Oxysterols are naturally occurring cholesterol oxidation products with osteogenic potential. In this study, we investigated the effects of a novel semi-synthetic oxysterol, Oxy133, on in vitro osteogenesis and an in vivo intramembranous bone-healing model. Rabbit bone marrow stromal cells (BMSCs) were treated with either Oxy133 or BMP-2. Alkaline phosphatase (ALP) activity, expression of osteogenic gene markers and in vitro mineralization were all examined. Next, collagen sponges carrying either Oxy133 or BMP-2 were used to reconstruct critical-sized cranial defects in mature rabbits and bone regeneration was assessed. To determine the mechanism of action of Oxy133 both in vitro and in vivo, rabbit BMSCs cultures and collagen sponge/Oxy133 implants were treated with the Hedgehog signalling pathway inhibitor, cyclopamine, and similar outcomes were measured. ALP activity in rabbit BMSCs treated with 1 μm Oxy133 was induced and was significantly higher than in control cells. These results were mitigated in cultures treated with cyclopamine. Expression of osteogenic gene markers and mineralization in BMSCs treated with 1 μm Oxy133 was significantly higher than in control groups. Complete bone regeneration was noted in vivo when cranial defects were treated with Oxy133; healing was incomplete, however, when cyclopamine was added. Collectively, these results demonstrate that Oxy133 has the ability to induce osteogenic differentiation in vitro in rabbit BMSCs and to promote robust bone regeneration in vivo in an animal model of intramembranous bone healing. Copyright © 2015 John Wiley & Sons, Ltd.

Mobile device technology has revolutionized interpersonal communication, but the application of this technology to the physician-patient relationship remains limited due to concerns over patient confidentiality and the security of digital information. Nevertheless, there is a continued focus on improving communication between doctors and patients in all fields of medicine as a means of improving patient care. In this study, we implement a novel communications platform to demonstrate that instantaneously sharing perioperative information with surgical patients and members of their support networks can improve patient care and strengthen the physician-patient relationship. 423 consecutive patients scheduled to undergo elective surgical procedures were offered complimentary registration to a secure, web-based service designed to distribute perioperative updates to a group of recipients designated by each patient via Short Message Service (SMS) and/or email. Messages were created by attending surgeons and delivered instantaneously through the web-based platform. In the postoperative period, patients and their designated message recipients, as well as participating healthcare providers, were asked to complete a survey designed to assess their experience with the messaging system. Survey results were statistically analyzed to determine satisfaction rates. Of the qualifying 423 patients, 313 opted to enroll in the study. On average, patients selected a total of 3.5 recipients to receive perioperative updates. A total of 1,195 electronic messages were generated for distribution to designated recipients during the study period and delivered to recipients located around the world. There were no documented errors or failures in message delivery. Satisfaction surveys were completed by 190 users of the service (73 %). Respondents identified themselves as either patients (n = 48, 25.5 %), family/friends (n = 120, 63.8 %), or healthcare providers (n = 15, 12 %). Satisfaction with the service was high: 94.2 % of users “enjoyed this software” and and 94.2 % of family/friends “felt more connected to their loved ones during surgery.” 92.5 % would “recommend their loved ones sign up for this service