Transcription factor scleraxis vitally contributes to progenitor lineage direction in wound healing of adult tendon in mice

Tendon is a dense connective tissue that transmits high mechanical forces from skeletal muscle to bone. The transcription factor scleraxis (Scx) is a highly specific marker of both precursor and mature tendon cells (tenocytes). Mice lacking scx exhibit a specific and virtually complete loss of tendons during development. However, the functional contribution of Scx to wound healing in adult tendon has not yet been fully characterized. Here, using ScxGFP-tracking and loss-of-function systems, we show in an adult mouse model of Achilles tendon injury that paratenon cells, representing a stem cell antigen-1 (Sca-1)–positive and Scx-negative progenitor subpopulation, display Scx induction, migrate to the wound site, and produce extracellular matrix (ECM) to bridge the defect, whereas resident tenocytes exhibit a delayed response. Scx induction in the progenitors is initiated by transforming growth factor β (TGF-β) signaling. scx-deficient mice had migration of Sca-1–positive progenitor cell to the lesion site but impaired ECM assembly to bridge the defect. Mechanistically, scx-null progenitors displayed higher chondrogenic potential with up-regulation of SRY-box 9 (Sox9) coactivator PPAR-γ coactivator-1α (PGC-1α) in vitro, and knock-in analysis revealed that forced expression of full-length scx significantly inhibited Sox9 expression. Accordingly, scx-null wounds formed cartilage-like tissues that developed ectopic ossification. Our findings indicate a critical role of Scx in a progenitor-cell lineage in wound healing of adult mouse tendon. These progenitor cells could represent targets in strategies to facilitate tendon repair. We propose that this lineage-regulatory mechanism in tissue progenitors could apply to a broader set of tissues or biological systems in the body

An injectable non-cross-linked hyaluronic-acid gel containing therapeutic spheroids of human adipose-derived stem cells

For chronic wounds, the delivery of stem cells in spheroidal structures can enhance graft survival and stem cell potency. We describe an easy method for the 3D culture of adipose-derived stem/stromal cells (ASCs) to prepare a ready-to-use injectable. We transferred suspensions of monolayer-cultured ASCs to a syringe containing hyaluronic acid (HA) gel, and then incubated the syringe as a 3D culture vessel. Spheroids of cells formed after 12 h. We found that 6 × 106 ASCs/ml in 3% HA gel achieved the highest spheroid density with appropriate spheroid sizes (20–100 µm). Immunocytology revealed that the stem cell markers, NANOG, OCT3/4, SOX-2, and SSEA-3 were up-regulated in the ASC spheroids compared with those in nonadherent-dish spheroids or in monolayer cultured ASCs. In delayed wound healing mice models, diabetic ulcers treated with ASC spheroids demonstrated faster wound epithelialization with thicker dermis than those treated with vehicle alone or monolayer cultured ASCs. In irradiated skin ulcers in immunodeficient mice, ASC spheroids exhibited faster healing and outstanding angiogenic potential partly by direct differentiation into α-SMA+ pericytes. Our method of 3D in-syringe HA gel culture produced clinically relevant amounts of ready-to-inject human ASC microspheroids that exhibited superior stemness in vitro and therapeutic efficacy in pathological wound repair in vivo

The Fate of Nonvascularized Fat Grafts: Histological and Bioluminescent Study

Background: Nonvascularized fat grafting has become one of the most popular options for breast contouring. However, the survival process of the grafts remains to be elucidated. In this study, we tracked the fate of nonvascularized fat grafts with in vivo bioluminescence and immunohistochemistry. Methods: Nonvascularized fat grafts or vascularized adiposal flaps from luciferase transgenic rats were transplanted to Lewis rats. The bioluminescent signals from the grafts were monitored longitudinally. In addition, nonvascularized fat grafts from Lewis rats were engrafted to Lewis rats and the viability of the adipocytes in the grafts was evaluated with immunohistochemical staining for perilipin at postoperative week 1, 2, 3, 4, and 6. Results: The bioluminescent signals from the nonvascularized fat grafts increased drastically from postoperative day 3 to 7, stayed flat from day 7 to 12, and declined from day 12 to 17, whereas those from the vascularized fat flaps remained throughout the entire postoperative period. Immunohistochemistry revealed that the survival zones with large adipocytes were decreased within 2 weeks and the regenerating zones with small adipocytes appeared after 3 weeks. Conclusions: Our study showed the process of survival and regeneration of nonvascularized fat grafts and suggested that graft-derived stromal cells proliferated within 7 days after transplantation and differentiated into adipocytes after postoperative week 3

Use of Multidirectional Cranial Distraction Osteogenesis for Cranial Expansion in Syndromic Craniosynostosis

Summary:. Patients with syndromic craniosynostosis often require a large amount of cranial expansion to avoid intracranial hypertension, but the surgical procedure remains controversial. A patient of severe syndromic craniosynostosis with multiple bony defects and anomalous venous drainage at the occipital region was treated by multidirectional cranial distraction osteogenesis (MCDO) at the age of 8 months. Distraction started 5 days after surgery and ceased on postoperative day 16. The distraction devices were removed 27 days after completing distraction. After device removal, the increase of intracranial volume was 155 ml and the cephalic index was improved from 115.5 to 100.5. The resultant cranial shape was well maintained with minimal relapse at postoperative 9 months. In cases of syndromic craniosynostosis with multiple bony defects and/or anomalous venous drainage at the occipital region, expansion of the anterior cranium by MCDO is a viable alternative to conventional methods

Contact Dermatitis Caused by Dermabond Advanced Use

Background:. Dermabond Advanced (DBA) has been widely used globally; however, severe contact dermatitis (CD) can be a serious adverse effect of DBA use. In this study, we investigated the characterization and incidence rate of CD after using DBA and the safe use of DBA. Methods:. One hundred consecutive patients who underwent skin closure with DBA were investigated. All patients were women undergoing breast reconstruction. DBA was applied to their trunk and limbs following reconstruction. Results:. Seven patients (7%) presented with CD. Of these, 4 patients exhibited CD after the second DBA use; sensitization influence by the first DBA use was considered. One of 3 patients presenting with CD after the first DBA use was allergic to cosmetic glue, and the influence of immunological cross-reaction of acrylates was suggested. Conclusion:. We consider that DBA use is inadequate for wounds with an improper margin and in dry and low-skin barrier areas such as the trunk and limbs because it may induce irritant CD and sensitization of DBA and subsequent allergic CD. Frequent use can also induce sensitization. If patients have a history of acrylate allergies, DBA use should be avoided because immunological cross-reaction from acetylates could result

Conversion of Mechanical Force into TGF-beta-Mediated Biochemical Signals

SummaryMechanical forces influence homeostasis in virtually every tissue [1, 2]. Tendon, constantly exposed to variable mechanical force, is an excellent model in which to study the conversion of mechanical stimuli into a biochemical response [3–5]. Here we show in a mouse model of acute tendon injury and in vitro that physical forces regulate the release of active transforming growth factor (TGF)-β from the extracellular matrix (ECM). The quantity of active TGF-β detected in tissue exposed to various levels of tensile loading correlates directly with the extent of physical forces. At physiological levels, mechanical forces maintain, through TGF-β/Smad2/3-mediated signaling, the expression of Scleraxis (Scx), a transcription factor specific for tenocytes and their progenitors. The gradual and temporary loss of tensile loading causes reversible loss of Scx expression, whereas sudden interruption, such as in transection tendon injury, destabilizes the structural organization of the ECM and leads to excessive release of active TGF-β and massive tenocyte death, which can be prevented by the TGF-β type I receptor inhibitor SD208. Our findings demonstrate a critical role for mechanical force in adult tendon homeostasis. Furthermore, this mechanism could translate physical force into biochemical signals in a much broader variety of tissues or systems in the body

Multidirectional Cranial Distraction Osteogenesis with Simplified Modifications for Treating Sagittal Synostosis

Background:. Multidirectional cranial distraction osteogenesis (MCDO) is a procedure of ours developed earlier for treating craniosynostosis. However, the numerous bone flaps led to prolonged operative time and occasional bone detachment from dura. We have since simplified the osteotomy design. In treating sagittal synostosis, required bone flaps have been reduced to 11 (from ~20). Methods:. In a 2-year period (2014–2015), 5 boys with sagittal synostosis underwent MCDO using our simplified and fixed-form osteotomy. Mean age at surgery was 9.4 months (range, 8–11 months). Pre- and postoperative cranial morphology was assessed by cephalic index and by mid-sagittal vector analysis. Results:. Improved cranial shape was confirmed by 3-dimensional CT scans and by mid-sagittal vector index. Mean preoperative cephalic index (68.7) progressively increased to means of 78.5 immediately after distraction device removal, 75.2 at postoperative month 6, and 75.1 at 1 year postoperatively. There were no major complications, although transient cerebrospinal fluid leakage and loosening of anchor pins occurred in 1 patient. Conclusions:. Simplified MCDO has a number of advantages over conventional distraction procedures such as discretionary reshaping/expansion of cranium and predictable osteogenesis and is a valid treatment option for patients with sagittal synostosis