Reconstruction Of Tissue Defects Research Articles

Single Stage Deltopectoral Flap for Reconstruction of the Soft Tissue Defects of Neck

Single Stage Deltopectoral Flap for Reconstruction of the Soft Tissue Defects of Neck

The sucker-like end-to-side arterial anastomosis for free flap in extremities reconstruction: a retrospective study of 78 cases

BackgroundThe application of end-to-side (ETS) anastomosis for flap transfer poses challenges, particularly in cases of significant size discrepancy between the donor and flap arteries. Herein, a novel ETS anastomosis technique, termed “sucker-like ETS anastomosis”, is developed to mitigate and rectify such vessel discrepancies. This study aims to evaluate the efficacy of this technique in tissue defect reconstruction through free flap transfer.MethodsBetween September 2018 and March 2023, the medical records and follow-up data of 78 patients who underwent free flap transfer using sucker-like ETS anastomosis for significant artery size discrepancies were collected and retrospectively analyzed.ResultsAmong the 78 cases that received free flap transfer, the range of artery size discrepancy (flap artery vs donor artery) was 1:1.6–1:4 (mean: 1:2.5). Following anastomosis with the sucker-like ETS technique, 75 cases achieved flap survival without requiring additional surgical intervention, yielding a one-stage success rate of 96.2%. Three cases experienced post-operative venous crises, with two cases surviving after vein exploration and one case undergoing flap necrosis, necessitating a secondary skin graft. Seven cases faced delayed wound healing but eventually achieved complete healing following dressing changes. No arterial crisis was observed during hospitalization. With an average follow-up of 13 months, the surviving flaps exhibited excellent vitality without flap necrosis or pigment deposition. Overall, the application of sucker-like ETS arterial anastomosis for flap transfer resulted in a high overall surgical success rate of 98.7% (77/78).ConclusionThe application of sucker-like ETS anastomosis for free flap transfer is highly effective, particularly in cases with significant size discrepancy between the recipient and donor arteries.

Virtual surgical planning in soft tissue reconstruction for oral cancer

Introduction. Reconstruction of soft tissue defects after radical surgeries in cancer patients is important for early surgical rehabilitation and improving quality of life. Our study presents technologies for virtual surgical planning (VSP) of soft tissue defect reconstruction in patients with squamous cell carcinoma of the oral cavity.Case presentation. We described VSP in a report of a 54-year-old patient with locally advanced buccal mucosa cancer after extensive radical resection and reported the results. VSP was used to construct a 3D model from CT images, which was used to accurately assess the margin of radical surgical resection, as well as to develop individually based reconstruction of soft tissue defects. Next, we reported a series of cases of patients with oral cancer of various locations, who, after radical surgery, underwent reconstruction with using of VSP (n=7) or conventional reconstruction (n=10). A comparative analysis of intra and postoperative results was carried out.Results. In a patient with locally advanced left buccal mucosa cancer, reconstruction of the postoperative defect was successful without local complications after reconstruction. Good functional and aesthetic results were obtained. The patient was observed for 2 years without signs of disease. A comparative assessment of the results of the main and control groups showed that patients in the VSP group had a shorter operation time and postoperative hospital stay, as well as fewer and milder postoperative local complications in comparison with the control group.Conclusion. Our results showed the effectiveness of using 3D technology in reconstructive surgery of soft tissue defects after radical surgery for oral SCC. This technology has significantly reduced operative time, hospital stay, and improved flap utilization. This method has great potential for wider application and provides greater benefits with further improvement of technology.

The Pedicled Sensate Osteocutaneous Groin Flap for Reconstruction of the Forearm and Hand

Background The groin flap is axial pedicled and versatile. Until now, this flap has been used with many modifications for the reconstruction of forearm and hand defects. However, this flap has not been used in forearm, hand, and thumb reconstruction as a pedicled sensate osteocutaneous flap. In this study, a pedicled sensate osteocutaneous groin flap was used for the reconstruction of composite tissue defects on the forearm, hand, and thumb. Patients and Methods A pedicled sensate osteocutaneous groin flap was used to reconstruction composite tissue defects on the forearm, hand, and thumb in 7 patients. The mean age of the patients was 42 years. The defects were located on the dorsal surface of the forearm and hand in 2 patients, the dorsal surface of the hand and finger in 2 patients, and the thumb in 3 patients. The dimensions of the flap skin paddle ranged from 7 × 11 cm to 8 × 23 cm, and the dimensions of the bone component ranged from 1 × 1.5 × 3.5 cm to 1 × 1.5 × 5 cm. The mean follow-up duration was 26 months. Results All the flaps survived. Flap debulking was performed using 3 flaps. Sensory recovery in the flaps was completed approximately 18 months after the first operation. When the results of static 2-point discrimination test and Semmes-Weinstein monofilament test were evaluated at 18 months postoperatively, it showed that protective sensation was obtained. Except for 1 patient, motion restriction did not develop in the wrist, elbow, or shoulder joints. An acceptable aesthetic result, minimal donor site deformity, and protective sensation were obtained in all patients. Conclusions The pedicled sensate osteocutaneous groin flap can be safely used in the reconstruction of forearm and hand composite tissue defects that do not have available vascular structures for free flaps in the recipient area and in thumb reconstruction where toe transfer and pollicization cannot be performed.

Frontal Flaps for Reconstruction of Nasal Defects

Nasal reconstruction is no longer just about filling in a nasal defect, it aims for an aesthetic and functional results. It is a three-dimensional reconstruction, restoring the mucosal plane, the osteo-cartilaginous architecture and the skin coverage to which Burget added a fourth dimension, the aesthetic result. Frontal flaps have been used for a very long time to repair nasal defects. Their popularity is mainly linked to their proximity to the recipient site, their good vascularization and especially the color and texture of the frontal skin which are significantly similar to those of the nasal skin. The frontal flap is the technique of choice in the reconstruction of full-thickness nasal tissue defects. We adopted the reconstruction by frontal flaps for the repair of multiple nasal defects, concerning multiple patients all treated at the plastic and aesthetic surgery department of the Mohammed VI University Hospital of Tangier over a period of 2 years going from March 2021 to March 2023. The goal of this study is to evaluate its contribution and answer the following question; What are the indications of using frontal flaps, its advantages and limitations in rhinopoiesis? and to draw practical recommendations regarding its use.

Reconstruction of an Abdominal Hernia after Wide Tumor Resection with Multilayer Acellular Dermal Matrix and Skin Graft: A Case Report

An abdominal hernia is a relatively common complication after abdominal surgery. However, no reports have previously described the reconstruction of a soft tissue defect with a hernia after wide excision of a tumor in the abdominal wall. A 41-year-old man presented with a painless, rapidly growing mass in his abdominal wall. Enhanced magnetic resonance imaging of the abdomen revealed a 7.8×6.4×4.2 cm mass, consistent with a soft tissue sarcoma suspected to be angiosarcoma in the subcutaneous layer of the left anterior upper abdominal wall. After wide excision of the mass, a hernia measuring 6.0×5.8 cm was observed. The abdominal hernia was repaired using multilayered acellular dermal matrix (ADM), and the soft tissue defect was covered with a split-thickness skin graft. A histopathological examination confirmed that the mass was fibrosarcomatous dermatofibrosarcoma protuberans (DFSP-FS). No complications occurred after surgery, and the patient was followed up for 10 months without any issues. Herein, we present a case of hernia after the removal of DFSP-FS in the abdominal wall, which was repaired using multilayer ADM and a split-thickness skin graft.

Laparoscopic harvest and free transplantation of great omentum flap for extensive tissue defects in complex wounds

IntroductionThe repair of extensive tissue defects remains a challenge, although great progress has been made in reconstructive surgery. The transplantation of a single huge flap or several flaps in combination will inevitably result in donor-site morbidity. Here we report our experience in the repair of these wounds with laparoscopically harvested great omentum flaps. MethodsTwelve patients with extensive tissue defects caused by deep burn injury, avulsion injury, and open fracture underwent free omental flap transplantation and split-thickness skin grafting. The patient demographics, wound characteristics, and complications postsurgical operation were recorded. Prior to omentum flap transplantation, these patients underwent debridement, vacuum sealing drainage treatment, and/or fixation of fractures. All omentum flaps harvested using laparoscopic technique were anastomosed to recipient vessels, and split-thickness skin grafting was performed 14 days after omental flap transplantation. ResultsThe mean defect size was 471 cm2 and the mean omental flap size was 751.1 cm2. Among all 12 cases, the omental flaps survived well except for distal partial necrosis in one case. Skin grafting was also achieved in all cases, and all patients achieved complete wound coverage. All donor sites achieved primary healing without major complications. The mean follow-up time was 30 months with satisfactory appearance and functional outcome. ConclusionFor the reconstruction of extensive tissue defects in complex wounds, the free transfer of an omental flap may be an ideal option because of its well-vascularized and pliable tissue with reliable vascular anatomy, as well as minimized donor-site morbidity.

An HA/PEEK scaffold with modified crystallinity via 3D-bioprinting for multiple applications in hard tissue engineering

Hard tissues, especially teeth and bones, are highly mineralized and the large-scale defect or total loss of them is irreversible. There is still no ideal strategy for the reconstruction of various hard tissue defects that can achieve the balance between biological and mechanical properties. Polyether ether ketone (PEEK) has the potential to substitute for natural hard tissue in defect areas but is limited by its biological inertness. The addition of hydroxyapatite (HA) can significantly improve the osteogenic properties and osteointegration of PEEK materials. But the mechanical properties of HA/PEEK scaffolds are far from satisfaction making scaffolds easy to fracture. We put forward a strategy to balance the mechanical and biological properties of HA/PEEK scaffolds via the regulation of the inner crystallinity and HA mixing ratio and we systematically evaluated the modified HA/PEEK scaffolds through material characterization, in vitro and in vivo experiments. And we found that the 20%HA/PEEK scaffolds with low crystallinity achieved the required strength and elasticity, and exhibited the characteristics of promoting the proliferation, migration and osteogenic differentiation of bone marrow mesenchymal stem cells. The results of the implantation of beagles’ teeth, mandible and rib showed that the 20%HA/PEEK scaffold with low crystallinity could well withstand the local complex force in the defect area and combine well with natural bone tissue, which made it a candidate for a practical versatile hard tissue engineering scaffold.

Anterolateral Thigh Chimeric Flap: An Alternative Reconstructive Option to Free Flaps for Large Soft Tissue Defects.

The anterolateral thigh (ALT) skin flap provides abundant, thin, pliable skin coverage with adequate pedicle length and calibre, and tolerable donor site morbidity. However, coverage of relatively large defects using the ALT flap alone is limited. We present our experience of using the ALT flap coupled with the vastus lateralis (VL) flap supplied by the same pedicle for large defect reconstruction. Between 2016 and 2020, ten patients with extensive lower-extremity or trunk defects were treated using the ALT/VL chimeric flap. The ALT portion was used to cover the cutaneous and joint defect while the VL part was used to resurface remnant defects, and a skin graft was performed. All flaps were based on the common descending pedicle, and branches to separate the components were individually dissected. All defects were successfully reconstructed using the ALT/VL chimeric flap. No surgery-related acute complications were observed, and the patients had no clinical issues with ambulation or running activities during the long-term follow-up period. With the separate components supplied by a common vascular pedicle, the ALT/VL chimeric flap allows us to reconstruct extensive defects with joint involvement or posterior trunk lesions. Thus, the ALT/VL chimeric flap may be a suitable alternative for extensive tissue defect reconstruction.

A brief discussion on the harvest of thinned perforator flap, detection of perforator vessels, and evaluation of flap blood supply

Repair and reconstruction surgery is not just a simple repair and reconstruction of tissue and organ defects in different parts, but also requires perfect repair that matches the defect and confuses the real. The thinning strategy of perforator flap is one of its main contents. In recent years, the concept of pure skin perforator flap and its clinical application have overturned the traditional concept that flaps must carry subdermal vascular plexus and improved our understanding of flap surgery, and it is expected to enhance the level of repair and reconstruction. This article explores the harvest of thinned perforator flaps, especially the harvest of innovative pure skin perforator flap with the thickness similar to full thickness skin, as well as the preoperative detection of perforator vessels, blood supply evaluation of perforator flaps, and their clinical applications. It proposes a "Jinshan" repair that perfectly matches the recipient area defect, and also prospects research on the perforasome and three-dimensional visualized digital anatomy of pure skin perforator flaps.

Latissimus dorsi muscle free flap for management of large complex wound

Background and objective: Dealing with a large complex wound is very challenging, and latissimus dorsi flap through history has been used as its very variable and flexible in the form of pedicle or free flap in the coverage of those large complex wounds as its large, well perfused, and flexible in configuration. The study aimed to evaluate the versatility of use and viability of latissimus dorsi free flap for coverage of large complex wounds in different parts of the body. Methods: A retrospective study was conducted from 2012 to 2019 in Erbil Rizgary teaching hospital, Rozhawa emergency hospital, and PAR private hospital, Kurdistan region, Iraq on 22 cases, (20) male (90.9%), and (2) female (9.1%), all with a large complex wound in different sites of the body that latissimus dorsi free flap in the form of myocutaneous mainly and only one with muscle free flap. Results: The complex large wounds ranged from (22*15 cm – 35*20 cm) indifferent sites of the body, (18) from the lower limb,(3) from the forearm and (1) from the scalp, from those 22 cases, we had 17 cases that survived totally(77.2%), and 5 failure cases (22.7%) those were from leg who associated with tibial bone fracture gestilo type 111B and C and large soft tissue defect with or without vascular injury, and in regard to flaps out of 22 cases 5 of them presented with total necrosis (55.6%), one case with partial necrosis(11.1%), and 3 cases with partial skin graft loss (33.33%), that managed conservatively, in all cases donor site closed primarily with few morbidities as happened in 5 cases (22.7%) like bleeding in 3 cases (60.0%) and stoppage needed operation theater, one case (20.0%) with seroma, and one with minor wound dehiscent (20.0%), that both managed conservatively. Conclusion: The latissimus dorsi myocutaneous free flap is the reliable, flexible and highly recommended for large soft tissue defect reconstruction in different sites of the body especially those associated with extensive bone damage.

3D Bioprinting of a Bioactive Composite Scaffold for Cell Delivery in Periodontal Tissue Regeneration.

Hydrogels have been widely applied to the fabrication of tissue engineering scaffolds via three-dimensional (3D) bioprinting because of their extracellular matrix-like properties, capacity for living cell encapsulation, and shapeable customization depending on the defect shape. However, the current hydrogel scaffolds show limited regeneration activity, especially in the application of periodontal tissue regeneration. In this study, we attempted to develop a novel multi-component hydrogel that possesses good biological activity, can wrap living cells for 3D bioprinting and can regenerate periodontal soft and hard tissue. The multi-component hydrogel consisted of gelatin methacryloyl (GelMA), sodium alginate (SA) and bioactive glass microsphere (BGM), which was first processed into hydrogel scaffolds by cell-free 3D printing to evaluate its printability and in vitro biological performances. The cell-free 3D-printed scaffolds showed uniform porous structures and good swelling capability. The BGM-loaded scaffold exhibited good biocompatibility, enhanced osteogenic differentiation, apatite formation abilities and desired mechanical strength. The composite hydrogel was further applied as a bio-ink to load with mouse bone marrow mesenchymal stem cells (mBMSCs) and growth factors (BMP2 and PDGF) for the fabrication of a scaffold for periodontal tissue regeneration. The cell wrapped in the hydrogel still maintained good cellular vitality after 3D bioprinting and showed enhanced osteogenic differentiation and soft tissue repair capabilities in BMP2- and PDGF-loaded scaffolds. It was noted that after transplantation of the cell- and growth factor-laden scaffolds in Beagle dog periodontal defects, significant regeneration of gingival tissue, periodontal ligament, and alveolar bone was detected. Importantly, a reconstructed periodontal structure was established in the treatment group eight weeks post-transplantation of the scaffolds containing the cell and growth factors. In conclusion, we developed a bioactive composite bio-ink for the fabrication of scaffolds applicable for the reconstruction and regeneration of periodontal tissue defects.

The antibiotic bead pouch - a useful technique for temporary soft tissue coverage, infection prevention and therapy in trauma surgery.

Soft tissue defects resulting from trauma and musculoskeletal infections can complicate surgical treatment. Appropriate temporary coverage of these defects is essential to achieve the best outcomes for necessary plastic soft tissue defect reconstruction. The antibiotic bead pouch technique is a reasonable surgical approach for managing temporary soft tissue defects following adequate surgical debridement. This technique involves the use of small diameter antibiotic-loaded bone cement beads to fill the dead space created by debridement. By applying antibiotics to the bone cement and covering the beads with an artificial skin graft, high local dosages of antibiotics can be achieved, resulting in the creation of a sterile wound that offers the best starting position for soft tissue and bone defect reconstruction. This narrative review describes the rationale for using this technique, including its advantages and disadvantages, as well as pearls and pitfalls associated with its use in daily practice. In addition, the article provides a comprehensive overview of the literature that has been published since the technique was introduced in surgical practice.

Reconstructing complex peripatellar defects using the descending genicular artery perforator flap.

Complex peripatellar defects are commonly reconstructed with free flaps or pedicled muscle flaps, whereas pedicled fasciocutaneous perforator flaps are commonly overlooked. The descending genicular artery perforator (DGAP) flap is a versatile flap that offers thin and pliable tissue that provides ideal 'like with like' peripatellar soft tissue defect reconstruction. This paper aims to demonstrate the safe use of a pedicled fasciocutaneous DGAP flap for extensive traumatic peripatellar defect reconstructions and to exhibit the surgical pearls via a case series. A retrospective cohort study of consecutive complex peripatellar reconstructions with DGAP flaps was conducted from January 2011 to December 2018. Patient demographics, medical comorbidities, aetiology/size/and location of the defects were reviewed. Flap, donor site, and overall surgical outcomes were clinically assessed and documented. Descriptive statistics were conducted and analysed by IBM SPSS Statistics 23. Five consecutive cases with complex peripatellar defects (5 × 8 to 8 × 10 cm) were recruited. Two were males, and three were females, with a mean age of 38.4 years. Four were trauma, and one was an oncological case. Descending genicular artery (DGA) perforators and DGA terminal branches were consistent. One patient needed a split-thickness skin graft to reconstruct the secondary defects. All the flaps survived with an average follow-up of 24 months. The DGAP flap provides a reliable alternative to free flap for the large, complex peripatellar defect. With the inclusion of the proximal long saphenous vein and judicious selection of DGA perforators and its terminal branches, the DGAP flap can be harvested and used safely in the high-velocity impacted knee.

Reconstruction of a soft tissue defect in the toe using a serratus anterior fascia free flap: a case report

Toe injuries frequently occur as traumatic or oncologic defects. Compared with finger reconstruction, toe reconstruction has been rarely reported in the literature, because of the difficulty of toes’ relatively thin soft tissue envelope, their requirement for relatively challenging surgical techniques, and the slight improvements in gait. Therefore, toe reconstruction can be challenging for plastic surgeons, especially in cases with exposure of a tendon, bone, or joint. Herein, we present a case study of a 54-year-old woman with squamous cell carcinoma in situ (Bowen disease) that subsequently resulted in a defect on her second toe. A serratus anterior fascia free flap could be a good option for toe reconstruction due to its large caliber, lengthy pedicle, relatively easy dissection, and thin muscle bulk. We present our unique experience using the serratus anterior fascia free flap for the reconstruction of an oncologic toe defect.

Individualized design of thoracodorsal artery perforator chimeric flap for customized reconstruction of complex three-dimensional defects in the extremities

BackgroundIt was always challenging to accurately and effectively reconstruct the complicated defects with three-dimensional tissue deficits in the extremities. Muscle-chimeric perforator flap is an excellent choice for repairing those complicated wound. However, problems like donor-site morbidity and time-consuming intramuscular dissection still exist. This purpose of this study was to present a novel design of the thoracodorsal artery perforator (TDAP) chimeric flap for the customized reconstruction of complex three-dimensional tissue defects in the extremities.MethodsFrom January 2012 to June 2020, 17 patients with complex three-dimensional deficits in the extremities were retrospectively analyzed. All patients in this series underwent extremity reconstruction using latissimus dorsi (LD)-chimeric TDAP flap. Three different types of LD-chimeric TDAP flaps were performed.ResultsA total of seventeen TDAP chimeric flaps were successfully harvested for the reconstruction of those complex three-dimensional defects in extremities. Among them, Design Type A flaps were used in 6 cases, Design Type B flaps were performed in 7 cases, and Design Type C flaps were used in the remaining 4 cases. The sizes of the skin paddles ranged from 6 cm × 3 cm to 24 cm × 11 cm. Meanwhile, the sizes of the muscle segments ranged from 3 cm × 4 cm to 33 cm × 4 cm. All the flaps survived. Nevertheless, one case required re-exploration owing to venous congestion. Moreover, the primary closure of the donor site was successfully achieved in all patients, and the mean follow-up time was 15.8 months. Most of the cases displayed satisfactory contour.ConclusionThe LD-chimeric TDAP flap is available for the reconstruction of complicated defects with three-dimensional tissue deficits in the extremities. It provided a flexible design for customized coverage of complex soft tissue defects with limited donor site morbidity.

EXPLORING THE APPLICATIONS OF ISLANDED KEYSTONE FLAP IN THE INDIAN POPULATION

This study aims to explore keystone ap for various soft tissue defect reconstruction, demonstrating its exibility, efciency, reliability and practicality in the Indian population. 30 aps were performed to cover various soft tissue defects. All aps were planned according to the original ap design and standard post-operative patient and ap care was given. All the aps were easy to perform and gave satisfactory 'like tissue' replacement for the defects. Intra-operative and post-operative period was uneventful. After being discharged with necessary advice, patients were followed up regularly for up to a period of six months. All aps settled well with tissue match in function, texture, colour and sensitivity. Hence keystone ap can be considered as a versatile and sturdy one with a short learning curve and can be useful tool for even novice surgeons.

Gracilis Muscle Interposition to Fill the Perianal Dead Space May Decrease Hospital Length of Stay in Fournier's Gangrene.

The treatment of Fournier's gangrene (FG) includes aggressive debridement of the affected necrotic area, broad-spectrum antibiotic therapy, and reconstructive procedures, respectively. One of the main reasons of unfavorable outcomes in FG surgery is that the dead space occurs in the perianal region because of destruction of fascias and soft tissues. In this study, we aimed to evaluate the results of gracilis muscle flap transposition to fill the FG-associated perianal dead spaces. Patients treated for FG-associated dead spaces in their perianal region between the years 2017 and 2021 were included in the study. The patients who underwent the pedicled gracilis muscle flap surgery were included in group 1, whereas group 2 consisted of the patients with no additional surgical procedure for dead spaces but only the reconstruction of the soft tissue defects. Demographic data (age, sex), comorbid diseases, localization and length of perianal dead space, and management method for the soft tissue defects and complications were noted. The length of hospital stay and discharge day after surgery were also recorded. In group 1, the mean duration of hospital stay was 23.5 ± 5.0 (range, 14-48) days, whereas the mean period between the surgery and discharge was 5.1 ± 2.2 (range, 3-12) days. These numbers were 31 ± 8.3 (range, 19-58) days and 12.7 ± 6.1 (range, 7-22) days in group 2, respectively. Statistical comparison of the periods between the surgery and discharge was found to be significantly different ( P = 0.022). The duration of hospital stay was also shorter in the patients with gracilis muscle flap ( P = 0.039). Perianal dead spaces accompanying many of the patients with FG provide appropriate conditions for bacterial colonization. Filling these pouches by the gracilis muscle flap prevented the progression of infection and enabled the patients to return to their normal life earlier.

Tissue engineering atthe dentin-pulp interface using human treated dentin scaffolds conditioned with DMP1 or BMP2 plasmid DNA-carrying calcium phosphate nanoparticles.

Hard dental tissue pathologies, such as caries, are conventionally managed through replacement by tooth-colored inert biomaterials. Tissue engineering provides novel treatment approaches to regenerate lost dental tissues based on bioactive materials and/or signaling molecules. While regeneration in the form of reparative dentin (osteo-dentin) is feasible, the recapitulation of the tubular microstructure of ortho-dentin and its special features is sidelined. This study characterized in vitro, and in vivo human EDTA-treated, freeze-dried dentin matrices (HTFD scaffolds) conditioned with calcium phosphate nanoparticles (NPs) bearing plasmids encoding dentinogenesis-inducing factors (pBMP2/NPs or pDMP1/NPs). The uptake and transfection efficiency of the synthesized NPs on dental pulp stem cells (DPSCs) increased in a concentration- and time-dependent manner, as evaluated qualitatively by confocal laser microscopy and transmission electron microscopy, and quantitatively by flow cytometry, while, in parallel, cell viability decreased. HTFD scaffolds conditioned with the optimal transfectability-to-viability concentration at 4µg Ca/mL of each of the pBMP2/NPs or pDMP1/NPs preserved high levels of cell viability, evidenced by live/dead staining in vitro and caused no adverse reactions after implantation on C57BL6 mice in vivo. HTFD/NPs constructs induced rapid and pronounced odontogenic shift of the DPSCs, as evidenced by relevant gene expression patterns of RunX2, ALP, BGLAP, BMP-2, DMP-1, DSPP by real-time PCR, and acquirement of polarized meta-mitotic phenotype with cellular protrusions entering the dentinal tubules as visualized by scanning electron microscopy. Taken together, HTFD/NPs constitute a promising tool for customized reconstruction of the ortho-dentin/odontoblastic layer barrier and preservation of pulp vitality. STATEMENT OF SIGNIFICANCE: In clinical dentistry, the most common therapeutic approach for the reconstruction of hard dental tissue defects is the replacement by resin-based restorative materials. Even modern bioactive materials focus on reparative dentinogenesis, leading to amorphous dentin-bridge formation in proximity to the pulp. Therefore, the natural microarchitecture of tubular ortho-dentin is not recapitulated, and the sensory and defensive role of odontoblasts is sidelined. This study approaches the reconstruction at the dentin-pulp interface using a construct of human treated dentin (HTFD) scaffold and plasmid-carrying nanoparticles (NPs) encoding dentinogenic factors (DMP-1 or BMP-2) with excellent in vitro and in vivo properties. As a future perspective, the HTFD/NPs constructs could act as bio-fillings for personalized reconstruction of the dentin-pulp interface.

Macrophage contribution to the survival of transferred expanded skin flap through angiogenesis.

Despite the application of tissue expansion in the reconstruction of significant tissue defects, complications with expanded random-pattern skin flaps remain a major challenge. Insufficient angiogenesis is one of the keys factors in flap ischemia and dysfunction. Macrophages play a key role in promoting tissue angiogenesis, but their effects on expanded flap angiogenesis and the survival of the transferred skin flap are still unknown. A rat scalp expansion model was established to evaluate the dynamic changes of macrophages in expanded skin. Clodronate liposomes (Clo-lipo) were injected into the expanded scalps to deplete the macrophages, and the expanded scalp flaps with macrophage depletion were orthotopically transferred. The remaining expanded rat scalp flaps were treated with either a macrophage-colony stimulating factor (M-CSF) alone or M-CSF in combination with Clo-lipo and transferred. The number of macrophages, blood perfusion, microvascular densities (MVDs), flap survival, histological changes, and gene expression related to macrophage polarization and angiogenesis were determined with immunofluorescence (IF) staining, full-field laser perfusion imager, hematoxylin and eosin (HE) staining, and quantitative real-time polymerase chain reaction. The number of pan-macrophages significantly increased in the expanded scalp on days 14 and 21 after expander placement. The depletion rate after treatment with Clo-lipo was 29.06%, and the number of macrophages was significantly reduced in the group that underwent Clo-lipo treatment on day 14 before flap transfer (P<0.05). Macrophage depletion resulted in decreased blood perfusion, reduced MVDs, lower expression of factors, and poor survival rate. The recruitment of macrophages with a M-CSF led to higher blood perfusion, increased MVDs, greater expression of angiogenic factors, and better flap survival after flap transfer. Alternatively activated macrophages in the expanded flap could significantly promote angiogenesis, improve blood perfusion, and ultimately increase the flap survival rate. Modulating alternatively activated macrophages may provide a key therapeutic strategy to promote expanded skin flap survival. Our study has provided a basis for clinically improving random-pattern skin flap survival.