What happens to an acellular dermal matrix after implantation in the human body? A histological and electron microscopic study

A Histological and Biomechanical Analysis of Human Acellular Dermis (HAD) Created Using a Novel Processing and Preservation Technique

Background

Large and complex defects requiring reconstruction are challenging for orthopaedic surgeons. The use of human acellular dermal (HAD) matrices to augment large soft tissue defects such as those seen in massive rotator cuff tears, knee extensor mechanism failures and neglected Tendo-Achilles tears has proven to be a valuable tool in surgeons reconstructive armamentarium. Different methods for allograft decellularization and preservation alter the native properties of the scaffold. Traditional processing and preservation methods have shown to have drawbacks that preclude its widespread use. Some of the common issues include inferior biomechanical properties, the risk of rejection, limited customization, difficulty in storing and transporting, the requirement of pre-operative preparation, and last but not the least increased cost.

Methods

We describe a novel processing and preservation method utilizing a two-step non-denaturing decellularization method coupled with preservation using a water-sequestering agent (glycerol) to remove immunogenic components while retaining biomechanical properties. The efficiency of this novel process was compared with the traditional freeze-drying method and verified by histological evaluation and biomechanical strength analysis.

Results

The absence of cellular components and matrix integrity in hematoxylin and eosin-stained glycerol-preserved HAD (gly-HAD) samples compared to freeze-dried HAD (FD-HAD) demonstrated effective yet gentle decellularization. Biomechanical strength analysis revealed that gly-HADs are stronger with an ultimate tensile load to the failure strength of 210 N compared to FD-HAD (124N). The gly-HADs were found to have an optimal suture-retention strength of 126 N. Finally, sterility testing of the resultant grafts was checked to ensure a sterility assurance level of 10-6 to establish implantability.

Conclusion

The novel processing and preservation technique is described in this paper to create a Human Acellular Dermis with higher biomechanical strength and superior histological characteristics. The processing and preservation technique ensured high sterility assurance levels to establish implantability.

Acellular dermal matrix for the treatment of multiple gingival recession defects associated with carious and previously restored cervical lesions: A case report with 10 years of follow-up

BACKGROUND

Limited evidence exists on the outcome of the modified coronally advanced tunnel (MCAT) with acellular dermal matrix (ADM) for the treatment of gingival recession defects (GRD) especially when complicated by restored cervical lesions. Therefore, the aim of this case report was to assess the short- and long-term clinical outcomes of maxillary Type 1 recession defects (RT1) associated with restored cervical lesions treated with MCAT with ADM.

METHODS AND RESULTS

A 43-year-old female patient, presented with multiple adjacent RT1 recessions in the left maxilla, previously treated with overhanging cervical resin restorations. The case was approached with a careful evaluation of the diagnostic determinants of root coverage, removal of the aberrant resin restorations, treatment with MCAT with ADM, and periodical evaluation over a follow-up of 10 years. The treatment was followed by complete root coverage, improvement of gingival phenotype, and perfect root coverage esthetic score. Outcomes were periodically assessed and were maintained over 10 years of follow-up.

CONCLUSION

MCAT with ADM is an effective technique for the treatment of multiple GRD complicated by cervical restorations. Complete root coverage and excellent esthetic outcomes were obtained and maintained in the long term.

Pre-pectoral Breast Reconstruction: Surgical and Patient-Reported Outcomes of Two-Stages vs Single-Stage Implant-Based Breast Reconstruction

BACKGROUND

Two-stages pre-pectoral breast reconstruction may confer advantages over direct to implant (DTI) and subpectoral reconstruction in selected patients who have no indication for autologous reconstruction. The primary endpoint of the study was to evaluate and compare the incidence of capsular contracture in the pre-pectoral two-stages technique versus the direct to implant technique. Complications related to the two surgical techniques and patient satisfaction were also evaluated.

METHODS

A retrospective review of 45 two stages and 45 Direct-to-implant, DTI patients was completed. Acellular dermal matrix was used in all patients. An evaluation of anthropometric and clinical parameters, surgical procedures and complications was conducted. Minimum follow-up was 12 months after placement of the definitive implant.

RESULTS

There was no statistically significant difference in the rate of capsular contracture in the two groups. Rippling occurred more in DTI reconstruction. In the two-stages reconstruction, lipofilling was applied more often and there was a higher incidence of seroma. Patient satisfaction extrapolated from the Breast Q questionnaire was better for patients submitted to two-stage implant-based breast reconstruction.

CONCLUSION

Dual-stage pre-pectoral reconstruction with acellular dermal matrix appears to be a good reconstructive solution in patients with relative contraindications for one-stage heterologous reconstruction with definitive prosthesis and no desire for autologous reconstruction.

Bringing innovative wound care polymer materials to the market: Challenges, developments, and new trends

The development of innovative products for treating acute and chronic wounds has become a significant topic in healthcare, resulting in numerous products and innovations over time. The growing number of patients with comorbidities and chronic diseases, which may significantly alter, delay, or inhibit normal wound healing, has introduced considerable new challenges into the wound management scenario. Researchers in academia have quickly identified promising solutions, and many advanced wound healing materials have recently been designed; however, their successful translation to the market remains highly complex and unlikely without the contribution of industry experts. This review article condenses the main aspects of wound healing applications that will serve as a practical guide for researchers working in academia and industry devoted to designing, evaluating, validating, and translating polymer wound care materials to the market. The article highlights the current challenges in wound management, describes the state-of-the-art products already on the market and trending polymer materials, describes the regulation pathways for approval, discusses current wound healing models, and offers a perspective on new technologies that could soon reach consumers. We envision that this comprehensive review will significantly contribute to highlighting the importance of networking and exchanges between academia and healthcare companies. Only through the joint of these two actors, where innovation, manufacturing, regulatory insights, and financial resources act in harmony, can wound care products be developed efficiently to reach patients quickly and affordably.

Pre-pectoral breast reconstruction with tissue expander entirely covered by acellular dermal matrix: feasibility, safety and histological features resulting from the first 64 procedures

Background

Reconstructive options that can be used following conservative mastectomy, skin-, nipple-sparing and skin-reducing mastectomies, allow a remarkable variety of safe methods to restore the natural shape and aesthetics of the breast mound. In case of two-stage breast reconstruction, tissue expanders (TEs) are usually placed in a subpectoral position. The purpose of this retrospective cohort study is to evaluate the feasibility and safety of two-step reconstruction with TE in pre-pectoral position covered by acellular dermal matrix (ADM).

Methods

Between March 2021 and May 2023, at the Azienda Ospedaliero Universitaria Careggi, University of Florence, 55 patients with BRCA 1/2 mutations or early breast cancer underwent conservative mastectomy with immediate pre-pectoral reconstruction using TE covered with ADM, followed by a second surgery with replacement of the expander with definitive prosthesis. Demographic, oncological, and histological data along with surgical complications were recorded.

Results

A total of 64 conservative mastectomies were performed. In 2 patients (3.1%) complications were found that required reintervention and, in both cases, the TE had to be removed. Two patients developed hematoma and one patient developed seroma. Two patients showed wound dehiscence, both healed after conservative treatment and without implant exposure. No case of necrosis of the skin or nipple-areola complex has been observed, neither of capsular contracture. Capsule formed around TE was populated with cells and blood vessels and showed a thin area of synovial metaplasia.

Conclusions

In selected cases it may be more cautious to perform a two-stage breast reconstruction after radical breast surgery by means of TEs. The placement of TEs in pre-pectoral position combines the excellent aesthetic and functional results of the pre-pectoral philosophy with a quite safer and more prudent two-step approach. Our experience reports optimistic results: the ADM covering the TE is seen successfully integrating during tissue expansion and becoming a vascularised new self-tissue. Complications rates are low and such ADM-assisted two-stage pre-pectoral reconstructive technique is a safe, practical, and reproducible method.

Reconstruction of the human nipple-areolar complex: a tissue engineering approach

Introduction: Nipple-areolar complex (NAC) reconstruction after breast cancer surgery is challenging and does not always provide optimal long-term esthetic results. Therefore, generating a NAC using tissue engineering techniques, such as a decellularization-recellularization process, is an alternative option to recreate a specific 3D NAC morphological unit, which is then covered with an in vitro regenerated epidermis and, thereafter, skin-grafted on the reconstructed breast. Materials and methods: Human NACs were harvested from cadaveric donors and decellularized using sequential detergent baths. Cellular clearance and extracellular matrix (ECM) preservation were analyzed by histology, as well as by DNA, ECM proteins, growth factors, and residual sodium dodecyl sulfate (SDS) quantification. In vivo biocompatibility was evaluated 30 days after the subcutaneous implantation of native and decellularized human NACs in rats. In vitro scaffold cytocompatibility was assessed by static seeding of human fibroblasts on their hypodermal side for 7 days, while human keratinocytes were seeded on the scaffold epidermal side for 10 days by using the reconstructed human epidermis (RHE) technique to investigate the regeneration of a new epidermis. Results: The decellularized NAC showed a preserved 3D morphology and appeared white. After decellularization, a DNA reduction of 98.3% and the absence of nuclear and HLA staining in histological sections confirmed complete cellular clearance. The ECM architecture and main ECM proteins were preserved, associated with the detection and decrease in growth factors, while a very low amount of residual SDS was detected after decellularization. The decellularized scaffolds were in vivo biocompatible, fully revascularized, and did not induce the production of rat anti-human antibodies after 30 days of subcutaneous implantation. Scaffold in vitro cytocompatibility was confirmed by the increasing proliferation of seeded human fibroblasts during 7 days of culture, associated with a high number of living cells and a similar viability compared to the control cells after 7 days of static culture. Moreover, the RHE technique allowed us to recreate a keratinized pluristratified epithelium after 10 days of culture. Conclusion: Tissue engineering allowed us to create an acellular and biocompatible NAC with a preserved morphology, microarchitecture, and matrix proteins while maintaining their cell growth potential and ability to regenerate the skin epidermis. Thus, tissue engineering could provide a novel alternative to personalized and natural NAC reconstruction.

Acellular dermal matrix in urethral reconstruction

The management of severe urethral stricture has always posed a formidable challenge. Traditional approaches such as skin flaps, mucosal grafts, and urethroplasty may not be suitable for lengthy and intricate strictures. In the past two decades, tissue engineering solutions utilizing acellular dermal matrix have emerged as potential alternatives. Acellular dermal matrix (ADM) is a non-immunogenic biological collagen scaffold that has demonstrated its ability to induce layer-by-layer tissue regeneration. The application of ADM in urethral reconstruction through tissue engineering has become a practical endeavor. This article provides an overview of the preparation, characteristics, advantages, and disadvantages of ADM along with its utilization in urethral reconstruction via tissue engineering.

Implant-Based Breast Reconstruction with Bovine Pericardium: Our Approach Using Tutopatch® and Review of Literature

OBJECTIVES

To describe the usage and advantages of bovine pericardium mesh (Tutopatch®) in breast reconstruction and to compare different mesh materials used in immediate breast reconstruction.

METHODS

Our study involved a single-center, retrospective analysis of 103 patients (comprising 114 breasts) who underwent immediate implant-based breast reconstruction using bovine pericardium bovine matrix. The procedures were performed by the same surgical team between April 2018 and May 2023.

RESULTS

The rates of early and late complications were examined after a median follow-up period of 30.2 ± 5.5 months. The results revealed that the rates of early complications stood at 9.7%, while late complications were observed in 14.5% of the cases. The most common late complication was seroma formation (7.7%) which six were resolved without any surgical intervention.

CONCLUSION

Tutopatch® can be used as an extension of the muscle to cover the prosthesis. It forms an extra layer over the silicone implant that helps to decrease the complications as capsular contracture and implant exposure. It also represents a significant 85 % reduction in cost when compared to a similar-sized mesh materials.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Delivery of adipose-derived growth factors from heparinized adipose acellular matrix accelerates wound healing

Dermal white adipocytes are closely associated with skin homeostasis and wound healing. However, it has not been fully investigated whether adipose-derived products improve wound healing. Here, we obtained adipose acellular matrix (AAM) and adipose-derived growth factors (ADGFs) from human adipose tissue and fabricated an ADGF-loaded AAM via surface modification with heparin. The product, HEP-ADGF-AAM, contained an adipose-derived scaffold and released ADGFs in a controlled fashion. To test its efficacy in promoting wound healing, mice with full thickness wound received three different treatments: HEP-ADGF-AAM, AAM and ADM. Control mice received no further treatments. Among these treatments, HEP-ADGF-AAM best improved wound healing. It induced adipogenesis in situ after in vivo implantation and provided an adipogenic microenvironment for wounds by releasing ADGFs. HEP-ADGF-AAM not only induced adipocyte regeneration, but also enhanced fibroblast migration, promoted vessel formation, accelerated wound closure, and enhanced wound epithelialization. Moreover, there was a close interaction between HEP-ADGF-AAM and the wound bed, and collagen was turned over in HEP-ADGF-AAM. These results show that HEP-ADGF-AAM might substantially improve re-epithelialization, angiogenesis, and skin appendage regeneration, and is thus a promising therapeutic biomaterial for skin wound healing.

Comparison of the Characteristics of Three Acellular Dermal Matrices Subjected to Distinct Processing Methods Using Five Types of Histochemical Staining

BACKGROUND

Acellular dermal matrix (ADM) is treated using various devitalization and aseptic processing methods. The processing effects on ADM were evaluated by histochemical tests.

METHODS

From January 2014 to December 2016, 18 patients [average age, 43.0 (range, 30-54) years] who underwent breast reconstruction with an ADM and tissue expander were prospectively enrolled. During the permanent implant replacement, a biopsy of the ADM was performed. We used three different human-derived products, namely, Alloderm®, Allomend®, and Megaderm®. Hematoxylin and eosin, CD68, CD3, CD31, and smooth muscle actin were used to evaluate the collagen structure, inflammation, angiogenesis, and myofibroblast infiltration. Each ADM was semi-quantitatively analyzed.

RESULTS

Significant differences in collagen degradation, acute inflammation, and myofibroblast infiltration were observed among the ADMs. Collagen degeneration (p<0.001) and myofibroblast infiltration (smooth muscle actin-positive, p=0.018; CD31-negative, p=0.765) were the most severe in Megaderm®. Acute inflammation, represented by CD68, was most severe in Alloderm® (p=0.024). Both radiation and freeze-drying treatment physically damaged the collagen structure. Collagen degeneration was most severe in Megaderm®, followed by Allomend® and Alloderm®. Since Alloderm® is treated using chemicals, an assessment of the chemical irritation is warranted.

CONCLUSIONS

The biopsy results were inconclusive. Therefore, to better interpret processing, more large-scale, serial, histochemical studies of each ADM are needed.

LEVEL OF EVIDENCE IV

This journal requires that authors 38 assign a level of evidence to each article. For a full 39 description of these Evidence-Based Medicine ratings, 40 please refer to the Table of Contents or the online 41 Instructions to Authors www.springer.com/00266 .

The influence of synthetic and biologic matrices on the choice of the implant plane during breast reconstruction. The modern state of the problem

Immediately after silicone implants were described, the technique of prepectoral implant placement dominated in breast reconstructive surgery. However, this plane soon had to be abandoned due to the high frequency of complications, such as infection, capsular contracture, explantation. For these reasons, surgeons soon had to switch to the subpectoral plane. Several decades later, thanks to the discovery of synthetic and biological meshes, surgeons returned to the prepectoral plane, but at a technically new level.

The purpose of this review was to analyze the role of biological and synthetic matrices as factors influencing the choice of the implant plane in one-stage breast reconstruction.

Treatment of multiple adjacent gingival recessions with an acellular dermal matrix or a connective tissue graft: a Meta-analysis

OBJECTIVES

To evaluate the effectiveness of an acellular dermal matrix or a connective tissue autograft in the treatment of multiple adjacent gingival recessions through Meta-analysis.

METHODS

Randomized controlled trials were screened in four electronic databases in English according to the inclusion and exclusion criteria until April 20, 2022. The main outcome indicators were keratinized gingival tissue width, recession depth, probing depth, clinical attachment level, complete root coverage, and root coverage esthetic score.

RESULTS

Seven randomized controlled trials were included. After 12 months, the connective tissue graft in the control group could increase the keratinized gingival tissue width [mean difference (MD)=-0.28 (-0.47, -0.08), P=0.006], reduce the gingival recession depth [MD=0.23 (0.12, 0.35), P<0.000 1], and improve the complete root coverage [risk ratio=0.80, 95% confidence interval (0.69, 0.93), P=0.003] compared with the acellular dermal matrix in the experimental group. No significant difference was found in probing depth, clinical attachment level, and root coverage esthetic score between groups.

CONCLUSIONS

Connective tissue grafts have advantages in increasing the keratinized gingival tissue width, reducing the gingival recession depth, and improving the complete root coverage in surgeries for treating multiple adjacent gingival recessions. Acellular dermal matrices also have some clinical value in terms of operation simplicity and similar effectiveness.

Biological Cover Mitigates Disruption of the Dermal Structure in Mechanically Expanded Skin in a Porcine Model

Tissue expansion is an integral procedure of the vast majority of breast reconstruction and has a significant impact on the final clinical outcomes. Therefore, technological advances leading to a fewer number of unfavorable outcomes and a decrease in complication rates are imperative. In this study, using a porcine model, we investigated an effect of acellular dermal matrix (ADM) used as a tissue expander cover on the dermal changes induced by mechanical forces during tissue expansion. After 14 days of expansion, skin samples were collected from one animal, while the second animal underwent radiation, and tissue was collected 8 weeks later. Tissue expanded without the use of ADM and unexpanded skin served as the controls. Collected skin biopsies were used for histological and immunohistochemical evaluation, and for gene expression analysis. We revealed that the biological cover incorporation into host tissue is facilitated by macrophages without inducing a broad inflammatory response. The utilization of ADM mitigated disruption in the dermal structure, excessive collagen deposition, and capsule formation in non-irradiated expanded skin. The protective effect was not fully maintained in irradiated skin. These results demonstrate that tissue expansion might be improved by using the tissue expander cover.

Observation of Palatal Wound Healing Process Following Various Degrees of Mucoperiosteal and Bone Trauma in a Young Rat Model

Simple Summary

The exact correlation of palatal trauma to maxillary inhibition has not been demonstrated. This paper determines the influence of different degrees of palatal trauma on maxillofacial growth and assesses whether usage of ADM can help rescue the inhibited growth during palatal wound healing. This research would help the surgeons comprehensively understand the impact of palatal trauma on maxillary growth and the therapeutic effect of the ADM.

Abstract

The accidental injury or surgery on soft and hard palatal tissue has an adverse impact on normal maxillary morphology. To design a single-factor experiment that excludes other interfering factors on maxillary growth, a young rat model was established to simulate the various degrees of palatal trauma. Eight maxillary parameters were measured to evaluate the impact of palatal trauma on maxillary growth. Furthermore, the acellular dermal matrix (ADM) was applied to cure the palatal trauma and alleviate the adverse impact of bone denudation on the maxillary growth. Micro-CT scanning and histology analyses were used. One-way ANOVA with least significant difference (LSD) post-test was used to evaluate the statistical significance. The palatal trauma mainly disturbed the transverse development of the maxilla. ADM promotes mucosa healing, but there is still an inhibitory effect on maxillofacial growth.

Application of Acellular Dermal Matrix in Gynaecology—A Current Review

The aim of our study is to draw attention to the multitude of applications of acellular dermal matrix (ADM) in the surgical treatment of urogynaecological disorders, such as reduction in the reproductive organs, and in reconstructive gynaecology. Despite the existence of numerous operational methods and materials, the effectiveness of transvaginal operation is still insufficient. Native tissue operations are often not durable enough, while operations with synthetic materials have numerous side effects, such as infections, hematomas, vaginal erosion, or dyspareunia. Hence, the search continues for a different material with a better efficacy and safety profile than those previously mentioned. It seems that ADM can meet these requirements and be a useful material for urogynaecological surgery. Key words related to the usage of ADM in gynaecological reconstructive surgery were used to search relevant databases (NCBI MedLine, Clinical Key, Clinicaltrials.gov). This manuscript is based on 43 literature sources, 28 (65.11%) of which were released after 2016. Older sources are cited for the purpose of presenting basic science, or other important issues related to the manuscript. ADM seems to be an ideal material for urogynaecological and reconstructive surgery. It has high durability, and thus high effectiveness. Moreover, it does not have the side effects typical for synthetic materials. There are no reports of material rejection, erosion or dyspareunia directly related to the presence of the mesh. Due to the difficulties in obtaining ADM and the need to perform additional tests, this material is not common in routine clinical practice. Therefore, the number of cases and the size of the research groups are insufficient to clearly define the potential of mesh from biological tissue. However, the results are so promising that it is worth considering a wider introduction to the use of this material. Our hope is that increasing clinicians’ awareness of this topic will lead to more studies comparing methods using native tissues or synthetic materials and those using ADM.

Investigating the Adipogenic Effects of Different Tissue-Derived Decellularized Matrices

Objective: Decellularized adipose-derived matrix (DAM) can promote adipogenic differentiation and adipose tissue remodeling, but the biological impact of tissue origin on DAM remains unknown. The present study aimed to investigate the effects of tissue origins on the adipogenic capacity of the decellularized matrix by comparing the cellular and tissue responses of DAM versus acellular dermal matrix (ADM).

Methods: The in vitro response of adipose-derived stem/stromal cells (ADSCs) to DAM and ADM was characterized by proliferation and differentiation. The in vivo remodeling response was evaluated in the subcutaneous injection model of immunocompromised mice, using histology, protein expression, and transcriptome analysis.

Results: Both DAM and ADM exhibited excellent decellularization effects and cytocompatibility. In the absence of exogenous stimuli, DAM could induce adipogenic differentiation of ADSCs compared with ADM. In the animal model, the levels of PDGF, VEGF, and ACRP30 were higher in the DAM groups than in the ADM group, and more neovascularization and extensive adipose tissue remodeling were observed. The mRNA-seq analysis indicated that the DAM implant regulated tissue remodeling by modulating Lat1/2 expression along with Hippo Signaling pathway in the early stage.

Conclusion: Tissue origin can influence the biological response of the decellularized matrix. DAM can retain favorable tissue-specific characteristics after the decellularization process and have unique adipogenic effects in vitro and vivo, which can be fully utilized for soft tissue repair and regeneration.

Postoperative Fluid Collections in Total Joint Arthroplasty: A Narrative Review

A post-operative fluid collection (POFC) represents a common finding in both primary and revision total joint arthroplasty (TJA). Fortunately, most resolve on their own, but in instances where they become symptomatic, prompt identification and management are paramount, especially when they occur adjacent to a joint arthroplasty because of the increased the risk of developing a periprosthetic joint infection. A strong clinical suspicion with appropriate clinical exam is required along with select imaging modalities to arrive at a diagnosis. Meticulous surgical technique is crucial to prevent POFC, but new emerging treatments continue to evolve. This article presents an updated overview of incidence, pathophysiology, diagnosis, and management of POFC in the setting of TJA. We review the role of select imaging modalities as well as summarize current literature regarding new treatments such as sclerotherapy agents, acellular dermal matrices, and negative pressure wound therapy. Future studies are necessary to explore the interplay of inflammatory mediators in POFC formation and to define their role in fluid collection resolution.

Clinical applications of acellular dermal matrices: A review

INTRODUCTION

The extracellular matrix (ECM) plays an integral role in wound healing. It provides both structure and growth factors that allow for the organised cell proliferation. Large or complex tissue defects may compromise host ECM, creating an environment that is unfavourable for the recovery of anatomical function and appearance. Acellular dermal matrices (ADMs) have been developed from a variety of sources, including human (HADM), porcine (PADM) and bovine (BADM), with multiple different processing protocols. The objective of this report is to provide an overview of current literature assessing the clinical utility of ADMs across a broad spectrum of applications.

METHODS

PubMed, MEDLINE, EMBASE, Scopus, Cochrane and Web of Science were searched using keywords 'acellular dermal matrix', 'acellular dermal matrices' and brand names for commercially available ADMs. Our search was limited to English language articles published from 1999 to 2020 and focused on clinical data.

RESULTS

A total of 2443 records underwent screening. After removing non-clinical studies and correspondence, 222 were assessed for eligibility. Of these, 170 were included in our synthesis of the literature. While the earliest ADMs were used in severe burn injuries, usage has expanded to a number of surgical subspecialties and procedures, including orthopaedic surgery (e.g. tendon and ligament reconstructions), otolaryngology, oral surgery (e.g. treating gingival recession), abdominal wall surgery (e.g. hernia repair), plastic surgery (e.g. breast reconstruction and penile augmentation), and chronic wounds (e.g. diabetic ulcers).

CONCLUSION

Our understanding of ADM's clinical utility continues to evolve. More research is needed to determine which ADM has the best outcomes for each clinical scenario.

LAY SUMMARY

Large or complex wounds present unique reconstructive and healing challenges. In normal healing, the extracellular matrix (ECM) provides both structural and growth factors that allow tissue to regenerate in an organised fashion to close the wound. In difficult or large soft-tissue defects, however, the ECM is often compromised. Acellular dermal matrix (ADM) products have been developed to mimic the benefits of host ECM, allowing for improved outcomes in a variety of clinical scenarios. This review summarises the current clinical evidence regarding commercially available ADMs in a wide variety of clinical contexts.

Skin Substitute Preparation Method Induces Immunomodulatory Changes in Co-Incubated Cells through Collagen Modification

Chronic ulcerative and hard-healing wounds are a growing global concern. Skin substitutes, including acellular dermal matrices (ADMs), have shown beneficial effects in healing processes. Presently, the vast majority of currently available ADMs are processed from xenobiotic or cadaveric skin. Here we propose a novel strategy for ADM preparation from human abdominoplasty-derived skin. Skin was processed using three different methods of decellularization involving the use of ionic detergent (sodium dodecyl sulfate; SDS, in hADM 1), non-ionic detergent (Triton X-100 in hADM 2), and a combination of recombinant trypsin and Triton X-100 (in hADM 3). We next evaluated the immunogenicity and immunomodulatory properties of this novel hADM by using an in vitro model of peripheral blood mononuclear cell culture, flow cytometry, and cytokine assays. We found that similarly sourced but differentially processed hADMs possess distinct immunogenicity. hADM 1 showed no immunogenic effects as evidenced by low T cell proliferation and no significant change in cytokine profile. In contrast, hADMs 2 and 3 showed relatively higher immunogenicity. Moreover, our novel hADMs exerted no effect on T cell composition after three-day of coincubation. However, we observed significant changes in the composition of monocytes, indicating their maturation toward a phenotype possessing anti-inflammatory and pro-angiogenic properties. Taken together, we showed here that abdominoplasty skin is suitable for hADM manufacturing. More importantly, the use of SDS-based protocols for the purposes of dermal matrix decellularization allows for the preparation of non-immunogenic scaffolds with high therapeutic potential. Despite these encouraging results, further studies are needed to evaluate the beneficial effects of our hADM 1 on deep and hard-healing wounds.

Abdominoplasty Skin-Based Dressing for Deep Wound Treatment-Evaluation of Different Methods of Preparation on Therapeutic Potential

The management of hard-to-heal wounds is a significant clinical challenge. Acellular dermal matrices (ADMs) have been successfully introduced to enhance the healing process. Here, we aimed to develop protocol for the preparation of novel ADMs from abdominoplasty skin. We used three different decellularization protocols for skin processing, namely, 1M NaCl and sodium dodecyl sulfate (SDS, in ADM1); 2M NaCl and sodium dodecyl sulfate (SDS, in ADM1); and a combination of recombinant trypsin and Triton X-100 (in hADM 3). We assessed the effectiveness of decellularization and ADM's structure by using histochemical and immunochemical staining. In addition, we evaluated the therapeutic potential of novel ADMs in a murine model of wound healing. Furthermore, targeted transcriptomic profiling of genes associated with wound healing was performed. First, we found that all three proposed methods of decellularization effectively removed cellular components from abdominoplasty skin. We showed, however, significant differences in the presence of class I human leukocyte antigen (HLA class I ABC), Talin 1/2, and chondroitin sulfate proteoglycan (NG2). In addition, we found that protocols, when utilized differentially, influenced the preservation of types I, III, IV, and VII collagens. Finally, we showed that abdominoplasty skin-derived ADMs might serve as an effective and safe option for deep wound treatment. More importantly, our novel dressing (ADM1) improves the kinetics of wound closure and scar maturation in the proliferative and remodeling phases of wound healing. In conclusion, we developed a protocol for abdominoplasty skin decellularization suitable for the preparation of biological dressings. We showed that different decellularization methods affect the purity, structure, and therapeutic properties of ADMs.

Histological Analyses of Capsular Contracture and Associated Risk Factors: A Systematic Review

BACKGROUND

Capsular contracture is a severe complication to breast surgery with implants. Previous studies suggest multiple risk factors are associated with capsular contracture, but the etiology is still unknown. We performed a literature review to investigate existing studies on histological analyses of breast implant capsules and how clinical risk factors impact the capsule morphology.

METHODS

The literature search was conducted in PubMed. Studies that performed histological analyses of breast implant capsules were included. Animal studies or studies with a study population of less than five patients were excluded.

RESULTS

Fifty-two studies were included. The histological analyses showed that the breast implant capsules were organized in multiple layers with an inner layer of synovial-like metaplasia which was reported to diminish in capsules with capsular contracture. The remaining layers of the capsule mostly consisted of collagen. The alignment of the collagen fibers differed between contracted and non-contracted capsules, and capsules with higher Baker grade were generally thickest and contained more tissue inflammation. Studies investigating capsules affected by radiotherapy found a more pronounced inflammatory response and the capsules were generally thicker and fibrotic compared with nonirradiated capsules.

CONCLUSIONS

The included studies offer valuable insights into the histological changes caused by capsular contracture and their relation to clinical risk factors. Further studies with larger sample sizes and more strict inclusion criteria are needed to further investigate implant capsules and the role of the synovial-like metaplasia for the development of capsular contracture.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors https://www.springer.com/00266 .

Direct comparison of CGCRYODERM and DermACELL in the same patient for outcomes in bilateral implant-based breast reconstruction: a retrospective case series

Background

The use of acellular dermal matrix (ADM) has been popularized in implant-based breast reconstruction (IBR). However, it is still controversial if ADM-associated complication rates differ with varying types of ADM products. The aim of this study was to compare postoperative complications between CGCRYODERM and DermACELL.

Methods

A retrospective chart review was performed on 32 patients (64 breasts) who underwent bilateral prosthetic breast reconstruction between June 2015 and December 2019. All patients received two different ADMs in each breast during the surgery. Demographic variables, operative characteristics, and postoperative outcomes were compared between the cryopreserved and pre-hydrated ADM.

Results

The overall major and minor postoperative complications developed in 7 and 1 out of 32 patients, respectively. Seroma and infection were the most common complications. There were no cases that infection and/or seroma involved both breasts in one individual. No significant differences were observed in terms of seroma, infection, hematoma, mastectomy flap necrosis, or drainage period between the CGCRYODERM and DermACELL groups (P=0.5637, 0.1797, 1.0000, 0.3173, and 0.2925, respectively). There was no case of reconstruction failure leading to explantation.

Conclusions

There were no statistically significant differences in postoperative complications between the two breasts reconstructed with CGCRYODERM and DermACELL in the same patient who underwent bilateral IBR. This is the first study to compare cryopreserved and pre-hydrated ADMs. We suggest that CGCRYODERM is a suitable option with a comparable safety profile for IBR.

In Vivo Comparison of Three Human Acellular Dermal Matrices for Breast Reconstruction

BACKGROUND/AIM

Acellular dermal matrices (ADMs) have become popular in implant-based breast reconstruction. The aim of this study was to compare three commonly used ADM products in vivo in an animal model.

MATERIALS AND METHODS

The nucleic acid content (residual double-stranded DNA) and the levels of the remaining growth factors after decellularization were measured for each ADM. Cytocompatibility with ADMs was documented using NIH 3T3 mouse fibroblast cells. In vivo, the implanted ADMs were histologically evaluated at 1, 2, 3, and 6 months (n=5) using male 8-week-old Sprague-Dawley rats.

RESULTS

Fibroblasts grew in the SureDerm HD and DermACELL with no cytotoxicity. In a rat model, SureDerm HD and DermACELL incorporated more readily into the surrounding host tissue, as measured by rapid cell influx and collagen deposition, and showed more delayed tissue remodeling with decreased matrix metalloproteinases levels compared to AlloDerm.

CONCLUSION

SureDerm HD and DermACELL can be used as biological materials for breast reconstruction.

Optimization of Novel Human Acellular Dermal Dressing Sterilization for Routine Use in Clinical Practice

Gamma rays and electrons with kinetic energy up to 10 MeV are routinely used to sterilize biomaterials. To date, the effects of irradiation upon human acellular dermal matrices (hADMs) remain to be fully elucidated. The optimal irradiation dosage remains a critical parameter affecting the final product structure and, by extension, its therapeutic potential. ADM slides were prepared by various digestion methods. The influence of various doses of radiation sterilization using a high-energy electron beam on the structure of collagen, the formation of free radicals and immune responses to non-irradiated (native) and irradiated hADM was investigated. The study of the structure changes was carried out using the following methods: immunohistology, immunoblotting, and electron paramagnetic resonance (EPR) spectroscopy. It was shown that radiation sterilization did not change the architecture and three-dimensional structure of hADM; however, it significantly influenced the degradation of collagen fibers and induced the production of free radicals in a dose-dependent manner. More importantly, the observed effects did not disrupt the therapeutic potential of the new transplants. Therefore, radiation sterilization at a dose of 35kGy can ensure high sterility of the dressing while maintaining its therapeutic potential.

Patient-Reported Outcomes and Aesthetic Results after Immediate Breast Reconstruction Using Human Acellular Dermal Matrices: Results of a Multicenter, Prospective, Observational NOGGO-AWOGyn Study

BACKGROUND

With the increased use of acellular dermal matrices (ADMs) in implant-based breast reconstructions (IBBRs), the evaluation of patient-reported outcomes becomes more important.

METHODS

Patients who underwent an immediate human ADM-assisted, submuscular IBBR were included in this noninterventional, multicenter, prospective cohort study. Patients with primary reconstruction (cohort A) and patients with a revision surgery after capsular fibrosis (cohort B) were followed up for 12 months after surgery. Quality of life (EORTC BR-23) and patient and surgeon satisfaction scores (1 ["very satisfied"] to 6 ["not satisfied"]) with the outcome and the aesthetic result evaluated by 2 independent, external experts were assessed.

RESULTS

Eighty-four patients were enrolled in the study. The mean patient satisfaction score was 2.1 ± 0.8, with higher satisfaction in cohort B (p = 0.041). The score did not change significantly during the follow-up (p = 0.479). The mean satisfaction score of the surgeons was 2.0 ± 0.7; it was also higher in cohort B (p = 0.016) and showed no changes over time (p = 0.473). The mean aesthetic result was 2.2 ± 0.7. 92.9% of the patients completed at least 1 quality of life questionnaire. Body image and sexual functioning increased during follow-up. One year after surgery, the mean scores were 77.2 ± 22.5 and 44.7 ± 27.3, respectively.

CONCLUSION

The level of satisfaction among patients and surgeons and the score of the aesthetic result were constantly high among patients after ADM-assisted IBBR. Higher satisfaction scores could be observed after revision surgery caused by capsular fibrosis (cohort B) compared to primary reconstruction (cohort A). Quality of life increased during the first year after surgery.

Chronic Diabetic Wounds and Their Treatment with Skin Substitutes

With the global prevalence of type 2 diabetes mellitus steeply rising, instances of chronic, hard-healing, or non-healing diabetic wounds and ulcers are predicted to increase. The growing understanding of healing and regenerative mechanisms has elucidated critical regulators of this process, including key cellular and humoral components. Despite this, the management and successful treatment of diabetic wounds represents a significant therapeutic challenge. To this end, the development of novel therapies and biological dressings has gained increased interest. Here we review key differences between normal and chronic non-healing diabetic wounds, and elaborate on recent advances in wound healing treatments with a particular focus on biological dressings and their effect on key wound healing pathways.

Novel Use of a Porcine Bladder Extracellular Matrix Scaffold to Treat Postoperative Seroma in a Total Knee Arthroplasty Patient

Seroma formation in a knee arthroplasty surgery is a rare complication. When seromas occur, they act as a nidus for bacterial growth and create an optimal environment for surgical site infections. In this case report, a 52-year-old woman presented with a seroma after multiple revision operations on the left knee. Owing to multiple failures of standard irrigation and drainage procedures to resolve the seroma, an orthoplastic colleague was consulted. Over five-and-a-half months, the patient underwent multiple procedures that failed to treat the seroma. However, in a final exploratory procedure, 3000 mg of urinary bladder matrix and negative pressure wound vacuum were placed. Seven months after the intervention, the patient had complete resolution.

Twenty years of histochemistry in the third millennium, browsing the scientific literature

Over the last twenty years, about 240,000 articles where histochemical techniques were used have been published in indexed journals, and their yearly number has progressively increased. The histochemical approach was selected by researchers with very different scientific interests, as the journals in which these articles were published fall within 140 subject categories. The relative proportion of articles in some of these journal categories did change over the years, and browsing the table of contents of the European Journal of Histochemistry, as an example of a strictly histochemical journal, it appeared that in recent years histochemical techniques were preferentially used to mechanistically investigate natural or experimentally induced dynamic processes, with reduced attention to purely descriptive works. It may be foreseen that, in the future, histochemistry will be increasingly focused on studying the molecular pathways responsible for cell differentiation, the maintenance or loss of the differentiated state, and tissue regeneration.

Complication Rate of Prepectoral Implant-based Breast Reconstruction Using Human Acellular Dermal Matrices

Implant-based breast reconstruction (IBR) is currently the most frequently performed reconstructive technique post mastectomy. Even though submuscular IBR continues to be the most commonly used technique, mastectomy technique optimization, the possibility to check skin viability with indocyanine green angiography, the enhanced propensity of patients undergoing prophylactic mastectomies, and the introduction of acellular dermal matrices (ADMs) have paved the way to the rediscovery of the subcutaneous reconstruction technique. The aim of this article is to update the complication rate of immediate and delayed prepectoral IBR using human ADMs (hADMs).

METHODS

A literature search, using PubMed, Medline, Cochrane, and Google Scholar database according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, was conducted to evaluate complication rates of prepectoral implant-based reconstructions using hADMs. The following MeSH terms were used: "prepectoral breast reconstruction acellular dermal matrix," "prepectoral breast reconstruction ADM," "human ADM breast reconstruction," and "human acellular dermal matrix breast reconstruction" (period: 2005-2020; the last search took place on April 2, 2020).

RESULTS

This meta-analysis includes 1425 patients (2270 breasts) who had undergone immediate or delayed prepectoral IBR using different types of hADMs. The overall complication rate amounted to 19%. The most frequent complication was represented by infection (7.9%), followed by seroma (4.8%), mastectomy flap necrosis (3.4%), and implant loss (2.8%).

CONCLUSIONS

The overall complication rate was 19%. The most frequent complications were infection, seroma, and mastectomy flap necrosis, while capsular contracture was rare.

State of the Art on Biomaterials for Soft Tissue Augmentation in the Oral Cavity. Part I: Natural Polymers-Based Biomaterials

Oral soft tissue thickening or grafting procedures are often necessary to cover tooth recession, re-establish an adequate width of keratinized tissue, correct mucogingival deformities improving esthetics, prepare a site for an implant or prosthetics, for ridge preservation procedures, and soft tissue contouring around dental implants. Gingival recession and root or implant exposure are commonly associated and have led to mucogingival deficiencies that have traditionally been treated with free gingival grafts and autogenous soft tissue grafts. The latter represents the gold standard in acquiring a functionally adequate zone of keratinized attached gingiva. However, soft tissue substitutes are more usually employed because they lessen morbidity and abbreviate surgical time. This review is aimed at assessing oral soft tissue augmentation techniques and biomaterials used from existing literature, principally concerning scaffolds from both human and animal-based tissue derivatives matrices. In order to avoid the use of human donor tissue, the xenogenic collagen matrices are proposed for soft tissue augmentation. In general, all of them have provided the remodeling processes and enhanced the formation of new connective tissue within the matrix body.

Peri-implant soft tissue phenotype modification and its impact on peri-implant health: A systematic review and network meta-analysis

BACKGROUND

The peri-implant soft tissue phenotype (PSP) encompasses the keratinized mucosa width (KMW), mucosal thickness (MT), and supracrestal tissue height (STH). Numerous approaches to augment soft tissue volume around endosseous dental implants have been investigated. To what extent PSP modification is beneficial for peri-implant health has been subject of debate in the field of implant dentistry. The aim of this systematic review was to analyze the evidence regarding the efficacy of soft tissue augmentation procedures aimed at modifying the PSP and their impact on peri-implant health.

METHODS

A comprehensive search was performed to identify clinical studies that involved soft tissue augmentation around dental implants and reported findings on KMW, MT, and/or STH changes. The effect of the intervention on peri-implant health was also assessed. Selected articles were classified based on the general type of surgical approach to increase PSP, either bilaminar or an apically positioned flap (APF) technique. A network meta-analysis including only randomized-controlled trials (RCTs) reporting on PSP outcomes was conducted to assess and compare different techniques.

RESULTS

A total of 52 articles were included in the qualitative analysis, and 23 RCTs were included as part of the network meta-analysis. Sixteen RCTs reported the outcomes of PSP modification therapy with bilaminar techniques, whereas 7 involved the use of APF. The analysis showed that bilaminar techniques in combination with soft tissue grafts (connective tissue graft [CTG], collagen matrix [CM], and acellular dermal matrix [ADM]) resulted in a significant increase in MT compared to non-augmented sites. In particular, CTG and ADM were associated with higher MT gain as compared to CM and non-augmented sites. However, no significant differences in KMW were observed across different bilaminar techniques. PSP modification via a bilaminar approach utilizing either CTG or CM showed beneficial effects on marginal bone level stability. APF-based approaches in combination with free gingival graft (FGG), CTG, CM, or ADM showed a significant KMW gain compared to non-augmented sites. However, compared to APF alone, only FGG exhibited a significantly higher KMW gain. APF with any evaluated soft tissue graft was associated with with reduction of probing depth, soft tissue dehiscence and plaque index compared to non-augmented sites compared to non-augmented sites. The evidence regarding the effect of PSP modification via APF-based approaches on peri-implant marginal bone loss or preservation is inconclusive.

CONCLUSIONS

Bilaminar approach involving CTG or ADM obtained the highest amount of MT gain, whereas APF in combination with FGG was the most effective technique for increasing KMW. KMW augmentation via APF was associated with a significant reduction in probing depth, soft tissue dehiscence and plaque index, regardless of the soft tissue grafting material employed, whereas bilaminar techniques with CTG or CM showed beneficial effects on marginal bone level stability.

Invited Discussion on: Skin Reducing Mastectomy and Prepectoral Breast Reconstruction in Large Ptotic Breasts

The applicability of acellular dermal matrix (ADM) for breast reconstruction is a consolidated reality, as skin and nipple sparing techniques became standard mastectomy approaches. ADM is a soft connective tissue graft generated via a decellularization process that preserves intact the extracellular skin matrix. ADM not only provides tissue reinforcement, but also better pocket control, and shape without the compressive effects of total sub-muscular coverage. Our preference is using one "Strattice®" ADM in pocket's format to cover the implant's inferior pole, protecting the totality of the implant in its inferior pole by the ADM. This technique besides its versatility is cheaper than other techniques presented. The success of ADM prepectoral breast reconstruction depends on three pillars: careful patient selection, flap perfusion and postoperative management. The challenge in large and/or ptotic breasts under the risk of large badly perfused flaps as well as of nipple, due to the nipple-furcules distance which can be handled with well-selected criteria as mentioned and safe management of nipple ascension as well as the nipple graft. Traditionally, they need to be associated with reducing mammoplasty techniques to achieve the expected aesthetic results in a single stage. Therefore, the plastic surgeon must be prepared for new reconstructive approaches postmastectomy, having the ADM as an excellent option for that.

Povidone-iodine Does Not Affect Acellular Dermal Matrix Integration in Patients Undergoing 2-staged, Prepectoral, Breast Reconstructive Surgery

Background:

Povidone-iodine has been traditionally used as an antimicrobial agent to irrigate the breast pocket and rinse the prosthesis before placement in the pocket. Use of povidone-iodine with breast implants was banned from 2000 to 2017. During this period, acellular dermal matrix (ADM) was introduced to breast surgery. In nonclinical studies, povidone-iodine can impair collagen synthesis and kill fibroblasts. Cellular repopulation was critical for ADM integration. Whether povidone-iodine impacts ADM integration was unknown.

Methods:

Patients who underwent immediate, prepectoral, 2-staged breast reconstruction were included in this retrospective study. Study population was divided into povidone-iodine–treated patients and triple-antibiotic–treated patients. The breast pockets were rinsed with the antimicrobial agent, and the prostheses and ADMs were presoaked in the agent perioperatively. At implant exchange, the extent of ADM integration was clinically assessed. ADM integration was defined as >25% of matrix vascularization. ADM integration and postoperative complications were compared between the groups.

Results:

A total of 111 patients (257 reconstructions) were included—58 patients (111 reconstructions) were exposed to povidone-iodine and 53 patients (97 reconstructions) to triple-antibiotic solution. ADM integration was noted in 97% of breasts in each group. Integrated matrices appeared healthy, had no signs of foreign body reaction, and demonstrated punctate bleeding. Complications did not differ between the groups, including the rate of infections, seroma, and expander loss.

Conclusion:

Irrigation of the breast pocket and presoaking of the prosthesis and ADM with povidone-iodine appear to have no adverse consequences on clinical outcomes and did not impede matrix integration.

In Vitro Characterization of a Novel Human Acellular Dermal Matrix (BellaCell HD) for Breast Reconstruction

In the past, acellular dermal matrices (ADMs) have been used in implant-based breast reconstruction. Various factors affect the clinical performance of ADMs since there is a lack of systematic characterization of ADM tissues. This study used BellaCell HD and compared it to two commercially available ADMs—AlloDerm Ready to Use (RTU) and DermACELL—under in vitro settings. Every ADM was characterized to examine compatibility through cell cytotoxicity, proliferation, and physical features like tensile strength, stiffness, and the suture tensile strength. The BellaCell HD displayed complete decellularization in comparison with the other two ADMs. Several fibroblasts grew in the BellaCell HD with no cytotoxicity. The proliferation level of fibroblasts in the BellaCell HD was higher, compared to the AlloDerm RTU and DermACELL, after 7 and 14 days. The BellaCell HD had a load value of 444.94 N, 22.44 tensile strength, and 118.41% elongation ratio, and they were higher than in the other two ADMs. There was no significant discrepancy in the findings of stiffness evaluation and suture retention strength test. The study had some limitations because there were many other more factors useful in ADM’s testing. In the study, BellaCell HD showed complete decellularization, high biocompatibility, low cytotoxicity, high tensile strength, high elongation, and high suture retention strengths. These characteristics make BellaCell HD a suitable tissue for adequate and safe use in implant-based breast reconstruction in humans.

Use of Mucograft Collagen Matrix® versus Free Gingival Graft to Augment Keratinized Tissue around Teeth: A Randomized Controlled Clinical Trial

Objectives

This study aimed to evaluate the mucograft collagen matrix (CM) to increase keratinized tissue around teeth compared to free gingival graft (FGG).

Materials and Methods

The present double-blind, randomized, controlled clinical trial studied 12 patients who had 2 mm or less keratinized gingiva bilaterally around mandibular premolars. The 6-month width of keratinized tissue, periodontal parameters (preoperatively and 1, 3, and 6 months postoperatively), color match, pain, and total surgical time were measured.

Results

The mean dimensional change of keratinized gingiva 6 months postoperatively was 4.1±0.7 mm for FGG and 8±1.7 mm for CM. Periodontal parameters were not affected in the two groups. The CM group had a significantly lower pain, experienced less surgery time, and gained better aesthetics compared to the FGG group.

Conclusion

CM appears to be a suitable substitute for FGG in procedures designed to increase keratinized tissue around teeth. It has remarkable benefits, such as acceptable keratinized tissue gain, less pain, less surgical chair time, and better aesthetics.

A journal of histochemistry as a forum for non-histochemical scientific societies

Histochemical techniques are widely applied in biomedical research and, during the last twenty years, they were among the methods used in more than 590,000 scientific articles in indexed journals. However, a very small percentage of these papers were published in strictly histochemical journals. A possible strategy to widen the audience of the histochemical journals making them attractive to non-histochemist authors might be to publish and make open-access available the proceedings of the meetings and conferences of valued scientific societies whose fellows use microscopy and histochemistry in their experimental activity. In the last years' experience of the European Journal of Histochemistry, this approach was effective to increase the number of published articles on stem cells and development, connective tissue and nerve cell biology.

Extracellular matrix-based scaffolding technologies for periodontal and peri-implant soft tissue regeneration

The present article focuses on the properties and indications of scaffold-based extracellular matrix (ECM) technologies as alternatives to autogenous soft tissue grafts for periodontal and peri-implant plastic surgical reconstruction. The different processing methods for the creation of cell-free constructs resulting in preservation of the extracellular matrices influence the characteristics and behavior of scaffolding biomaterials. The aim of this review is to discuss the properties, clinical application, and limitations of ECM-based scaffold technologies in periodontal and peri-implant soft tissue augmentation when used as alternatives to autogenous soft tissue grafts.

Acellular Dermal Matrix Mistaken as Recurrence of Malignancy Following Surgery on Positron Emission Tomography/Computed Tomography: A Case Report

OBJECTIVES

To report a rare clinical presentation of an acellular dermal matrix (ADM) used during lateral temporal bone resection mimicking recurrence of cancer of external auditory canal (EAC) on positron emission tomography/computed tomography (PET/CT) 9 months after surgery.

METHODS

Case report and literature review.

RESULTS

A 71-year-old woman underwent lateral temporal bone resection 9 months earlier for management of squamous cell carcinoma of the EAC. She exhibited recurrence of the tumor on ¹⁸F-FDG PET/CT with an intense uptake value (SUV_max 12.8) at the operated site. Exploration was conducted as the location of the lesion was unfavorable to perform biopsy. However, histopathologic evaluation revealed that the lesion was the ADM implanted during surgery.

CONCLUSIONS

Care should be taken when using an ADM during malignant tumor surgery if the site of surgery is not conducive for fine needle aspiration or biopsy.

Acellular dermal matrix and coronally advanced flap or tunnel technique in the treatment of multiple adjacent gingival recessions. A 12-year follow-up from a randomized clinical trial

AIM

To evaluate the long-term outcomes of Acellular Dermal Matrix (ADM) with Coronally Advanced Flap (CAF) or Tunnel technique (TUN) in the treatment of multiple adjacent gingival recessions (MAGRs).

MATERIAL AND METHODS

Nineteen of the original 24 patients contributing to a total number of 33 sites for CAF and 34 for TUN were available for the 12 years follow-up examination. Recession depth, mean root coverage (mRC), keratinized tissue width (KTW), gingival thickness (GT) were evaluated and compared with baseline values and 6-months results. Regression analysis was performed to identify factors related to the stability of the gingival margin.

RESULTS

A highly significant drop in mRC was observed for both groups from the 6 months timepoint to the 12 years recall (p < .001). While there were no statistically significant differences between the two groups in terms of Clinical Attachment Level (CAL), KTW, GT changes and Root Coverage Esthetic Score at each timepoint (p > .05). KTW ≥ 2 mm and GT ≥ 1.2 mm at 6-months were two predictors for stability of the gingival margin (p = .03 and p = .01, respectively).

CONCLUSIONS

A significant relapse of the gingival margin of MAGRs treated with CAF or TUN + ADM was observed after 12 years.

Ultrastructural histochemistry in biomedical research: Alive and kicking

The high-resolution images provided by the electron microscopy has constituted a limitless source of information in any research field of life and materials science since the early Thirties of the last century. Browsing the scientific literature, electron microscopy was especially popular from the 1970’s to 80’s, whereas during the 90’s, with the advent of innovative molecular techniques, electron microscopy seemed to be downgraded to a subordinate role, as a merely descriptive technique. Ultra -structural histochemistry was crucial to promote the Renaissance of electron microscopy, when it became evident that a precise localization of molecules in the biological environment was necessary to fully understand their functional role. Nowadays, electron microscopy is still irreplaceable for ultrastructural morphology in basic and applied biomedical research, while the application of correlative light and electron microscopy and of refined ultrastructural histochemical techniques gives electron microscopy a central role in functional cell and tissue biology, as a really unique tool for high-resolution molecular biology in situ.