Attenuating Chronic Fibrosis: Decreasing Foreign Body Response with Acellular Dermal Matrix

Surgical implants are increasingly used across multiple medical disciplines, with applications ranging from tissue reconstruction to improving compromised organ and limb function. Despite their significant potential for improving health and quality of life, biomaterial implant function is severely limited by the body's immune response to its presence: this is known as the foreign body response (FBR) and is characterized by chronic inflammation and fibrotic capsule formation. This response can result in life-threatening sequelae such as implant malfunction, superimposed infection, and associated vessel thrombosis, in addition to soft tissue disfigurement. Patients may require frequent medical visits, as well as repeated invasive procedures, increasing the burden on an already strained health care system. Currently, the FBR and the cells and molecular mechanisms that mediate it are poorly understood. With applications across a wide array of surgical specialties, acellular dermal matrix (ADM) has emerged as a potential solution to the fibrotic reaction seen with FBR. Although the mechanisms by which ADM decreases chronic fibrosis remain to be clearly characterized, animal studies across diverse surgical models point to its biomimetic properties that facilitate decreased periprosthetic inflammation and improved host cell incorporation. Impact Statement Foreign body response (FBR) is a significant limitation to the use of implantable biomaterials. Acellular dermal matrix (ADM) has been observed to decrease the fibrotic reaction seen with FBR, although its mechanistic details are poorly understood. This review is dedicated to summarizing the primary literature on the biology of FBR in the context of ADM use, using surgical models in breast reconstruction, abdominal and chest wall repair, and pelvic reconstruction. This article will provide readers with an overarching review of shared mechanisms for ADM across multiple surgical models and diverse anatomical applications.

Acellular dermal matrix in reconstructive surgery: Applications, benefits, and cost

Modern tissue engineering has made substantial advancements that have revolutionized plastic surgery. Acellular dermal matrix (ADM) is an example that has gained considerable attention recently. ADM can be made from humans, bovines, or porcine tissues. ADM acts as a scaffold that incorporates into the recipient tissue. It is gradually infiltrated by fibroblasts and vascularized. Fortunately, many techniques have been used to remove cellular and antigenic components from ADM to minimize immune system rejection. ADM is made of collagen, fibronectin, elastin, laminin, glycosaminoglycans, and hyaluronic acid. It is used in critical wounds (e.g., diabetic wounds) to protect soft tissue and accelerate wound healing. It is also used in implant-based breast reconstruction surgery to improve aesthetic outcomes and reduce capsule contracture risk. ADM has also gained attention in abdominal and chest wall defects. Some studies have shown that ADM is associated with less erosion and infection in abdominal hernias than synthetic meshes. However, its higher cost prevents it from being commonly used in hernia repair. Also, using ADM in tendon repair (e.g., Achilles tendon) has been associated with increased stability and reduced rejection rate. Despite its advantages, ADM might result in complications such as hematoma, seroma, necrosis, and infection. Moreover, ADM is expensive, making it an unsuitable option for many patients. Finally, the literature on ADM is insufficient, and more research on the results of ADM usage in surgeries is needed. This article aims to review the literature regarding the application, Benefits, and costs of ADM in reconstructive surgery.

Effect of gelatin methacryloyl hydrogel on healing of the guinea pig vaginal wall with or without mesh augmentation

INTRODUCTION AND HYPOTHESIS

The aims of this study were to evaluate the effectiveness of gelatin methacryloyl as an adjunct to anterior vaginal wall injury with or without vaginal mesh compared with traditional repair with suture.

METHODS

Virginal cycling Hartley strain guinea pigs (n = 60) were randomized to undergo surgical injury and repair using either polyglactin 910 suture or gelatin methacryloyl for epithelium re-approximation or anterior colporrhaphy with mesh augmentation using either polyglactin 910 suture or gelatin methacryloyl for mesh fixation and epithelium re-approximation. Noninjured controls (n = 5) were also evaluated. After 4 days, 4 weeks, or 3 months, tissues were analyzed by hematoxylin & eosin in addition to immunolabeling for macrophages, leukocytes, smooth muscle, and fibroblasts.

RESULTS

Surgical injury repaired with suture was associated with increased inflammation and vessel density compared with gelatin methacryloyl. Vimentin and α-smooth muscle actin expression were increased with gelatin methacryloyl at 4 days (p = 0.0026, p = 0.0272). There were no differences in changes in smooth muscle or overall histomorphology after 3 months between the two closure techniques. Mesh repair with suture was also associated with increased inflammation and vessel density relative to gelatin methacryloyl. Quantification of collagen content by picrosirius red staining revealed increased thick collagen fibers throughout the implanted mesh with gelatin methacryloyl compared with suture at 4 weeks (0.62 ± 0.01 μm2 vs 0.55 ± 0.01, p = 0.018). Even at the long-term time point of 3 months, mesh repair with suture resulted in a profibrotic encapsulation of the mesh fibers, which was minimal with gelatin methacryloyl. Smooth muscle density was suppressed after mesh implantation returning to baseline levels at 3 months regardless of fixation with suture or gelatin methacryloyl.

CONCLUSIONS

These results suggest that gelatin methacryloyl might be a safe alternative to suture for epithelium re-approximation and anchoring of prolapse meshes to the vagina and may improve chronic inflammation in the vaginal wall associated with mesh complications.

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.

A Novel Technique Combining Human Acellular Dermal Matrix (HADM) and Enriched Platelet Therapy (EPT) for the Treatment of Vaginal Laxity: A Single-Arm, Observational Study

BACKGROUND

There is a paucity of knowledge about cosmetic vaginal tightening procedures; therefore, the present study aimed to describe the clinical effects of a novel combination technique of human acellular dermal matrix (HADM) and enriched platelet therapy (EPT) for the treatment of vaginal laxity.

METHODS

This single-arm, observational study was conducted on 52 patients with grade II to III vaginal relaxation. HADM biological band (U-shaped) was implanted in these patients by submucosal puncture in vagina under anesthesia. This was followed by thrice administration of EPT injection, once at the time surgery followed by each dose at a time interval of one month. Patients were followed up for a period of 6 months based on Female Sexual Function Index (FSFI) and Vaginal Health Index (VHI) scores. Patient satisfaction was measured using Visual Analogue Score (VAS).

RESULTS

About 52 women with median age of 39 years were included in the study. The average time reported to complete HADM surgery was reported as 27 minutes. Following implantation, it was found that labia minora was significantly closed and perineal length was increased from 1.5 to 2.2 cm. Moreover, there was improvement in elasticity, contractility and lubricity of vaginal mucosa. The sexual function scores from pre- to post-surgery were significantly increased (7.95 vs. 30.09; p value: <0.001). The mean VHI score also increased significantly after 6 months of treatment (mean ± S.D. before vs after treatment: 11.2 ± 3.3 vs. 19.6 ± 4.1, P < 0.0001). The mean VAS after surgery was 1.61 ± 0.31. About 96% of the patients did not feel any pain after treatment at 6-month follow-up. No adverse effects were reported in this study.

CONCLUSIONS

These findings supported that combination treatment with HADM and EPT was safe and associated with both improved vaginal laxity and sexual function. These results may provide a novel surgical technique for this prevalent and undertreated condition.

LEVEL OF EVIDENCE IV

Therapeutic Study 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 .

Anterior colporrhaphy compared with collagen-coated transvaginal mesh for anterior vaginal wall prolapse: a randomised controlled trial

OBJECTIVE

To investigate the anatomical cure rate and complications related to collagen-coated mesh for cystocele, compared with a conventional anterior colporrhaphy.

DESIGN

A randomised controlled study.

SETTING

Six departments of obstetrics and gynaecology in Norway, Sweden, Finland, and Denmark.

POPULATION

Women aged 55 years or older, referred for surgery with a prolapse of the anterior vaginal wall of stage 2 or higher.

METHODS

Women scheduled for primary cystocoele surgery were randomised to either anterior colporrhaphy or a collagen-coated Prolene mesh. Power analysis indicated that 130 patients had to be randomised. All patients were evaluated using the Pelvic Organ Prolapse-Quantification (POP-Q) measurement. Quality of life, symptoms, and sexual function were evaluated using the Pelvic Floor Impact Questionnaire, the Pelvic Floor Distress Inventory, and the Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire.

MAIN OUTCOME MEASURES

The primary outcome was objective cure, defined as prolapse below POP-Q stage 2 at the 12-months follow-up. Secondary outcomes were quality of life, symptoms, and presence (or not) of complications.

RESULTS

In total, 161 women were randomised to either anterior colporrhaphy or mesh (participant ages 64.9 ± 6.4 years versus 64.7 ± 6.6 years, respectively; mean ± SD). The objective cure rate was 39.8% (95% CI 28.6-50.9%) in the anterior colporrhaphy group, compared with 88.1% (95% CI 80.7-95.6%) in the mesh group (P < 0.001). Vaginal mesh exposure occurred in ten women (13.3%) and dyspareunia occurred in two women (2.7%, not significant) in the mesh group at the 12-months follow-up. Questionnaires revealed no difference between the groups.

CONCLUSIONS

Our study demonstrates a significantly improved objective cure rate associated with a high exposure rate among women with mesh surgery as opposed to conventional surgery.