Self-retained cryopreserved amniotic membrane for treating severe corneal ulcers: a comparative, retrospective control study

Amniotic Membrane Transplantation: Clinical Applications in Enhancing Wound Healing and Tissue Regeneration

Chronic wounds and non-healing tissue defects pose significant clinical challenges, necessitating innovative therapeutic approaches. A comprehensive literature review of amniotic membrane transplantation for wound healing and tissue repair evaluates the efficacy and safety of amniotic membrane transplantation in enhancing wound healing and tissue repair. Amniotic membranes promote wound closure and reduce inflammation and scarring via abundant growth factors, cytokines, and extracellular matrix components, which foster conducive environments for tissue regeneration. Amniotic membrane transplantation is effective in various medical disciplines, including ophthalmology, dermatology, and orthopedics. Low immunogenicity and anti-microbial properties ensure their safe application. Amniotic membrane transplantation offers a promising therapeutic approach for wound healing and tissue repair, and further research is warranted to explore its regenerative potential fully.

Amniotic membrane transplantation: structural and biological properties, tissue preparation, application and clinical indications

The amniotic membrane is a single epithelial layer of the placenta. It has anti-inflammatory, anti-scarring, anti-angiogenic and possibly bactericidal properties. The basement membrane of the amniotic membrane acts as a substrate to encourage healing and re-epithelialisation. It has been used in many ocular surface diseases including persistent epithelial defects (corneal or conjunctival), chemical or thermal burns, limbal stem cell deficiency, cicatrising conjunctivitis, ocular graft versus host disease, microbial keratitis, corneal perforation, bullous keratopathy, dry eye disease, corneal haze following refractive surgery and cross-linking, band keratopathy, ocular surface neoplasia, pterygium surgery, and ligneous conjunctivitis. This review provides an up-to-date overview of amniotic membrane transplantation including the structural and biological properties, preparation and application, clinical indications, and commercially available products.

Surgical management of infectious keratitis

The successful management of infectious keratitis is usually achieved with a combination of tools for accurate diagnosis and targeted timely antimicrobial therapy. An armamentarium of surgical interventions is available in the acute stage which can be resorted to in a step wise manner or in combination guided by the response to treatment. Simple surgical modalities can facilitate accurate diagnosis e.g. corneal biopsy and alcohol delamination. Surgery to promote epithelial healing can vary from tarsorrhaphy, amniotic membrane transplantation or conjunctival flaps depending on the extent of infection, visual prognosis, availability of tissue and surgeon's experience. Collagen crosslinking has been increasingly utilized with successful results to strengthen the cornea and reduce the infective load consequently the need for further elaborate surgical interventions. It has shown encouraging results specially in superficial bacterial and fungal keratitis but for deeper infections, viral and acanthamoeba keratitis, its use remains questionable. When globe integrity is compromised, corneal gluing is the most commonly used procedure to seal small perforations. In larger perforations/fulminant infections a tectonic/therapeutic graft is advisable. Partial thickness grafts are increasingly popular to treat superficial infection or internally tamponade perforations. Peripheral therapeutic grafts face challenges with potential requirement for a manually fashioned graft, and increased risk of rejection due to proximity to the limbal vessels. Late stage visual rehabilitation is likely to require further surgical interventions after complete resolution of infection and inflammation. A preliminary assessment of corneal sensation and integrity of the ocular surface are key for any successful surgical intervention to restore vision.

Amniotic membrane transplantation in a patient with impending perforated corneal ulcer caused by Streptococcus mitis: A case report and review of literature

BACKGROUND

Streptococcus mitis (S. mitis) is an opportunistic pathogen that can lead to severe ocular infections. In previous reports, penetrating keratoplasty (PK) was usually adopted for the treatment of persistent corneal ulcers. This report describes an unusual case of nonhealing descemetocele caused by S. mitis treated by antibiotics plus amniotic membrane transplantation (AMT).

CASE SUMMARY

A 63-year-old woman presented with a right persistent corneal ulcer that she had suffered from for the past 9 mo. The culture of a corneal scraping yielded S. mitis. The right eye descemetocele decreased in diameter from 3 to 0.8 mm after the continuous administration of topical vancomycin and ceftriaxone for 2 wk. Due to the slow healing, AMT was performed. Her corneal erosion healed and gradually became clear. Her visual acuity recovered from initially counting fingers to 100/200 at the last follow-up, 67 mo after AMT.

CONCLUSION

Antibiotics plus AMT may be an effective alternative treatment other than PK to promote epithelialization and to reduce inflammation in the corneas complicated by S. mitis keratitis.

Visual Acuity and Number of Amniotic Membrane Layers as Indicators of Efficacy in Amniotic Membrane Transplantation for Corneal Ulcers: A Multicenter Study

BACKGROUND

To evaluate new indicators in the efficacy of amniotic membrane transplantation (AMT) for non-healing corneal ulcers (NHCUs).

METHODS

Retrospective, multicenter study. In total, 223 AMTs for NHCU in 191 patients were assessed. The main outcomes studied were the success rate of AMT (complete re-epithelization), postoperative visual acuity (VA) gain, and number of AM layers transplanted.

RESULTS

The overall AMT success rate was 74.4%. In 92% of our patients VA stability or improvement. Postoperative VA was significantly higher than preoperative VA in the entire cohort (p < 0.001) and in all etiological groups of ulcers (post-bacterial, p ≤ 0.001; post-herpetic, p ≤ 0.0038; neurotrophic ulcers, p ≤ 0.014; non-rheumatic peripheral, p ≤ 0.001; and ulcers secondary to lagophthalmos and eyelid malposition or trauma, p ≤ 0.004). Most participants (56.5%) presented a preoperative VA equal to or less than counting fingers (≤0.01). Of these, 13.5% reached a postoperative VA equal to or better than legal blindness (≥0.05) after AMT. A higher success rate was observed in the monolayer than in the multilayer AMT (79.5% and 64.9%, respectively; p = 0.018). No statistically significant values were found between the number of layers transplanted and VA gain (p = 0.509).

CONCLUSION

AMT is not only beneficial in achieving complete re-epithelialization in NHCUs but also in improving postoperative VA; these improvements are independent of etiologies of ulcers. Furthermore, the use of monolayer AMT seems to be a more appropriate option than multilayer AMT for NHCU since the multilayer AMT did not present better outcomes (success rate and VA gain) compared to monolayer AMT in the different types of ulcers studied.