Estudio coste-beneficio del trasplante de membrana amniótica para úlceras venosas de extremidades inferiores refractarias a tratamiento convencional

Bio-Fabrication of Human Amniotic Membrane Zinc Oxide Nanoparticles and the Wet/Dry HAM Dressing Membrane for Wound Healing

The preparation of unique wet and dry wound dressing products derived from unprocessed human amniotic membrane (UP-HAM) is described. The UP-HAM was decellularized, and the constituent proteins were cross-linked and stabilized before being trimmed and packed in sterile Nucril-coated laminated aluminium foil pouches with isopropyl alcohol to manufacture processed wet human amniotic membrane (PW-HAM). The dry type of PD-HAM was prepared by decellularizing the membrane, UV irradiating it, lyophilizing/freeze-drying it, sterilizing it, and storing it at room temperature. The UP-HAM consists of a translucent yellowish mass of flexible membranes with an average thickness of 42 μm. PW-HAM wound dressings that had been processed, decellularized, and dehydrated had a thinner average thickness of 30 μm and lacked nuclear-cellular structures. Following successful decellularization, discrete bundle of fibrous components in the stromal spongy layers, microvilli and reticular ridges were still evident on the surface of the processed HAM, possibly representing the location of the cells that had been removed by the decellularization process. Both wet and dry HAM wound dressings are durable, portable, have a shelf life of 3–5 years, and are available all year. A slice of HAM dressing costs 1.0 US$/cm². Automation and large-scale HAM membrane preparation, as well as storage and transportation of the dressings, can all help to establish advanced technologies, improve the efficiency of membrane production, and reduce costs. Successful treatment of wounds to the cornea of the eye was achieved with the application of the HAM wound dressings. The HAM protein analysis revealed 360 μg proteins per gram of tissue, divided into three main fractions with MWs of 100 kDa, 70 kDa, and 14 kDa, as well as seven minor proteins, with the 14 kDa protein displaying antibacterial properties against human pathogenic bacteria. A wide range of antibacterial activity was observed after treatment with 75 μg/ml zinc oxide nanoparticles derived from human amniotic membrane proteins (HAMP-ZnO NP), including dose-dependent biofilm inhibition and inhibition of Gram-positive (S. aureus, S. mutans, E. faecalis, and L. fusiformis) and Gram-negative bacteria (S. sonnei, P. aeruginosa, P. vulgaris, and C. freundii).

Use of Amniotic Membrane as a Biological Dressing for the Treatment of Torpid Venous Ulcers: A Case Report

Chronic venous disease manifested as ulcers in the lower limb is a highly prevalent pathology in our population. Antiseptics and dressings designed to improve epithelialization are often used to cure the ulcer during outpatient therapy. Despite careful management, sometimes ulcers do not respond to treatment. In this report, we discuss the antiseptic and potentially immunomodulatory effects of the amniotic membrane as a biological dressing for the treatment of venous ulcers refractory to conventional therapy.

Human acellular amniotic membrane is adopted to treat venous ulcers

Venous lower limb ulcers are very common and affect ~1% of the general population. The human acellular amniotic membrane (HAAM), which is isolated from the amniotic membrane (AM) via excluding the majority of cellular components, has lower antigenicity than the AM. The aim of the present study was to evaluate the effectiveness and safety of the HAAM, adopted to treat venous ulcers (VUs) of the lower extremities. The HAMM was isolated from the AM by the Stem Cells and Tissue Engineering laboratory at the West China Hospital of Sichuan University (Chengdu, China). HAMMs were grafted onto VUs in 4 patients, with follow-up evaluations performed on the 3rd day and at the end of the 1st, 2nd and 3rd week, and 2nd, 3rd and 6th month after the HAAMs were applied. The size and depth of the VU (determined based on whether the depth of VU reaches the tibial plane), the proportion of granulation tissue (whether >50%) and the degree of secretion (measured by asessing the degree of satuation in the outer gauze) and infection (assessed qualitatively via the appearance of purulence or peripheral swelling) were assessed. Pain score was monitored at the same intervals using a visual analog scale. Complete epithelialization (healed tissue) occurred in 2 cases: The first at the end of the 3rd week and the second, at the 2nd month following HAAM induction. In one of the remaining cases, ulcer size was reduced by >60%; however the ulcer size of the remaining case only reduced by <20%. Overall, the size of ulcer in cases 1, 2, 3 and 4 decreased to 1.2×1.1 and 1.4×0.4 cm, 1.3×1.8 and 2.3×1.4, respectively, with evident decreases in ulcer depth. The proportion of granulation tissue in each case was >50%. Furthermore, purulence and secretion completely disappeared in all 4 cases. Additionally, the medical cost of HAAM treatment is substantially lower than that of AM treatment, skin autografts and biomaterial transplantation, thus alleviating the patients' financial burden. These findings suggest that HAMM was highly effective in treating VUs in patients.

Effects of the application of the amniotic membrane in the healing process of skin wounds in rats

PURPOSE

To evaluate the efficacy of the application of the human amniotic membrane (HAM) on the inflammatory process, fibroblast proliferation, formation of collagenand reduction of skin wound areas in rats.

METHODS

Thirty six rats were submitted to a surgical injury induction and divided into two groups (n = 18): group C (control) and T (treated with the HAM). The macroscopic evolution in the wound area and the histological characteristics of the skin samples were evaluated.

RESULTS

The regression of the wound area was greater in group T. The histological analysis revealed a significant reduction (p < 0.05) in the inflammatory infiltrate in group T at all experimental periods compared with that in the control group. Furthermore, the group T presented a significant increase in the proliferation of fibroblasts at 14 and 21 days compared with group C (p < 0.05). Regarding the deposition of mature collagen fibers, there was an increase in the replacement of type III collagen by type I collagen in group T (p < 0.05).

CONCLUSION

Treatment with the HAM reduced the healing time as well as the inflammatory responses, increased the proliferation of fibroblasts, and induced a higher concentration of mature collagen fibers.

Advancing biomaterials of human origin for tissue engineering

Biomaterials have played an increasingly prominent role in the success of biomedical devices and in the development of tissue engineering, which seeks to unlock the regenerative potential innate to human tissues/organs in a state of deterioration and to restore or reestablish normal bodily function. Advances in our understanding of regenerative biomaterials and their roles in new tissue formation can potentially open a new frontier in the fast-growing field of regenerative medicine. Taking inspiration from the role and multi-component construction of native extracellular matrices (ECMs) for cell accommodation, the synthetic biomaterials produced today routinely incorporate biologically active components to define an artificial in vivo milieu with complex and dynamic interactions that foster and regulate stem cells, similar to the events occurring in a natural cellular microenvironment. The range and degree of biomaterial sophistication have also dramatically increased as more knowledge has accumulated through materials science, matrix biology and tissue engineering. However, achieving clinical translation and commercial success requires regenerative biomaterials to be not only efficacious and safe but also cost-effective and convenient for use and production. Utilizing biomaterials of human origin as building blocks for therapeutic purposes has provided a facilitated approach that closely mimics the critical aspects of natural tissue with regard to its physical and chemical properties for the orchestration of wound healing and tissue regeneration. In addition to directly using tissue transfers and transplants for repair, new applications of human-derived biomaterials are now focusing on the use of naturally occurring biomacromolecules, decellularized ECM scaffolds and autologous preparations rich in growth factors/non-expanded stem cells to either target acceleration/magnification of the body's own repair capacity or use nature's paradigms to create new tissues for restoration. In particular, there is increasing interest in separating ECMs into simplified functional domains and/or biopolymeric assemblies so that these components/constituents can be discretely exploited and manipulated for the production of bioscaffolds and new biomimetic biomaterials. Here, following an overview of tissue auto-/allo-transplantation, we discuss the recent trends and advances as well as the challenges and future directions in the evolution and application of human-derived biomaterials for reconstructive surgery and tissue engineering. In particular, we focus on an exploration of the structural, mechanical, biochemical and biological information present in native human tissue for bioengineering applications and to provide inspiration for the design of future biomaterials.

Amniotic membrane transplantation in the treatment of chronic lower limb ulcers

INTRODUCTION

Approximately 1% of the general population have venous or arterial lower limb ulcers. These lesions can be treated with biological skin substitutes such as cadaver skin or tissue-engineered skin equivalents, but treatment fails in 25% of cases, resulting in pain and loss of patient autonomy, as well as increased morbidity and health care costs. In the treatment of corneal ulcers, amniotic membrane has been shown to have antimicrobial and bacteriostatic properties, and to protect the wound without eliciting an immune response. The same properties have been reported in the treatment of burns and postthrombotic ulcers.

OBJECTIVES

To assess the effectiveness of amniotic membrane transplantation in the treatment of refractory chronic leg ulcers.

PATIENTS AND METHODS

Amniotic membrane was grafted onto 4 refractory ulcers in 3 patients. The mean time required for partial and complete re-epithelialization was calculated by measuring the wound area at weeks 0, 4, 8, 12, and 16. Pain intensity was assessed at the same intervals using a visual analog scale.

RESULTS

Complete wound re-epithelialization was achieved for 1 ulcer by week 8; in the other 3 cases, there was a 50% reduction in size compared to baseline. At week 16, the mean reduction in wound size for the 4 ulcers was 81.93%. The corresponding reduction in pain intensity was 86.6%. No adverse effects were observed.

CONCLUSIONS

Amniotic membrane transplantation might be an effective alternative for the treatment of refractory chronic vascular ulcers on the lower limbs.