Integrated environmental and health economic evaluations of novel xeno-keratografts address a growing public health crisis – Scientific Reports

Educational design

This study used performance-based LCA to measure the environmental impacts of two distinct xeno-keratoplasty procedures involving native corneas and decellularized corneal scaffolds that can be regenerated as grafts. specific. The process took place at the Khalifa University of Medicine and Health Sciences (KU CMHS) in Abu Dhabi, UAE. The organization is one of the top centers involved in regenerative medicine in the UAE, producing hundreds of xenografts each year, and is involved in primary and stem cell engineering to address a large and growing need for corneal transplantation. The functional component of this method was a single xeno-keratoprosthesis model involving a single ovine eye.

Xeno-keratoplasty model derived from slaughterhouse waste

All the tons were collected from the Abu Dhabi Automated Slaughterhouse, one of the largest slaughterhouses in the UAE, which can accommodate up to 37,000 slaughterhouses and carcasses. For our purposes, sheep eyes were collected from animals directly after slaughter and transported to KU CMHS, where they were used to create xenografts for our in vitro model. transplantation, presented in Figure 1. This model consists of allogeneic native corneas and cell-engineering personalized xenografts derived from decellularization / recellularization methods transferred to transplanted eyes found in other animals. In-depth information on biological and tissue engineering applications^3,4 and transplantation²⁷ are listed in the literature. All experimental protocols were approved by the Animal Research Control Committee (AROC) at Khalifa University of Science and Technology. The study was also conducted according to the ARRIVE guidelines. All procedures were performed in accordance with appropriate guidelines and regulations.

Corneal processing and xenograft preparation

The principles of handling natural corneas and corneal scaffolds made of cells used in this study were based on methods based on our previous research.^3,4,28. Fresh sheep eyes were removed from the Abu Dhabi Automated Slaughterhouse and transported to KU CMHS under sterile conditions. In earlier studies, native corneas were dissected, washed with sterile saline, and treated with antibiotics to reduce infection. These corneas were tested in their unmodified state, focusing on structural integrity, transparency, and biomechanical properties (referring to the relevant previous study).

We previously used a decellularization process for corneal scaffolds made of cells using a 4% zwitterionic biosurfactant solution, followed by vigorous washing to remove residual surfactants. These decellularized scaffolds were analyzed by histological and polymerase chain reaction (PCR) tests to confirm the absence of cellular materials and pathogens. The results of these analyzes provided the basis for evaluating the potential of damaged corneas as xenografts.²⁸.

Although the current study does not directly replicate these experiments, we have built on these previously proven processes to perform a life cycle assessment (LCA) and a cost-effectiveness assessment (CEA) of indigenous and synthetic scaffolds. decellularized from slaughter waste. This analysis was used to assess the environmental and economic impacts of using these materials in clinical settings.

Product life cycle model

The Life Cycle Assessment (LCA) carried out in this study aimed to measure the environmental impacts of xeno-keratoplasty by following a systematic, multi-step approach based on the ISO 14,040 framework. LCA includes four main steps: definition of purpose and scope, life cycle inventory (LCI), life cycle impact assessment (LCA), and interpretation. Below, each parameter used in LCA is detailed according to how it was selected and evaluated.

Definition of purpose and scope

The aim of the LCA was to assess the environmental impacts of a single xeno-keratoplasty procedure, from tissue harvesting to post-operative patient care. The selected functional area was selected as the production of one pair of corneas taken from sheep for transplantation. The scope of the system was set to include all processes from sheep tissue harvesting, sterilization, packaging, and transportation to operating room procedures and final conditions to make the model. each keratoplasty. Rights included environmental impacts other than the management of the process itself, such as moving patients to clinics and non-surgical hospital energy use. Sensitivity analyzes were performed to assess the significance of this exclusion. All inputs were correlated with body weight and normalized. Therefore, impacts related to the processing and packaging of meat, leather, and other products are not included in this study. The system boundary is shown in Fig. S1 in Supplementary File. It is important to note that for the main analysis, only the life of the material used will be considered. An overview of the useful life of the components and their role is given in the Appendix. Therefore, some items (e.g. drapes) were not considered in the analysis as their life depends on the quality of the fabric and includes items related to washing, ironing and ironing. prove again, beyond the scope of modern education.

Life cycle inventory (LCI)

Part of the life cycle analysis involved collecting quantitative data for each step of the xeno-keratoplasty process. Each parameter was measured, estimated, or obtained from LCA databases such as the Ecoinvent database. Data were collected on sheep cornea extraction, including energy consumption, water consumption and waste generation. Information about the sterilization process was obtained from hospital records, including energy use, chemicals involved (eg, ethylene oxide), and water use. The environmental footprint of the product is taken from Ecoinvent. Transportation impacts are calculated based on the distance traveled by the corneal tissue from the animal facility to the surgical facility, and by considering the mode of transportation (ie, refrigerated truck). Standardized emissions data for transportation were used, including fuel consumption and greenhouse gas emissions per kilometer traveled. Detailed information was collected on the surgical instruments used, including consumables (gloves, scalpels, sutures) and their disposal. Energy consumption (electricity for lighting, HVAC, and surgical equipment) is estimated using hospital energy audits. Information on waste generation (hazardous and non-hazardous) during surgery is also recorded.

Life cycle impact assessment (LCA)

The LCIA phase translated material data into environmental impacts using an impact assessment model. SimaPro software was used to estimate 18 central markers using the ReCiPe method in a Hierarchical view. Where data was not available in the Ecoinvent database for individual inputs, published protocols were implemented based on chemical characteristics or functional comparisons. the owner of the study as appropriate for the scope of the study. The equation for the contributions of individual gases in the system is given by equation (1).

Here App represents the input (i) within the supply chain, according to the management boundary shown in Figure 1; this includes extraction of raw materials, energy consumption, and production processes; n is the total number of entries (i), and Ep is the emission power of the selected influence components mentioned above, for each factor (i) in the supply chain. A detailed description of the LCA parameters is provided in the Supplementary file.

Explanation

The final phase of the LCA involved interpreting the results to identify the most important contributors to the environmental impact of xeno-keratoplasty. A sensitivity analysis was performed to assess whether changes in key parameters (eg, transport location, energy use) affected the overall results. Recommendations to reduce the environmental impact of xeno-keratoplasty are taken from this category, highlighting areas such as improving transport properties and improving energy efficiency in sterilization processes.