A Scoping Review on the Ethical Issues in the Use of CRISPR-Cas9 in the Creation of Human Disease Models

1. Chair, Department of Education, UNESCO Chair in Bioethics, Melbourne, Australia; Professor, Department of Organisational Psychological Medicine, International Institute of Organisational Psychological Medicine, Melbourne, Victoria, Australia. 2. Professor and Head, Department of Pathology, Kasturba Medical College, Manipal Academy of Higher Education (MAHE), Manipal, Karnataka, India. 3. Professor (Biochemistry) and Head, Department of Medical Education, Panimalar Medical College Hospital and Research Institute, Varadharajapuram, Poonamallee, Chennai, Tamil Nadu, India.

Abstract

Introduction: The remarkable advances in molecular science and technology have dramatically changed the landscape of Deoxyribonucleic Acid (DNA). With the rapid pace of new gene editing technologies like Clustered Regularly Interspaced Short Palindromic Repeats and CRISPR-associated protein 9 (CRISPR-Cas9), human disease models can be created to reduce the burden of morbidity and mortality caused by genetic defects and congenital malformations. However, despite its potential to advance human health and well-being, the use of CRISPR-Cas9 technology raises numerous ethical concerns, including the lack of a well-defined regulatory framework.

Aim: To outline the ethical concerns that arise in the creation of human disease models using CRISPR-Cas9 technology and to design a conceptual framework to identify the ethical challenges and address these concerns.

Materials and Methods: The data on ethical issues in the use of CRISPR-Cas9 in the creation of human disease models were obtained by reviewing 530 articles retrieved from scientific databases such as Google Scholar, PubMed, Scopus, and Excerpte Medica dataBASE (EMBASE) from the year 2015. Based on the eligibility criteria, 24 publications from 56 full-text articles that were screened were included in this study. The selection process was conducted in three phases-screening of the title, abstract, and full text. The articles selected after full-text screening were analysed, and the data was scrutinised independently. Tables, charts, figures, and graphs were used to organise and illustrate the obtained data. The entire paper was drafted using the Preferred Repoting Items for Systematic Reviews and Meta-analyses (PRISMA) extension for scoping review reporting criteria.

Results: The present study included 24 articles for review after the screening process. The articles emphasised the bioethical issues related to CRISPR-Cas9 technology and gene editing while also shedding light on the current level of research in the field. The studies included different countries, with the maximum number of papers from the United States of America (USA), followed by the United Kingdom (UK), China, Turkey, Spain, Canada, Pakistan, Australia, Italy, France, Korea, and Sri Lanka. These articles were published between 2015 and 2021. The disease for which models were created was not mentioned in the majority of articles, while a few investigated the application of CRISPR-Cas9 in genetic disorders, cardiovascular diseases, neurodegenerative diseases, and eye disorders. The major ethical concerns identified included safety, efficacy, unintended consequences, harm to the environment, off-target effects, obtaining informed consent, and the risk of misuse.

Conclusion: The use of CRISPR-Cas9 technology in creating human disease models has raised many ethical concerns. One of the primary ethical issues is the potential for unintended consequences, which could have serious long-term effects on individuals and their offspring. To address these ethical issues, it is important to develop ethical guidelines and best practices, as well as to support ongoing research to investigate the long-term effects of gene modifications.

Ethical concerns, Framework, Genetic editing, Gene modifications, Human diseases, Research, Technology

Genes are the basic units of inheritance that influence the fundamental existence of all forms of life (1). Alteration of the genome of an individual resulting in mutations is known to cause over 10,000 different types of genetic disorders, impacting the lives of 80 million people worldwide (2). Nevertheless, the phenomenal advancements in molecular science and technology have remarkably changed the destiny of our Deoxyribo Nucleic Acid (DNA), with ground breaking technological applications that can completely renovate the genetic makeup of an individual and reduce the burden of morbidity and mortality due to genetic diseases and congenital abnormalities (3). Gene editing is one such promising genome engineering technique that has accelerated the quantum leap in novel discoveries of disease modeling, gene therapy, drug development, and molecular treatment strategies (4).

The CRISPR-Cas9 has emerged as the most influential and outstanding technique of genome editing in recent years. This “Clustered Regularly Interspaced Short Palindromic Repeats-Associated Protein 9” system is a marvel of life sciences that gives mankind the power to resculpt DNA and potentially ‘erase’ and/or ‘alter’ genetic sequences that can cause life-threatening diseases (5). This CRISPR-Cas9 system in the bacterial genome, which serves as a self-protective tool against invading viruses, can be applied to cleave foreign genetic material using Ribonucleic Acid (RNA)-guided endonucleases, enabling desired alterations to be made in the human genome (6),(7),(8).

The creation of genetically altered animal and cellular models for various human illnesses, such as mutagenesis models with site-direction, gene knockin and knockout models, constitutes the most significant use of CRISPR-Cas9 systems in medicine (9). However, despite its ability to make groundbreaking changes in the field of science and technology, there are many ethical challenges concerning the application of CRISPR-Cas9. This issue raises questions about the protection of subsequent generations at risk for non Mendelian (single gene) disorders, as well as challenges that this technology may pose regarding changes in societal values, socioeconomic background, personality, inequities, and affordability (10).

As many ethical challenges arise in the use of CRISPR-Cas9 in the creation of human disease models, proper guidelines and frameworks are essential for the successful implementation of such gene editing technology. Keeping these concerns in mind, the authors intend to analyse the ethical issues associated with CRISPR-Cas9 technology by scrutinising this technology and its intended uses.

Gaps in Literature

The creation of human disease models using CRISPR-Cas9 technology poses significant ethical questions that have been covered in the literature. However, there are still some gaps in the literature concerning these moral concerns, including disagreements over the standards for choosing target diseases, ambiguity regarding the security and effectiveness of CRISPR-Cas9, uncertainty surrounding the informed consent procedure, and issues with the commercialisation of CRISPR-Cas9 technology. Hence, research focusing on creating policies and best practices for the ethical use of this technology in the healthcare environment is warranted. This study provides an overview of ethical concerns in using CRISPR-Cas9 technology for creating human disease models and a conceptual framework emphasising the need for well-defined ethical regulations and frameworks.

Material and Methods

From the search for relevant papers to the analysis and reporting of the study’s conclusions, the present scoping study was conducted following the five-stage systematic approach designed by Arksey H and O’Malley L (11). The information was organised to meet the criteria of the PRISMA-ScR Checklist, which is an extension of PRISMA (PRISMA reporting items for systematic reviews and meta-analyses) (12).

Identification of Relevant Studies

The relevant papers for the present study were searched on online databases such as Google Scholar, PubMed, Scopus, and EMBASE. The primary keywords and Medical Subject Headings (MeSH) used were: ‘CRISPR-Cas9’; ‘ethics’; ‘gene editing’; ‘human disease models’; ‘bioethics’; ‘ethical issues’. The present scoping review was conducted from November 2022 to March 2023.

Selection of Studies

The relevant publications for the present review were chosen based on the inclusion criteria listed in (Table/Fig 1). Publications and papers that did not meet the objectives of the present study were excluded based on the criteria indicated in (Table/Fig 1). In the initial search for “ethical issues in the use of CRISPR-Cas9 in human disease models” and using BOOLEAN logic of “AND,” “OR,” and “NOT” in PubMed, 530 full-text publications were obtained from the databases and were first screened by title. The initial search resulted in 39 papers from PubMed, 449 articles from Google Scholar, 18 from Scopus, and 24 from EMBASE, covering the years 2015 to 2023. Brief abstracts, conference abstracts, books, and cross-sectional studies were not included. 356 papers were excluded due to duplication, redundancy, and unrelated information. A total of 176 papers were included for abstract screening, but 120 were rejected as they did not meet the inclusion requirements. Out of the 56 papers that were included for full-text screening, 24 research articles were chosen (13),(14),(15),(16),(17),(18),(19),(20),(21),(22),(23),(24),(25),(26),(27),(28),(29),(30),(31),(32),(33),(34),(35),(36). (Table/Fig 2) displays the PRISMA selection criteria for publications.

Data Charting

All the selected publications were screened and scrutinised before plotting the data for additional analysis. Each article was thoroughly examined in the initial round of examination. The findings from the second phase of the study were cross-checked to resolve any differences in data extraction or graphing.

Collating, Reporting and Summarising the Findings

Every article was assigned a study Identity Document (ID), which was used to represent the studies in the results. Each publication was reviewed for title, abstract, and full text. In the initial stage of analysis, each paper was assessed and then validated with the findings following the second round of review. Any discrepancies in the data extraction in the first round were cross-checked in the second. The information is categorised as follows: Study ID, year of study, study design, country, keywords, ethical issues, disease under study, and conclusion or recommendations. Extracted data is presented using graphs, charts, and figures.

Results

Data Extraction and Graphing

The results of the rigorous data extraction and graphing process are presented in (Table/Fig 3),(Table/Fig 4) (13),(14),(15),(16),(17),(18),(19),(20),(21),(22),(23),(24),(25),(26),(27),(28),(29),(30),(31),(32),(33),(34),(35),(36).

Characteristics of Charted Data

The studies included in the present scoping review provide a broad outline of the current state of research and ethical considerations related to CRISPR-Cas9 and gene editing. They cover various aspects such as human disease models, bioethics, responsible research, and precision medicine (Table/Fig 3) lists 24 studies on the topic of CRISPR-Cas9 and gene editing, conducted in different countries and published in different years.

Out of these 24 studies, there are 14 reviews, three commentaries, one report, one opinion paper, and five studies without specified study designs. The study design is presented diagrammatically in (Table/Fig 5). In terms of the year of study, there were three studies published in 2015, two in 2016, seven in 2017, four in 2018, two in 2019, five in 2020, and one in 2021. This distribution is represented in (Table/Fig 6).

The countries where the studies were conducted include China (13),(16),(33), Turkey (14), Spain (15),(31), Canada (17), Pakistan (18), the UK (19),(25),(26), the USA (20),(21),(22),(28),(34),(35),(36), Australia (23), Italy (24),(27), France (29), Korea (30), and Sri Lanka (32). The highest number of studies came from the USA (n=7) (20),(21),(22),(28),(34),(35),(36), followed by three each from China (13),(16),(33) and the UK (19),(25),(26). The geographical distribution of the selected articles is depicted in (Table/Fig 7).

Additionally, the most common keywords used in these studies include CRISPR-Cas9, gene editing, ethics, disease modelling, and genome engineering. (Table/Fig 4) depicts the list of ethical challenges concerning the use of CRISPR-Cas9, along with the diseases under study and the conclusions or recommendations.

The table includes various ethical dilemmas and challenges that arise when using CRISPR-Cas9 technology in different disease contexts.

Safety is a major concern across all disease areas, with specific attention given to issues such as unwanted alterations in the genome, off-target effects, and unintended consequences. Informed consent is also highlighted as an important ethical consideration. Other issues include the potential for misuse, concerns about designer babies and unnatural features, harm to the environment, and the breeding of humans and their impact on animals and agriculture.

Some studies (16),(20),(23),(25),(27) address the issue of trust and the future implications of the technology, while others discuss the potential for unjust eugenic futures (21),(28). Specific disease areas addressed include monogenic diseases, infectious diseases, cancer, psychiatric disorders, cardiovascular diseases, neurodegenerative diseases, eye diseases, and genetic disorders. This suggests that while the potential applications of CRISPR-Cas9 are vast, there are significant ethical and moral issues that must be addressed.

The development of clear ethical frameworks, legal procedures, and regulatory guidelines is essential to ensure that advancements in human health and knowledge continue with minimal ethical concerns while upholding ethical principles. The use of CRISPR-Cas systems to alter genes has the potential to transform the way illnesses are treated and advance our knowledge of genetic diseases. However, to ensure the ethical and safe use of this technology, certain serious issues must be resolved.

To distinguish between ethically appropriate and socially acceptable uses of gene editing and to prevent its abuse, clear regulatory frameworks must be put in place. It is important to consider the probability of unforeseen negative consequences as well as the risk of abuse, such as for bioterrorism or biowarfare. Genome editing will only be successful if decision-makers and researchers move in the right direction and uphold ethical standards. The moral ramifications of altering the genetic composition of future generations to remove genes associated with mental problems must be considered in CRISPR psychology trials.

There is a consensus that CRISPR has benefits and drawbacks, and further research is required to prevent unethical practices. The circumstances under which this technique should be employed and the ethical and legal framework are yet to be fully discussed. The development of a therapeutic tool using CRISPR-Cas9 for treating human illnesses is essential, but the ethical and legal ramifications must be taken into account. Drafting international legislation to protect the safety of genome editing technology is vital to promote this tool as a therapeutic intervention.

Discussion

The present scoping review has outlined the major issues concerning the use of CRISPR-Cas9 technology in the creation of human disease models. The majority of the studies reviewed were conducted in the USA (20),(21),(22),(28),(34),(35),(36), followed by three each from China (13),(16),(33) and the UK (19),(25),(26). Safety, informed consent, and unintended harm are the major ethical issues that need to be considered when using CRISPR-Cas9 technology. However, CRISPR-Cas9 remains an invaluable tool in gene editing that should not be compromised due to the ethical and legal challenges associated with its use.

The rapid adoption of CRISPR-Cas9 reflects its usefulness, simplicity, and effectiveness. It has revolutionised biomedical sciences by enabling precise genome alterations in various cell types and organisms (37). The CRISPR-Cas9 system holds great therapeutic promise for treating diseases with a known genetic cause, as well as for researching these diseases through the creation of human disease models (38). CRISPR-Cas9 offers several advantages over other gene editing methods, allowing scientists to develop human disease models using knockin, knock-out, insertion, or deletion mutation strategies for a wide range of conditions, including cancer, cardiovascular disease, Huntington’s disease, cystic fibrosis, Duchenne muscular dystrophy, haematological disorders, and viral disorders. Continued advancements in CRISPR-Cas9 technology will facilitate the creation of important human disease models for the discovery of new drugs and gene therapies (39),(40).

Employing CRISPR-Cas9 technology for creating human disease models poses several ethical challenges. The most prominent ethical dilemmas are safety and efficacy concerns, as these methods may not be as accurate as anticipated (41),(42). Another issue is the safety concern regarding off-target effects. Despite ongoing efforts to improve the accuracy of CRISPR-Cas9 technology, it has been found to have more off-target complications compared to other gene editing tools (43). Therefore, it is crucial to advance the current understanding of genetic and epigenetic impacts so that it will be possible to identify and anticipate the phenotypic consequences of genetic editing. This will help prevent any negative effects and off-target issues associated with CRISPR-Cas9 (44).

Another ethical dilemma arises from the use of germ cells for disease modelling. The use of somatic or embryonal cells does not pose many ethical conflicts, as they are generally not inherited and any masked effects are not at risk of being exposed in subsequent generations (45). However, the use of germ cells could potentially affect the off-spring, as the DNA changes have a higher chance of being inheritable. Some scientists argue that using human embryos for research is unethical, as it involves dealing with living entities that have personhood, the right to live, and dignity (46). However, the “European Society of Human Reproduction and Embryology” (ESHRE) and the “European Society of Human Genetics” (ESHG) have no objections to using leftover or wasted embryos in research. They believe that the moral “status” of an embryo is lower than that of a foetus, who in turn has a lower moral “status” than a newborn or an adult (47).

These arguments, particularly when utilising germ cells to create human disease models, expand the potential for disease elimination and treatment, thereby improving the health and well-being of humans in accordance with the United Nations Sustainable Development Goals (48). However, this places a greater ethical burden on the use of CRISPR-Cas9 technology, despite its undeniable therapeutic potential for the treatment of various diseases and the construction of human disease models.

Conceptual Framework

The conceptual framework, which emphasises the need for a well-defined ethical framework for the usage of CRISPR-Cas9 in the creation of human disease models and highlights their advantages over conventional methods, is illustrated in (Table/Fig 8).

Problem: The use of CRISPR-Cas9 technology for editing the genome and creating human disease models has raised numerous ethical challenges, particularly regarding safety, off-target effects, and potential harm to the environment. Obtaining informed consent for the use of germ cells or other somatic cells in the gene editing process is also a major concern. Additionally, the acceptance of the process or its results may vary among individuals, as this technique is seen by many as contradicting nature. Moreover, the high reproducibility of this technology poses potential risks for misuse or exploitation of human disease models.

Methods: These ethical challenges can be addressed through the establishment of a well-defined ethical framework for the implementation of CRISPR-Cas9 in the creation of human disease models. This framework should be developed based on existing policies and laws that govern the ethical use of novel tools like CRISPR-Cas9. It should involve stakeholders and provide explicit guidelines on the appropriate use of the CRISPR-Cas9 technique, while ensuring that users are well-informed about the potential harms.

The framework should also prioritise transparency and enhance surveillance of every procedure and its results, involving all stakeholders such as policymakers, funders, governmental or private organisations, and healthcare providers. By involving all relevant parties and implementing clear guidelines, this ethical framework can help ensure responsible and ethical use of CRISPR-Cas9 in the creation of human disease models.

Intended outcomes: With the implementation of such a framework, it will be possible to establish ethically and legally bound usage of CRISPR-Cas9 technology for creating human disease models. By following the guidelines provided in the framework, there will be a clear understanding of the process, potential results, and implications by both the public and the scientific community, leading to increased acceptance and consensus.

The availability of clear strategies for managing potential harm or off-target effects will help alleviate concerns about safety and other complications. Additionally, adherence to these guidelines can demonstrate that CRISPR-Cas9 poses minimal to no threat to the environment when used with caution.

Finally, with well-defined rules and regulations in place, the misuse or exploitation of this technology can be controlled by taking strict action against unlawful or unethical practices.

Directions for Future Research

The development of ethical guidelines and best practices, research into the long-term effects of genetic modifications, examination of the social and cultural implications of CRISPR-Cas9 technology, investigation into the ethical ramifications of commercialisation, and enhancement of informed consent procedures should be the main objectives of future research concerning the ethical challenges in using CRISPR-Cas9 technology for creating human disease models. To ensure that these recommendations consider the viewpoints of all stakeholders, cooperation between researchers, physicians, patients, and ethicists is required.

Limitation(s)

The present scoping review has certain limitations. Firstly, authors did not assess the quality of individual studies included in this review, which makes it challenging to determine the strength of evidence and reliability of the findings. Additionally, the review employed a broad search strategy, and it is possible that not all relevant studies were captured.

Conclusion

The creation of human disease models using CRISPR-Cas9 technology has raised profound ethical questions that require thorough exploration. While this technology holds the potential to revolutionise the treatment of genetic diseases, it also presents risks and challenges that need to be addressed. One of the primary ethical concerns with CRISPR-Cas9 technology is the possibility of unintended consequences, which could have negative long-term effects on individuals and their future generations. To address these ethical concerns, it is crucial to establish robust ethical standards and best practices for the use of CRISPR-Cas9 technology in developing human disease models. Additionally, funding should be allocated to continuous studies that examine the social and cultural implications of this technology and investigate the long-term consequences of genetic alterations.

DOI and Others

DOI: 10.7860/JCDR/2023/68275.18809

Date of Submission: Oct 25, 2023
Date of Peer Review: Nov 10, 2023
Date of Acceptance: Nov 18, 2023
Date of Publishing: Dec 01, 2023

AUTHOR DECLARATION:
• Financial or Other Competing Interests: None
• Was Ethics Committee Approval obtained for this study? NA
• Was informed consent obtained from the subjects involved in the study? NA
• For any images presented appropriate consent has been obtained from the subjects. NA

PLAGIARISM CHECKING METHODS:
• Plagiarism X-checker: Oct 26, 2023
• Manual Googling: Nov 15, 2023
• iThenticate Software: Nov 17, 2023 (4%)

ETYMOLOGY: Author Origin

EMENDATIONS: 5