Harnessing Genetics to Combat Tobacco Addiction
Dr. Manish Mohan Gore
Each puff of a cigarette or hookah perpetuates a cycle of addiction that traps millions, impeding their pursuit of happiness and well-being. The World Health Organization (WHO) has recognised 'World No Tobacco Day' on May 31 to raise awareness about tobacco's health risks and advocate for policies to reduce consumption.
Each year, ‘World No Tobacco Day’ is commemorated with a specific theme, seeking to tackle various aspects of tobacco control, including advocating for smoke-free spaces, enhancing the availability of cessation support, countering tobacco industry influence, and championing policy adjustments like higher taxes on tobacco goods and restrictions on advertising, alongside public awareness initiatives. The theme for 2024 is "Protecting Children from Tobacco Industry Interference." The theme focuses on safeguarding the youth from tobacco corporations' marketing strategies, urging for protective policies to shield them from such influences.
Tobacco: A Public Health Issue in India
Tobacco addiction is a significant public health issue in India, with a high prevalence of tobacco use across various forms such as smoking and smokeless tobacco. Tobacco addiction among Indians is fuelled by various factors including cultural norms, social acceptance, and aggressive marketing by the tobacco industry. Despite efforts to regulate tobacco products and implement tobacco control measures, tobacco consumption remains widespread, particularly among men and in rural areas.
The consequences of tobacco addiction in India are severe, contributing to a wide range of health problems including respiratory diseases, cardiovascular disorders, cancers, and reproductive health issues. Additionally, exposure to Second- Hand Smoke (SHS) further exacerbates health risks, affecting non-smokers as well.
Efforts to combat tobacco addiction in India include tobacco control policies such as pictorial warnings on tobacco products, bans on tobacco advertising, promotion, and sponsorship, as well as tobacco cessation programmes. However, the multifaceted nature of tobacco addiction requires a comprehensive approach involving coordinated efforts from government agencies, healthcare providers, civil society organisations, and the community to effectively address this public health challenge and reduce the burden of tobacco-related diseases in India.
What Makes Tobacco Addictive
When we discuss of tobacco and its ill effects, the most pertinent question that comes to mind is - what makes tobacco so hard to resist?
Nicotine, this potent alkaloid, nestled within the leaves of Nicotianatabacum, holds the key to tobacco’s addictive grip. Nicotine affects the brain by binding to nicotinic acetylcholine receptors, causing neurotransmitters like dopamine to be released. This process contributes to the cravings and compulsions associated with addiction. Nicotine is found in the leaves of tobacco plant and is generally consumed by addicts by smoking the dried leaves. Using a snuff preparation or chewing the leaves, tobacco may also be absorbed through the nasal mucosa or oral-buccal cavity. This yields complex effects in the brain that are presumably related to the behavioural effects of relaxation, mental stimulation, and focussed attention experienced by tobacco users. By increasing heart rate and blood pressure, Nicotine also stimulates the cardiovascular system.
Health Consequences of Tobacco Consumption
The toxic ramifications of tobacco consumption on human health are multifaceted and severe, affecting nearly all human bodily system. Chronic exposure to nicotine sets the stage for a cascade of health complications, with cardiovascular disease at the forefront. This chronic exposure increases the risk of heart attacks and strokes, as nicotine constricts blood vessels and elevates blood pressure.
Moreover, tobacco smoking is notorious for its association with lung diseases, notably lung cancer and emphysema. The smoke itself, rife with irritants and carcinogens, wreaks havoc on the delicate lung tissues, paving the way for malignant transformations and debilitating respiratory conditions. Adding insult to injury, carbon monoxide, a noxious component of tobacco smoke, compounds the cardiovascular strain by impairing the blood's oxygen-carrying capacity.
Beyond nicotine, tobacco harbours a sinister arsenal of carcinogenic compounds, chief among them being nitrosamines. These insidious substances, generated during tobacco curing, inflict DNA damage and fuel tumor growth, precipitating various forms of cancer, particularly in long-term smokers. While not directly responsible for addiction, their presence in tobacco products amplifies the overall health hazards associated with tobacco use.
The spectrum of tobacco's detrimental effects extends far beyond the confines of cancer and cardiovascular disease. Smokeless tobacco products, such as chewing tobacco and snuff, pose their own set of perils, primarily targeting the oral cavity. Oral cancers, gum disease, tooth decay, and precancerous lesions proliferate in the wake of prolonged exposure to these products, escalating the risk of gastrointestinal malignancies.
Furthermore, the dangerous reach of tobacco extends to non-smokers and children through second-hand smoke exposure. This involuntary inhalation of toxic chemicals and carcinogens engenders a plethora of health issues, ranging from respiratory infections to exacerbated asthma symptoms and heightened cardiovascular risks.
The devastating impact of tobacco on human health is undeniable, resulting in a significant burden of disease, premature death, and reduced quality of life worldwide. Yet, amidst this bleak reality, a ray of hope emerges: the potential for genome editing of tobacco plants to regulate nicotine levels.
Genome Editing for Reduced Nicotine Content
The tobacco plant has been the subject of genetic exploration by researchers worldwide aiming to unravel their genetic makeup, seeking insights into traits, disease resistance, and nicotine content. Employing genetic engineering techniques, efforts have been made to manipulate tobacco plants for various ends, including lowering nicotine levels as part of harm reduction strategies or bolstering their resilience against pests and diseases.
In India, scientists at the Council of Scientific and Industrial Research-Central Institute of Medicinal and Aromatic Plants (CSIR-CIMAP) have made significant strides in reducing nicotine content in tobacco plants using genome editing tools, marking a promising development in tobacco harm reduction strategies with potential implications for public health.
Nicotine, the primary addictive component of tobacco, plays a central role in sustaining tobacco addiction. CSIR-CIMAP's innovative approach to lowering nicotine levels in tobacco plants addresses this critical issue by targeting the genetic pathways responsible for nicotine synthesis. By employing genome editing tools such as CRISPR-Cas9, CSIR-CIMAP researchers have been able to precisely modify specific genes involved in nicotine biosynthesis within the tobacco plant genome. This targeted genetic modification allows for the development of tobacco plants with significantly reduced nicotine content while maintaining other desirable agronomic traits.
Recent advancements in genome editing, particularly CRISPR-Cas9 technology, have revolutionised the field of molecular biology. CRISPR-Cas9 allows for precise modification of DNA sequences, offering unprecedented control over genetic traits. CSIR-CIMAP researchers have leveraged this technology to target genes involved in nicotine biosynthesis within tobacco plants.The research team at CSIR-CIMAP identified key genes responsible for nicotine biosynthesis in tobacco plants. By using CRISPR-Cas9 technology, CIMAP scientists selectively disrupted these genes, thereby inhibiting nicotine production while preserving the overall integrity and viability of the plants. This targeted approach represents a significant breakthrough in tobacco modification, offering a promising avenue for reducing 60-70% nicotine content without compromising plant health.
Advantages of Genome Editing in Tobacco Plants
· Reduced Nicotine Content: Genome editing techniques offer the possibility of lowering nicotine levels in tobacco plants. This reduction could significantly diminish the addictive nature of tobacco products.
· Reduced Allure for New Users: By reducing the addictive allure of cigarettes, genome-edited tobacco plants could help prevent the onset of nicotine dependence and subsequent tobacco-related diseases.
· Facilitate Smoking Cessation: With lower nicotine levels, smokers may find it easier to quit smoking or reduce their tobacco consumption.
· Reduced Healthcare Cost: Nicotine addiction lies at the core of tobacco-related diseases. By addressing this key factor through genome editing, the widespread adoption of low-nicotine tobacco varieties has the potential to yield substantial public health benefits, including a reduction in disease burden and healthcare costs.
Challenges to Genome Editing of Tobacco Plant
While CSIR-CIMAP's genome editing approach offers promising prospects, several challenges and considerations must be addressed. Regulatory approval processes for Genetically Modified Organisms (GMOs) vary across jurisdictions, posing potential barriers to the commercialisation and widespread adoption of low-nicotine tobacco varieties. Additionally, concerns regarding unintended off-target effects and ecological impacts necessitate rigorous safety assessments and monitoring protocols.
Ethical Implications
The ethical implications of genome editing in tobacco plants warrant careful examination. Questions regarding consumer acceptance, informed consent, and equitable access to modified tobacco products must be addressed. Moreover, the potential for unintended consequences, such as the emergence of resistant tobacco pests or unintended alterations to other plant traits, underscores the importance of responsible stewardship and regulatory oversight.
Conclusion
CSIR-CIMAP's innovative use of genome editing tools to reduce nicotine content in tobacco plants represents a significant stride towards addressing the public health challenges associated with tobacco use. By targeting the addictive properties of tobacco at the source, this approach has the potential to usher in a new era of harm reduction and tobacco control. However, the successful translation of this research into tangible public health benefits hinges on addressing regulatory, ethical, and technical considerations in a comprehensive and collaborative manner. Conclusively, the journey towards a tobacco-free future requires sustained commitment, interdisciplinary collaboration, and evidence-based policy-making.
(The author is a Scientist with CSIR-National Institute of Science Communication and Policy Research, New Delhi)
Views expressed are personal.