As a university focused on using research for the upliftment of its community, The University of the West Indies, St Augustine (UWI STA), the premier tertiary institution in the region, producing world-class scholars, believes science should be accessible to the public. We are pleased to present our media series, UWI Scientists Speak. In this series, our scientists—three of whom received the nation’s highest honour, the Order of the Republic of Trinidad and Tobago, in 2023 and one in 2024—will showcase some of their work.
This week, we hear from Dr Rajini Haraksingh, who discusses using our DNA to treat medical conditions in the country.
Principal, UWI STA
Lecturer in Biotechnology,
The University of the West Indies
Have you ever wondered why two different people could react differently to the same medicine?
One explanation lies in the unique biochemistry of each individual encoded by the DNA comprising our genomes.
The information in our genomes can tell us what diseases we are prone to from birth, which acquired mutations may cause disease later on, and how our bodies may respond to certain treatments.
Over the past two decades, research on diverse human genomes worldwide has provided vast insights showing that different individuals and populations may have varying molecular causes of common diseases. Therefore, different treatments tailored to the specific molecular cause of the disease in an individual are required.
Yet, Caribbean genomes are largely underexplored and underrepresented in the global genomics landscape. Additionally, most clinical trials are conducted on a very narrow representation of humanity, which does not necessarily include Caribbean genomes. So, medical advances from such studies may not necessarily apply to Caribbean people.
My colleagues and I believe that closing that gap provides opportunities to improve our health by harnessing the unique information in our genomes. As we and others work towards equitable representation in this field, we have made some unsurprising but deeply concerning discoveries about our current healthcare practices.
The Caribbean faces the highest burden from non-communicable diseases (Heart Disease, Diabetes, and Cancer) among developing countries in the Americas, and Trinidad and Tobago has the highest prevalence of cardiovascular disease in the Caribbean.
Clopidogrel (Plavix) is the most prescribed medication for cardiovascular conditions globally. However, there are known genetic variants that cause individuals to either not metabolise or have reduced metabolic capability for this medication.
The frequency of these variants is higher in some ethnicities than others. This means the medication may work less efficiently in some people and not in others due to their unique genetic makeup.
Further, the use of this medication in patients with these genetic variants is associated with an increased risk of major adverse cardiovascular events such as stroke and heart attack.
Notably, there are alternative medications whose metabolism is not affected by these genetic variants, and these are available in T&T.
Recent international guidelines, including from the American Heart Association (June 2024), support using genetic data to select medication for cardiovascular disease patients. However, this is not currently practised in this region. Until now, the prevalence of these genetic variants in Caribbean populations suffering from cardiovascular disease was unknown.
For the first time in a Caribbean cohort, we reported a high proportion of patients with cardiovascular disease in T&T who are prescribed clopidogrel and carry genetic variants associated with clopidogrel resistance.
We sampled 10 per cent of patients in the major public cardiovascular clinic in the country, and found that almost two-thirds of the patients carried genetic variants that confer some resistance to clopidogrel.
This was the most prescribed drug in its class in our cohort, and the majority of patients prescribed this drug carry genetic variants that confer resistance to it!
Indo-Trinidadian patients were 3–4 times more likely to carry these genetic variants than Afro-Trinidadian patients.
My research group in the Department of Life Sciences at The UWI, St Augustine, recently published these findings in Springer Nature Cardiology and Therapy.
The team included Daniele Jones and Shana Persad-Ramdeensingh (MSc in Biotechnology students), and Sheherazade Abrahim (Research Assistant), working in collaboration with Dr Naveen Seecheran (lead cardiologist at the Cardiac Catherization Lab at the Eric Williams Medical Sciences Complex and Senior Lecturer).
Our findings revealed that using patient-specific genetic data to help guide treatment selection may benefit patients with cardiovascular disease in T&T. In this example, a straightforward, inexpensive PCR-based genetic test using a saliva sample can determine whether a patient has these problematic variants to help guide drug selection.
While this test is not currently available to the public, post-pandemic, all the public health labs are now well-equipped to implement it. This approach represents a paradigm shift in treating patients, which may result in improved health outcomes and substantial economic benefits.
We are just scratching the surface of how the massive amount of information in our genomes can inform clinical practice. We have a responsibility to investigate ourselves and our clinical practices using the most advanced methods available to achieve the best outcomes for our population’s health.
However, there is need for significant investments in science and technology for this goal to become a reality.