New study shows a method to individually distinguish cells in the body in order to advance precision medicine or personalised therapeutic treatments.
Precision medicine is a new model of healthcare in which genetic data, microbiome data and overall information on a patient’s lifestyle, individual needs and surroundings is used to identify and classify a disease and then provide a better, customized or specialized therapeutic solution or even an effective prevention strategy in the future. This molecular-targeting approach has been progressing a lot in the past decade and is now starting to make a strong impact as a new paradigm to ‘classify, diagnose and treat’ a disease. Precision medicine involves first data, and then tools/systems/techniques/technologies to interpret and process this data. It also needs proper regulations by statutory bodies and of course collaboration between health care workers because at every level humans are involved. The most crucial stepin precision medicine is to understand the importance of genetic profiles of patients and how it needs to be interpreted efficiently. This will involve establishing reforms, carrying out training etc. Thus, the practise of precision medicine as of today is elusive because its implementation requires robust data infrastructure, and most importantly“mindset” reform. Interestingly, in 2015, over a quarter of all new drugs approved by the FDA, USA were such personalized medicines since these more “targeted” medicines are supported by smaller and shorter clinical trials with far more precisely defined patient selection criteria and turn out to be more efficient and successful. It is being estimated thatpersonalized medicines in development will increase by almost 70% between by 2020.
Understanding a disease at the molecular level
A recent ground-breaking study has discovered a novel method which can provide insights into how a disease develops and spreads in the body at the molecular level. This understanding is seen to be crucial for developing what is discussed as ‘precision medicine’. The method described in the study very efficiently and quickly recognizes the sub types of cells in the body, which can help in pinpointing the “exact” cells involved in a particular disease. This recognition has been achieved for thevery first time and this makes the study published in Nature Biotechnology highly interesting and relevant for future of the medical field.
So, the question is how the cell types can be recognized in the body. There are about 37 trillion cells in a human body and thus distinguishing each cell individually cannot be adjudged to be a simple task.All cells in our body carry a genome - a complete set of genes encoded within the cell. This pattern of what genes inside the cell (or rather ‘expressed’ in the cell) is what makes a cell unique, for example is it a liver cell or a brain cell (neuron). These “similar” cells of one organ could still be distinctive from each other. A method demonstrated in 2017 showed that cell types that are being profiled can be distinguished by chemical markers which are inside the cell’s DNA. These chemical markers are the pattern of methyl groups connected in each cell’s DNA – referred to as the cell’s “methylome”. However, this method is very restrictive in the sense that it allowsonly single-cell sequencing. Researchers at the Oregon Health and Science University, USA, extended this existingmethod to profile thousands of cells simultaneously. So, this new method exhibits almost 40-fold increase in throughout and it adds unique DNA sequence combinations (or indexes) to each cell which are read out by a sequencing instrument.The team has used this method successfully to index several human cell lines and also mouse cells to reveal information on around 3200 single cells. The authors note that simultaneous read also leads to reduced costs bringing it down to approximately 50 cents (USD) when compared to $20 to $50 for one cell, making methylation libraries of single-cell DNA more cost-effective.
Aspects of precision medicine
This study is a ground breaking one and has the potential to advance the development of precision medicine or precise treatments for many conditions where cell type heterogeneity or diversity is present such as cancer, disorders which affect the brain (neuroscience) and cardiovascular disease which affect the heart. However, it is still a long way to go before we embrace precision medicine because it requires good collaboration between pharma and healthcare workers which can include stakeholders, experts from various sectors, data analytics and consumer-protection groups. Scientific and technological advancements are definitely helping towards development of specialist, targeted therapies and creating more patient-centric solutions, because of which the future of precision medicine looks bright. Once diagnostics are in place, the patients “mindset” could be studied and understood so that empowered patients can themselves demand more information and choice on the options that they have leading to more cost-effective outcomes.
On negative aspect of molecularly based precision medicine is that it is not practicable or affordable for all therapy areas if we talk about and also across health systems, and it not going to be better anytime soon in the future. Gathering all information which is specific to patients firstly requires huge data storage. This information, specifically the genetic data is vulnerable to cyber attacks therefore the security and privacy is at risk, also abuse of such data. The data being collected is mostly from volunteers therefore we are able to gather only a percentage of the entire population which can affect the design of technologies. And the most important aspect is the “ownership” of this data, who is the owner and why, that’s a big question which is still to be addressed. Pharma companies will need to engage more collaboratively with governments and healthcare providers to gather support and momentum for targeted therapies but then the private genetic data being handed over to private companies is a big debate.
For chronic diseases likes diabetes or heart related conditions, digitally powered precision medicine is one alternative i.e. wearables which are normally scalable and are an affordable solution compared to providing expensive personalized care. Also, all medicines cannot really become precision medicine because health systems around the world are already burdened and its nearly impossible as well as ridiculously expensive to provide targeted therapies for small population groups, or those in middle-income or low-income countries. These therapies have to be provided in a well though out and more focused manner. Population and people-based health care paradigms will continue to be important, with precision medicine approaches enhancing these in selected therapy areas and health care systems.It is still a long way before we can genetically map a population, interpret and analyse the information, store it safely and securely, and develop personalised recommendations and therapeutic treatments.
MulqueenR.M. et al. 2018, ‘Highly scalable generation of DNA methylation profiles in singles cells’, Nature Biotechnology, DOI: https://doi.org/10.1038/nbt.4112