Monday, June 11, 2012
Molecular Diagnostics: Emerging Technologies
Human born from two haploid cells forming a zygote cell, divides up to 10 trillion cells in life-time. Each nucleated cell has 22 pairs plus either one pair of XY or XX chromosomes in the nucleus. Human genome is stored in 23 chromosome pairs and a small mitochondrial DNA. Haploid human genome occupies a total of over three billion DNA base pairs. Nearly 30,000 to 40,000 protein-coding genes each individual possesses. Humans also carry over 90 trillion microbes in the gut. Each human life is an orchestra of manifestation of events in an environment, emanating from own 10 trillion cells and carried 90 trillion microbes. Human possesses more DNA from environment than what it inherits and magnifies in its life process. In a physical environment, all the manifestations of health or diseases emanate from own and acquired cells, where expressions stem from the genes through transcription and translation, manifesting a wide range of properties through enzymes, diverse metabolites and other substances. All precise predictions reside in the understandings that emanate and spread from the DNA level.
The aim of effective molecular diagnostics is to find effective biomarkers. A biomarker is a molecule or a response of the cells/tissues/body, which can be objectively measured /evaluated as an indicator of normal biologic processes, pathogenic processes, or pharmacologic responses. In microbial diseases, cancer, cardiovascular diseases or diabetes or other chronic diseases a biomarker refers to a substance or a process that is indicative of the presence or dormant stage of the disease in the body. Genetic, epigenetic, proteomic and glycomic biomarkers can be used for diagnosis, prognosis and epidemiology. These markers can be assayed non-invasively from the collected biological fluids/ body fluids. Examples of genetic biomarkers are: BRCA1 for breast cancer, GDF15 for bladder cancer, Troponin I and CRP for cardio vascular diseases etc.
In molecular diagnostics, the aim is to measure polymorphism of SNPs, haplotype blocks, candidate genes (genes suspected to be involved in an expression), certain proteins and metabolytes as also the spectra of microbial genome in the gut. Information on and about polymorphism is to be generated, measured and correlated with health or disease status.
The key issues in the development hover around measurement of polymorphism, the speed of measurement and the instruments used. Worldwide floods of information are being generated and validated presently correlating with disease risks though new information on: SNPs, haplotype blocks, disease linked DNA/RNA sequences, candidate genes and allelies, novel proteins, novel metabolites, study of cell systems at a single cell level and study of human gut microbial genetics. Computational methods are being developed through robust cyber infrastructure. In all such studies, effective linkages are being established between environmental, dietary, and behavioral data-sets for eco-genetic analysis. High throughput measurements are being evolved to integrate phenotypes with genotypes and to enable application of personalized medicines. Breakthrough tests from the above techniques and analysis shall predict the present and future states of body and evolve suggestive /predictive care. Our expectations are that simple, doable and cost-effective diagnostic device should appear soon to serve human health better.
The main of molecular diagnostics is to predict and prevent diseases well in advance and to support more appropriate personalized medicines. In future, scenario of molecular diagnostics seems to appear like this: a patient would come for an examination to a physician; the physician will collect a sample of body fluid and subject the sample to genomic sequencing; the SNP and the haplotype pattern, for example shall be known where from the physician shall link the status with problems in the body of the patient through computational software programs, which are already prepared and available through a computer. The physician would therefore be able to suggest if the patient needs a medication or what should be done to prevent a disease that is going to appear soon or what additional test must be carried out to conclude about the ailment of the patient. In some cases, the physician may pick up blood samples or samples from the solid tumors and would find the extent of mutated cells in the body to have insight on whether the patient is going to get into the symptoms of certain chronic diseases. In many cases the sequencing data would enable the physician to correlate what medicine would be more suitable for the patient suffering from certain chronic diseases. Such would be the feat and power of molecular diagnostics!
Molecular diagnostics are gaining importance because of high speed of innovative research; discovery of more reliable advanced techniques and machines as well as better understanding of disease progression. People are also becoming more health conscious and as there is an increase in the middle class families, their abilities to pay are also increasing. This situation is also seen as an advantage by the manufacturers as the services are supposed to be more remunerative. The government policies are also supportive to the development as molecular diagnostics are eventually promising better health opportunities to the people.
The future of molecular diagnostics is therefore seen to proceed as under:
1. Knowledge about our body at DNA level would become more profound.
2. Correlations between individual genomic information with own microbial genomics information shall be stronger and methods would be available to make change in the microbial flora in individual gut.
3. Genetics and genome studies would become more personal for individual care, individualized therapy and individualized cure.
4. Genomics & Proteomics would hold the key for innovation in discovery of predictive biomarkers.
5. Every individual will have his/ her genome sequenced fully and would know distinct SNP patterns and haplotype blocks , empowering the physicians for decision making, for choosing more appropriate drugs in chronic diseases.
6. All validated molecular techniques shall lead to more patient empowerment.
7. In the coming years low cost, simple, non-invasive and predictive tests are going to take very important position in our lives and healthcare system.