Arxiu d'etiquetes: genomics

From traditional medicine to personalized medicine

From prehistory, where medicine started began with plants, minerals and parts of animals; until today, medicine has evolved very quickly. Much of the “fault” of his fact is due to genetics, which allows us to talk about personalized medicine. In the following article we discuss this.

THE EVOLUTION OF DISEASES

To talk about medicine, we have first to know diseases. We cannot think that all diseases are genetic, but there are diseases related to anatomical changes, fruit of our evolution.

Chimpanzees are the closest animal to us, humans, with which we share 99% of our genome. Despite this, humans have very particular phenotypic characteristics as the brain most develop, both in size and expansion of the cerebral cortex; hairless sweaty skin, bipedal posture and prolonged dependence on offspring, allowing the transmission of knowledge for longer; among other.

Possibly, the bipedal position was key to the early development of the divergence between the chimpanzee lineage and that of humans; and is also the reason for the appearance of some diseases related to anatomical factors. Among them are hernias, haemorrhoids, varices, disorders of the spine, such as herniated intervertebral discs; osteoarthritis in the knee joint, uterine prolapse and difficulties in childbirth.

The fact that the pelvis was remodelled (Figure 1) and narrower resulted in obstetric problems millions of years later, when the brain expanded. Consequently, the skull as well. The heads of the foetuses were longer and larger, making birth difficult. This explains why the deliveries of humans are longer and longer compared to those of chimpanzees and other animals.

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Figure 1. Comparison between human pelvis and chimpanzee pelvis in bipedal position (Source: Libros maravillosos – La especie elegida (capítulo 5))

The evolution towards modern life has behaved many changes in every way. In comparison to our hunter-gatherer ancestors (Figure 2), our diet has changed a lot and has nothing to do with what other primates eat. For the latter, the fruit represents most of the intake, but for us it is red meat. In addition, we are the only animals that continue to feed us milk after the lactation period.

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Figure 2. Picture of hunter-gatherer humans (Source: Río Verde en la historia

If we add to the sedentary lifestyle and the limited physical activity of modern humans, it can help explain the seriousness and frequency of some modern human diseases.

Lifestyle can also affect us. For example, myopia, which rate is higher in western individuals who read a lot or do activities of near vision, compared to individuals of Aboriginal’s towns.

Another clear example is the alteration in the female reproductive stage. Currently, women have children more and more later. This is also linked to a decrease in the duration of breastfeeding. These changes, which can be considered socially positive, have negative effects on the health of the reproductive organs. It has been shown that the combination of early menarche, limited or no breastfeeding and later menopause are the main risk factors for breast and ovarian cancer.

Humans increasingly live more years and we want the best quality of life. It is easy for more longevity to appear more diseases, by the deterioration of the organism and its cells.

THE EVOLUTION OF MEDICINE

The history of medicine is the history of the struggle of men against disease and since the beginning of this century, is also the history of human effort to maintain health.

We have acquired the scientific knowledge of medicine based on observation and experience, but it has not always been so. Our ancestors experienced sickness and the fear of death before a rational picture could be made of them, and the medicine of that time was immersed in a system of beliefs, myths and rites.

However, in the last years it has been born personalized genomics, which tells you your risk factors. This opens a door to personalized medicine, which adjusts treatments to patients depending on their genome (Figure 3). It uses information from a person’s genes and proteins to prevent, diagnose and treat a disease, all thanks to the sequencing of the human genome.

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Figure 3. Personalized medicine that treats people individually, according to their genome (Source: Indiana Institute of Personalized Medicine)

Molecular methods that make precision medicine possible include tests of gene variation, proteins, and new treatments targeting molecular mechanisms. With the results of these tests and treatments can determine the state of the disease, predict the future state of the disease, the response to the drug and treatment or even the role of the food we eat at certain times, which results of great help to the doctors to individualize the treatment of each patient.

To do this, we have within our reach the nutrigenetics and the nutrigenomics, that like the pharmacogenetics and the pharmacogenomics, they help the advance of a medicine is more and more directed. Therefore, these disciplines are today one of the pillars of personalized medicine since it involves treating each patient individually and tailor-made.

The evolution towards precision medicine is personalized, preventive, predictive and participatory. There is increasing access to information and the patient is more proactive, getting ahead of problems, preventing them or being prepared to deal with them efficiently.

REFERENCES

  • Varki, A. Nothing in medicine makes sense, except in the light of evolution. J Mol Med (2012) 90:481–494
  • Nesse, R. and Williams, C. Evolution and the origins of disease. Sci Am. (1998) 279(5):86-93
  • Mackenbach, J. The origins of human disease: a short story on “where diseases come from”. J Epidemiol Community Health. (2006) 60(1): 81–86
  • Main picture: Todos Somos Uno

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Nutritional genomics: À la carte menu

When Hipprocrates said “let food be your medicine and medicine be your food” he knew that food influences our health. And it tells us that nutritional genomics, which I will discuss in this article; a new science appeared in the post genomic era as a result of the sequencing of human genome (all DNA sequences that characterize an individual) and the technological advances that allow the analysis of large amounts of complex information.   

WHAT IS NUTRITIONAL GENOMICS?

The aim of nutritional genomics is to study the interactions of genes with elements of the human diet, altering cellular metabolism and generating changes in the metabolic profiles that may be associated with susceptibility and risk of developing diseases.

This study wants to improve the health and to prevent diseases based on changes in nutrition. It is very important not understand nutritional genomics how that specific food or nutrients cause a particular answer to certain genes.

When we talk about diet we have to distinguish between what are nutrients and what are food. Nutrients are compounds that form part of our body, while foods are what we eat. Food can take many nutrients or only one (such as salt).

NUTRIGENOMICS vs. NUTRIGENETICS

Within nutritional genomics we find nutrigenomics and nutrigenetics, but although their names we may seem to mean the same is not the case (Figure 1).

Nutrigenomics is the study of how foods affect our genes, and nutrigenetics is the study of how individual genetic differences can affect the way we respond to nutrients in the foods we eat.

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Figure 1. Schematic representation of the difference between nutrigenomics and nutrigenetics (Source: Mireia Ramos, All You Need is Biology)

NUTRIGENOMICS IN DETAIL

Nutrients can affect metabolic pathways and homeostasis (balance) of our body. If this balance is disturbed chronic diseases or cancer may appear, but it can also happen that a disease, which we have it, be more or less severe. It means that impaired balance can give the appearance, progression or severity of diseases.

The aim of nutrigenomics is that homeostasis is not broken and to discover the optimal diet within a range of nutritional alternatives.

Thus, it avoids alterations in genome, in epigenome and/or in expression of genes.

ALTERATIONS IN GENOME

Free radicals are subproducts that oxidise lipids, proteins or DNA. These can be generated in mitochondria, organelles that we have inside cells and produce energy; but we can also incorporate from external agents (tobacco, alcohol, food, chemicals, radiation).

In adequate amounts they provide us benefits, but too much free radicals are toxic (they can cause death of our cells).

Antioxidants neutralize free radicals. But where can we get these antioxidants? There are foods that contain them, as Table 1 shows.

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Table 1. Example of antioxidants and some foods where we can find them (Source: ZonaDiet)

The way we cook food or cooking is important for avoid to generate free radicals. In barbecues, when we put the meat on high heat, fats and meat juices fall causing fire flames. This produces more flame and it generates PAHs (a type of free radicals). These adhere to the surface of the meat and when we eat it can damage our DNA.

ALTERATIONS IN EPIGENOME

Epigenome is the global epigenetic information of an organism, ie, changes in gene expression that are inheritable, but they are not due to a change in DNA sequence.

Epigenetic changes may depend on diet, aging or drugs. These changes would not have to exist lead to diseases as cancer, autoimmune diseases, diabetes…

For example, with hypomethylation, in general, cytosines would have to be methylated are not. What does it mean? Hypomethylation silenced genes and then, they cannot be expressed. Therefore, we need methylated DNA. A way of methylate DNA is eating food rich in folic acid.

ALTERATIONS IN GENE EXPRESSION

There are agents (UV rays) that activate pathways that affect gene expression. Occurring a cascade that activates genes related to cell proliferation, no differentiation of cells and that cells survive when they should die. All this will lead us cancer.

It has been found that there are foods which, by its components, can counteract activation of these pathways, preventing signal transduction is given. For example curcumin (curry), EGCG (green tea) or resveratrol (red wine).

 REFERENCES

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