Posts Tagged 'Health'

Swine Flu, Update

First of all, thanks to the team and people of Nature Blogs for accept my blog in their list!

Second… Being a Grad Student, usually I have little time to dedicate to post something really interesting and good-quality content. Today, it’s one of these days (the workbench took all of my day… and now I am getting ready to sleep). But I wanted to recommend these links about the Swine Flu on Nature and Science.

First, an interview from ScienceInsider with Ruben Donis, chief of the molecular virology and vaccines branch at the CDC. I tried to investigate about the genetics of the virus, but it seems that I have to wait to see a paper in a Journal. Anyway, Donis talks in the interview about some interesting features of the virus, and about the history of the Swine Flu. Also check the special from Science here.

Second, the special from Nature is also interesting. By the way… this blogger lives in Chile. Sometimes, here we hear things like “we are so far from everything… we are isolated and safe”. But in the news I watched about the first confirmed case in Peru, next to us. Chile has been very efficient so far in the preparation for the disease and the checking of the tourists and travellers in the International Airport. By now, there are about 42 cases in our country; 16 of them have been ruled out; 26 are being studied, and several of them are people who travelled to Mexico or USA. I guess the meetings and courses around there will suffer by now.

About Stem Cells and the Holy Grail

A recent news article in Nature caught me into deep thoughts. The article reviewed some of the main developments in the field of induced Pluripotent Stem (iPS) cells. The formula seems simple: I have my “whatever” cell, and by introduction of a cocktail of genes, eventually I will find out that three or four genes are able to reprogramming the cell.

However, it seems that not every tale about iPS cells is so simple. Several issues are of the concern of scientists and medical doctors. For example, the efficiency of the production of the iPS cells, and the purity. Also, whether this cells will induce the formation of teratomas or tumours. I strongly recommend the News Article by Monya Baker in Nature [1] to read about the subject.

I share some of the enthusiasm about iPS cells. Working with primary cultures of stem cells is hard, slow and sometimes disappointing. For example, working with bone marrow derived stem cells is a slow process; from obtaining the sample until reaching a fourth passage, can take even four months, when cells are isolated from older donors (I worked with this model four years; I know what I’m talking about). If we can use these cells for the treatment of a disease, months can be lethal for the patient. Even so, cells are progressively loosing their “stemness”. iPS cells seems to circumvent some issues regarding efficiency. However, the artificial induction of a stemness state is a subject of relatively little study; by now, the focus of the scientists has been the improving of the methods for the development of the iPS cells, without worry about the mechanisms [1]. Then, the next step should be the further knowledge of mechanisms. In this scenario, Systems Biology should take an important place. We need to gain insight about what genes, what metabolic pathways, what proteins, what non-coding RNAs, what micro-RNAs, are being induced, are working, are being repressed.

From Bruneau Lab

From Bruneau Lab

Maybe a fresh approach is provided by the work by Takeuchi and Bruneau published online in Nature [2]. The authors showed that mouse mesoderm cells can be transdifferentiated into cardiac myocytes by the introduction of three genes: Gata4, Tbx5 (two cardiac transcription factors) and Baf60c (a cardiac-specific subunit of the BAF chromatin-remodelling complex). The novelty resides in that the authors further handle their work providing data about the mechanisms (something which is lacking in several other works): they show that Gata4 binds Tnnt2 and Nppa (cardiac genes) only in the presence of Baf60c, using chromatin immunoprecipitation. They even provide a model and a “minimal” regulatory gene network. This work can be considered a step forward in the way researchers are studying reprogramming. It is not a matter of just “we will insert these genes and quantify how fast the cells are induced to pluripotency”, but also the “how”. And it seems very reasonable thinking about the possible effect of the genes being introduced.

References

[1] News Feature Article:

Fast and Furious. M. Baker. Nature, 2009, Vol 458, pp. 962-965

[2] Takeuchi, J.K. and Bruneau B.G.

Directed transdifferentiation of mouse mesoderm to heart tissue by defined factors.

Nature, 2009, doi:10.1038/nature08039

[3] Bruneau’s Lab Page (including videos):

http://web.mac.com/bruneaulab/Bruneau_lab/Welcome.html

Swine Flu, reloaded

I found some interesting information about the Swine Flu outbreak in Science Insider [1,2]. Two topics are really disturbing: one of them is related with a previous outbreak in 1976. It seems that a swine flu strain swept from a military base in New Jersey, and several soldiers were infected. But only one soldier died. You can read more about this story in [2].
The second topic is very perturbing. The news from ScienceInsider claims that in USA, none of the suspected diseased people have died; all of them had a mild disease. However, in Mexico, 80 deaths are attributed to the virus. One should ask: Why? If these numbers are correct, why in one country, there are no deaths from a virus, but in the next country, there are so many? In this case, one can propose that economical factors are influencing in the outcome of the treatment. But, there is such a difference between USA and Mexico? I could accept a difference maybe between England and Bolivia, for example.
Maybe another explanation can be even more deep. Ona explanation regarding something even more powerful than economics: Single Nucleotide Polymorphisms (SNPs). There is no scientific fact to assume that two populations will have the same genetical background. And, indeed, some mutations are more prevalent in specific genes in specific populations. I have some knowledge about one specific gene: ATP7B. Mutations in this gene is related with the Wilson Disease, and more than 250 mutations have been reported. Strikingly, mutations are “country-specific”. Even between neighbor countries, the differences are surprising. A database with more than 300 mutations has been implemented. And this is only one example.
Being hard with this idea, I can imagine that the influence of genetic variations in the response to pathogens and drugs, for example, will be important when someone is analyzing two populations. And then, we have Genome-Wide association studies: the only available tool that we can use in a quick way to asses two population’s response to an infectious disease, in this case. Are we ready to develop and implement fast and global responses to global threats such as Swine Flu? Of note, a recent news in Science talks about a debate regarding the real value of genome-wide association studies, where some scientists are saying that these studies are not bringing valuable clinical information about diseases, and the trend seems to be the support to full-genome sequencing in patients. That approach could be very useful in the study of diseases such as cancer. But, when we are dealing with global outbreaks, as Swine Flu now, we need to handle all the information available. Including the properties in our genome that can influence the response of a country, or even the entire human kind, to a inminent threat.

References and links:

[1] http://blogs.sciencemag.org/scienceinsider/2009/04/swine-flu-sprea.html
[2] http://blogs.sciencemag.org/scienceinsider/2009/04/retrospective-w.html
[3] Koenig, R. Science, 2009, April 24, Vol. 324, page 448.


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