(Online) - An increasing number of recent studies are asking an important question: Do gut bacteria hold the key to healthy aging? New research, recently presented at the London Microbiome Meeting, brings us closer to the answer.
As human life expectancy increases, the world population is aging at much higher rates. In fact, the United Nations estimate that the senior population that is, the number of people aged 60 and above is increasing at a rate of approximately 3 percent per year.
Currently, there are 962 million people aged 60 and above across the globe, according to the most recent estimates. By the year 2050, this number is projected to more than double, and the number of people aged 80 and above is expected to triple.
A range of chronic diseases accompanies aging. By the year 2060, for example, the Alzheimer’s disease burden in the United States will have doubled, say the Centers for Disease Control and Prevention (CDC).
They predict that almost 14 million people will have Alzheimer’s and other forms of dementia by then, and researchers are hard at work trying to prevent this and other age-related diseases.
So, the question "How can we live longer and healthier lives?" is slowly replacing that of "How can we live longer?" As scientists embark on the quest for a longer health span, it is becoming clearer that aging is not just an inevitable process that simply "happens," but that there are precise molecular mechanisms that regulate it.
Marina Ezcurra, Ph.D. a lecturer in neuroscience at the School of Biological & Chemical Sciences at Queen Mary University of London in the United Kingdom dedicates her time to understanding these mechanisms. Her research focuses on how aging and its related diseases occur in a worm called Caenorhabditis elegans. More recently, Ezcurra and her team have been examining gastrointestinal aging and the role of the microbiome in this process.
In her presentation entitled "The worm-bug: a combined model system to study host-microbiome interactions" Ezcurra introduced C. elegansas a viable model for studying aging. C. elegans has a lifespan of only 2–3 weeks, but as it ages, it develops several pathologies just like the human organism.
However, in the case of C. elegans, all the pathologies come down to a single one: gastrointestinal aging.
As Ezcurra explained in her talk, all the lifespan-increasing treatments that scientists have applied to C. elegans work by suppressing intestinal aging.
Using C. elegans, researchers can examine a host of age-related processes, such as resistance to stress, growth, fecundity, and lifespan. Experts have also used C. elegans as a model for several human diseases, such as Alzheimer’s.
Ezcurra quotes existing research that saw C. elegans fed with Escherichia coli. As the worm feeds on bacteria, the researchers created about 4,000 mutant strains of E. coli, each with a specific gene deleted. Then, the team fed C. elegans each of these strains and examined the effects.
Senior study author Meng Wang who is an associate professor of molecular and human genetics at the Baylor College of Medicine in Houston, TX reported on the findings, saying, "We fed C. elegans each individual mutant bacteria and then looked at the worms’ lifespan.
Of the nearly 4,000 bacterial genes we tested, 29, when deleted, increased the worms’ lifespan. Twelve of these bacterial mutants also protected the worms from tumor growth and accumulation of amyloid-beta, a characteristic of Alzheimer’s disease in humans."
Also, the researchers found that one bacterial mutant overproduced a substance called colanic acid; this compound increased longevity by stimulating activity in the mitochondria, the so-called powerhouses of the cell, which are responsible for turning nutrients into energy.
In her talk, Ezcurra mentioned another example of successful research into C. elegans that showed the effects of the microbiome on the aging process. This study involved the common diabetes drug metformin.
Metformin is currently the world’s most widely prescribed diabetes drug. Previous research has found that the oral medication does not only reduce blood sugar levels, but that it also reduces the risk of cancer.
Scientists found that the drug can delay aging in mice and C. elegans. Metformin is currently being tested in clinical trials as a potential treatment against aging and aging-related diseases.
As the researcher explained in her talk, this means that metformin could potentially target several age-related chronic diseases at once. Metformin may be able to target not just diabetes, but also cancer and Alzheimer’s pathologies.