Cytomegalovirus (CMV) is one of the less immediately harmful members of the family of herpesviruses. It is very prevalent: most people have it in their system by the time they are old, but probably never even noticed, as the symptoms for a healthy individual are essentially nonexistent. Nonetheless like all herpesviruses CMV is very successful at remaining within the body after initial exposure, establishing a life-long infection despite the best efforts of the immune system to get rid of it. The recurring campaigns waged against CMV by your immune cells appear to have a long-term cost: we have evolved to support a given number of immune cells as adults, and as ever more of those immune cells become specialized to a specific pathogen, such as CMV, there is ever less space left in the inventory for cells that can tackle new threats or keep up with all the other jobs of the immune system, such as destroying precancerous and senescent cells.

If you eye the publications of an open access journal like Immunity and Ageing, you'll see a steady flow of papers looking at the role of CMV in age-related immune system decline, a fair-sized component of the frailty of old age. There are a range of possible approaches to this problem, but the most direct and potentially effective don't actually involve doing anything about CMV itself. Instead there are proposals to either add large numbers of new, fresh, and capable immune cells to the body or eliminate the CMV-specialized cells to free up space. Both of these approaches are quite near-term: only a a couple of years would be needed to develop a viable prototype therapy from where we are now, were a research group fully funded and tasked with the effort. Both the ability to culture immune cells and the ability to destroy specific cells in the body based on their surface markers are progressing rapidly.

Some research groups are working on a vaccine for CMV - but a successful vaccine won't do much good for those high percentage of adults in much of the world who have been infected for a long time. Their immune systems are already badly misconfigured as a result of the extended exposure. So tackling CMV isn't a good enough approach on its own, as it only stops the very slow pace of ongoing harm.

Here is a paper to suggest that the progressive disarray in the immune system caused by CMV starts early, even while young.

Rudimentary signs of immunosenescence in Cytomegalovirus-seropositive healthy young adults

Ageing is associated with a decline in immune competence termed immunosenescence. In the elderly, this process results in an accumulation of differentiated 'effector' phenotype memory T cells, predominantly driven by Cytomegalovirus (CMV) infection.

Here, we asked whether CMV also drives immunity towards a senescent profile in healthy young adults. One hundred and fifty-eight individuals (age 21?±?3 years, body mass index 22.7?±?2.7) were assessed for CMV serostatus, the numbers/proportions of CD4+ and CD8+ late differentiated/effector memory cells, plasma interleukin-6 (IL-6) and antibody responses to an in vivo antigen challenge (half-dose influenza vaccine). Thirty percent (48/158) of participants were CMV+.

A higher lymphocyte and CD8+ count and a lower CD4/CD8 ratio were observed in CMV+ people. Eight percent (4/58) of CMV+ individuals exhibited a CD4/CD8 ratio of less than 1.0, whereas no CMV- donor showed an inverted ratio. The numbers of late differentiated/effector memory cells were?~fourfold higher in CMV+ people. Plasma IL-6 was higher in CMV+ donors and showed a positive association with the numbers of CD8+CD28- cells. Finally, there was a significant negative correlation between [vaccine response and the levels of CMV particles present]. This reduced vaccination response was associated with greater numbers of total late differentiated/effector memory cells.

This study observed marked changes in the immune profile of young adults infected with CMV, suggesting that this virus may underlie rudimentary aspects of immunosenescence even in a chronologically young population.

Source:
https://www.fightaging.org/archives/2013/08/measuring-the-impact-of-cytomegalovirus-in-younger-people.php

There has been interest in extending increasing telomerase expression as a means to slow aging for some years. The available tools other than gene therapy are sparse on the ground, however. Telomerase extends telomere length, the caps of repeating DNA sequences at the ends of chromosomes that shorten with each cell division. Telomerase may have other roles that more directly impact aging, however, such as an influence on mitochondrial function.

Shorter telomeres in at least some tissues correlate with stress and ill health and aging, but this is a very dynamic system - average telomere length can change in either direction on a short time scale. It is far from clear that progressively shorter telomere length is a cause of aging rather than just a reflection of other changes and damage, and the same goes for natural variations in levels of telomerase in the body. While increasing expression of telomerase is shown to extend life in mice, that may or may not have anything to do with telomere length, and mouse telomerase biology is quite different from that of humans.

So all this said, it was only a matter of time before researchers evaluated all the existing approved drugs for treatment of age-related conditions to see if any of them altered telomerase activity. There are regulatory incentives to beware of here, however, in that it is much cheaper for research institutions to try to find marginal new uses of already approved drugs than to work on new and radically better medical technologies that would then have to go through the exceedingly and unnecessarily expensive approval process. So don't expect anything of great practical use to result from this:

Not only do statins extend lives by lowering cholesterol levels and reducing the risks of cardiovascular disease, but new research [suggests] that they may extend lifespans as well. Specifically, statins may reduce the rate at which telomeres shorten, a key factor in the natural aging process. This opens the door for using statins, or derivatives of statins, as an anti-aging therapy. "By telomerase activation, statins may represent a new molecular switch able to slow down senescent cells in our tissues and be able to lead healthy lifespan extension."

To make this discovery, Paolisso and colleagues worked with two groups of subjects. The first group was under chronic statin therapy, and the second group (control), did not use statins. When researchers measured telomerase activity in both groups, those undergoing statin treatment had higher telomerase activity in their white blood cells, which was associated with lower telomeres shortening along with aging as compared to the control group. This strongly highlights the role of telomerase activation in preventing the excessive accumulation of short telomeres.

"The great thing about statins is that they reduce risks for cardiovascular disease significantly and are generally safe for most people. The bad thing is that statins do have side effects, like muscle injury. But if it is confirmed that statins might actually slow aging itself - and not just the symptoms of aging - then statins are much more powerful drugs than we ever thought."

Link: http://www.eurekalert.org/pub_releases/2013-08/foas-sms082913.php

Source:
https://www.fightaging.org/archives/2013/08/statin-use-correlates-with-higher-telomerase-activity.php

Building patches for damaged hearts is a popular implementation in tissue engineering at the moment: it's an achievable stepping stone on the way to more complex goals, such as the creation of entire organs starting from only a patient's stem cells, something that still lies in the future. Progress towards a long-term goal in any field requires useful intermediary products, as they help pull in the greater support and funding needed for the next phase of research and development.

When heart cells die from lack of blood flow during a heart attack, replacing those dead cells is vital to the heart muscle's recovery. But muscle tissue in the adult human heart has a limited capacity to heal, which has spurred researchers to try to give the healing process a boost. Various methods of transplanting healthy cells into a damaged heart have been tried, but have yet to yield consistent success in promoting healing.

Now, [researchers] have developed a patch composed of structurally modified collagen that can be grafted onto damaged heart tissue. Their studies in mice have demonstrated that the patch not only speeds generation of new cells and blood vessels in the damaged area, it also limits the degree of tissue damage resulting from the original trauma. The key [is] that the patch doesn't seek to replace the dead heart-muscle cells. Instead, it replaces the epicardium, the outer layer of heart tissue, which is not muscle tissue, but which protects and supports the heart muscle, or myocardium.

The epicardium - or its artificial replacement - has to allow the cell migration and proliferation needed to rebuild damaged tissue, as well as be sufficiently permeable to allow nutrients and cellular waste to pass through the network of blood vessels that weaves through it. The mesh-like structure of collagen fibers in the patch has those attributes, serving to support and guide new growth. Because the patch is made of acellular collagen, meaning it contains no cells, recipient animals do not need to be immunosuppressed to avoid rejection. With time, the collagen gets absorbed into the organ.

Link: http://www.eurekalert.org/pub_releases/2013-08/sumc-scp082613.php

Source:
https://www.fightaging.org/archives/2013/08/a-collagen-patch-to-spur-heart-tissue-repair.php

Mammalian (or mechanistic, depending on who you ask) target of rapamycin (mTOR) is the most likely candidate for the next round of billion-dollar research funding devoted to the search for drugs that can slow aging. It will be a repeat of the overhyped and ultimately largely futile interest in sirtuin research, which generated knowledge but nothing of real practical application, except that this time there is far more compelling evidence that manipulation of mTOR actually extends life in laboratory animals. Though as always, there are those who believe that this is not in fact the case - that mTOR alteration only reduces cancer risk, rather than impacting the processes of aging per se. Just as resveratrol and resveratrol-derivatives are the compounds of choice for those investigating sirtuin biology, so rapamycin and rapamycin-derivatives are the compounds of choice for research groups focused on manipulating mTOR and its related signaling networks. I would imagine that we're in for another decade or so of overhyped claims and public and research community interest in what is in fact an inefficient, expensive, and time-consuming path towards only slightly extending healthy life.

Drugs to slow aging through alterations to metabolism are not the path to radical life extension. Slowing aging does nothing for people already old. The research community should focus instead on rejuvenation through therapies that repair and remove the cellular damage that causes aging, an approach that can actually meaningfully help the aged when realized. For all that rejuvenation is the obviously superior research strategy, however, it's taking time to convince the world of that truth. Time spent on trying to slow aging is little different in outcome to time spent investigating the details of aging but choosing to do nothing about it: a few years here and there, and nothing that is as effective as simple exercise and calorie restriction. There's no such thing as useless knowledge in the long term, but we already know enough to work effectively on human rejuvenation.

The new study quoted below will no doubt bolster the prospects of those groups presently raising funds for attempts to slow aging or further develop drug candidates derived from rapamycin. While looking at the results, however, you might compare them with plain old calorie restriction in mice, something that can produce twice the extension of healthy life shown here.

Mutant Mice Live Longer

MTOR is a kinase involved in myriad cellular processes, from autophagy to protein synthesis. Genetic studies of TOR in other organisms, such as yeast and flies, have implicated a role for the enzyme in lifespan. In mammals, however, mTOR is required for survival, making a knockout mouse model unfeasible. So the National Heart, Lung and Blood Institute's Toren Finkel and his colleagues decided to use a mouse in which transcription was only partially disrupted, reducing the levels of mTOR to about 25 percent of the normal amount.

All else being equal, the researchers found that normal mice typically lived 26 months, while those with less mTOR survived around 30 months. Finkel said the increase in lifespan was greater than other researchers have seen using the immunosuppressant rapamycin to inhibit mTOR. It's possible that having mTOR reduced beginning in the womb, rather than at middle age, could explain the disparity. Additionally, this new mutant affected the levels of both forms of mTOR - mTORC1 and mTORC2 complexes - rather than preferentially impacting one, as rapamycin would.

The paper on this research is open access, so head on over and take a look. I think you'll find it interesting. In particular note the author's cautions regarding the size of the life extension effect and the life span of the control mice in the discussion section: the number of mice used isn't large, and it's possible that the controls were just randomly a slightly short-lived group.

Increased Mammalian Lifespan and a Segmental and Tissue-Specific Slowing of Aging after Genetic Reduction of mTOR Expression

We analyzed aging parameters using a mechanistic target of rapamycin (mTOR) hypomorphic mouse model. Mice with two hypomorphic (mTOR?/?) alleles are viable but express mTOR at approximately 25% of wild-type levels. These animals demonstrate reduced mTORC1 and mTORC2 activity and exhibit an approximately 20% increase in median survival. While mTOR?/? mice are smaller than wild-type mice, these animals do not demonstrate any alterations in normalized food intake, glucose homeostasis, or metabolic rate. Consistent with their increased lifespan, mTOR?/? mice exhibited a reduction in a number of aging tissue biomarkers. Functional assessment suggested that, as mTOR?/? mice age, they exhibit a marked functional preservation in many, but not all, organ systems. Thus, in a mammalian model, while reducing mTOR expression markedly increases overall lifespan, it affects the age-dependent decline in tissue and organ function in a segmental fashion.

Source:
https://www.fightaging.org/archives/2013/08/decreased-mtor-expression-provides-20-mean-life-span-extension-in-mice.php

The immune system declines greatly with aging, and poor immune response is an important component of age-related frailty: old people become vulnerable to infections that the young can shrug off with ease. So we might expect to see that long-lived people have better immune systems, and that whatever underlying mechanisms cause that difference are to some degree inherited.

People may reach the upper limits of the human life span at least partly because they have maintained more appropriate immune function, avoiding changes to immunity termed "immunosenescence." Exceptionally long-lived people may be enriched for genes that contribute to their longevity, some of which may bear on immune function. Centenarian offspring would be expected to inherit some of these, which might be reflected in their resistance to immunosenescence, and contribute to their potential longevity. We have tested this hypothesis by comparing centenarian offspring with age-matched controls. We report differences in the numbers and proportions of both CD4+ and CD8+ early- and late-differentiated T cells, as well as potentially senescent CD8+ T cells, suggesting that the adaptive T-cell arm of the immune system is more "youthful" in centenarian offspring than controls. This might reflect a superior ability to mount effective responses against newly encountered antigens and thus contribute to better protection against infection and to greater longevity.

The goal of future medicine is to make inherited differences of this nature irrelevant. There are a number of promising approaches that may remove much of the age-related decline of immune function: regrow the atrophied thymus, where immune cells are cultured; create new immune cells in the clinic and infuse them regularly into older people; destroy the population of over-specialized memory cells that exist in the elderly, thus freeing up space for effective immune cells that can combat new threats.

Link: http://www.ncbi.nlm.nih.gov/pubmed/23974207

Source:
https://www.fightaging.org/archives/2013/08/children-of-long-lived-parents-have-better-immune-systems.php