Cells generate all sorts of garbage, the byproducts of metabolism, and also have garbage thrust upon them through a range of mechanisms. Some of the root causes of aging involve forms of garbage that impair the ability to remove garbage - thus leading to the downward spiral that is actually known in the literature as a garbage catastrophe. Diseases like Alzheimer's and Parkinson's are also thought to have a strong component related to the buildup of specific unwanted compounds in and around cells.
The desired approach is to find ways to safely remove garbage. Boosting the ability of cells to do this, through the processes collectively known as autophagy, should be beneficial. The same goes for training immune cells to destroy clumps of unwanted compounds that form between cells. Ultimately, however, some form of biotechnology will be needed to remove those unwanted molecules and structures that autophagy and immune cells don't do well with - such as those that form lipofuscin, a mixed collection of gunk that builds up in long-lived cells and is implicated in a range of different age-related conditions. The SENS Research Foundation works on finding suitable enzymes from soil bacteria to use as a starting point, for example, but there are numerous other potential approaches to building infusions that might break down unwanted garbage in and around cells.
It has to be said that outside of the named diseases that involve aggregates, such as Alzheimer's, there's not a great deal of applied work taking place on this sort of thing. Further, most researchers are more interested in adjusting the underlying mechanisms of cellular metabolism to generate less garbage than in producing a means to periodically clear out garbage. That's pretty much the standard story when it comes to the foundations for rejuvenation biotechnology - not enough is being done to work towards therapies, even though the path ahead is quite clear. Where potentially applicable research is underway, it's slaved to the regulatory structures and restrictions that ensure it will only be used to treat patients suffering end stage diseases of aging, or only takes place in the context of the biology of late-stage disease.
That said, I noticed a couple of recent research publicity releases on the topic of autophagy, garbage, and the degeneration of the brain with aging, and thought I'd point them out.
In research involving both worms and mice, [scientists] have found that age-related dementia is likely the result of a declining ability of neurons to dispose of unwanted aggregated proteins. As protein disposal becomes significantly less efficient with increasing age, the buildup of these unwanted proteins ultimately leads to the development and progression of dementia.
To make this discovery, scientists carried out their experiments in both worm and mouse models that had a genetically-determined dementia in which the disease was caused by protein accumulation in neurons. In the worm model, [researchers] could inactivate distinct routes used for the disposal of the unwanted proteins. Results provided valuable insight into the mechanisms that neurons use to cope with protein accumulation. These pathways were then assessed in young and aged mice. This study provides an explanation of why dementias exponentially increase with age. Additionally, neuron protein disposal methods may offer a therapeutic target for the development of drugs to treat and/or prevent dementias.
The most common mutations responsible for the familial form of Parkinson's disease affect a gene called leucine-rich repeat kinase-2 (LRRK2). The mutations cause the LRRK2 gene to code for abnormal versions of the LRRK2 protein. But it hasn't been clear how LRRK2 mutations lead to the defining microscopic sign of Parkinson's: the formation of abnormal protein aggregates inside dopamine-producing nerve cells of the brain.
"Our study found that abnormal forms of LRRK2 protein disrupt an important garbage-disposal process in cells that normally digests and recycles unwanted proteins including one called alpha-synuclein - the main component of those protein aggregates that gunk up nerve cells in Parkinson's patients. We showed that when LRRK2 inhibits chaperone-mediated autophagy, alpha-synuclein doesn't get broken down and instead accumulates to toxic levels in nerve cells."
"We're now looking at ways to enhance the activity of this recycling system to see if we can prevent or delay neuronal death and disease. We've started to analyze some chemical compounds that look very promising."