The most efficient approach to developing ENS will be by a coordinated "Manhattan Project" in which substantial funds are targeted appropriately and systematically. This may be best achieved by setting up a research institute. This page summarises my current vision of how such an institute would work, why it is the best use of a billion dollars, and what main projects it would oversee. I have tried to write it in a form that could be shown to people who might be interested in providing such capital (or a substantial proportion of it) over ten years. If you know such a person, please show it to them!

Summary
What science would be funded?
     Obviating mitochondrial mutations
     Degrading intracellular junk
     Preventing and curing cancer
     Removing unwanted, toxic cells
     Breaking extracellular crosslinks
     Degrading extracellular junk
How long would it take?
Would it work well on mice?
Would it be done without IBG?
Would it expedite success in humans?
References

Summary

This memorandum briefly outlines the case for the setting-up of an Institute of Biomedical Gerontology (hereafter "IBG"), whose remit would be to promote, co-ordinate and fund a range of projects leading, jointly, to a genuine cure for human aging. The memorandum is in two parts. In the first section I provide answers to the following key questions:

A. Answers to key questions

1) What main projects, at what funding level, would IBG support?

The main projects that IBG would support are those that:

Finally, IBG would organise and sponsor conferences dedicated to the field of biomedical gerontology. These would include focused, invitation-only roundtable workshops with only ten or so participants, standard academic meetings covering the broad range of the field, and public meetings designed to communicate IBG's work to the layman. Total outlay on such meetings would be at most $0.5m per year.

2) Why are these projects likely to succeed within about 10 years?

This expected timeframe derives directly from the criteria listed in the last section. With (a) a substantial body of groundwork and (b) a defined plan of action that has no clearly severe obstacles, the only things that can stretch such a timeframe are unavailability of funds, unavailability of experts interested in doing the work, or unforeseen technical hurdles. The existence of IBG and of applicants for its funds would remove the first two possibilities; the third can never be ruled out entirely, but is made unlikely by the fact that specialists have been sufficiently confident to make the investment in groundwork.

Since all these projects already have the detailed structure typical of a commercial R&D project (and atypical of a basic science topic), interim milestones and timelines can readily be specified down to the level of annual or biennial subgoals. IBG would typically commit to a basal level of funding of a given project for at least five years up-front, but this would be subject to large supplementation (typically doubling of an annual budget) on successful achievement of specified milestones. This would provide the correct balance between security (so that high risk but aggressive approaches to the given problem can be pursued) and incentive to achieve progress as speedily as possible.

3) Why are these projects likely to confer robust mouse rejuvenation?

First we must define "robust mouse rejuvenation". For present purposes it will be defined as a treatment applied to a mouse only after it has reached 2/3 of its life expectancy, and which increases its total healthy life expectancy by at least 2/3. (This equates to trebling its remaining healthy life expectancy.) Also, the mouse must be of a strain whose life expectancy (in the absence of any treatment) is at least three years (which is long for a mouse).

These projects are likely to confer robust mouse rejuvenation because, jointly with a handful of other research areas that are already being well funded by other means, they reverse all the major deleterious molecular and cellular differences between a middle-aged adult and a young adult. Dr. de Grey has published detailed analyses of this question both in concert with eminent senior biologists of aging (de Grey et al. 2002a, 2002b) and alone (de Grey 2003). Briefly, there are only seven categories of such change that are not already amenable to effective medical intervention; five of these are addressed by the projects listed earlier and discussed in the second section of this memorandum, and the other two (cell loss and accumulation of extracellular aggregates) are being pursued by relatively well-funded groups. All aspects of age-related decline are the eventual result of one or more of these changes, so if they were all reversed (either periodically or continuously) and thus did not accumulate with time, aging as we now know it would not occur. It would eventually (at an older age) re-emerge as a result of slower accumulation of other changes that do not cause pathology in what we now consider a normal lifetime; it will be possible to address such changes only when they can be identified, due to having been unmasked by the removal of the changes we already know about. However, the degree of life extension defined as "robust mouse rejuvenation" above will be achieved without solving such "second-generation" problems.

4) Why is robust mouse rejuvenation in 10 years unlikely without IBG?

At present, no organisation is supporting work of the sort described above, except where it can be packaged as having applications outside life extension. Moreover, when such funding is available it is always targeted at the most modest, short-term projects and/or those with a "basic science" purpose, i.e. directed at improving our understanding of some aspect of biology as opposed to our manipulation of it. At the opposite end of the spectrum is work on what we now think of as "anti- aging medicine", namely supplements and other interventions aimed at a very modest extension of life expectancy. The projects on which IBG would focus fall between these two stools: too ambitious-sounding to be medically respectable but too goal-directed to be biologically respectable. Thus, without a source of funding whose specific remit is to fill this vacuum, this work is likely to be delayed by up to a decade. That translates into a prediction of roughly half a billion people dying of old age without IBG but not if it were set up now.

Moreover, IBG would, as principal funder of all these projects, be in a strong position to facilitate and accelerate their co-operation and thus the rapid generation of mice benefiting from all projects. This is much less likely to occur in traditional funding environments.

5) Why is robust mouse rejuvenation the quickest route to curing human aging?

The reason is a combination of science and sociology. The later stages of developing a true cure for human aging will be funded publicly, as a result of a vigorous demand from society to develop it as soon as possible. That demand will arise only when society begins to feel that curing human aging is foreseeable, in contrast to the present situation where virtually everyone considers it totally impossible within their or their children's lifetimes and thus does not agitate for it. Thus, the quickest route to curing human aging is to achieve results in the lab that are sufficiently impressive to effect this change in public attitude. Robust mouse rejuvenation, as defined above, should suffice to do this and is doable more quickly than any comparably impressive advance. This is because of the great wealth of knowledge and technical expertise in mouse manipulation that has been built up over the past century, together with the mouse's relative similarity to humans (as compared with fruit flies, for example).

B. Prospective IBG-targeted projects: status and near-term directions

This section briefly outlines the status and next steps of five key strands of translational research that will form components of robust mouse rejuvenation. The motivation for pursuing that goal, and hence these projects, is summarised in the previous section. Funding level estimates are also given, based on an average cost to the funding source of $200,000 per full-time researcher per year including salary, research equipment and supplies.

a) Functional introduction of all 13 mitochondrial protein-coding genes into the nucleus, so making mitochondrial mutations harmless

Basis: mitochondrial mutations accumulate with age, with the result that some cells become unable to use oxygen. This happens faster in shorter-lived species, suggesting that it contributes to aging. Only 13 proteins are susceptible to such mutations; the other 1000 or so proteins in mitochondria are encoded in nuclear DNA, which is hugely better protected. Thus, we should introduce copies of the 13 genes into the nucleus (by gene therapy in humans, but first by much more established techniques in mice) so that these 13 proteins are present even if mitochondrial mutations have occurred. This will mean that cells remain able to use oxygen and therefore healthy and non-toxic.

Origin: First suggested as an anti-aging therapy by Hoeben in 1993. Usually termed "allotopic expression". The general concept of introducing mitochondrial genes into the nucleus was first proposed and implemented (in yeast) by Nagley's group in 1986.

Status: Three of the 13 proteins have been expressed from the nucleus and shown to work (allowing oxygen utilisation when the mitochondrial counterpart was mutant). However, this has only been done in cell culture so far, not in live mice.

Next steps: Several approaches to making all 13 genes work, first in culture and then in mice, have been proposed, reviewed by (de Grey 2000). A key recent advance has been to clone four of these genes from green algae, which naturally have them in the nucleus; this will allow emulation of the tricks that evolution has found to make them work. However, several of these genes have never been found in the nucleus of any species, so this may not solve the whole problem (though it may, because we can apply a solution that exists for one gene to other genes more easily than evolution can). Two main alternative approaches exist: modifying the genes with sequences called "inteins" (see de Grey 2000) and using proteins that do not pump protons.

Key investigators: At least a dozen laboratories are currently doing work related to this problem. Most of them and their relevant work are cited in (de Grey 2000). In all cases, however, the work is proceeding fitfully as a result of very limited funding. The idea of allotopic expression as a human therapy is relatively long-term (might take 5-10 years to get working in mice), and such projects are not favoured by traditional funding agencies. This situation has actually become worse in the past year or two since the initial successes mentioned above, because prior to that it could be argued that allotopic expression was basic science (finding out why these proteins are hard to encode in the nucleus) whereas now it is "only" technology. But this recent history means that there is abundant appropriate expertise available, which needs only adequate funding to be remobilised.

Funding level and priorities: The first task is to make all 13 genes work in cell culture. There are three major approaches to this that presently seem feasible (see "Next steps" above), each of which is being pursued by at least one laboratory, but for each of which several variations exist that would be best pursued in other labs. Thus, a realistic estimate is that a call for applications would receive 8-12 applications that strongly merited funding. Each of these applications would typically be for two to four full-time researchers for five years, with the goal of making some or all of the 13 genes work in cell culture. In all cases, the translation of that success to live mice would be the subject of a further five-year period of funding at a similar level. Total cost to IBG would be in the range $5m-$7m per year.

Milestones: Manipulation of mitochondrial DNA has recently improved, such that it will very soon be possible to engineer mutations in particular mitochondrial genes while leaving others intact. This will greatly facilitate work on each of the 13 genes in isolation. An initial milestone will be to get each gene working in cells in which it is the only one whose mitochondrial copy is mutant. Some will be easier than others, and we cannot know which technique will work best. Milestones would thus be set on a case-by-case basis, depending on the specifics of the approach being pursued. After a given gene had been made to work, a key next step would be to make more than one gene work in the same cell; this may again throw up unexpected problems but they would be likely to be relatively easy to solve compared with the initial one-gene problems. By the five year point, a key goal would be to have all 13 genes working in the same cell. This clear requirement for collaboration between the various groups would be reflected in the call for applications, and also in the organising by IBG of regular meetings and mutual site visits between the grant holders. Before that point, some groups will be ready to move to live mice and they must be given maximum opportunity to do so (such as by large supplementary funding, as summarised in section A). During that phase the milestones will be similar: getting one or two genes working in live mice will be easier and quicker than getting them all working.

b) Enhancement of lysosomal catabolic versatility with non-mammalian hydrolytic enzymes, so removing undegradable aggregates

Basis: Aggregates accumulate in cells with age, in special compartments called lysosomes. This happens faster in shorter-lived species, suggesting that it contributes to aging; also, it is known to cause several of the most important diseases of aging including dementia and atherosclerosis. It happens because cells naturally generate or take up a very wide variety of large molecules that they need to break down, and even though the cell's machinery for breaking things down is very sophisticated it is not able to degrade everything. The lysosome is the machinery of last resort for this degradation: it is a highly acidified compartment with many powerful enzymes. Anything that cannot be broken down there is just stored within the lysosome, because there it cannot do much harm whereas if it were ejected it would be more toxic. Unfortunately, it still does some harm once there is too much of it. Thus, we should improve the versatility of the lysosome by giving it new enzymes that help it break down the most abundant of the things that it currently cannot. Such enzymes exist in soil micro-organisms, as reasoned theoretically (if they did not, these substances would accumulate in the soil) and also established experimentally (de Grey 2002). The task is thus to find them and add them to mammalian cells.

Origin: first suggested as an anti-aging therapy by de Grey in 1999 (de Grey 2002). Generally termed "lysosomal enhancement". The general concept of biotechnological use of soil micro-organisms to degrade recalcitrant molecules is much older and widely exploited.

Status: Proof of concept has been established (de Grey 2002). A team of experts in all areas relevant to the application of this scheme to atherosclerosis has been assembled; atherosclerosis was chosen as a first target because the evidence that lysosomal aggregates cause it is more universally accepted than for other targets. However, it is still a longer-term project than traditional funding bodies favour, so no funding has been secured as yet. With sufficient funding, the focus on atherosclerosis would be broadened so that neurodegeneration, macular degeneration and lipofuscin accumulation would all also be targeted simultaneously.

Next steps: The project breaks down into the following stages: 1) Isolate micro-organisms that can degrade the target substance; 2) Isolate the genes encoding the enzymes that perform this; 3) Construct lysosome-targeted forms of these genes to assay their toxicity and efficacy in cell culture; 4) Assay toxicity and efficacy in live mice. Step 1 is relatively simple and cheap: the technique is to isolate a crude extract from soil and expose it to the target substance in the absence of any other material that could support growth. Then, those organisms that grow into colonies will be specifically the ones that can degrade the target substance (and thereby extract energy from it). Steps 2 through 4 are more expensive and laborious but are not specific to this project: the techniques are very well established.

Key investigators: These fall into several categories. Experts in the isolation of degradation-competent strains and in the purification of the target substance from tissue will be required throughout the project. Experts in the identification of breakdown products of target substances will also be vital in identifying the degradation pathway, so as to help in finding the responsible genes. Lysosomal targeting experts and those involved in introducing genes into cells and mice and testing toxicity and efficacy would be involved at a later stage, typically in year 3 onward. There are many ideal researchers in all these areas, though none of them have pursued this application of their speciality.

Funding level and priorities: A call for applications would specify a range of age-related aggregates whose degradation IBG seeks to fund. I would expect IBG to receive 8-12 applications that strongly merited funding, mainly focused on atherosclerosis and neurodegeneration but with at least one each on macular degeneration and lipofuscin. Each of these applications would typically be for two to four full-time researchers for five years, but beginning at two FTEs for the first two years. Typical applications will be collaborations between labs with expertise in the specific age-related pathology and those with expertise in bioremediation. Expertise in lysosomal targeting would typically be proposed to enter the project in year 3. Bioremediation and lysosomal targeting groups would generally be in a position to work with more than one pathology-specific group, but the specifics of particular enzymes (as regards both their isolation and their engineering) will limit the scope for avoiding duplication of effort. However, as with allotopic expression, IBG would work actively to foster communication and collaboration between initially separate projects. Total cost to IBG would be in the range $2m-$4m per year in years 1 and 2 and $5m-$10m per year thereafter, possibly rising to the order of $15m per year in the last stages when mouse toxicity and efficacy assays are involved and the various identified enzymes are combined in the same mouse.

Milestones: These arise from the breakdown into four stages as outlined above. Isolation of degradation-competent micro-organisms should be achieved quickly; for each target substance, the aim should be to isolate a dozen strains with high diversity, because many will fail at subsequent stages (e.g. be toxic). This should be done within year 1. Isolation of the responsible genes in each such strain will occupy a further year. There are several mechanisms for lysosomal targeting, and the choice may vary depending on the enzyme; it is likely that constructing suitable engineered genes and testing them for targeting to lysosomes will take a further year, during which initial work on toxicity will also occur. Assays of efficacy and translation to live mice will take between one and three more years.

c) Deletion of all telomere elongation capability with compensation by autologous stem cell reseeding, so preventing cancer

Basis: Cancer, unlike any other aspect of aging, uses natural selection to become worse with time. All existing or forthcoming anti-cancer therapies fail to address this key property, because they all have loopholes that a cancer can escape through by turning genes on or off. Turning genes on and off by spontaneous mutation is a rather common event, so there are always some cells in a cancer that have done it to the right genes to resist the therapy; they thus survive and take over the cancer, so after a possible period of shrinkage the cancer returns to its original potency but with total resistance to the therapy. A way to avoid this is to delete genes that the cancer cell needs to divide. They cannot be reliably deleted only from the cancer, however; they must therefore be pre-emptively deleted from all cells in the organism. But this has the effect of damaging other, normal tissues that also need to divide, like skin and blood. However, if the genes chosen are those for telomere elongation, the cancer (which must divide hundreds of times before it can become dangerous) will be stopped from growing to a pathological size but all normal tissues should be able to keep going for about a decade. Then, they can be "reseeded" once per decade with stem cells that have been engineered to have normal length telomeres (and hence to have a replicative lifetime of about a decade), which will support the tissue after the old cells have lost the ability to divide any more. Moreover, these new cells can also be engineered to be chemoresistant, so that any cancer that arises from natural cells (that can maintain telomeres indefinitely) can be treated with higher-dose chemotherapy than is possible now.

Origin: First suggested as an anti-aging therapy by de Grey in 2000 (de Grey et al. 2002a, 2004). Termed "whole-body interdiction of lengthening of telomeres" (WILT). All component technologies (stem cell reseeding, deletion of genes, engineering chemoresistance) are already established in mice, and some of them in humans.

Status: This therapy is a new idea and has not been tested directly. However, the logic underlying both its potential efficacy and the relative non-efficacy of anything else appears to be solid. This issue was explored in depth at a roundtable conference in Cambridge in 2002, at which world leaders in all the relevant fields gave detailed scrutiny to the therapy's feasibility on a 10-20 year timescale in humans (and on a 7-10 year timescale in mice). The participants are the coauthors of (de Grey et al 2004).

Next steps: Unlike allotopic expression and lysosomal enhancement, this project will initially comprise several more-or-less separate strands whose interim progress will not be of direct relevance to each other. These are (detailed in de Grey et al 2004):

- identifying the genes underlying ALT ("alternative lengthening of telomeres");
- improving the redifferentiation of adult stem cells into stem cells of various tissues;
- developing techniques to extend telomeres of cells that have had their telomerase genes deleted;
- improving the removal of endogenous stem cells to make way for engineered ones;
- constructing protocols for reliable selection of cells that have had their telomerase and ALT genes deleted but have not had any other adventitious genetic alteration;
- improving gene targeting (disruption of an endogenous gene) in live mice; - improving the longevity of bone marrow transplants;
- refining the reseeding of gut stem cells;
- improving the regeneration of skin from stem cells.

Key investigators: In each of the relevant areas there are several groups with the necessary expertise, and most of them are already focused on the relevance of telomere maintenance to cancer. Thus, not all aspects of the project will necessarily fulfil the IBG funding criterion of poor fundability from existing sources. The main components of WILT that clearly do warrant IBG funding are:

1) identifying the genes underlying ALT;
2) improving oligonucleotide-mediated gene targeting in live mice;
3) refining the reseeding of gut stem cells

and others may need to be added to this list if their success in attracting adequate funding elsewhere falters.

Funding level and priorities: A call for applications would mention all the specific aspects of WILT listed above, not only the three most clearly in need of funding. This is for two reasons: first, some others may be more in need of better-targeted funding than is yet apparent, and second, there is a clear need for co-ordination between all strands of the project, irrespective of the extent to which IBG was funding them. Funds might thus be targeted towards simultaneous administration of multiple therapies (bone marrow transplant and gut reseeding, for example, or skin regeneration in a telomerase-negative mouse). Hence, the anticipated funding level for this project as a whole is more dependent than the others on exactly what applications are received. It will be in the range $2m to $10m per year, but a more precise estimate cannot be given.

Milestones: Unlike most of the projects discussed in this document, progress in most of the areas comprising WILT will be incremental. With the exception of identifying the genes underlying ALT, all component technologies already exist; the need is for them to be improved in efficiency and safety so that they can be combined. Thus, milestones will consist of quantitative improvements. The ten-year goal is a mouse that never develops advanced cancers, even in the absence of treatments that are known to work well in mice but not so well in humans (such as inhibiting angiogenesis), has short enough telomeres that highly proliferative tissues are compromised at young adulthood, and is effectively protected from this problem by stem cell reseeding. The reseeding technology can be developed in telomerase-negative mice, which are a model of WILT that has some imperfections (such as retention of ALT) but do show pathology of highly proliferative tissues; the goal is steadily to increase the age at which such pathology appears. Improvements in the efficiency of gene targeting, by contrast, can be developed just as effectively in normal mice as in telomerase-negative ones. Milestones should be set realistically but ambitiously, as a year- on-year improvement in measures such as these which exceeds recent rates of progress by a factor of about two. This would give a good chance of implementing full WILT in mice within ten years.

d) Removal/killing of unwanted, toxic cells

Basis: Cells of various types occasionally change, in the body, into a state called "senescence" which is similar to that seen in cell culture after large numbers of divisions (though this may not be how it normally arises in the body). Such cells are identified by the expression of a different pattern of genes than normal. Some of the proteins that become overexpressed in senescent cells are secreted from the cell and act as growth signals to other cells. Thus, it is possible that senescent cells, even though they cannot themselves divide, help nearby cells to divide -- including ones that are precancerous. Other secreted chemicals may be toxic in other ways. Thus, it is potentially valuable to kill these cells.

Note that the same general strategy is likely also to be effective in removing visceral fat (fat cells in the abdominal cavity), which have been shown to be a principal cause of insulin resistance leading to type II diabetes, and removing clonally expanded but inactive white blood cells, which inhibit the proliferation of active ones and thus impair immune response.

Origin: First suggested as an anti-aging therapy by Campisi in 1995 (de Grey et al. 2002a). Also pursued by Barzilai's group for fat and Pawelec's group for white blood cells.

Status: Research is proceeding on this in the above labs, but at a grossly inadequate level of funding. There are two potential approaches: to incorporate an inducible "suicide gene" into cells which is activated if and when the cell becomes senescent, or to target cell-killing signals to senescent cells via cell-surface markers diagnostic of the senescent state. The former approach is technically simpler in mice but less promising in some ways: for example, cells that undergo silencing of the suicide gene are permanently un-killable. The latter method is more comprehensive -- but only if appropriate cell surface markers can be found that provide adequately accurate selectivity (killing of most senescent cells without killing many non-senescent ones).

Next steps: "Just do it". This is a much simpler project than any of those discussed above and simply needs adequate resources in the hands of suitable expert investigators.

Key investigators: Drs. Campisi, Barzilai and Pawelec are the main investigators presently pursuing this approach in their respective cell types. Dr. Campisi is focusing on the cell suicide option. This is a technique that has been used in many other research contexts in recent years and several other labs would be in just as strong a position to use it here. The other approach would be an appropriate project for immunologists, since the immune system kills foreign cells (and cancerous cells) in just this way.

Funding level and priorities: Both the above lines of attack should be pursued with at least four to eight full-time researchers each, in at least five laboratories each to account for the differences in approach indicated with different cell types. This equates to a total cost to IBG of $5m-8m per year.

Milestones: This project should be complete too soon to need interim milestones. It should take only three to five years with adequate funding. However, an aspect that is as yet unknown is whether some cell types will be harder to kill when senescent than others; that will be revealed by the results achieved in the first couple of years.

e) Breaking extracellular protein-protein crosslinks, so restoring matrix biophysical properties (mainly elasticity)

Basis: Long-lived extracellular proteins (such as in cartilage) become progressively linked to each other by chemical reactions, mostly with sugars. These links make the material less elastic, which in many cases (such as the artery wall) makes them work less well. Moreover, this process happens more rapidly in shorter-lived species, suggesting that it contributes to aging. Since the proteins in question perform only mechanical/structural roles, rather than catalysing chemical reactions like enzymes, their function would be restored if the links were chemically broken, even though there would be side-chains present that were not native to the proteins.

Origin: Inhibition of cross-link formation was first proposed as an anti- aging therapy by Cerami and Monnier in 1981 (when breaking of existing cross-links was presumed impossible). First description of breaking of cross-links was by Cerami and colleagues in 1996.

Status: The compound discussed in 1996 has been refined slightly to a form now known as ALT-711. The patent for ALT-711 is held by Alteon, a small biotech startup. This compound has shown very promising efficacy in live animals of several species and has undergone phase I and II clinical trials. However, the underlying chemistry is quite simple, so big pharma have declined to invest in phase III trials; it is considered too likely that a clever chemist could develop a compound not covered by ALT-711's patent but working in the same way. Only one other report of a cross-link cutter has appeared; that is in a patent from India and no supporting publications exist. Also, it is known that ALT-711 only breaks a subset of cross-links.

Next steps: Two important lines of attack are of paramount importance. First, the chemical nature of the cross-links cut by ALT-711 is still in dispute because they are also easily broken by the acid treatment used to extract relevant chemicals from cartilage. Gentler assays are needed, so that a wider range of the cross-links that accumulate in vivo can be identified and compounds designed that can cut those which ALT-711 cannot. Second, it is believed that some cross-links are chemically too stable to be amenable to chemical cleavage; they would have to be broken by enzymes that could couple the necessary energy to an exergonic process such as ATP hydrolysis. We do not yet know whether these very stable cross-links are present in living organisms at an abundance that makes it important to cut them, though recent work has shown that some links of intermediate stability are indeed abundant.

Key investigators: The field of extracellular cross-links comprises a dozen or so world-class research groups. Unfortunately, most work currently in progress is focused on inhibiting the formation of cross-links rather than on breaking existing ones. This is largely because the chemistry of inhibition is easier: the original breaker, the precursor of ALT-711, was found by luck. But all these labs have the expertise to progress the science of cross-link breakers; it just needs a change in priorities, which would be achieved by the availability of targeted funds.

Funding level and priorities: Both lines of research noted above must be pursued, and ALT-711 itself must not be allowed to languish in its present poorly-supported state on account of the patent situation. Research on better extraction methods merits the attention of three to five labs, each with two to four full-time researchers, so the total cost to IBG would approximate $2m-$3m per year. Work on the enzymatic cleavage of abundant, known, highly stable cross-links is potentially an offshoot of lysosomal enhancement, but the approach described there is unlikely to work, because the cross-links are a very small part of the material and also are not energy-rich. This therefore constitutes a more basic research project than anything discussed elsewhere in this document and any IBG funding would be subject to the provision of a more concrete project plan than any known to me. Funding is thus impossible to estimate but may be zero, at least in the short term. Support for ALT-711 may include support for phase III clinical trials, but a more effective method may be to fund a wider variety of phase II trials than have so far occurred, so as to establish its broad-range biomedical efficacy. This should cost $5m-$15m per year.

Milestones: Improvement in extraction methods to allow more faithful identification of cross-links is an incremental process, so the most appropriate milestones will be in terms of rate of progress in identifying new cross-link species or in improving the accuracy with which their abundance in tissue can be determined. (The latter is a key prerequisite for determining the effectiveness of any cross-link breaker.) These should be set year-on-year, set as twice the recent rate of progress, and with the offer of large supplementary funding in the event of success.

f) Stimulation of the immune system to engulf and degrade amyloid

Basis: In various organs, proteins accumulate in the spaces between cells in fibrous structures called "amyloid" that resist degradation. Amyloid is a major hallmark of Alzheimer's disease and is also seen frequently in the pancreas in diabetics and in the heart in elderly people generally. In each case, though a different protein forms the major constituent, the deposits are likely to be harmful (though the mechanism of this toxicity is generally not known for sure). The machinery inside cells is much more powerful at breaking things down than anything that operates outside cells, so if cells can be induced to engulf this material then they may be able to break it down. Cells of the immune system often work by engulfing the bacteria (or infected cells) that they are stimulated agaiinst, so they are the natural type of cell to try to stimulate in this way. Stimulation of the immune system against a particular substance is simply vaccination.

Origin: First explored by Schenk's group at Elan Pharmaceuticals during the late 1990s, with initial work in mice published in 1999.

Status: Following the spectacular initial results in mice, which focused on a mouse model of Alzheimer's disease, Elan and collaborators moved rapidly to clinical trials. The first trial had to be aborted because 6% of patients suffered complications. However, these complications are now thought to be understood and ways to avoid them are apparent, so second-generation clinical trials are already underway. No such work has yet been attempted against amyloid in other organs, however, even in mouse models.

Next steps: The main next step is to develop immunisation approaches for the non-brain amyloids. The work on the brain is going well enough and is well enough funded that there is currently little reason for the IBG to supplement it.

Key investigators: Elan and their coworkers are the spearhead for the brain amyloid work. For each other affected organ there are a few groups working on methods to inhibit formation but no one working on removal. Thus, this is a good case where the IBG can take a lead in forming new academic collaborations to hasten the application of the brain amyloid immunisation techniques to other tissues.

Funding level and priorities: The development of antibodies ("passive vaccination") against brain amyloid, the preferred approach for the new clinical trials, has not been a slow process, so there is reason to be optimistic that a similar procedure can be developed quickly in other tissues. However, since this work has not yet begun, the timeframe for completion in mouse models may be 4-7 years even with good funding. A minimum of two teanms should be working on each relevant amyloid, so if brain amyloid is excluded the ideal would be 4-5 teams, each with four to seven full-time researchers, so the total cost to IBG would approximate $5m per year.

Milestones: The development of antibodies that do not cause inflammation by attacking the un-aggregated (monomeric) form of the amyloidogenic protein is the first milestone. Once those exist, safety and then efficacy in mice can be evaluated routinely.