A DNA spider follows a path on a DNA origami scaffold towards the red-labeled goal by cleaving the visited substrates.                  Image: Paul Michelotti

The-Scientist.com, May 12, 2010, by Jef Akst  –  Scientists are one step closer to creating molecular robots that may eventually perform complex tasks, such as building nanomolecules or delivering drugs to target tissues.

They have constructed DNA-based robots that can walk along a specific path unaided or collect various nanoparticles along an assembly line, according to two studies published this week in Nature.

“This has the feel to me of the beginning of a technology revolution,” said Andrew Ellington, an evolutionary engineer at the University of Texas at Austin and the vice president of the International Society for Nanoscale Science, Computation and Engineering, who was not involved in the research. “This work will absolutely pave the way for how you build molecular robots.”

The robots built in one study are a type of DNA walker, called a molecular “spider.” They are minute, mobile molecules that move along a flat surface made out of folded DNA, known as DNA origami, binding to and unbinding from the surface as they go.

The movement of these spiders is largely random, however, said biochemist and study co-author Milan Stojanovic of Columbia University. But together with several other big players in the nanotechnology and DNA computing fields, including Nils Walter of the University of Michigan, Erik Winfree of the California Institute of Technology, and Hao Yan of Arizona State University, Stojanovic designed a DNA origami surface that directed the DNA spider down a specified path (see video).

“You just have to start it, and it walks the path,” said chemist Kurt Gothelf, director of Centre for DNA Nanotechnology at Aarhus University in Denmark, who was not involved in the research.

The spider is fueled by the chemical interactions its single-stranded DNA “legs” have with the origami surface. In order to take a “step,” the legs first cleave a DNA strand on the surface, weakening its interaction with that part of the origami surface. This encourages the spider to move forward, pulled towards the intact surface, where its interactions are stronger. When the spider binds to a part of the surface that it is unable to cleave, it stops.

In essence, the researchers created a DNA spider that can “sense the environment,” Stojanovic said — “molecules that respond [to environmental] cues and behave [in] certain programmable ways on their own.” The next step, he added, is to increase the complexity of movements performed by such autonomous robots by compiling “a collection of rules [of] interactions between molecules and between molecules and environment.”

A fluorescence video microscopy-generated animation of a DNA spider moving along the designated path from the green-labeled start site towards the red-labeled goal. Each colored dot represents its position at a given time over the 40-minute observation period (see legend).

Credit: Nils Walter, Anthony Manzo, Nicole Michelotti and Alexander Johnson-Buck, University of Michigan

Meanwhile, Nadrian Seeman of New York University and his colleagues have designed another type of DNA walker that can collect nano-sized “cargo” as it moves. Unlike the autonomous spider, the cargo-collecting walker is controlled by single strands of DNA added by the researchers to direct the robot. These strands instruct the robot to move past an “assembly line” of three small loading devices, also made out of DNA, each containing a gold nanoparticle. Each loading device can be programmed to either donate its cargo to the passing walker, or keep it, such that the walker can receive anywhere from zero to three particles along its short (less than 200 nanometers) journey.

It’s “like an automobile assembly line,” Seeman said. “We have the option to either add or not add various components to [the walker] depending on how the devices are programmed.”

One possibility for future experiments will be to combine the advances of each of the two papers into one complex, autonomous DNA robot, said Lloyd Smith of the University of Wisconsin, who wrote an accompanying review in Nature. “It’s going to take more work to take it to that next level, [but] bringing those two things together is going to be the next step towards” a fully autonomous, functional nano-sized robot.

Another future direction, the researchers agree, would be to scale up the length of the pathways and the complexity of the behaviors. But even once greater levels of complexity are achieved, what can actually be done with the little robots is still up for debate. “This whole field,” which is still in its early stages, Smith said, “hasn’t really found the application yet.” DNA robots have thus far proven to be capable of fairly sophisticated manipulation at the nanoscale, but the practical uses of this novel technology are still a little unclear.

One popular idea is to use cargo-collecting robots to construct nanomolecules that would be difficult to make using traditional methods, because of the control they offer researchers at such a tiny scale. “The ability to hold a molecule in a particular position and hold another molecule in a defined position could open up possibilities in organic synthesis,” said Smith. Another possibility is their use in drug delivery, said biochemist William Shih of Harvard University, who did not participate in the studies. “Having a very smart robotic delivery system could do a lot better job of killing the disease tissue and do far less damage to our otherwise healthy tissue,” he explained.

But most agree that these potential applications are yet to be realized; the current work merely shows “proof of principle” that such complex behavior might one day be achieved using this technology, Seeman said.

“I think these are both really, really significant papers, not because of what we can do with [these robots] now, but because of what we can do with them in the future,” said Ellington. They are “paving the way to a future where we can do practical DNA technology.”

H. Gu, et al., “A proximity-based programmable DNA nanoscale assembly line,” Nature, 465:202-5, 2010.

K. Lund, et al., “Molecular robots guided by prescriptive landscapes,” Nature, 465:206-10, 2010.

Read more: DNA robots get sophisticated – The Scientist – Magazine of the Life Sciences http://www.the-scientist.com/blog/display/57400/#ixzz0njtuIZ5G

By Jeffrey A. Bluestone

Tipping the immune system’s homeostasis makes the difference between tolerance and autoimmune disease.

The-Scientist.com, May 12, 2010, by Jeffrey A. Bluestone MD  –  During the past five to ten years, an evolution of thinking has taken place for scientists involved in autoimmunity research. The foundation of that new vision is this: Autoimmunity, at some level, exists in everyone. The human immune system does not eliminate all the potential cells that can attack the body that made them. Moreover, the immune system does this on purpose, to generate a system that has a broad repertoire for detecting infectious agents and cancer cells, and one that can self-regulate unwanted responses.

In most people, the immune system has a number of checks and balances that regulate self-reactive cells through a series of intrinsic and extrinsic factors – at least, most of the time. One class of T cells, called regulatory T cells, is designed to see self-antigen and control the potentially damaging cells.1 Consequently, immunologists adjusted their focus from trying to determine why autoreactive cells escape deletion to exploring how the immune system maintains a homeostatic balance and why it sometimes fails. It seems clear that understanding this balance – a peaceful coexistence of protective immunity without self-destructing – will reveal how the immune system really works and how autoimmunity is triggered.

The challenge resides in the complexity of the biochemical and cellular pathways involved in tolerance, which is the immune system’s ability to distinguish self from non-self, allowing the body to recognize and destroy invading viruses, bacteria, and other pathogens while ignoring the body’s own tissue and organs. Moreover, genetic and environmental influences that we don’t fully understand multiply the complications of the pathways. The discovery and characterization of the regulatory pathways, however, will lead to new drugs and cell therapies for autoimmune diseases.

Distinguishing the Diseases

More than 80 diseases with an autoimmune etiology have been identified. Clinicians divide autoimmune diseases into multiple categories based on systemic versus organ-specific autoimmunity, distinct roles of pathogenic antibodies versus pathogenic T cells, and complex mechanisms of action in the different disease settings. In some autoimmune diseases, an antibody acts against cell-surface or matrix antigens. This mechanism appears in Graves’ disease, insulin-resistant diabetes, myasthenia gravis, pemphigus vulgaris, and other autoimmune diseases. In Graves disease, for example, autoreactive T cells promote the development of autoantibodies that then bind to thyroid cells that express the receptor for thyroid stimulating-hormone. The cells are destroyed by a combination of complement-mediated lysis (a cascade of proteins that poke holes in cells) and antibody-dependent cellular cytotoxicity (in which an antibody forms a bridge between cytotoxic and target cells), causing cell lysis. Together these mechanisms of cell destruction lead to hypothyroidism.

Some autoimmune diseases, such as systemic lupus erythematosus (SLE) and thrombocytopenia, involve immune complexes of autoantigens bound to antibodies. These multimeric complexes can attach to a cell’s surface leading to the deposition of complement, an immune mediator that causes inflammation and destruction of cells and tissues. For example, autoantibody-antigen complexes deposited in various organs such as the kidneys prove especially damaging in SLE.

The largest group of autoimmune diseases consists of T cell-mediated autoimmune diseases, including type 1 diabetes (T1D), rheumatoid arthritis (RA), psoriasis, inflammatory bowel disease, and multiple sclerosis (MS), to name a few. In these diseases, T cells – including helper T cells and cytotoxic T cells, which express the CD4 and CD8 surface protein, respectively – generate cytokines and cytolytic granules that directly destroy the targeted tissues. There are multiple pathways to this tissue destruction. The CD8+ T cells can interact directly with a target cell, such as an islet or a neuron, and lyse the cell. Moreover, cytokines including tumor necrosis factor-α (TNF-α), also destroy tissues by triggering a suicide event (apoptosis) with the target cell. Apoptosis also can be triggered in tissues by way of Fas ligand (FasL), another pro-apoptotic membrane protein.

Consider the mechanism behind T1D: T cells attack beta cells, the insulin producers, in islets of the pancreas. Once those cells are destroyed, the production of insulin is dramatically compromised and patients lose control of blood-glucose levels, resulting in the complications of high blood sugar. This disease, like many autoimmune diseases, is a slow, progressive disease with relapses and remissions that often take years to manifest. This is especially true in T1D, as each individual has a great excess of insulin-producing islets of Langerhans. Thus, more than half of the 1,000,000 islets must be destroyed or inactivated before the disease is manifested.

T Cells in Immunity

T cells are often considered the conductor of the immune orchestra. Like the individual sections of woodwinds, strings, and percussion, T cells come in a number of subtypes. The CD8+ T cells recognize antigens in the context of class I major histocompatibility complex (MHC) molecules and largely recognize proteins made within the cells; CD4+ T cells recognize processed antigens, picked up exogenously and presented in the context of class II MHC molecules. Together, these T cells can recognize proteins picked up by the antigen presenting cells (APCs) – dendritic cells, macrophages, and B cells – as well as directly infected cells. The T-helper lymphocytes (Th1) primarily produce interferon-γ (IFN-γ) and interleuken-2 (IL-2), which promote the development of CD8+ T cells and intracellular immunity. Th2 cells, on the other hand, produce IL-4, IL-5, and IL-13, which drive humoral immunity. Finally, the newly defined Th17 subset produces IL-17, which promotes inflammatory immunity, especially in the gut. Together these processes combat infections through a combination of cellular immunity to destroy infected cells and antibody production that mops up the circulating infectious agents, such as viruses and bacteria.

The immune system battles invaders in several general ways. First, innate mechanisms can block microbes with epithelial barriers or engulf them with phagocytes. Within a day of an invasion, adaptive mechanisms also start. B cells can recognize antigens from microbes, which leads to B cells producing antibodies that mark invaders for attack. Likewise, some cells that engulf microbes break up the antigens and display parts of them on their surface, thereby becoming antigen-presenting cells. These cells activate T cells that help kill infected cells.

Recent attention finally has been paid to a small population of CD4+ T cells that express the high-affinity IL-2-receptor-achain, CD25.5 These cells express a specific transcription factor, forkhead box p3 (Foxp3), which has been associated with a homeostatic activity focused on regulating an ongoing immune response and, as will be described below, the pathogenic autoreactive cells crucially involved in autoimmunity. The majority of CD4+ CD25+ Foxp3+ regulatory T cells (Tregs) develop in the thymus in response to self-antigens. However, Tregs with a similar phenotype can develop from CD4+ CD25 cells in the periphery. It is interesting that unique transcription factors – Tbet for Th1 cells, GATA-3 for Th2 cells, ROR a for Th17 cells, and FoxP3 for Tregs – control the individual subsets of T cells. Finally, this T-cell orchestra is greatly influenced by a number of critical cell-cell interactions with antigen presenting cells (i.e., dendritic cells, macrophages and B cells), which help target foreign proteins to the naive T cells and promote differentiation down the individual T-cell pathways.

The Basics of Balance

Autoimmunity arises from a combination of genetic predisposition and environmental factors that lead to a failure of the immune system’s tolerance mechanisms. Given the right constellation of events – perhaps stress, a viral infection, or general deterioration of the regulatory pathways – CD4 + T cells can start responding to self-tissues, initiating an autoimmune cascade. Those CD4 + T cells support the development of autoreactive B cells, which make autoantibodies that attack the self-tissues and organs. The CD4 + T cells also produce pro-inflammatory and cytotoxic cytokines that directly destroy tissues, as well as growth and differentiation factors that stimulate the development of CD8 + cytotoxic T cells, inflammatory macrophages, and autoantibody production by B cells. In combination, the autoantibodies and cytotoxic cells damage tissue, release more autoantigens, and exacerbate the autoimmune response.

The discovery and characterization of the regulatory pathways will lead to new drugs and cell therapies for autoimmune diseases.

Autoimmune diseases could develop in most anyone, but they don’t. Historically, a simple explanation – that the immune system eliminates all autoimmune cells during T- and B-cell development through “central” tolerance – has been the dominant paradigm in the field. This elimination takes place when the autoreactive T cells that develop in the thymus undergo “negative selection,” a process that deletes the majority of potentially autoreactive cells. Autoreactive B cells undergo negative selection in the bone marrow, where receptor editing replaces an autoantigen-reactive receptor with one that is poised to react with foreign proteins rather than self-proteins.

It is now clear, however, that large numbers of potentially autoreactive cells escape negative selection and clonal elimination, for several reasons. For example, the self-antigen might get expressed only in specialized organs, and not when the cells are “seeing” self-antigens in the bone marrow or thymus. In addition, autoreactive cells develop as part of the critical Treg subset, both inside and outside the thymus to control autoreactivity. This and other “peripheral tolerance” mechanisms exist to control these unwanted T- and B-cell reactivities.

 

Shutting Down the Autoreactive Spigot

Peripheral-tolerance mechanisms fall into three broad categories: cell inactivation (anergy) and cell elimination (apoptosis), both due to suboptimal activation; activation-induced cell death (AICD), which occurs as a consequence of overactivation; and active suppression mediated by regulatory cells and cytokines.

Jeffrey Bluestone

Courtesy of Jeffrey Bluestone

The induction of anergy or apoptosis occurs as a consequence of a weak or altered T-cell-receptor signal or an ineffective costimulatory signal. When T cells encounter antigen, the T-cell receptor (TCR) interacts with a specific antigenic peptide/MHC molecule. This leads to a series of intracellular phosphorylation events, enzyme activation, and gene transcription that initiate the primary activation events (called signal one). This process is promoted in a number of ways, including the use of altered antigenic peptides that deliver an ineffective TCR signal or blockade by monoclonal antibodies, which prevents the TCR from interacting effectively with peptide-MHC on professional APCs.

Even if the TCR signal is effectively delivered, full T-cell activation and differentiation require a second, “costimulatory” signal that enhances the TCR signal (signal one) and promotes unique biochemical signals to the T cells, or B cells in a similar fashion. In this step, B7 proteins (also called CD80 and CD86) on the APC bind to the T cell’s CD28 receptor, which leads to a second biochemical-signaling cascade (called signal two). Among other things, this costimulatory signal upregulates CD40L, a ligand for CD40. When CD40L (also called CD154) binds with CD40 on an APC, this enhances the expression of the B7 proteins, which creates a positive-feedback loop between CD28 and CD40. This combination of signals results in: effective signal transduction, which leads to increased cell-cycle progression; induction of survival factors that preempt apoptosis; and production of essential cytokines, which are essential for a productive immune response.

Costimulation plays an essential role in autoimmunity. In mice, for example, blocking CD40:CD154 costimulation shuts down a variety of autoimmune diseases, including T1D in nonobese diabetic mice, experimental autoimmune encephalitis (the mouse equivalent of MS), and mouse models of RA. Similarly, blocking CD28/CD86 pathways can inhibit a number of autoimmune syndromes in small animals, as well as in humans. Together the TCR and costimulatory antagonist have developed as part of a new drug arsenal for the treatment of autoimmune diseases. (For more information, see “Fine Tuning Our Defenses.”)

Although the above costimulatory pathways lead to positive immune activation, some cell-surface interactions can negatively regulate immunity by turning off T and B cells. These negative regulatory pathways include: receptor-ligand interactions, such as CTLA-4/CD806; programmed death (PD)-1/PD-L1; and B and T lymphocyte attenuator (BTLA)-4. Thus, during an immune response, these negative regulators are expressed on the activated T cells and result in shut down of the functional activity. Moreover, the genetic disruption of these molecules leads to immune dysregulation. For example, dysregulation of CTLA-4 leads to death of a mouse in less than one month due to a massive autoimmune response.

Peripheral tolerance can also come from AICD. Here, a peptide-MHC on a professional APC binds a TCR inducing the expression of Fas. The Fas protein can bind to FasL on various cell types, which activates a cysteine aspartate protease, caspase-8, that triggers a cell-death cascade. The Fas-FasL interaction can also eliminate autoreactive B cells through apoptosis. Thus, it is not surprising that mutations in Fas or FasL can prevent AICD, leading to both T- and B-cell mediated autoimmunity.

How Tregs suppress immune responses, though, remains poorly understood, but a variety of properties appear to give these cells their suppressive capabilities.

Perhaps the most potent regulation of autoimmune diseases is mediated by a specialized class of regulatory T cells, the CD4 + Tregs that control unwanted immune responses.7 These cells can actively suppress ongoing autoimmunity and restore self-tolerance in patients with autoimmune diseases. How Tregs suppress immune responses, though, remains poorly understood, but a variety of properties appear to give these cells their suppressive capabilities. For example, many in vitro and in vivo studies show that Tregs can function in the lymph nodes as well as in the peripheral tissues. In vivo, Tregs act through dendritic cells to limit autoreactive T-cell activation, which prevents their differentiation and acquisition of effector functions. Moreover, CD4+ FoxP3+ Tregs act through cell-cell contact. This might involve the negative regulator, CTLA-4, or other cell-surface molecules. Finally, CD4+ Tregs suppress an immune response through a cytokine-dependent mechanism where both IL-10 and transforming growth factor β (TGF-β) have been implicated. Sister regulatory T cells – Tr1 and Th3 cells – also mediate suppression by cytokine-dependent pathways.

By limiting the supply of activated pathogenic cells, the autoantigen-specific Tregs prevent or slow down the progression of autoimmune diseases. Thus, precisely the same antigenic self-proteins that have been implicated in causing autoimmunity can be recognized by this specialized regulatory T-cell population to shut it down. This raises the obvious question: Why is this protective mechanism insufficient in autoimmune-prone individuals to control the pathogenic T- and B-cell responses? Is it due to a shortage of Tregs cells, the development and accumulation of Treg-resistant pathogen T cells, or the production of other cytokines or innate immune responses, such as those elicited during an infection that compromise Treg activity? Defining these parameters has important implications for enhancing Treg activity in patients with disease, but more importantly, it may help advance research into the use of cell-based therapies (either Tregs or regulatory dendritic cells). Such therapies could be used to expand Treg cells for reinfusion of this robust, homeostatic T-cell subset to restore self-tolerance in patients with autoimmune diseases such as MS, T1D, and RA. However, it should be noted that successful regulatory cell therapy will undoubtedly require a concomitant debulking step to remove pathogenic B and/or T cells.

CTLA-4lg impacts several biochemical pathways. It can interact with B7 receptors on dendritic cells, and that leads to the production of indoleamine 2,3-dioxygenase (IDO), which suppresses the activation of T cells (1). It can also block B7-CD28 binding, and that blocks cell differentiation and leads to anergy and an increase in cell death (2). CTLA-4lg also can increase the immune response in two ways: It can block binding between B7 and CTLA-4 on already activated helper or cytotoxic T cells (3); and it can prevent B7 from binding CD28 on regulatory T cells (4).

Redrawn from JA Bluestone et al. “CTLA-4Ig: Bridging the basic immunology with clinical application,” Immunity, 24: 233-8, 2006.

 

Attacking Autoimmunity

Traditional treatments for autoimmune disease essentially blindfold the immune system as a whole. For example, nonspecific immunosuppressants such as cyclosporin A and anti-inflammatory agents such as steroids can inhibit immune responses in general, reducing the impact of autoimmune diseases in the process. Unfortunately, these treatments have transient effects and so must be used for the lifetime of the patient. In addition, suppressing the entire immune system makes patients vulnerable to infections. Worse still, overall immune suppression increases the risk of cancer. On the other hand, an explosion of novel immunotherapies to treat autoimmunity take advantage of the various aforementioned pathways of peripheral immune regulation to suppress disease symptoms and potentially induce a state of immune tolerance.

One of these advances in autoimmune treatments came in December, 2005, when the US Food & Drug Administration approved a new Bristol-Myers Squibb drug, Orencia (abatacept) for the treatment of RA. This protein, CTLA-4Ig, is created through recombinant technology, connecting human CTLA-4 (a CD28 antagonist) to human immunoglobulin G1 (IgG1). Specifically, the drug inhibits costimulation via the CD28 receptor on T cells by binding the CD28 ligands (CD80 and CD86) on APCs, thus preventing effective CD28-signal transduction and leading to anergy, apoptosis, and tolerance in some systems. Other interesting drugs in this same class of costimulation blockers include monoclonal antibodies that block the CD154-CD40 pathway, the inducible-costimulator pathway, and the B-cell-specific (Baff) pathway.8

Another encouraging class of new immune therapies relies on cell depletion as a means of debulking the pathogenic cells. For example, the anti-CD20 monoclonal antibody therapy, Rituxan (rituximab), which Genentech originally developed to deplete CD20+ tumor cells, has been successfully used to treat RA, MS, and lupus. By depleting B cells, the drug eliminates some autoantibody-producing cells and a major population of APCs that are essential for maintaining autoimmune T-cell activation in these and perhaps other diseases. Importantly, this illustrates the potential for these depleting agents and others, such as thymoglobulin and alemtuzumab (Campath-1H), to cross over – bringing new approaches to autoimmunity that are already in use for other diseases.

We need biomakers that reveal when autoimmune diseases exist, even at the earlist stages, and that show when therapies work or fail.

Despite the growing knowledge of autoimmune mechanisms and how to treat these diseases, many avenues of research need much more work. For example, scientists must find the genetic elements that determine the propensity for autoimmune disease. In addition, we need biomarkers that reveal when autoimmune diseases exist, even at the earliest stages, and that show when therapies work or fail. Scientists studying autoimmunity strive to better understand the homeostasis in the immune system, including balance within and between central and peripheral tolerance.9 Armed with such understanding, we can leverage this knowledge for developing new treatments, essentially mimicking what the body already does on its own. Only then can science develop powerful yet specific means for keeping our immune system in harmony to fight off pathogens but not attack the very system designed to protect us.

Jeffrey A. Bluestone is the A.W. and Mary Clausen Distinguished Professor of Medicine, Pathology, Microbiology, and Immunology, and the director of the Diabetes Center at the University of California, San Francisco. He is also director of the Immune Tolerance Network.

References

1. Q. Tang et al., “Regulatory T-cell physiology and application to treat autoimmunity,” Immunol Rev , 212:217-37, 2006.

2. R.J. Looney, “B cells as a therapeutic target in autoimmune diseases other than rheumatoid arthritis,” Rheumatology , 44(Suppl2):ii13-ii17, 2005.

3. L. Chatenoud, “CD3-specific antibodies as promising tools to aim at immune tolerance in the clinic,” Int Rev Immunol , 25:215-33, 2006.

4. N. Bottini et al., “Role of PTPN22 in type 1 diabetes and other autoimmune diseases,” Semin Immunol , 18:207-13, 2006.

5. J.A. Bluestone et al., “How do CD4+CD25+ regulatory T cells control autoimmunity?” Curr Opin Immunol , 17:638-42, 2005.

6. J.A Bluestone et al., “CTLA-4Ig: bridging the basic immunology with clinical application,” Immunity , 24:233-8, 2006.

7. L. Chatenoud et al., “Suppressor T cells – they’re back and critical for regulation of autoimmunity!” Immunol Rev , 182:149-63, 2001.

8. M.P. Cancro, “The BLyS/BAFF family of ligands and receptors: key targets in the therapy and understanding of autoimmunity,” Ann Rheum Dis , 65(Suppl3):iii34-iii36, 2006.

9. E.W. St. Clair et al., “New reagents on the horizon for immune tolerance,” Annu Rev Med , 58:22.1-22.18, 2006.

Networking for cures: James Heywood, cofounder of the for-profit patient networking and data aggregation site PatientsLikeMe, is developing new ways to study disease based on self-reported patient information.   Credit: Technology Review

 

Startup PatientsLikeMe is harvesting and analyzing patient information in a whole new way.

MIT Technology Review, May 12, 2010, by Emily Singer  –  Earlier this month, the journal Lancet Neurology published a study showing that the generic drug lithium did nothing to slow the course of amyotrophic lateral sclerosis (ALS), a devastating neurological disease. The findings would likely have been a disappointment to patients–they refuted an earlier, much smaller study suggesting that lithium could alter the disease’s rapid decline–but many already suspected this outcome. Eighteen months earlier, PatientsLikeMe, a for-profit patient networking site and data aggregator based in Cambridge, MA, had come to a similar conclusion, much more quickly and at much less cost.

The site, part social networking and part health 2.0, has gathered a wealth of data on its 65,000 members, which span 16 different disease communities, including epilepsy, fibromyalgia, and depression. It provides users with tools to track their health status and communicate with other patients, and then removes the personal details and sells the data to pharmaceutical companies and others. The company’s cofounder, James Heywood, believes the site will ultimately change the way drugs and other interventions are evaluated. Heywood, his brother Ben, and a former MIT classmate, Jeff Cole, founded PatientsLikeMe in 2006 as a way to help a third brother, Stephen, who was diagnosed with ALS in 1998.

The approach won’t replace clinical trials, at least anytime soon. But some experts do believe it could have enormous benefits, highlighting how different types of patients use drugs, when they stop, or what side effects they experience. “The beauty of observational trials is that you can see how an intervention works in the real world,” says Mark Roberts, a physician and professor of Health Policy and Management at the University of Pittsburgh. For example, many trials eliminate patients with secondary ailments, such as renal failure or chronic obstructive pulmonary disorder. “All my patients have those things, so how do I know it works in people I see?” he says.

PatientsLikeMe put its database to the test in 2008, after a small Italian study published in Proceedings of the National Academy of Sciences suggested that lithium could delay the progression of ALS. About 10 percent of PatientsLikeMe’s ALS users began taking the drug, not wanting to wait for a larger trial to confirm the results. Inspired by a member in Brazil who wanted to know if lithium was truly helping, the company rolled out a number of tools to allow patients to track their progress.

The founders, who trained as engineers at MIT, began building models of how the disease typically progressed in individuals with certain characteristics, incorporating variables such as age, gender, disease severity, time since diagnosis, and other factors. Heywood says the models allow researchers to predict the course of an individual’s disease more accurately than the standard prognostic tools. “We can predict when a patient will die 16 months ahead of time, compared to the typical doctor report of ‘you have two to five years to live,’ ” he says.

Because the company had such extensive data on the patients, researchers could analyze how an individual’s symptoms changed 12 months before they began taking lithium, as well as after. Unlike a typical clinical trial, this allowed scientists to search for unique characteristics in the people who decided to take the drug. They found that people who chose to take it were somewhat worse off before starting the drug than those who didn’t. (This group may have been more motivated to try an experimental treatment.)

The researchers could also compare lithium takers to controls in a more nuanced way. By compiling data from patients with similar backgrounds and disease characteristics who did not take lithium, they created a model predicting the course of the disease in that group. They could then determine whether a patient who fit those criteria pretreatment deviated from that progression after taking the drug. The answer was no, meaning lithium had no effect–positive or negative–on the disease.

Criticisms of the approach mimic those typically made of observational trials, which lack a “blind” placebo control group. Outside of a controlled clinical trial, it’s difficult to determine whether the drug or some other factor was the key to the outcome. “The problem with PatientsLikeMe is that it involves observational information. If patients think medication is helping, they will be biased toward recognizing whatever positive events they have and vice versa,” says Paul Bleicher, founder of PhaseForward, a clinical trial data-management company. “Most people aren’t even aware of the bias. That’s why blind trials exist.”

University of Pittsburgh’s Roberts concurs. “What kinds of patients are willing to report their data? Is it the full range of disease? Were people who didn’t do well as likely to report findings as those who didn’t?” he asks. However, Roberts is also optimistic, pointing out that statistical methods can correct for many of these issues. “As long as you are really careful about understanding the possible biases, I think you can begin to approximate the control you have in clinical trials,” he says.

“The types of things you can get from observational studies are the generation of valuable hypotheses, which is not easy to do,” says Bleicher, who also works for Humedica, a health-care informatics company that collects data from electronic medical records. “Using databases, you can come up with observations you believe are strong enough to be worthy of doing a controlled trial.”

Swati Aggarwal, a physician at Massachusetts General Hospital in Boston who led the Lancet study on lithium and ALS, sees PatientsLikeMe as a rich resource for accessing the ALS community. “We could use the database to try to understand why patients don’t like to use BPAP” (bilevel positive airway pressure), a ventilator to help patients breathe, she says.

PatientsLikeMe is currently building models for its other disease communities and next plans to look at the effects of some treatments for multiple sclerosis, as well as nondrug factors in ALS. “The diseases we focus on tend to be those with patients who know more about their health than the medical community does,” says Heywood. “It’s easier to get patients to tell us than to get medical systems to change.”

www.PatientsLikeMe.com

By Vitoon Vonghangool and Dr. Pham Hong Thai

May 12, 2010  –  The world vaccine market is growing at the very fast pace of 15 percent annually, with the key drivers being increased demand, the accelerated introduction of new vaccines, mergers and acquisitions, the emergence of new vaccine players, and the growth of the biotech sector through new technologies.

The vaccine market in Thailand has also grown fast, reaching around THB 4.0 billion ($US120 million), with the Ministry of Public Health (MOH) being the major customer. The MOH purchases for its National Immunization Program mainly pediatric vaccines but also vaccines for women and travelers and for postexposure rabies treatment. Vaccines are also available on the private market and mainly imported as finished products, though some are imported in bulk form or in naked vials to be filled and packed by GPO-MBP, a local joint venture between the GPO (Government Pharmaceutical Organization) and a multinational. A few traditional vaccines are also produced by two local organizations: the Queen Saovabha Memorial Institute (QSMI), which is part of the Thai Red Cross Society, and the GPO.

Thus Thailand is one of only three out of the 10 members of the Association of South East Asian Nations (ASEAN) that produces vaccines.

Thailand is also known for its academic research on vaccines against diseases prevalent in the country and as a top location for conducting clinical trials of vaccines against diseases such as Japanese encephalitis and dengue.

Thailand’s government has recently made some efforts to strengthen the pharmaceutical biotech industry with tax and nontax incentives such as an 8-year income tax exemption, a 200 percent tax credit on R&D activities, and permission to bring in foreign workers. Only time will tell whether these measures have created a favorable enough environment or whether more incentives are needed to attract pharma and biotech companies to the country.

Considerations for biotech start-ups developing vaccines include product technology, location of development operations, skills of the development and operation team, and opportunities for local public–private partnerships. The production of vaccines requires very large investments, therefore new companies should thoroughly assess their manufacturing and business strategies, including production capacity, competency of the local workforce, product needs for both domestic and export markets, and options for funding.

While progress in attracting foreign bioindustries in Thailand has been remarkable, so far not many biotech companies have set up their development or manufacturing facilities in the country apart from Thai-owned pharmaceutical companies upgrading their plants or investing in new projects.

BioNet has started a research program on an acellular pertussis vaccine in collaboration with Mahidol University and is exploring various public–private partnerships with other institutions and organizations in the field of vaccine R&D.

Vitoon Vonghangool is the Managing Director, and Dr. Pham Hong Thai is the Joint-Managing Director, BioNet-Asia Co., Ltd.

Shakespeare Garden

One of the many hidden gems of Central Park, the Shakespeare Garden is a lovely spot to “stop and smell the roses”.

Nestled between Belvedere Castle and The Swedish Cottage the garden first came into existence in 1913. Known as the Garden of the Heart it was patterned after Victorian era rock gardens. Then, in 1916, to celebrate the tercentennial of Shakespeare’s death, it was rechristened in honor of the Bard and only plants mentioned in his plays were planted there. These include columbine, primrose, wormwood, quince, lark’s heel, rue, eglantine, flax and cowslip, many of which sound as if they would be right at home boiling and bubbling in a cauldron.

Weeds are shallow-rooted, Suffer them now, and they’ll o’ergrow the garden, And choke the herbs for want of husbandry.
William Shakespeare: King Henry the Sixth, Part II (Queen Margaret at III, i)

This quote could have easily applied to Central Park’s Shakespeare Garden by the mid-1970’s. After years of neglect due to budget constraints and general disinterest the Garden had become run down and overgrown. Then in 1975 a group of volunteers stepped in and started to bring the garden back to its former glory. In 1986 the rescue of the garden was complete as a full restoration was undertaken funded by Samuel and May Rudin. The garden was replanted and expanded upward towards Belvedere Castle. The Shakespeare Garden is once again a popular attraction in the park and the perfect place to ruminate after a performance in the nearby Delacorte Theater.

Location: West Side between 79th and 80th Streets