Under pressure: A bioengineered kidney takes advantage of silicon membranes that allow very low-pressure filtration. The membrane in this image is layered with kidney cells. The cells’ nuclei are shown in blue, their microtubules in red, and a junction protein called ZO-1 in green. Credit: William Fissell, The Cleveland Clinic.
A prototype uses kidney cells to help it perform vital functions.
MIT Technology Review, September 16, 2010, by Lauren Gravits — Nearly 400,000 people in the United States–and as many as two million worldwide–rely on dialysis machines to filter toxins from their blood because of chronic kidney failure.
Patients must be tethered to machines at least three times a week for three to five hours at a stretch. Even then, a dialysis machine is only about 13 percent as effective as a functional kidney, and the five-year survival rate of patients on dialysis is just 33 to 35 percent. To restore health, patients need a kidney transplant, and there just aren’t enough donor organs to go around. In August, there were 85,000 patients on the U.S. waiting list for a kidney in the U.S., while only 17,000 kidney transplants took place last year.
A collaborative, multidisciplinary group of labs is working to create the first implantable artificial kidney. The prototype, revealed last week, is compact, no larger than a soup can. It not only filters toxins out of the bloodstream but also uses human kidney cells to perform other vital functions, such as regulating blood pressure and producing vitamin D.
“Dialysis is not only time-consuming, but it’s also debilitating. Many patients don’t feel good, because it’s not doing all the functions of a normal, healthy kidney,” says bioengineer Shuvo Roy, whose lab at the University of California, San Francisco produced the new device and is already testing it in animals. “The kidney doesn’t just filter toxins. It also has metabolic functions and hormonal functions, and dialysis doesn’t capture these abilities.”
Making an artificial kidney small enough to fit inside the body is, however, a big challenge. A healthy kidney filters 90 liters of water each day. Current dialysis machines are the size of a small refrigerator, and require substantial pressure to pump enough water through the machine’s porous membranes to allow contaminants to be filtered out of the blood.
The new implant is a fusion of multiple lines of research, and takes advantage of two recent advances in the field. University of Michigan nephrologist David Humes has shown that human kidney cells could be used in a room-sized filtration machine to greatly improve the health of patients whose kidneys have stopped functioning. Meanwhile, Roy and William Fissell, a nephrologist at the Cleveland Clinic, have produced a nano-pore silicon membrane that–with its dense and precise pore-structure–could help miniaturize dialysis machines.
The prototype is a two-part system: half consists of a toxin-removing filter, in which thousands of silicon membranes are stacked together. Their nano-pores are so dense, and so precisely shaped, that they can filter very precisely using only the force of the body’s own blood pressure. Blood flows in through this filter, where the toxins, sugars, water, and salts are removed as a filtered solution.
The clean blood and watery filtrate are both shunted into the other half of the system: a separate cartridge. Here, they flow over more silicon membranes, these ones coated with a single type of human kidney cell, which helps the device reabsorb some of the water, sugars, and salts, as well as produce vitamin D and help prevent blood pressure from sinking too low–normal kidney functions that are not offered by dialysis. The waste that’s not reabsorbed is shunted to a tube attached to the bladder and removed as waste in the urine–just like a normal kidney would do.
It’s far from a complete system, and the researchers note that they don’t ever expect it to replace kidney transplants. “Your kidney has 20 to 30 cell types in it, all of which accomplish different functions. But we’d like to overcome a critical issue that’s emerged in renal failure,” says Fissell. “If you’re listed for a kidney transplant, you’re far more likely to die on the waitlist than you are to get a kidney.” He says the device could act as a bridge for patients awaiting transplant.
“From a general perspective, any implantable device would sharply reduce the burden that patients now experience,” says Glenn Chertow, the chief of nephrology at the Stanford University School of Medicine. “And if some of the additional magic that a native kidney provides could be added to an implantable device, we could come closer to a restoration of good health.”
The researchers have already worked out some of the more difficult issues: Humes has worked out how to culture kidney cells on the necessary scale (he can culture enough cells for 100,000 devices from a single kidney). He’s also determined the best way to freeze them for future use. And Roy, a TR35 winner in 2003, has tested the implant in a dozen rats and a handful of pigs. They still have to scale up the implant’s efficiency to something that could work effectively in humans, but they hope to start human trials in five-to-seven years. Right now the biocartridge can filter between 30 to 35 liters of water per day, and it needs to be able to filter at least 43. They also have to find ways to ensure that the devices don’t cause blood clots or immune reactions.
Other groups are also working toward alternatives to thrice-weekly dialysis appointments, although most are concentrating on wearable dialysis devices–a difficult proposition in itself, given the challenge of constant filtration at such large volumes without an external pump. One such device is already in the second stage of clinical trials. But even constant dialysis can’t take the place of the kidney’s other functions.
Allen Nissenson, CMO of DaVita, one of the country’s largest dialysis provider, says the implantable concept holds appeal. “It’s a bioreactor kidney, an incredibly innovative concept, and really exciting if it proves to be workable on a larger scale,” he says.
The prototype greenhouse. Credit: University of Arizon
MIT Technology Review, September 16, 2010, by Brittany Sauser — Researchers have demo-ed a prototype lunar greenhouse, showing plants can be grown without soil.
Researchers at the University of Arizona have developed a greenhouse that grows plants without soil. The prototype greenhouse is an 18-foot long tube that contains water-cooled sodium vapor lamps and “envelopes” to hold the seeds.
Dubbed the lunar greenhouse, the idea is that something similar could one day supply food to astronauts on the moon or Mars. It would be buried beneath the moon’s surface, so to not be destroyed by cosmic rays and solar flares, and would be operated autonomously, so that food could be ready when astronauts arrive. A lunar greenhouse could be essential for colonizing the moon, which has no atmosphere, no natural water, and extreme temperatures.
The Arizona system works by feeding carbon dioxide into the greenhouse through pressurized tanks. At a lunar base astronauts would provide carbon dioxide by breathing and water for the plants could be extracted from their urine. Sunlight could be channeled to the underground plants through fiber optic cables.
According to the Arizona researchers, lead by Gene Giacomelli, the system contains about 100 kilograms of wet plant material that can provide 53 quarts of drinkable water and a small amount of oxygen during a 24-hour period, while consuming about 100 kilowatts of electricity and half a kilogram of carbon dioxide. It can even be collapsed into a four-foot wide disk for interplanetary travel and deployed in less than ten minutes.
By Andrew Weil MD
September 15, 2010
If an American doctor of the late 19th century stepped into a time warp and emerged in 2010, he would be shocked by the multitude of pharmaceuticals that today’s physicians use. But as he pondered this array (and wondered, as I do, whether most are really necessary), he would soon notice an equally surprising omission, and exclaim, “Where’s my Cannabis indica?”
No wonder — the poor fellow would feel nearly helpless without it. In his day, labor pains, asthma, nervous disorders and even colicky babies were treated with a fluid extract of Cannabis indica, also known as “Indian hemp.” (Cannabis is generally seen as having three species — sativa, indica and ruderalis — but crossbreeding is common, especially between sativa and indica.) At least 100 scientific papers published in the 19th century backed up such uses.
Then the Marihuana Tax Act of 1937 made possession or transfer of Cannabis illegal in the U.S. except for certain medical and industrial uses, which were heavily taxed. The legislation began a long process of making Cannabis use illegal altogether. Many historians have examined this sorry chapter in American legislative history, and the dubious evidence for Cannabis addiction and violent behavior used to secure the bill’s passage. “Under the Influence: The Disinformation Guide to Drugs” by Preston Peet makes a persuasive case that the Act’s real purpose was to quash the hemp industry, making synthetic fibers more valuable for industrialists who owned the patents.
Meanwhile, as a medical doctor and botanist, my aim has always been to filter out the cultural noise surrounding the genus Cannabis and see it dispassionately: as a plant with bioactivity in human beings that may have therapeutic value. From this perspective, what can it offer us?
As it turns out, a great deal. Research into possible medical uses of Cannabis is enjoying a renaissance. In recent years, studies have shown potential for treating nausea, vomiting, premenstrual syndrome, insomnia, migraines, multiple sclerosis, spinal cord injuries, alcohol abuse, collagen-induced arthritis, asthma, atherosclerosis, bipolar disorder, depression, Huntington’s disease, Parkinson’s disease, sickle-cell disease, sleep apnea, Alzheimer’s disease and anorexia nervosa.
But perhaps most exciting, cannabinoids (chemical constituents of Cannabis, the best known being tetrahydrocannabinol or THC) may have a primary role in cancer treatment and prevention. A number of studies have shown that these compounds can inhibit tumor growth in laboratory animal models. In part, this is achieved by inhibiting angiogenesis, the formation of new blood vessels that tumors need in order to grow. What’s more, cannabinoids seem to kill tumor cells without affecting surrounding normal cells. If these findings hold true as research progresses, cannabinoids would demonstrate a huge advantage over conventional chemotherapy agents, which too often destroy normal cells as well as cancer cells.
As long ago as 1975, researchers reported that cannabinoids inhibited the growth of a certain type of lung cancer cell in test tubes and in mice. Since then, laboratory studies have shown that cannabinoids have effects against tumor cells from glioblastoma (a deadly type of brain cancer) as well as those from thyroid cancer¸ leukemia/lymphoma, and skin, uterus, breast, stomach, colorectal, pancreatic and prostate cancers.
So far, the only human test of cannabinoids against cancer was performed in Spain, and was designed to determine if treatment was safe, not whether it was effective. (In studies on humans, such “phase one trials,” are focused on establishing the safety of a new drug, as well as the right dosage.) In the Spanish study, reported in 2006, the dose was administered intracranially, directly into the tumors of patients with recurrent brain cancer. The investigation established the safety of the dose and showed that the compound used decreased cell proliferation in at least two of nine patients studied.
It is not clear that smoking marijuana achieves blood levels high enough to have these anticancer effects. We need more human research, including well-designed studies to find the best mode of administration.
If you want to learn more about this subject, I recommend an excellent documentary film, “What If Cannabis Cured Cancer,” by Len Richmond, which summarizes the remarkable research findings of recent years. Most medical doctors are not aware of this information and its implications for cancer prevention and treatment. The film presents compelling evidence that our current policy on Cannabis is counterproductive.
Another reliable source of information is the chapter on cannabinoids and cancer in “Integrative Oncology” (Oxford University Press, 2009), a textbook I edited with integrative oncologist Donald I. Abrams, M.D. (Learn more about integrative cancer treatment from Dr. Abrams.)
After more than 70 years of misinformation about this botanical remedy, I am delighted that we are finally gaining a mature understanding of its immense therapeutic potential.
Andrew Weil, M.D
This camera sharpens both what’s near and what’s far in one image. It focuses on the foreground, snaps a pic, and then refocuses to capture the background. The processor looks at the two images’ textures to judge where the two parts split and combines them in less than three seconds. $300; sony.com
Breakthrough in Disease Modeling and Cell-Based Therapy
WorldHealth.net, September 16, 2010 — By creating diseased liver cells from a small sample of human skin, scientists have for the first time shown that stem cells can be used to model a diverse range of inherited disorders. The University of Cambridge (United Kingdom) researchers’ findings may soon lead to new treatments for those suffering from liver diseases.
For their research, the scientists took skin biopsies from seven patients who suffered from a variety of inherited liver diseases and three healthy individuals (the control group). They then reprogrammed cells from the skin samples back into stem cells. These stem cells were then used to generate liver cells which mimicked a broad range of liver diseases – the first time patient-specific liver diseases have been modelled using stem cells – and to create ‘healthy’ liver cells from the control group. Importantly, the three diseases the scientists modelled covered a diverse range of pathological mechanisms, thereby demonstrating the potential application of their research on a wide variety of disorders. Writing that: “We report a simple and effective platform for hepatocyte generation from patient-specific human [induced pluripotent stem] cells,” the team concludes that: “These patient-derived hepatocytes demonstrate that it is possible to model diseases whose phenotypes are caused by pathological dysregulation of key processes within adult cells.”
Soy Compound May Reduce Cardiovascular Risk Factor
WorldHealth.net, September 16, 2010 — Endothelial cell dysfunction, affecting the cells that line the blood vessels and control the ability of the vessels to expand and contract, is associated with an increased risk for coronary artery disease and cardiovascular events. Some recently published studies suggest that soy isoflavones may reduce cardiovascular disease risk factors, most notably endothelial dysfunction and blood pressure. D.P. Beavers, from Wake Forest University School of Medicine (North Carolina, USA), and colleagues completed a meta-analysis of 17 studies on the effect of isoflavones on endothelial function. The team found that the overall change in flow-mediated dilation, a marker of endothelial function, for isoflavone-containing soy product interventions, to be 1.15%. They urge that this significant improvement in flow-mediated dilation is clinically relevant, positing that the mechanism of effect involves the promotion of nitric oxide production, which is otherwise impaired in endothelial dysfunction and causes blood vessels to constrict. The researchers conclude that: “Cumulative evidence … indicates that exposure to soy isoflavones can modestly, but significantly, improve [endothelial function]. Therefore, exposure to isoflavone supplements may beneficially influence vascular health.”
Berries Boost Brain Health
WorldHealth.net, September 16, 2010 — Blueberries and strawberries are high in antioxidant and anti-inflammatory compounds. Shibu M. Poulose, from the Tufts University Human Nutrition Research Center on Aging (Massachusetts, USA), and colleagues have found that polyphenol antioxidants present in berries help microglia, cells in the brain, to clean up toxic proteins linked to age-related memory loss and cognitive decline. Explaining that polyphenolics in berries appear to help maintain proper microglial functioning, the team concludes that: “The results strongly suggest that the benefits of both berries extend beyond the antioxidant and anti-inflammatory effects to cellular toxic clearance through induction of autophagy in brain.”
Coffee Promotes Blood Vessel Health
WorldHealth.net, September 16, 2010 — Hypertension (high blood pressure) makes blood vessels less responsive to signals to expand, and the lower elasticity of the aorta serves as a significant predictor of cardiovascular events. Christina Chrysohoou, from the University of Athens (Greece), and colleagues analyzed coffee consumption patterns among 435 hypertensive individuals, ages 65 to 100 years, enrolled in a larger study involving the permanent inhabitants of Ikaria Island, where many residents reach 90 years and older. As compared to those who rarely drank coffee, moderate consumption of one or two cups a day associated with a lower prevalence of diabetes, lower prevalence of high cholesterol, lower body mass index, lower prevalence of cardiovascular disease, and higher values of aortic distensibility. Proposing that the presence of phenol compounds in coffee may be responsible for these effects, the researchers conclude that: “Moderate coffee consumption has beneficial effects on the aortic distensibility in hypertensive elderly individuals.”
Grapefruit Compound May Intervene in Diabetes
WorldHealth.net, September 16, 2010 — Naringenin is an antioxidant compound present in grapefruit. Previous studies have shown the compound to have cholesterol lowering properties and may ameliorate some of the symptoms associated with diabetes. Yaakov Nahmias, from Hebrew University of Jerusalem (Israel), and colleagues have shown that naringenin promotes the cellular pathways (PPAR-alpha, PPAR-gamma and LXR-alpha) by which the liver breaks down fat and increases insulin sensitivity. Explaining that: “This effect results in the induction of a fasted-like state … in which fatty acid oxidation increases, while cholesterol and bile acid production decreases,” the team submits that: “Our findings explain the myriad effects of naringenin and support its continued clinical development.”
Regular Walking Enhances Brain Circuit Connections
WorldHealth.net, September 16, 2010 — The default mode network (DMN) is a brain circuit which dominates brain activity when a person is least engaged with the outside world (such as being a passive observer). Previous studies have found that a loss of coordination in the DMN is a common symptom of aging and in extreme cases can be a marker of disease, and data has suggested that older adults who are more fit tend to have better connectivity in specific regions of the DMN than their sedentary peers. Arthur Kramer, from the University of Illinois (Illinois, USA), and colleagues followed 65 adults, ages 59 to 80 years, who were sedentary (two or fewer episodes of physical activity lasting 30 minutes or more in the previous six months), who joined a walking group or stretching and toning group for a year. The researchers measured participants’ brain connectivity and performance on cognitive tasks at the beginning of the study, at six months and after a year of either walking or toning and stretching. The team employed functional magnetic resonance imaging (fMRI) to determine whether aerobic activity increased connectivity in the DMN or other brain networks. At the end of the year, DMN connectivity was significantly improved in the brains of the older walkers, but not in the stretching and toning group. Additionally, the walkers also had increased connectivity in parts of the fronto-executive network, which aids in the performance of complex tasks; and they performed significantly better on cognitive tests than their toning and stretching peers. The researchers write that: “The study provides the first evidence for exercise-induced functional plasticity in large-scale brain systems in the aging brain … and offers new insight into the role of aerobic fitness in attenuating age-related brain dysfunction.”
15 Super Healthy Foods, September 16, 2010
2. Button Mushrooms
3. Acai Berry
8. Grapefruit (pink or red)
9. Wheat Germ
10. Yogurt (low-fat)
13. Tea (green or black)
14. Sweet Potato