Vitamin A Compound Might Aid in Colon Cancer Fight

In continuation of my update on Retinoic acid

Retinoic acid, a compound derived in the body from vitamin A, might have a role in suppressing colon cancer, new animal research suggests.

"Retinoic acid has been known for years to be involved in suppressing inflammation in the intestine," said study senior author Dr. Edgar Engleman, professor of pathology and medicine at Stanford University School of Medicine in Palo Alto, Calif.

Meanwhile, the development of colon cancer has been linked to inflammation. For example, inflammatory bowel disease, such as ulcerative colitis, has been associated with colon cancer, he said in a university news release.

"We wanted to connect the dots and learn whether and how retinoic acid levels directly affect cancer development," Engleman added.

When the researchers looked at mice with colon cancer, they saw lower levels of retinoic acid in the intestines of the mice.

The researchers also found that boosting levels of retinoic acid in the intestines of mice with colon cancer slowed progression of the disease.

In humans, colon cancer patients who had high levels of a protein that degrades retinoic acid in their intestinal tissue tended to have worse outcomes than other patients, the study authors noted.

The findings suggest new ways to prevent or treat colon cancer. However, it's important to note that animal research doesn't always produce the same results in humans.

"The intestine is constantly bombarded by foreign organisms. As a result, its immune system is very complex," Engleman said.

"We found that bacteria, or molecules produced by bacteria, can cause a massive inflammatory reaction in the gut that directly affects retinoic acid metabolism," he said.

He said that retinoic acid levels are normally regulated very tightly.

"Now that we've shown a role for retinoic acid deficiency in colorectal cancer, we'd like to identify the specific microorganisms that initiate these changes in humans. Ultimately we hope to determine whether our findings could be useful for the prevention or treatment of colorectal cancer," he concluded.

The study was published online Aug. 30 in the journal Immunity.

Is Okra Good for Diabetes?

According to a handful of recent studies, okra may reduce symptoms of diabetes - a group of diseases that includes type 1 diabetes, type 2 diabetes, and gestational diabetes.

 

Diabetes claimed the lives of 75,578 Americans in 2013, according to the United States Centers for Disease Control and Prevention (CDC). In 2014,8.5 percent of adults worldwide had the condition, the World Health Organization (WHO) report. By 2030, diabetes may be the seventh leading cause of death.

A number of factors increase a person's risk of developing diabetes, including a family history of the disease. Lifestyle factors also play a role, so doctors routinely recommend diet changes and increased exercise to reduce blood sugar levels.

Okra may help reduce blood sugar levels in some people with diabetes. Research into the effects of this seedy vegetable is still in the early stages, but the results are promising.

Okra thrives in temperate climates, producing large hibiscus-like flowers that eventually give rise to green seed pods. It is a member of the mallow family, which includes a number of other popular plants, including hibiscus, cocoa, and cotton.

Scientifically known as Abelmoschus esculentus, okra may have been grown as long ago as 2000 BCE in Egypt.

Okra's flavor is mild, and the entire seed pod can be eaten. This vegetable-like fruit also has a long history in traditional medicine.

Kew Royal Botanic Gardens report that in Eastern traditional medicine, okra leaves and fruit were used as pain relievers, moisturizers, and to treat urinary disorders. In Congolese medicine, okra is used to encourage a safe delivery during childbirth.

Can okra help with symptoms of diabetes?

Diabetes can often be well-managed with increasing a hormone called insulin and other medical therapies. However, some people with diabetes wish to avoid regular insulin injections. Others experience blood sugar dips and other unpleasant side effects, and diabetes medications do not work for everyone.

The possibility that a readily available seed pod could help control diabetes is an exciting one. But there is no evidence yet that okra can cure diabetes. So far, the research on okra has only looked at its effects on animals. Human bodies are similar to animals, but not all research on animals has worked out in humans.

Increased absorption of sugar by muscles

A 2005 study published in Planta Medica investigated the effects of okra on rats with diabetes. A substance called myricetin is present in okra and some other foods, including red wine and tea.

Researchers isolated myricetin from okra, then administered it to the rat. The treatment increased absorption of sugar in the rats' muscles, lowering their blood sugar.

A 2012 Food Science and Human Wellness review points to a number of other laboratory and animal studies that have linked myricetin to lower blood sugar. The study argues that myricetin may also reduce other risk factors for diabetes.

Reduction in blood sugar spikes after eating

A 2011 study published in ISRN Pharmaceutics found a link between okra and decreased blood sugar spikes after eating.

Researchers fed rats liquid sugar as well as purified okra through a feeding tube. Rats who consumed the okra experienced a reduction in blood sugar spikes after feeding. The study's authors think this is because the okra blocked the absorption of sugar in the intestines.

The study also explored possible interactions between okra and metformin, a drug that can reduce blood sugar in type 2 diabetes. Okra appeared to also block absorption of metformin. This suggests that okra could reduce the effectiveness of metformin, and should therefore not be eaten at the same time as the drug.

Lower blood sugar levels

A 2011 study published in the Journal of Pharmacy and Bioallied Sciences points to a link between eating okra and lower blood sugar. The researchers allowed the blood sugar of rats with diabetes to stay level for 14 days. They then gave the rats powdered okra peel extracts and seeds dosages of up to 2,000 milligrams per kilogram of body weight.

There were no poisonous effects linked with these relatively high doses of okra. The rats that ate okra had reduced blood sugar levels after up to 28 days of eating okra. The study ended on day 28, so it is unclear if the effects on blood sugar levels would have lasted longer.

Considerations for using okra

Few studies have linked okra to negative side effects, but some negative side effects are possible:

• Okra may make the drug metformin less effective.
• Okra is high in substances known as oxalates. Oxalates may increase the risk of kidney stones in people vulnerable to kidney stones.
• Okra can contain bacteria, pesticides, and other dangerous substances if it is not thoroughly washed. People should never consume rotten okra, frozen okra that is past its expiration date, or okra that has not been thoroughly washed.
• People with an okra allergy should not consume okra. Those with an allergy to other plants in the mallow family, such as hibiscus or cotton, may also be allergic to okra.
• Even if okra proves to be ineffective in fighting diabetes, it remains a safe snack for people with diabetes. A single serving of 100 grams contains just 30 calories, but offers a number of nutritional benefits:
  • Okra contains no saturated fats or cholesterol
  • Okra is rich in fiber, containing 9 percent of the recommended daily value (RDV)
  • Okra contains 8 percent of the RDV of calcium, 43 percent of the RDV of manganese, 10 percent of the RDV of iron and copper, and 44 percent of the RDV of vitamin K
  Okra is rich in protective substances known as antioxidants, including myricetin. According to the National Center for Complementary and Integrative Health, antioxidants may reduce oxidative stress, a process that damages cells in the body. Oxidative stress plays a role in the development of diabetes, as well as diseases such as:
  • Parkinson's disease
  • Alzheimer's disease
  • Cataracts
  • Macular degeneration
  • Heart and blood vessel disease
  • Cancer
  In addition to its antioxidant benefits, okra may also reduce tiredness. A 2015 study published in Nutrients found that substances found in okra seeds known as polyphenols and flavonoids could reduce fatigue.

FDA Approves Rayaldee (calcifediol) to Treat Secondary Hyperparathyroidism in Patients with Chronic Kidney Disease

OPKO Health, Inc. announced that the U.S. Food and Drug Administration (FDA) has approved Rayaldee (calcifediol) extended release capsules for the treatment of secondary hyperparathyroidism (SHPT) in adults with stage 3 or 4 chronic kidney disease (CKD) and serum total 25-hydroxyvitamin D levels less than 30 ng/mL. Rayaldee is a patented extended release product containing 30 mcg of a prohormone called calcifediol (25-hydroxyvitamin D3).

 calcifediol

"FDA's approval of Rayaldee represents an important milestone for OPKO," noted Dr. Phillip Frost, CEO and Chairman of OPKO. "Rayaldee is the first product to receive FDA approval for this important indication and is one of OPKO's many pharmaceutical products being developed for significant medical problems which will benefit from new treatment options."

Results from two 26 week placebo controlled, double blind phase 3 trials demonstrated that a larger proportion of stage 3 or 4 CKD patients with SHPT and vitamin D insufficiency achieved ≥30% reductions in plasma intact parathyroid hormone (iPTH) when treated with Rayaldee than with placebo. Vitamin D insufficiency was corrected in more than 80% of the patients receiving Rayaldee compared with less than 7% of subjects receiving placebo. Mean serum calcium and phosphorus levels increased by 0.1 mg/dL during Rayaldee treatment compared to placebo treatment, but these changes were deemed clinically irrelevant. No differences in Rayaldee's efficacy or safety were observed between patients with stage 3 CKD or stage 4 CKD.

"Rayaldee fills a large void in the current treatment options for SHPT in predialysis patients," commented Dr. Charles W. Bishop, CEO of OPKO's Renal Division. "The current standard of care is high dose vitamin D supplementation, an approach for treating SHPT that is neither FDA approved nor demonstrated to be safe and effective in this population. SHPT is a progressive disease that becomes increasingly debilitating and difficult to treat, necessitating timely and effective treatment."

"Rayaldee is an important new option for treating SHPT in patients with stage 3 or 4 CKD and vitamin D insufficiency," stated Kevin J. Martin, Director of Research, Division of Nephrology at Saint Louis University School of Medicine. "The great majority of SHPT cases in this patient population are associated with vitamin D insufficiency, a problem that Rayaldee can correct."

About Rayaldee

Rayaldee (calcifediol) extended release capsules are approved by the U.S. Food and Drug Administration (FDA) for the treatment of SHPT in adult patients with stage 3 or 4 CKD and serum total 25-hydroxyvitamin D levels less than 30 ng/mL. Rayaldee has a patented formulation designed to raise serum total 25-hydroxyvitamin D (prohormone) concentrations to targeted levels (at least 30 ng/mL) and to reduce elevated iPTH. OPKO expects to launch Rayaldee in the U.S. through its dedicated renal sales force in the second half of 2016. Rayaldee is not indicated in patients with stage 5 chronic kidney disease or end-stage renal disease on dialysis. The full prescribing information for Rayaldee will be available at www.opkorenal.com.

Potential side effects of Rayaldee include hypercalcemia (elevated serum calcium), which can also lead to digitalis toxicity, and adynamic bone disease with subsequent increased risk of fractures if intact PTH levels are suppressed by Rayaldee to abnormally low levels. Severe hypercalcemia may require emergency attention; symptoms of hypercalcemia may include feeling tired, difficulty thinking clearly, loss of appetite, nausea, vomiting, constipation, increased thirst, increased urination, and weight loss. Digitalis toxicity can be potentiated by hypercalcemia of any cause. Excessive administration of Rayaldee can cause hypercalciuria, hypercalcemia, hyperphosphatemia, or oversuppression of intact PTH. Common symptoms of vitamin D overdosage may include constipation, decreased appetite, dehydration, fatigue, irritability, muscle weakness, or vomiting. Patients concomitantly taking cytochrome P450 inhibitors, thiazides, cholestyramine, phenobarbital or other anticonvulsants may require dose adjustments and more frequent monitoring.

The most common adverse reactions in clinical trials (≥3% and more frequent than placebo) were anemia, nasopharyngitis, increased blood creatinine, dyspnea, cough, congestive heart failure and constipation.

Metabolite of oral DMF drug for multiple sclerosis appears to slow onset of Parkinson's disease

In continuation of my update on dimethylfumarate 

The metabolite of a drug that is helping patients battle multiple sclerosis appears to significantly slow the onset of Parkinson's disease, researchers say.

The oral drug, dimethylfumarate, or DMF, and its metabolite, monomethylfumarate, or MMF, both increase activity of Nrf2, a protein that helps protect the body from oxidative stress and inflammation, hallmarks of both diseases, said Dr. Bobby Thomas, neuroscientist in the Department of Pharmacology and Toxicology at the Medical College of Georgia at Augusta University.

 dimethylfumarate  monomethylfumarate, 

But the new study provides the first evidence that the metabolite, which is essentially the active portion of the parent drug, more directly targets Nrf2, potentially reducing known side effects of the parent drug that include flushing, diarrhea, nausea, vomiting, abdominal pain and the brain infection encephalopathy, said Thomas, corresponding author of the study in The Journal of Neuroscience.

Particularly, the gastrointestinal side effects can exacerbate some problems patients with Parkinson's already experience, said Dr. John Morgan, neurologist, neuroscientist and Parkinson's disease specialist in the MCG Department of Neurology. In addition to destroying neurons in the brain that produce dopamine, a neurotransmitter that enables movement and learning, Parkinson's causes nerve cell death in the gastrointestinal tract and related problems such as severe constipation.

"Nrf2 is a natural protective mechanism we have for oxidative stress," Thomas said. The fact that multiple sclerosis and Parkinson's have in common evidence of declining activity of the Nrf2 pathway has generated interest in the drug for Parkinson's and other neurodegenerative diseases.

DMF was approved for multiple sclerosis three years ago by the Food and Drug Administration. While its metabolite MMF is not quite as potent as the parent drug in increasing Nrf2 activity, the new study indicates that its action is sufficient to dramatically slow the loss of dopamine-producing neurons as well as the parent drug, in an animal model of Parkinson's.

In their model, mice given the neurotoxin MPTP experience a dramatic loss of dopamine-producing neurons, losing about half within a handful of days, and rapidly develop Parkinson's-like symptoms. Patients, on the other hand, slowly develop symptoms over many years. By the time they seek medical care, patients may have lost 30-50 percent of their dopaminergic neurons, said Morgan, a study coauthor. "Presentation is after the disease is kind of out of the gate."

To accommodate the very compressed timeline in their model and the fact that several daily doses are needed before the drug starts to work, the researchers first gave the mice either the drug or metabolite the day before they started the toxin.

Dopamine-producing neurons are located in a darker-pigmented central portion of the brain called the substantia nigra. Even in the absence of disease, making dopamine is a stressful job for these neurons that makes them generally more fragile and actually results in oxidative stress even in a healthy scenario, Morgan said. To make a difficult situation worse, increased oxidative stress can make dopamine toxic to neurons, he said.

To increase Nrf2 activity, the parent drug DMF also appears to first make bad matters worse. DMF increases oxidative stress by depleting the natural antioxidant, glutathione, and reduces the power of cell powerhouses, called mitochondria, by limiting their ability to use oxygen and glucose to make energy leading to reduced viability of dopamine-producing cells, Thomas said.

The metabolite MMF appears to more directly activate Nrf2, and actually increases glutathione and improves mitochondrial function, brain cell studies showed. While the parent drug ultimately produces a higher Nrf2 activation, the researchers found the MMF effect was sufficient to stop the dramatic neuron loss in the animal model.

Both DMF and MMF slowed neuron loss to a more normal level, and the neurons that survived continued to make dopamine. Inflammation and oxidative stress levels also were significantly reduced, the researchers said.

As a next step, they are working toward a clinical trial of MMF in patients with early Parkinson's disease. Although the metabolite could be easily formulated for humans, it has not yet been done, Thomas notes.

"If we can catch them early enough, maybe we can slow the disease," Morgan said. "If it can help give five to eight more years of improved quality of life that would be great for our patients."

Clinical studies of the drug in Parkinson's are being planned in the United Kingdom and additional analogues of its metabolite, which could be used clinically and which the researchers think ultimately will be the best option for patients, are under development.

Oxidative stress is a byproduct of the body's use of oxygen. Free radicals, generated by oxygen use, are unstable molecules that can interfere with usual cell function and are believed to contribute to a wide range of conditions from normal aging to Alzheimer's disease. Simply giving antioxidants, such as vitamin E, which work more like scavengers to scarf up free radicals, has not worked in combating neurodegenerative disease, Thomas said. He's optimistic that directly targeting Nrf2 will be effective in at least slowing the disease, but there remains a need for clinically safe Nrf2 activators.

Activity of the Nrf2 pathway tends to slowly decline with age. Exercise upregulates Nrf2, and Morgan regularly encourages his patients to be as active as possible. A small group of patients with Parkinson's in Europe has a concentrated activation of Nrf2 that at least delays their disease onset. Parkinson's tends to be diagnosed in the mid-to-late 50s and early 60s and is more common in men.

One concern with chronically elevating anti-oxidant and anti-inflammatory molecules with drugs like DMF and MMF is creating some of the same problems that immunosuppressive drugs given to organ transplant patients create. Chronic suppression of the immune response makes patients more susceptible to invaders like cancers and infections.

Ref : http://www.jneurosci.org/content/36/23/6332.short?sid=e7a934c5-6996-4fff-bfa9-f2c600507e1f

Metabolite of oral DMF drug for multiple sclerosis appears to slow onset of Parkinson's disease

One-third of osteoporotic women taking oral bisphosphonates have elevated risk for bone fracture

Chemical structure of pyrophosphate (A, above) and bisphosphonates (B, below). P = phosphorus, O = oxygen, H = hydrogen, C = carbon, R = side chain. In bisphosphonates, the central oxygen atom is replaced with a carbon atom. All bisphosphonates share a common phosphorus-carbon-phosphorus motif with two side chains (R1 and R2 in the figure). The R2 side chain determines the chemical properties of the drug, and distinguishes individual types of bisphosphonates. This chemical structure affords a high affinity for calcium hydroxyapatite, allowing for rapid and specific skeletal targeting.

More than 53 million Americans age 50 and older, primarily women, have osteoporosis or are at high risk for the condition due to low bone density. A recent study of oral bisphosphonates, the most commonly prescribed osteoporosis treatment, found that approximately a third of women prescribed these drugs continue to be at elevated risk for bone fracture, an outcome that may have several origins.

Oral bisphosphonates are a pillar of preventive treatment for patients with osteoporosis and have been shown to be effective in reducing the risk of disabling bone fractures. It is known from clinical trials that no medication completely eliminates the risk of fracture. Additionally, medication effectiveness may be different in clinical practice compared to well-controlled research trials.

Research from the Regenstrief Institute-Merck (Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc.) collaboration suggests that many women still have indicators consistent with higher risk of fracture while taking these medications. The cross-sectional population health study was based on a retrospective database analysis of 7,435 women age 50 and older taking bisphosphonates for at least two years during the 2000-2012 time period. The analysis was published in the peer-reviewed journal Bone.

"While we found that a substantial proportion of patients who took oral bisphosphonates remain at risk for hip, spine, and other major fractures, this class of drug does improve bone density in the majority of patients and should remain a mainstay of osteoporosis management," said Erik Imel, M.D., the Indiana University School of Medicine endocrinologist and Regenstrief Institute-affiliated scientist who led the study.

"We limited our study to patients who were considered to be compliant with taking their medication, based on drug dispensing days covered, with the presumption being that those who filled prescriptions took the medication properly. We would expect even less benefit if patients fail to take their medication properly. To increase treatment effectiveness, patients and their doctors should be vigilant that the drug is taken reliably and properly. However, osteoporosis drugs are not enough. Physicians and their patients are well advised to discuss additional important modifications to decrease fall risk and fracture risk. These include exercise, smoking cessation, use of assistive devices such as canes or walkers, modifying the home to avoid obstacles that might lead to falls, and taking appropriate amounts of vitamin D and calcium."

Conducted under the auspices of a Regenstrief Institute-Merck collaboration, the retrospective cohort study utilized anonymized data from the Indiana Network for Patient Care, a health information exchange founded by the Regenstrief Institute. The study authors note that the data they used reflects real-life medical practice and patient behavior from a wide range of physicians and patient backgrounds. Adherence to bisphosphonate therapy was determined by prescription fulfillment records. Clinical data included information on bone density and fractures.

"We know that taking bisphosphonates decrease fracture risk compared to those not taking these drugs," Dr. Imel said. "But what about those women who weren't getting the anticipated benefit and are not improving bone density or even are losing bone density? What predicted that? The purpose of this study was to focus attention on those not doing well, in order to begin to decrease the odds of future fractures in this large group of vulnerable patients.

"Not everyone responds the same way to oral bisphosphonates or any drug. Various factors could convey continued risk of fracture in spite of bisphosphonate therapy, including other medical problems and risk factors for falling. Since we know that such a high percentage of women continue to have elevated fracture risk we -- doctors and patients -- need to focus on these factors," Dr. Imel said. "For example, we found that women who had other medical conditions in addition to low bone density--a frequent occurrence in this older population--had higher fracture risk. Taking some medications in combination with bisphosphonates seemed to increase fracture risk. However, having more medical conditions and taking more drugs are most likely markers of heightened risk rather than causative factors."

Neurologic problems, often linked to heightened risk of falls, as well as inflammatory and other chronic joint conditions including arthritis were found to be associated with higher odds of having a fracture among those taking bisphosphonates.

"I always tell my osteoporosis patients, 'Don't fall,'" said Dr. Imel. "They usually chuckle, and then we talk about things they can do to decrease the risk of falling, including proper footwear and assistive devices. Many patients are reluctant to use a cane or a walker. I try to get them to understand the importance of using any tool that decreases the chance of falling."

Taking vitamin D with quetiapine can help avoid new-onset diabetes risk

In continuation of my update on quetiapine

Atypical antipsychotics, though effective for treating disorders like schizophrenia, bipolar disorder, and depression, gives patients a heightened risk of developing new-onset diabetes. A new data mining study, however, has found a way to relieve this side effect. The study, published in Scientific Reports, shows that taking vitamin D ameliorates the risk of developing new-onset diabetes from atypical antipsychotics like quetiapine.

 quetiapine.

The consequences of developing diabetes from taking antipsychotics are dire, as they occasionally cause life-threatening conditions and sometimes even death.

Members of Shuji Kaneko's lab at Kyoto University looked for potential antidotes on the US FDA's Adverse Event Reporting (FAERS) system, which is the largest database of self-reported adverse side effects. "We found that patients who had coincidentally been prescribed vitamin D with quetiapine were less likely to have hyperglycaemia," says Kaneko. "It's unusual for vitamin D to be prescribed with quetiapine because it is typically prescribed to treat osteoporosis; in fact, there were only 1232 cases in the world where vitamin D was prescribed with quetiapine. Data mining proved helpful in locating these cases."

The team confirmed this finding with further tests on mice; the group of mice that was fed vitamin D along with quetiapine had significantly lower levels of blood sugar than those that took only quetiapine.

"Interestingly, vitamin D on its own doesn't lower diabetes risk, but it certainly defends against the insulin-lowering effects of quetiapine," elaborates lead author Takuya Nagashima. "We clarified the molecular mechanisms of how quetiapine causes hyperglycaemia using datasets in a genomics data repository. Through this we found that quetiapine reduces the amount of a key enzyme called PI3K that gets produced. Vitamin D stops quetiapine from lowering PI3K production."

"Databases like FAERS aren't just for making drug regulations; they have so much potential for side-effect relief using pre-existing drugs," says Kaneko. "There's a lot we can hope for from reverse translational research like this. "

Ref : http://www.kyoto-u.ac.jp/en/research/research_results/2016/160523_2.html

Walnuts may improve your colon health: Eating walnuts changes the gut microbiome and reduces cancer growth, study shows

In continuation of my update on walnuts  

A team of researchers from UConn Health and The Jackson Laboratory for Genomic Medicine found that mice that ate 7-10.5 percent of their total calories as walnuts developed fewer colon cancers. The effect was most pronounced in male mice, which had 2.3 times fewer tumors when fed walnuts as part of a diet similar to the typical American's. That's equivalent to a human eating about an ounce of walnuts a day.

"Our results show for the first time that walnut consumption may reduce colon tumor development," said Principal Investigator Dr. Daniel W. Rosenberg of UConn Health. "There is accumulating evidence that eating walnuts may offer a variety of benefits related to health issues like cancer. This study shows that walnuts may also act as a probiotic to make the colon healthy, which in turn offers protection against colon tumors."

Walnuts are packed with compounds known to be important nutritionally. They have the most polyunsaturated fatty acids of all the commonly eaten tree nuts, as well as the highest ratio of omega-3 to omega-6 fatty acids, and high levels of a form of Vitamin E with anti-cancer properties.

But walnuts are not merely the sum of their chemical parts, and it may be as a whole food that they pack the most significant anti-cancer punch against colon cancer, the third most common cancer in the world. Other studies have shown walnuts have promise warding off diseases connected to diet and lifestyle, including heart disease, diabetes and neurological disorders.

Rosenberg, a cancer researcher and professor of medicine at UConn Health and Dr. Masako Nakanishi, a research associate in the Center for Molecular Medicine at UConn Health tested the cancer prevention qualities of walnuts on mice fed two different diets. One group of mice ate a standard lab mouse chow, while the other group ate a chow that captured the nutritional profile of the typical American diet. Subsets of both groups were supplemented with walnuts.

Interestingly, male mice fed the Western diet fortified with 10.5 percent walnuts showed the greatest decrease in colon tumors compared with mice fed no walnuts.

To figure out why walnuts were beneficial, the UConn Health team collaborated with Dr. George Weinstock and colleagues at The Jackson Laboratory. Weinstock's lab took fecal samples from the mice and analyzed the communities of bacteria living in their digestive tracts. They found that walnut consumption tended to push the gut microbiome toward an ecology that was potentially protective against cancer. It's not clear exactly how this works, but there are clues. For example, previous research has shown that some gut bacteria digest fiber into compounds with anti-inflammatory properties that may reduce tumor initiation. The microbiome analyses also reflected interesting differences between male and female. Males on walnut-free diets tended to have less-diverse gut flora than females. Adding walnuts to the diets of male mice brought their microbiomes closer to those of female mice on either of the diets. Whether this change contributes to the protection seen in male mice remains to be determined.

Because the studies were done only in mice, more testing needs to be done in humans before walnuts can be unequivocally recommended as a cancer-prevention agent. Rosenberg's group is working with a nutritionist and surveying human colonoscopy patients about their diets as part of a longer term study in humans.

However, Rosenberg isn't waiting for the final word. Even right now, he says, "I try to eat walnuts every day."

Revolutionary drug explained by scientists: Scientists figured out how the world's first drug that protects the cell mitochondria from damage by aggressive oxygen can work

Recently, Russian researchers, led by Prof. Vladimir P. Skulachev, managed to create an antioxidant drug that selectively accumulates within mitochondria and protects them from oxidative damage. Under the trade name "Visomitin" the drug was approved for treatment of such eye diseases as cataracts and dry eye. Prof. Armen Mulkidjanian of the Faculty of Bioengineering and Bioinformatics of the Lomonosov Moscow State University and the University of Osnabrück, Germany, and his colleagues have explained why very small doses of synthetic antioxidants such as "Visomitin" could give a pronounced therapeutic effect, despite the presence of large quantities of natural mitochondrial antioxidants.

 Visomitin

Mitochondria are intracellular structures that conduct respiration. Respiration, however, is accompanied by formation of reactive oxygen species (ROS) as by-products. The ROS are capable of damaging the mitochondria. Damaged mitochondria produce even more ROS, which can destroy cells and tissues, so that nature has special mechanisms, such as mitophagy and apoptosis, for elimination of damaged mitochondria and cells. These mechanisms are triggered after a signal of a disorder passes through the double membrane surrounding the mitochondria. Several laboratories have shown that it is possible to avoid the decay of cells and tissues by preventing the oxidation of a particular component of the mitochondrial membrane -- cardiolipin, because the oxidized molecules of cardiolipin are exactly the triggers of the signal chain.

The group of Prof. Vladimir Skulachev, the Dean of the Faculty of Bioengineering and Bioinformatics and the Director of the Belozersky Institute of Physical and Chemical Biology, (the Lomonosov Moscow State University), has developed a line of mitochondria-targeted antioxidants, the so-called SkQ-ions, specifically protecting the molecules of mitochondrial cardiolipin from oxidation. In animal trials, the SkQ-ions cured inflammatory eye diseases, helped to overcome the ischemia-simulating conditions, and even reduced the manifestation of senescence. Although similarly acting drugs have been developed and studied in the US and UK laboratories, the Russian group was the first to get an approval for their drug -- as eye drops. The researchers hope that SkQ-based drugs, in the form of pills and injections, after their certification, would help to attenuate the pathological symptoms that accompany strokes, heart attacks and serious traumas.

Armen Mulkidjanian and his collaborators have managed to suggest answers to some intriguing questions. Specifically, it was not clear why cardiolipin, of all the components of the membrane, it specifically oxidized. Molecules of cardiolipin, while making only 10-20% of total membrane lipids, are specifically targeted by ROS and, after getting oxidized, trigger the self-destruction of cells. Secondly, it was not clear why the natural antioxidants, namely coenzyme Q (ubiquinol) and vitamin E (alpha-tocopherol), which are present in mitochondrial membranes in large quantities, fail in the case of cardiolipin. It remained a mystery why these substances could not protect cardiolipin from oxidation, whereas artificial, mitochondria-targeted antioxidants, designed either by the Skulachev's group in Moscow, or by their counterparts in the US and the UK, perfectly coped with this task, in spite of very small doses of the administered drugs.

Armen Mulkidjanian says that the goal of the study was set by Prof. Skulachev.

'Prof. Skulachev asked our group in Germany to tackle these puzzles,' says Armen Mulkidjanian. 'Most of the work was carried out by the post-graduate students and the employees of the Moscow University, who worked in Russia and in Germany, so that their contribution was decisive. As to the research, we have developed an experimental system to investigate quantitatively the oxidation of the cardiolipin membranes and the ability of various antioxidants to prevent it. It turned out that the SkQ-ions and the molecules of coenzyme Q protected the cardiolipin membranes from oxidation equally well, whereas vitamin E performed much worse'.

To understand why cardiolipin molecules are the main target of the ROS, the researchers compared the experimental data with their previous results and the structures of respiratory enzymes. A fraction of cardiolipin molecules is occluded within respiratory protein complexes, just those that generate ROS. 'These molecules should be the first to be oxidized,' Mulkidjanian says.

The bulky, water-insoluble molecule of coenzyme Q cannot get to these "hidden" cardiolipin molecules, as opposed to small, agile molecules of artificial antioxidants, which, as shown in the study, are capable of protecting cardiolipin molecules from oxidation by accessing them both from the membrane and from the aqueous phase.

"The essence of our work is that we have proposed a mechanism that explains how very low doses of mitochondria-targeted antioxidants could provide a distinct therapeutic effect, even being applied over large amounts of natural antioxidants, which were ineffective in this case. The mechanism should be valid for the whole class of similar drugs. We hope that our findings would help to develop new drugs,' says Armen Mulkidjanian.

Revolutionary drug explained by scientists: Scientists figured out how the world's first drug that protects the cell mitochondria from damage by aggressive oxygen can work: An international team now clarifies the molecular mechanism of a drug created in Russia and designed to prevent the damaging of cell mitochondria by reactive oxygen species.