July 2012 Blog with Durk and Sandy
by Jamie Riedeman on Jul 02, 2012
(D&S: This is true. Local police tend to respond to lower numbers as indicative of higher-status local residents.)
So much of left-wing thought is a kind of playing with fire by people who don’t even know that fire is hot.— George Orwell
Wealth is not without its advantages and the case to the contrary, although it has often been made, has never proved widely persuasive.— John Kenneth Galbraith, The Affluent Society
A common mistake that people make when trying to design something completely fool-proof is to underestimate the ingenuity of complete fools.— Douglas Adams
The Hitchhiker’s Guide to the Galaxy
More on the Developing Field of Hydrogen Therapy
We wrote a long paper [see “Hydrogen Therapy” in the June issue] on the exciting new research being published on hydrogen therapy, in which hydrogen acts as a highly selective antioxidant that particularly targets hydroxyl radicals and less efficiently the potent oxidant peroxynitrite (that forms from the chemical reaction between superoxide and nitric oxide). Moreover, and of particular importance, hydrogen is able to move rapidly throughout the body and is able to penetrate mitochondria, which are the source of much of the ROS (reactive oxygen species) that plays a key role in many diseases resulting from increased oxidative stress, such as diabetes, cardiovascular disease, cancer, and aging. Interestingly, most antioxidants are not able to penetrate mitochondria or do so poorly, so that mitochondria (which do not have a very effective antioxidant defense system and are, therefore, vulnerable to oxidative damage) cannot be easily protected by supplemental antioxidants. Indeed, lifespan studies using antioxidants have not generally been very successful in increasing maximum lifespan and it is suspected that this is due to most antioxidants not being able to get into mitochondria very well.1
As we explained in our paper, some researchers are trying to develop mitochondria-targeted antioxidants to overcome the problem of limited ability of most antioxidants to get into mitochondria.
As noted in some of the papers we reviewed for “Hydrogen Therapy,” hydrogen has been administered in animal studies and/or human clinical trials by inhaling it, by consuming it as hydrogen enriched saline or hydrogen dissolved in water or (and this was of particular interest to us) by consuming certain prebiotics (carbohydrates that are not fully absorbed in the upper digestive tract and, therefore, reach the lower digestive tract) to increase hydrogen gas production by resident intestinal bacteria. The hydrogen gas produced by the resident intestinal bacteria (you need a little help from your friends) reaches virtually all body tissues, including mitochondria, ultimately being exhaled from the lungs.
Here we report on four very recent papers that describe new developments in hydrogen therapy. We just downloaded the paper on molecular hydrogen and radiation protection2today (May 13, 2012) from the Informa Healthcare website.
Molecular Hydrogen and Radiation Protection
This new paper2 describes work on radioprotective potential of hydrogen. The authors showed that in HIEC cells pretreated with hydrogen and then irradiated, cell survival fractions were increased by hydrogen treatment but that treating cells with hydrogen AFTER they were irradiated resulted in no significant protection. In another experiment, the authors examined the radioprotective effects of hydrogen in an animal study on testis; hydrogen was administered by intraperitoneal injection in C57BL/6 mice. “H2-rich saline significantly reduced the testicular fluorescence intensity in irradiated C57BL/6 mice. However, when we treated these mice with the hydroxyphenyl fluorescein peroxidized by hydroxyl radicals the intensity did not decrease, supporting that H2directly reduced hydroxyl radicals.”2 Moreover, additional studies by the authors on the late radiation damage in cardiac myocytes (heart muscle cells) and pulmonary alveoli showed that pretreatment with H2 significantly suppressed the radiation-induced fibrosis.
The authors also describe a randomized, placebo-controlled human study done by others that found consumption of hydrogen to improve the quality of life of patients treated with radiotherapy for liver tumors, while no differences in tumor response to radiotherapy as a result of hydrogen therapy were observed.
The paper2 also described the process by which colonic bacteria in the human body under physiological conditions produce hydrogen (H2) gas (approximately 12 liters of hydrogen per day),* with the amounts possibly reaching the concentration required to exert selective antioxidant effects. For that reason, the authors suggest that some of the side effects of systemic antibiotics “are related to suppression of intestinal bacteria which generate the endogenous H2.” The authors also mention that “[s]ome reports showed that up-regulation of the ‘endogenous H2’ [the H2 produced by the resident colonic bacteria] could be a strategy for [treating] diseases.”
* This is 1 gram or 1/2 mole of hydrogen per day. (Not everybody produces this much.) This amount is enough hydrogen to saturate over 500 kg of water. See www.engineeringtoolbox.com
The authors explain that they found only 3 researches that tested molecular H2 not as an antioxidant but for other possible mechanisms. Itoh et al was reported to suggest for the first time that H2 may become a gaseous signaling molecule like nitric oxide, carbon monoxide, and hydrogen sulfide. The Itoh group showed that H2 suppressed FcepsilonR1-associated signal transduction and prevented degranulation of mast cells, but not through the reduction of hydroxyl radicals;2b they also demonstrated that H2inhibited lipopolysaccharide/interferon gamma-induced nitric oxide production through modulation of signal transduction in the macrophage.2c Of particular interest, a paper was cited by the authors3 that reported an assay of DNA microarrays in the livers of rats after 4 weeks of drinking hydrogen-enriched water that found 548 upregulated genes and 695 downregulated genes; of those, genes for oxidoreduction-related proteins were enriched in the up-regulated groups. Consequently, we see that some progress is being made in an attempt to track down mechanisms other than the scavenging of hydroxyl radicals and peroxynitrite to explain the effects of hydrogen therapy. This study2 of radioprotection and hydrogen was supported by a grant from the National Natural Science Foundation of China, presumably a government entity. In fact, considering the affiliation of the corresponding author, Dr. Jianming Cai, who is at the Dept. of Radiation Medicine, Faculty of Naval Medicine, Second Military Medical University in Shanghai, China, the study appears to have been supported by the Chinese military.
References
- See, for example, Miquel. Can antioxidant diet supplementation protect against age-related mitochondrial damage?Ann N Y Acad Sci959:508-516 (2002).
2. Chuai, Sun, and Cai. Molecular hydrogen and radiation protection. 10.3109/10715762.2012.689429.
2b. Itoh et al. Molecular hydrogen suppresses FcepsilonRI-mediated signal transduction and prevents degranulation of mast cells. Biochem Biophys Res Commun 389(4):651-6 (2009).
2c. Itoh et al. Molecular hydrogen inhibits lipopolysaccharide/interferon γ-induced nitric oxide production through modulation of signal transduction in macrophages. Biochem Biophys Res Commun 411(1):143-9 (2011).
3. Nakai et al. Hepatic oxidoreduction-related genes are upregulated by administration of hydrogen-saturated drinking water. Biosci Biotechnol Biochem 75:774-776 (2011).
Human Study Finds that Drinking Hydrogen-Rich Water Can Protect Against Exercise-Induced Muscle Fatigue in Elite Athletes
Researchers investigated the potential protective effects of hydrogen-rich water against oxidative stress and muscle fatigue in response to acute exercise.
The subjects of the study4 were ten young (20.9 ± 1.3 years old) male soccer players. They were studied in a cross-over design (where they received either HW (hydrogen-rich water) or PW (placebo water) for one week intervals. The subjects were “requested” (presumably there was no test for compliance) to use a cycle ergometer at a 75% maximal oxygen uptake for 30 minutes, followed by measurement of peak torque and muscle activity throughout 100 repetitions of maximal isokinetic knee extension, during which oxidative stress and creatine kinase in the peripheral blood were sequentially measured.
The results showed that: “Although acute exercise resulted in an increase in blood lactate levels in the subjects given PW, oral intake of HW prevented an elevation of blood lactate [as occurs during muscle fatigue] during heavy exercise. Peak torque of PW significantly decreased during maximal isokinetic knee extension, suggesting muscle fatigue, but peak torque of HW didn’t decrease at early phase. There was no significant change in blood oxidative injury markers … or creatine kinase after exercise.”4
The authors therefore conclude: “Adequate hydration with hydrogen-rich water pre-exercise reduced blood lactate levels and improved exercise-induced decline of muscle function.” We note that increased availability of hydrogen via fermentation by intestinal microbiota wouldn’t, unlike hydrogen in water, provide water for hydration (e.g., protection against dehydration, which can be important in athletes doing vigorous exercise), but water for hydration can be easily obtained and consumed — it is the hydrogen that requires a special source.
- Aoki et al, “Pilot study: Effects of drinking hydrogen-rich water on muscle fatigue caused by acute exercise in elite athletes,”Med Gas Res2:12 (2012) doi:10.1186/2045-9912-2-12URL: http://www.medicalgasresearch.com/content/2/1/12.
Review Paper: Data on Protective Effects of Hydrogen in Brain Trauma, Stroke and Neonatal Hypoxia-Ischemia
A 2012 paper5 provides a summary of findings of recent preclinical studies on hydrogen administration, either via gas inhalation or ingestion in water, in treatment for neurological disorders including traumatic brain injury, surgically induced brain injury, stroke, and neonatal hypoxic-ischemic insult. The authors note that “[m]ost reviewed studies demonstrated neuroprotective effects of hydrogen administration. Even though antioxidative potentials have been reported in several studies, further neuroprotective mechanisms of hydrogen therapy remain to be elucidated. Hydrogen may serve as an adjunct treatment for neurological disorders.”
Rather naively, we think, the authors note: “Currently, to our knowledge, there are no FDA approved therapeutic regimens involving hydrogen gas or dissolved hydrogen.” Considering the immense expense for getting FDA approval (currently estimated at about $3 billion or more for a prescription drug) it is unlikely that anybody will seek such approval. Even if FDA approval as a medical device, generally much less expensive than for prescription drugs, were to be sought, however, the federal government has imposed a special new medical devices tax that is going to impose extra costs on manufacturers of medical devices in America; worse yet, however, because there is a chemical component of hydrogen therapy, another new regulation (decreed by FDA despite Congressional statutory wording that precludes it* will require that hydrogen therapy via gas or dissolved hydrogen be deemed a drug.
* The reason for this is that agencies have been able to get extremely broad deference from the courts for nearly any interpretation the agency wants to attach to a Congressional statute. Lots of dysfunctional agency rules are thus largely the result of two failures: the failure of Congress to oversee the rules devised by regulatory agencies pursuant to Congressional statute and the failure of courts to strike down rules created by regulatory agencies in the absence of Congressional authority and when they deviate significantly from the clear wording of a statute.
The good news, though, is that the FDA has no authority beyond regulating health and safety to limit marketing of prebiotics, food carbohydrates such as long chain fructooligosaccharides that reach the lower digestive tract and provide food for certain gut microbiota to ferment, producing hydrogen gas and short chain fatty acids. Tough luck, FDA! (Of course, the agency will still attempt to prohibit the communication of truthful information on labels or ads on the health effects of hydrogen produced by gut microbes, since FDA deems information on the prevention or treatment of disease to turn a food into a drug. Still, the information will get around. It just takes longer.)
Some of the nine animal studies that examined neuroprotection by hydrogen that were reviewed here4 were reviewed in our “Hydrogen Therapy” [see “Hydrogen Therapy” in the June issue]. In all, the new review provided 37 references. We got and read one of the papers6 cited in the review on the effects of hydrogen on mitochondrial dysfunction that we had not seen before and review it below briefly.
Hydrogen May Protect Against Diseases Resulting from Mitochondrial Dysfunction
We are particularly interested in new work revealing effects of hydrogen on mitochondrial dysfunction. A recent paper6 on hydrogen therapy in a small sample of patients with mitochondrial and inflammatory myopathies (muscle disorders) provided some data. The researchers performed an open-label (no blinding) trial of drinking 1.0 liter per day of hydrogen-enriched water for 12 weeks in five patients with progressive muscular dystrophy (PMD), four patients with polymyositis/dermatomyositis (PM/DM), and five patients with mitochondrial myopathies (MM, muscle disorders due to mitochondrial dysfunction). The researchers also conducted a randomized, double-blind, placebo controlled, crossover trial of 0.5 liter per day of hydrogen enriched water or placebo water for 8 weeks in 10 patients with DM and 12 patients with MM.
These were very small, short-term trials. In the open-label trial, hydrogen-enriched water was found to improve mitochondrial function in MM and inflammatory processes in PM/DM as measured by significant effects on lactate-to-pyruvate ratios in PMD and MM, fasting blood glucose in PMD, serum matrix metalloproteinase-3 (MMP-3) in PM/DM and serum triglycerides in PM/DM. No objective improvement or worsening of symptoms of the disorders was observed.
In the double-blind trial, the researchers observed significant improvements in lactate levels in MM. They also reported favorable responses in lactate-to-pyruvate ratios in MM and MMP3 in DM but these changes were not significant. As in the open-label trial, there were no objective improvement or worsening of symptoms of the disorders observed. In one insulin-treated MELAS (a type of MM) patient, there was a hypoglycemic episode, which subsided by reducing the insulin dose.
A few comments: These are very preliminary works. As the authors note: “[s]mall numbers of participants in both the open-label and double-blind studies might have failed to disclose statistical significant effects of HEW [hydrogen enriched water].”6 In MM, mitochondrial DNA mutations cause defective mETS (mitochondrial electron transfer system). “Thus, lactate and L/P ratio are useful surrogate markers to estimate functions of mETS, and are usually abnormally elevated in MM.”6 Also, a limitation in the open-label study was that drinking of 1.0 liter of hydrogen enriched water (HEW) was difficult for most myopathic patients, which was the reason for decreasing the amount of HEW to 0.5 liters in the double-blind studies. The authors note that hydrogen doesn’t show simple dose-response relationships in rodents, and ad lib administration of even 5%-saturated HEW significantly attenuated development of Parkinson’s disease in a mouse study. Having to drink a lot of HEW wouldn’t be a problem with hydrogen derived from the activities of gut microbiota.
Here we see what it takes to begin to develop a new area of medical science especially during a period of economic decline when scientific funding is difficult to find. Fortunately, the selective antioxidant effects of hydrogen and its ability to penetrate into tissues including mitochondria, combined with the inexpensiveness of ingesting a prebiotic for the gut microbiota to use in generating additional hydrogen makes this a low risk and low cost method for people who want to try hydrogen for mitochondrial and/or inflammatory disorders. No prescription required!
- Eckermann et al. Potential application of hydrogen in traumatic and surgical brain injury, stroke, and neonatal hypoxia-ischemia.Med Gas Res2:11 (2012). doi:10.1186/2045-9912-2-11URL: http://www.medicalgasresearch.com/content/2/1/11http://www.medicalgasresearch.com/content/2/1/11.
Ito et al. Open-label trial and randomized, double-blind, placebo-controlled, crossover trial of hydrogen-enriched water for mitochondrial and inflammatory myopathies. Med Gas Res 1:24 (2011) http://www.medicalgasresearch.com/content/1/1/24.
How to Store Minimally Processed Vegetables
to Avoid Survival and Growth of Pathogens
As you have probably read, there is a rapid increase in the number and severity of foodborne illnesses due to pathogens such as Escherichia coli, Salmonella spp. and Listeria monocytogenes.1 A new paper1 gave a breakdown on the types of produce most likely to carry these pathogens. “Between 1998 and 2006, 5 types of commodity produce comprised 76% of produce-related outbreaks: (1) lettuce/leafy greens (30%), (2) tomatoes (17%), (3) cantaloupe (13%), (4) herbs (basil, parsley, 11%) and (5) green onions(5%).”1
The researchers purchased vegetables (romaine lettuce, iceberg lettuce, perilla leaves, and sprouts) at a local food store and prepared samples, cutting the veggies with an alcohol-sterilized knife, pathogens were pipetted on the samples (S. Typhimurium, S. aureus, L. monocytogenes, or E. Coli (which were then dried in a fume hood for 1 hour), and inoculated samples then placed into sterile plastic bags, which were stored at 4 degrees C for 3, 6, 9, 12, or 15 days or at 15 degrees C for 1, 2, 3, 5 or 7 days.
The results indicated that in order to prevent the growth of foodborne pathogens, minimally processed vegetables should be stored at 4 degrees C.
The only time we feel comfortable eating raw tomatoes is in the short growing season here in central Nevada, when we grow our own. Otherwise, we eat canned tomatoes or cooked fresh tomatoes.
- Tian et al. Survival and growth of foodborne pathogens in minimally processed vegetables at 4 and 15 degrees C. J Food Sci 71(1):M48-M50 (2012).
Improved Creative Problem Solving in Humans
By Alcohol Intoxication to Nearly the Legally Drunk Level
Here’s a fun way to increase your creativity! But don’t make it a disaster by driving or operating hazardous machinery while you’re doing this.
A paper1 was published in which researchers tested the hypothesis that getting slightly zonked on alcohol is a way to increase creative problem solving. As the authors say in their introduction: “A popular belief is that altered cognitive processing, whether due to insanity, sleep state, mood, or substance use, may spark creativity among artists, composers, writers, and problem solvers.” But, they go on to say, there has actually been little in the way of scientific investigation to demonstrate the connection empirically.
So, they decided that the time had come to investigate the empirical connection. They describe a possible mechanism for such an alcohol-creativity relationship by suggesting that the reduced ability to control one’s attention (part of executive function) may have a positive effect on certain cognitive tasks by releasing the brain to operate more fluidly to use associational or discontinuous problem solving processes. “One interesting prediction is that superior executive functioning, such as increased attentional control, may in fact be detrimental to reaching creative solutions. Increased attentional control implies that one is better able to screen out peripheral information which, while useful during analytical problem solving, would be disadvantageous in a situation where the assimilation of information outside of the perceived problem space may be useful.”1
The authors describe previous research on the effects of alcohol on problem solving. In one study they describe, for example, intoxicated individuals had particularly poor memory for sequentially presented items, while their memory for simultaneous lists was relatively unimpaired as compared to sober participants. The researchers used a test of moderate alcohol intoxication (.07 blood alcohol concentration, which is in fact just slightly below the usual blood level (.08) considered legally drunk) and a creative problem solving task called RAT, Remote Associates Test. (Ha! Betcha they named it while intoxicated!) For each item on the test, participants are given three target words such as PEACH, ARM, and TAR and are supposed to find a fourth word, such as PIT that forms a good two-word phrase with each of the target words. They suggest that when the initial ideas for the fourth word turn out not to work, it would require divergent thinking and the ability to overcome fixation from earlier guesses in order to “solve” the problem. Thus, participants in the intoxicated condition should solve more RAT items than those in the sober condition or solve them more quickly.
Another way to detect a changed way to solve problems from the sober condition is to notice “flashes” of insight that would suddenly produce a solution as compared to the step-by-step analytical process. The results supported the hypothesis: “intoxicated individuals solved more RAT items, in less time, and were more likely to perceive their solutions as the result of a sudden insight.”1
The authors claim that the results of the current study “begs for continued research using conceptually related measures, such as classical insight problems, and other measures of executive control to generalize these findings.” Go to it!!
Reference
- Jarosz et al. Uncorking the muse: alcohol intoxication facilitates creative problem solving. Conscious Cogn 21:487-93 (2012).
Increasing Neurogenesis in Mice With (-)-Epigallocatechin-3-gallate (EGCG)
While in a creative intoxicated state, you may also like to increase your brain’s supplies of newly created neurons via neurogenesis. The hippocampus of the brain, critically important in learning and memory, is one of the two known brain areas that contain resident neuronal progenitor cells, which can generate new neurons throughout life.
In the new study,1 researchers provided male C57BL/6J mice EGCG by oral administration (25 mg/kg)* and BrdU by intraperitoneal injection for incorporation into the newly formed neurons, thus allowing for their detection. Neuronal development was detected by Ki67 as an endogenous marker of proliferation and DCX as a marker for neuroblasts.
* This is roughly equivalent to a dose of 100 to 200 mg per day of EGCG for a human as scaled by metabolism.
The researchers observed that, “oral administration of EGCG for 4 weeks enhanced the number of proliferating cells in the SZDG [subgranular zone of dentate gyrus, where progenitor cells reside] based on Ki67 and BrdU immunohistochemistry. EGCG induces rescue of the brain volume alteration in accelerated senescence mice (SAMP 10) and DYRK1a gene-deleted mice. DYRK1a, an essential gene for normal postembryonic neurogenesis, is involved in the neuronal differentiation of hippocampal progenitor cells in rats. … [t]hese findings suggest that the treatment of EGCG promotes the cell proliferation.” In addition, “[a]dult neurogenesis is stimulated by brain-derived neurotrophic factor (BDNF). It has been reported that EGCG diet enhances BDNF mRNA levels in the hippocampus of the human brain.” The authors note that EGCG can easily pass through the blood-brain barrier and reach the brain parenchyma, unlike most other blood-borne substances.
Finally, the scientists observed “an increase in numbers of DCX+ cells in the EGCG-treated group compared to those in the vehicle-treated group.”1
Newly Created Neurons Perform Differently From “Mature” Neurons: Youthful Vigor
Something that has been recently discovered is that the newly minted neurons function somewhat differently than older neurons, acting as a sort of vigorous childhood version of the old neurons.2 It has been reported that the new cells learn more easily and have greater overall levels of activity than older ones, with a threshold to induce long-term potentiation (a process required for learning and memory) signal transmission that is reduced in comparison with the older, mature neurons.2 It has been proposed that for a short period of time after their formation, the young neurons are more sensitive to excitatory input as compared to older ones.2
Marin-Burgin et al, researchers in the field of neurogenesis, speculate that, “the mix of young and old cells imparts a particular functionality to the dentate gyrus. Young neurons are good integrators and tuned to a broad variety of inputs, whereas old cells display high input specificity and hence are better separators.”2,3 The CELL study3authors sum their findings: “[o]ur data suggest that as adult-born GCs [granule cells] age, their function switches from pattern separation to rapid pattern completion.”
References
- Yoo et al. (-)-Epigallocatechin-3-gallate increases cell proliferation and neuroblasts in the subgranular zone of the dentate gyrus in adult mice. Phytother Res 24:1065-70 (2010).
- Kempermann, “Perspectives: Youth culture in the adult brain,” Science 335:1175-6 (2012).
- Nakashiba et al, “Young dentate granule cells mediate pattern separation, whereas old granule cells facilitate pattern completion,” Cell 149:188-201 (2012).
Chronic Stress Interferes With Regulation of
Inflammation via Glucocorticoid Receptor Resistance
A considerable amount of research is being published on the subject of stress and inflammation. This is very useful since the more we understand how stress works, the more we can manipulate the process so as to avoid its most costly effects. In a new paper,1 researchers report that, in 276 human volunteers exposed to stressful life events (as determined in interviews with subjects) and then exposed to a rhinovirus (cause of the common cold), “those with recent exposure to a long-term threatening stressful experience demonstrated GCR [glucorticoid receptor resistance]; and those with GCR were at higher risk of subsequently developing a cold.”1
Glucocorticoid Receptor Resistance in COPD
Glucocorticoid receptor resistance is a potentially important mechanism of dysfunctional inflammation regulation that, by allowing pro-inflammatory mediators such as inflammatory cytokines to run wild, reduces the appropriate regulation of inflammatory processes. “Evidence for GCR in response to chronic stress has been found in parents of children with cancer, spouses of brain-cancer patients, and in persons reporting high levels of loneliness.” Because glucocorticoids are important in controlling inflammation, GCR can increase the risk for inflammatory conditions such as asthma and autoimmune diseases, as well as for conditions with chronic inflammation such as cardiovascular disease and type 2 diabetes1 as well as increasing the difficulty of treating inflammatory diseases such as COPD (chronic obstructive pulmonary disease).2
In another paper,3 higher body mass index was associated with reduced glucocorticoid inhibition of inflammatory cytokine production following psychosocial stress in men. This resulted in reduced ability to suppress TNF-alpha (an inflammatory cytokine) production that occurred during stress, prolonging inflammation and suggested to the researchers that “[t]his might suggest a new mechanism linking BMI [body mass index] with elevated risk for adverse cardiovascular outcomes following stress.”3 Blunted glucorticoid suppression of NF-kappaB, a key pro-inflammatory transcription factor, in human monocytes was also reported to result from stress,4 with the authors suggesting that “[t]his persistent activation of inflammatory mechanisms may contribute to stress-related morbidity and mortality.”
Restoring Glucocorticoid Sensitivity with Curcumin
Another paper5 reports that curcumin is able to restore corticosteroid sensitivity in human monocytes by maintaining levels of HDAC2 (histone deacetylase 2) which is known to be deficient in COPD and asthma patients. Deficiency of HDAC2 correlates with the severity of disease. The amount of curcumin required in vitro to restore HDAC2 activity and corticosteroid efficacy in cigarette smoke extract exposed cells is exceptionally small, having an EC(50) of approximately 30 nM (NANOmoles) and 200 nM (NANOmoles) respectively.5 Theophylline, a natural methylxanthine chemically related to caffeine, is also able to restore HDAC2 activity.6
Reference
- Cohen et al. Chronic stress, glucocorticoid receptor resistance, inflammation, and disease risk. Proc Natl Acad Sci USA 109(16):5995-9 (2012).
- Marwick et al. A role for phosphoinositol 3-kinase delta in the impairment of glucocorticoid responsiveness in patients with chronic obstructive pulmonary disease. J Allergy Clin Immunol 125(5):1146-53 (2010).
- Wirtz et al. Higher body mass index (BMI) is associated with reduced glucocorticoid inhibition of inflammatory cytokine production following acute psychosocial stress in men. Psychoneuroendocrinology 33:1102-10 (2008).
- Miller et al. A functional genomic fingerprint of chronic stress in humans: blunted glucocorticoid and increased NF-kappaB signaling. Biol Psychiatry 64:266-72 (2008).
- Meja et al. Curcumin restores corticosteroid function in monocytes exposed to oxidants by maintaining HDAC2. Am J Respir Cell Mol Biol 39(3):312-23 (2008). PMID: 18421014 [PubMed - indexed for MEDLINE]
- Marwick et al. Oxidative stress and steroid resistance in asthma and COPD: pharmacological manipulation of HDAC-2 as a therapeutic strategy. Expert Opin Ther Targets 11(6):745-55 (2007). PMID: 17504013 [PubMed - indexed for MEDLINE]
Scientists Develop Mitochondria-targeted Antioxidants That Protect Pancreatic Beta-cells Against Oxidative Stress and Improve Insulin Secretion
A recent paper1 reports on experimental benefits of two mitochondria-targeted antioxidants, MitoTempol and Mitoquinone (MitoQ). The researchers exposed pancreatic beta cells to glucotoxic (toxic, high levels of glucose) and glucolipotoxic (high levels of glucose and fats), which result in increased mitochondrial ROS (reactive oxygen species) production, leading to the sort of damage that is found in patients with type 2 diabetes.
MitoTempol or Mitoquinone were shown to prevent the deleterious effects to the pancreatic beta-cells under the glucotoxic and glucolipotoxic conditions, promoting their survival and increasing insulin secretion.
“Mitotempol and Mitoquinone (MitoQ) are two promising mitochondria-targeted antioxidants derived from tempol (an antioxidant nitroxide) and ubiquinone, which are targeted to mitochondria by covalent attachment to a lipophilic [fat loving] triphenylphosphonium cation.”1 The antioxidant MitoTempol (for example) “decreases ROS generation, reduces abdominal fat and the weight gain, decreases blood glucose and normalizes blood insulin and creatinine levels in obese/Zucker rats fed a high fat diet [references given here have been deleted].”1 Moreover, the authors explain, “[p]ancreatic beta-cells are particularly susceptible to destruction by mitochondrial ROS because the expression level of antioxidant enzymes in pancreatic islets is low.”1
We hypothesize that, since hydrogen easily enters mitochondria and has substantial antioxidant effects, especially against the hydroxyl radical, the most toxic type of free radical and one for which no physiological control mechanism has yet been identified, and the potent toxicant peroxynitrite (created by the chemical reaction of superoxide and nitric oxide) might provide benefits similar to mitochondria-targeted antioxidants. Importantly, we note that this hypothesis has NOT yet been experimentally tested. Indeed, the identification of the mechanisms that explain the source of hydrogen’s beneficial effects is still sketchy and in the very early stages. There are no data yet available that compare the effects of hydrogen with mitochondria-targeted antioxidants such as the two described above.
Hence, we have written this up as a thought experiment, that hydrogen, like antioxidants such as those described above that can penetrate mitochondria, may offer protection that improves on the results that have been obtained with antioxidants heretofor in the attempted treatment of oxidative stress arising in mitochondria.
Reference
- Lim et al. Mitochondria-targeted antioxidants protect pancreatic beta-cells against oxidative stress and improve insulin secretion in glucotoxicity and glucolipotoxicity. Cell Physiol Biochem 28:873-86 (2011)
Modification of Intestinal Microbiota for the Treatment of Disease: Cardioprotection in Rats Experiencing a Heart Attack
With the discovery of the importance of the resident intestinal microbes (microbiota) in the maintenance of normal host physiology, researchers are now beginning to publish work on how the modification of the intestinal microbiota can be used to promote improved health or amelioration of disease states. A new paper1 is, therefore, of considerable interest. In this 2012 paper, researchers report that treatment of Dahl S rats with a minimally absorbed antibiotic vancomycin in their drinking water resulted in decreased circulating leptin levels by 38%, 27% smaller myocardial infarcts (death of heart cells as a result of an experimental occlusion of the left anterior descending coronary artery), and improved recovery of postischemic mechanical function (35%) in treated as compared to untreated control rats.
The Dahl S rat “is an established model of increased susceptibility to injury from myocardial ischemia/reperfusion injury.”1 The minimally absorbed antibiotic vancomycin was used because it modifies the makeup of the resident intestinal bacteria, reducing infarct size “despite the absence of the antibiotic in the coronary perfusate at the time of ischemia/reperfusion, suggesting that a direct effect of the antibiotic on the heart is not responsible for the decrease in IS [infarct size].”1 In fact, the authors report that “when administered directly into the coronary circulation, [vancomycin] had no effect on severity of myocardial infarction.”1 The rats were treated with vancomycin for its effects on the resident intestinal microbes, decreasing the total numbers while altering the abundance of individual groups of the gut microbiota.1
“The minimum treatment time vancomycin needed to decrease IS was 48 h.”(1) One of the effects of vancomycin was to decrease circulating leptin levels by 38 ± 4% and the researchers found that the administration of leptin to the vancomycin treated rats before ischemia/reperfusion abolished the decrease in IS.
Additional studies were performed by the researchers in which the rats were fed a commercial blend (Goodbelly®) of two probiotics, Lactobacillus plantarum (Lp299v) and Bifidobacterium lactis (Bi-07) for 14 days before receiving ischemia/reperfusion treatment, resulting in a 29% decrease in infarct size in the probiotic supplemented rats as compared to the rats subject to the ischemia/reperfusion procedure but without probiotics pretreatment. Treatment with the two probiotics also decreased leptin levels in blood by 41% and, like vancomycin, pretreatment with leptin abolished the cardioprotection by the two probiotics.
The authors explain that leptin is synthesized and secreted into the circulation largely by white adipocytes (fat cells), but that the heart also produces and is responsive to leptin. They suggest that their data support a model of leptin resistance in the heart in which persistently high levels of leptin desensitizes the heart to leptin signaling. Conversely, reduced levels of leptin in the circulation increase the sensitivity of the heart to leptin. They suggest that the probiotics may have a cardioprotective effect by decreasing circulating leptin levels.
Interestingly, the researchers compared the protective effects of the vancomycin or probiotics to that of other widely used medical therapies. For example, they note that the vancomycin resulted in a 27% reduction in IS, while the two probiotics reduced IS by 29%. Early ischemic preconditioning, on the other hand, can cause an 86% reduction in IS, while late ischemic preconditioning can reduce IS by 66%. Remote preconditioning (where transient periods of nonlethal ischemia and reperfusion, such as can be produced by a short period of on and off by a blood pressure gauge cuff on a limb) can also provide substantial cardioprotection of 52% reduction in IS. Hence, the protection resulting from vancomycin or the two probiotics was much less than these other methods. However, the authors also note that the results with these agents are similar to the protection resulting from treatment with erythopoietin (39% reduction in IS) or thrombopoietin (34% reduction in IS). These are encouraging results and supplementation with the two identified probiotics is likely to be safer and cheaper than the use of therapeutic drugs and it must be remembered that the experimental investigation of probiotics for medical therapy has barely begun.
Reference
- Lam et al. Intestinal microbiota determine severity of myocardial infarction in rats. FASEB J 26:1727-35 (2012).
Two Strains of Lactobacillus, Lactic Acid Bacteria,
Identified As Inhibitors of Helicobacter pylori Infection
In another recent paper1 researchers have identified two strains of Lactobacillus, L. gasseri Chen and L. plantarum as having significant anti-Helicobacter pylori activity. Helicobacter pylori is a bacteria that resides in the gastrointestinal tract of more than half of the world’s human population1 and that can cause serious disease (chronic gastritis, peptic ulcer, or gastric cancer) but only does so in a fraction of those infected with it.
Helicobacter pylori was tested for its ability to adhere to human gastric epithelial cells (SGC7901 cells) in the presence of the two lactobacilli. After two hours of incubation in cell-free supernatants from the lactobacilli, the activity of an enzyme (urease) released by H. pylori adhering to the SGC7901 cells was reduced from 100% to approximately 50%.
The authors point out that these Lactobacilli can be used as probiotics to manufacture dairy products that could reduce the risk of H. pylori-induced disease. What these scientists may not realize, however, is that the FDA would deem a health claim of disease risk reduction to make a food such as yogurt (or other dairy product) containing the Lactobacilli into a drug. It could be marketed without the claim, of course, but that would make it much more difficult to sell.
Reference
- Chen et al. Antagonistic activities of Lactobacilli against Helicobacter pylorigrowth and infection in human gastric epithelial cells. J Food Sci 71(1):M9-M14 (2012).
