Health,Stem Cells, and Technology

Monday, January 31, 2011

Adult Skin Cells Converted to Beating Heart Cells

Professor Sheng Ding, PhD at the Scripps Research Institute in San Diego, CA and team have converted adult skin cells directly into beating heart cells efficiently without having to first go through the laborious process of generating embryonic-like stem cells. This is a new technology platform that could lead to new treatments for a range of diseases and injuries involving cell loss or damage, such as heart disease, Parkinson's, and Alzheimer's disease.The work was published January 30, 2011, in an online issue of Nature Cell Biology

During development, embryonic-like stem cells multiply and transform themselves into more mature cell types through a process known as differentiation, producing all of the body's different cell types and tissues. Past the embryonic stage, however, the human body has limited capacity to generate new cells to replace ones that have been lost or damaged. Scientists have been trying to develop ways to "reprogram" adult human cells back to a more embryonic-like, or pluripotent, state, from which the cells are able to divide and then change into any of the body's cell types. Using these reprogramming techniques, scientists hope to someday be able to use a patient's own cells, for example skin cells, convert them into heart or brain cells, and then insert them back into the patient to repair damaged tissues. In 2006, Japanese scientists reported that they could reprogram mouse skin cells to become pluripotent simply by inserting a set of four genes into the cells.

Although the technology to generate these cells, dubbed induced pluripotent stem (iPS) cells, represents a major advance, there are some hurdles to overcome before it can be adapted to therapies. The iPS technique requires a long time to generate iPS cells and then differentiate them into tissue-specific functional cell types, and the iPS cells generated in this manner are not ideal. Specifically, the procedure requires about four weeks for scientists to create iPS cells from skin cells and the process is far from efficient, with only one cell out of thousands making the complete transformation. Furthermore, once scientists obtain iPS cells, the cells have to go through the tricky procedure of inducing the iPS cells to differentiate into desired types of cells, requiring an additional two to four weeks.

Further, the process of generating mature cells from iPS cells is not foolproof. When, for example, scientists induce iPS cells to become heart cells, the resulting cells are a mix of heart cells and some lingering iPS cells. Scientists are concerned that giving these new heart cells (along with the remaining pluripotent cells) to patients might be dangerous. When pluripotent cells are injected into mice, they cause cancer-like growths. Because of these concerns, Ding and colleagues decided to try to tweak the process by completely bypassing the iPS stage and going directly from one type of mature cell (a skin cell) to another (a heart cell).
The team introduced the same four genes initially used to make iPS cells into adult skin fibroblast cells, but instead of letting the genes be continuously active in cells for several weeks, they turned off their activities just after a few days, before the cells had turned into iPS cells. Once the four genes were switched off, the scientists initiated a signal in the cells to make them turn into heart cells. In 11 days the skin cells were transformed into beating heart cells.

In addition to better understanding the basic biology of stem cells, the next step will be further modification of the technique to remove the need for inserting the four genes, which has been linked to the development of cancer. As a result, many scientists, including Ding, have been working on new techniques to develop iPS cells without use of these genes. That has proven difficult. But with the new protocol that bypasses the iPS cell stage, the genes are needed for a much shorter time, and further refinement of the technique is likely to emerge quickly.

Sunday, January 30, 2011

Stem Cells Reset Immune Systems in Diabetes

A number of studies have now shown that the majority of patients with Type 1 diabetes who underwent transplantation with their own stem cells to reset their immune systems became insulin free, several for more than three years. These studies also report that these patients also showed an increased level of a substance, called C-peptide, that indicates improved functioning of their beta cells, a cell in the pancreas that secretes insulin. Some of these studies have been performed by Professor Richard Burt, MD at the Northwestern University Feinberg School of Medicine. Dr Burt has also had success treating MS with the patient’s own stem cells, but more work needs to be done to understand the efficacy of such treatments.

Thursday, January 27, 2011

Meditation Training Changes Brain Structure in Eight Weeks

New studies reported today by Sara Lazar, PhD show that participating in an 8-week mindfulness meditation program appears to make measurable changes in brain regions associated with memory, sense of self, empathy and stress. In a study appearing in the January issue of Psychiatry Research: Neuroimaging, a team led by Massachusetts General Hospital (MGH) researchers are the first to document meditation-produced changes over time in the brain's grey matter, i.e. the cells of the brain.

Although the practice of meditation is associated with a sense of peacefulness and physical relaxation, practitioners have long claimed that meditation also provides cognitive and psychological benefits that persist throughout the day. Professor Lazar's study demonstrates that changes in brain structure may underlie some of these reported improvements and that people are not just feeling better because they are spending time relaxing, rather profound physical changes are occurring in the brain.
Previous studies from Dr. Lazar's group and others found structural differences between the brains of experienced mediation practitioners and individuals with no history of meditation, observing thickening of the cerebral cortex in areas associated with attention and emotional integration. But those investigations did not document that the differences were produced by meditation.
In the current study, MR images of the brain structure using 16 study participants two weeks before and after they participated in the 8-week Mindfulness-Based Stress Reduction (MBSR) Program at the University of Massachusetts Center for Mindfulness. In addition to weekly meetings that included practice of mindfulness meditation, which focuses on nonjudgmental awareness of sensations, feelings and state of mind, participants received audio recordings for guided meditation practice and were asked to keep track of how much time they practiced each day. A set of MR brain images were also included from a control group of non-meditators over a similar time interval.
Meditation group participants reported spending an average of 27 minutes each day practicing mindfulness exercises, and their responses to a mindfulness questionnaire indicated significant improvements compared with pre-participation responses. The analysis of MR images, which focused on areas where meditation-associated differences were seen in earlier studies, found increased grey-matter density in the hippocampus, known to be important for learning and memory, and in structures associated with self-awareness, compassion and introspection. Participant-reported reductions in stress also were correlated with decreased grey-matter density in the amygdala, which is known to play an important role in anxiety and stress. Although no change was seen in a self-awareness-associated structure called the insula, which had been identified in earlier studies, the authors suggest that longer-term meditation practice might be needed to produce changes in that area. None of these changes were seen in the control group, indicating that they had not resulted merely from the passage of time.
These studies show how dramatically plastic the brain is and how our behaviors can modify the brain's physical structure, doing so in a very meaningful and positive manner when meditation is practiced routinely.

Wednesday, January 26, 2011

Probiotics: Bifidobacteria can protect from enteropathogenic infection through production of acetate

Japanese researchers report in the journal Nature that Bifidobacteria, sometimes used in yoghurts and other food products as 'probiotics', protect mice from potentially fatal E. coli O157:H7 by promoting host defence mechanisms in epithelial cells.

The human gut is colonized with a wide variety of microorganisms, including species, such as those belonging to the bacterial genus Bifidobacterium, that have beneficial effects on human physiology and pathology. Among the most distinctive benefits of bifidobacteria are modulation of host defence responses and protection against infectious diseases. Nevertheless, the molecular mechanisms underlying these effects have barely been elucidated. To investigate these mechanisms, mice were associated with certain bifidobacterial strains and a simplified model of lethal infection with enterohaemorrhagic Escherichia coli O157:H7, together with an integrated ‘omics’ approach. The study showed that genes encoding an ATP-binding-cassette-type carbohydrate transporter present in certain bifidobacteria contribute to protecting mice against death induced by E. coli O157:H7. The authors found that this effect can be attributed, at least in part, to increased production of acetate, and that translocation of the E. coli O157:H7 Shiga toxin from the gut lumen to the blood was inhibited. The authors propose that acetate produced by protective bifidobacteria improves intestinal defence mediated by epithelial cells and thereby protects the host against lethal infection.

More and more evidence demonstrates that the microbiome , i.e. the whole collection (system) of microbes in your gut, is important for your health, including the manner in which you digest your food, fight infection, and even in the way you process the prescription drugs that you ingest as a tablet or capsule.

Tuesday, January 25, 2011

Genetic Sequencing Alone Is Not Predictive of Human Disease

A new study in Nature Genetics (Jan. 3, 2011) amplifies what I have pointed out in previous publications (Maguire et al, 2006), namely that genetic sequencing alone is not enough to understand human disease.
Dr. Erica Davis and Dr. Nicholas Katsanis, professors of Cell Biology at Duke University Medical Center have shown that functional tests are absolutely necessary to understand the biological relevance of the results of genetic sequencing studies of the disease called ciliopathy, which can cause patients to have many different abnormal traits. Nicholas Katsanis, Ph.D. is a world expert in ciliopathies such as Bardet-Biedl Syndrome, in which the primary cilium of cells is abnormal and leads to many problems. About one child in 1,000 live births will have a ciliopathy, an incidence that is similar to that of Down's syndrome.
The current paradigm for genetic testing is to sequence a number of patients and determine what sequence variants exists. The key finding of this study shows that such a genetic approach is important, but insufficient for proper diagnosis. For precision of the diagnosis, the diagnostician must have a robust way to test the functional relevance of mutations found in patients. Consider a person at risk of type two diabetes, schizophrenia, or atherosclerosis, analyzing their genome sequenced is not enough. A functional interpretation of the data, using another diagnostic, for example metabolomics (Maguire et al, 2006), is required to understand the disease state of a particular patient.
The authors show that mutations in TTC21B, which encodes the retrograde intraflagellar transport protein IFT139, cause both isolated nephronophthisis and syndromic Jeune asphyxiating thoracic dystrophy. Further, although resequencing of TTC21B in a large, clinically diverse ciliopathy cohort and matched controls showed a similar frequency of rare changes, in vivo and in vitro evaluations showed a significant enrichment of pathogenic alleles in cases (P < 0.003), suggesting that TTC21B contributes pathogenic alleles to ~5% of ciliopathy cases

Thus, this study demonstrates the need to know the extent to which gene variants in question are detrimental, i.e. how do the gene variants affect individual cells or organs and what is the result on human development or disease? Every patient has his or her own set of genetic variants, and most of these will not be found at sufficient frequency in the general population so that a diagnostician can make a clear medical statement about their case.
Although a few of the mutations could readily be shown to cause two main human disorders, a kidney disease and an asphyxiating thoracic condition, the significance of the majority of DNA variants could not be determined. Professor Davis then tested these genetic variants in a zebrafish model (this a very powerful vertebrate model used in medical research because of, amoung other reasons, an easily imaged, transparent embryo during development), in which many genes are similar to humans, and showed that TTC21B appears to contribute disease-related mutations to about 5 percent of human ciliopathy cases.

 Thus, by sequencing genes to identify genetic variation, followed by functional diagnostic studies, one can attain a much better idea of the architecture of complex, inherited disorders.

Sunday, January 23, 2011

Double Standard Of Republican House Members Seeking To Repeal Health Care Reform

Republican House members seeking repeal of the Affordable Care Actplan to take away many health care benefits and rights from America's families, but they intend to retain those same benefits and rights for themselves.

This double standard is the theme of a new analysis released by the consumer health organization Families USA.

The new report, H.R. 2: Guilty of a Double Standard,documents 14 health care benefits and rights that would be withdrawn from America's families but retained by the House members seeking health reform repeal, including the following:

- The proposed repeal eliminates new protections for America's families that prohibit insurance companies from denying health coverage to people with pre-existing conditions-but members of Congress would retain those protections for themselves.

- It eliminates new tax credit subsidies that make insurance premiums affordable for middle-class families, but members of Congress would retain the taxpayer subsidies that pay for almost three-fourths of their premiums.

- The Affordable Care Act eliminates the big gap in prescription drug coverage for Medicare enrollees known as the "doughnut hole." The repeal takes away that new Medicare benefit-while members of Congress would retain their own comprehensive drug coverage.

- The Affordable Care Act limits how much people have to spend out of pocket when they become sick, thereby protecting America's families from going into debt or facing bankruptcy. The repeal eliminates this protection, but members of Congress would retain the ability to select taxpayer-subsidized coverage that limits their own out-of-pocket costs.

- The repeal would eliminate new rights Americans have to contest claims denials by insurance companies, but members of Congress plan to retain a similar right for themselves.

- The repeal eliminates new rights Americans have that stop insurance companies from rescinding health coverage when they get sick or charging discriminatory premiums if they have health problems, rights that would be retained by members of Congress. 

Congress should represent the people, not use the people for their own good. Hyprocrosy and greed are running rampant in our government and in those corporations buying congressional votes. We need a constitutional amendment to stop corporate money from buying votes.


Saturday, January 22, 2011

Quantum Computing: New Entanglement Device Helps Pave The Path

Because humans have evolved to interact within the world at a macroscopic level and in time frames and velocity frames that are much slower than the speed of light, quantum mechanics is very much a counterintuitive means for describing our physical world; i.e. our everyday experiences are not at the level described by quantum mechanics and therefore one does not relate to quantum mechanics other than through mathematical reasoning. An important concept in quantum mechanics is that of Entanglement; that most counterintuitive quantum phenomenon by which particles share an unseen link that aligns their properties, such as spin. Recently two groups of researchers reported entangling a photon with a crystal-based device, potentially paving the way for solid-state memories that can store and then release entangled particles as needed.

A paper published online January 19 in Nature describes how the physicists at the Quantum Spin Dynamics Group at Oxford have developed the capability to churn out pairs of entangled particles, billions at a time. The advance may someday allow for the streamlined development of quantum processors with a large number of quantum bits working in parallel. The group 
created entangled states in phosphorus atoms embedded in a silicon crystal, entangling the spin of each atom's nucleus with the spin of one of its electrons. Spin is a quantum property analogous to the pointing of a tiny bar magnet, and an atomic nucleus or an electron can spin up or spin down.

Phosphorus-doped silicon holds promise for solid-state quantum computing and quantum information processing, because each phosphorus atom has a relatively free electron that is open to manipulation, and because information can be encoded on both the spin of that electron and on the spin of the nucleus itself. And quantum devices based on silicon offer a relatively clear path to integration with existing, classical electronics all of which are based on silicon or silicon hybrids. Previous to this study, no one had demonstrated the ability to mass-produce entanglement in such silicon crystals, which is necessary for many implementations of solid-state quantum information processing.

Ultimately, ensembles of entangled particle pairs could find use as quantum bits, or qubits, in quantum computers. A qubit's capacity to be both 0 and 1 simultaneously, and to interact with its neighbors via entanglement, would give quantum computers a huge advantage over ordinary machines that rely on classical binary digital computations (bits) of 0 or 1.

HIV Therapeutics: A New Approach Using Chimaeric RNA Molecules

Dr. John Rossi, a molecular biologist at the Beckman Research Institute of the City of Hope in Duarte, California has reported developing an RNA molecule engineered to attack HIV in two different ways, that is showing positive results, according to a study in Science Translational Medicine. The researchers report that the molecule, which both curbs viral replication inside infected cells and neutralizes free-floating virus, may help patients who have developed resistance to HIV drugs.

The molecule is known as a chimaera, and is composed of two different types of RNA: 1) a small interfering RNA (siRNA), designed to enter infected cells and block the expression of two genes that HIV needs to replicate, and 2) an RNA sequence known as an aptamer, which binds tightly to gp120, a protein found on the surface of HIV and HIV-infected cells. The aptamer plays two parts: 1) ferrying the siRNA into infected cells, and 2) neutralizing free-floating virus in the blood.

The chimaera is not new, but this is the first time it has been tested in animals. To test the chimaera, the team used mice genetically engineered to be susceptible to HIV. When the researchers injected mice with either the chimaera or the aptamer alone, the amount of virus circulating in the animals blood fell markedly. The chimaera, however, was much more potent and suppressed the virus for a week longer than just the aptamer.
Professor Rossi says that the molecule could be used as a stand-alone therapy, or in combination with other drugs that treat HIV. Because the antiviral effect of the chimaera lasts only about a week, patients would need to have regular injections.

Many more studies are required to determine whether this approach will have value as a drug candidate to be developed for human HIV.

Wednesday, January 12, 2011

Myelin Damage Reversed Using Stem Cells: Hope For Multiple Sclerosis

Scientists at Cambridge and Edinburgh Universities have found that Stem cells in the brain regenerate myelin sheath. Myelin is a fatty sheath that surrounds the nerve fibers and functions to protect the fibers, and to help conduct electrical signals that flow from the brain to other parts of the nervous system. Patients with multiple sclerosis (MS) have multiple areas where the myelin has disappeared, leaving scar tissue instead (sclerosis).

Professor Robin J M Franklin, lead author,and team, found a biological "switch" that helps stem cells in the brain regenerate myelin in laboratory rats. The study was published in Nature Neuroscience.

Although it will be several years before any treatment for humans is developed and approved, these data and the technological development may help in the development of new medications that target the pathway identified here to halt and perhaps even reverse MS.

In this study the scientists looked at how the MS patient's own stem cells repair myelin. They identified RXR-gamma, a specific type of molecule, that seems to play a key role in myelin repair. By targeting RXR-gamma in laboratory rats with MS, their brains' own stem cells were encouraged to regenerate myelin.

A drug already exists in cancer treatment that targets RXR-gamma. The scientists are trying to find out how this might be used as a treatment for MS patients. The group intends to work towards the next step of setting up clinical trials to find out how safe and effective a treatment might be for humans with MS.

The results from this study indicate that the stem cell related protein, RXR-γ is a positive regulator of endogenous oligodendrocyte precursor cell differentiation and remyelination and might be a pharmacological target for regenerative therapy in the CNS.

Saturday, January 8, 2011

Potential For Improved Bone Marrow Transplants Following Stem Cell Discovery

Scientists at the University of California, Santa Cruz, report in the January issue of Cell Stem Cell identifying a key molecule for establishing hematopoietic stem cells (HSCs) in their niche within the bone marrow (BM). These data may lead to improvements in the safety and efficiency of bone marrow transplants. Bone marrow transplants are a type of stem cell therapy used to treat cancers such as lymphoma and leukemia and other blood-related diseases. In a bone marrow transplant, the "active therapeutics" are hematopoietic stem cells that live in the bone marrow and give rise to all the different kinds of mature blood cells. The new study shows that hematopoietic stem cells use a molecule called Robo4 to anchor themselves in the bone marrow.

Dr. Camilla Forsberg, professor at the Institute for the Biology of Stem Cells, UCSC, and her team demonstrated that the guidance molecule Robo4 functions to specifically anchor HSCs to BM niches. Robo4-deficient HSCs displayed poor localization to BM niches and drastically reduced long-term reconstitution capability while retaining multilineage potential. Cxcr4, a critical regulator of HSC location, is upregulated in Robo4−/− HSCs to compensate for Robo4 loss. Robo4 deletion led to altered HSC mobilization efficiency, revealing that inhibition of both Cxcr4- and Robo4-mediated niche interactions are necessary for efficient HSC mobilization. They also found that WT HSCs express very low levels of Cxcr4 and respond poorly to Cxcr4 manipulation relative to other hematopoietic cells. Therefore, Robo4 cooperates with Cxcr4 to endow HSCs with competitive access to limited stem cell niches, and Robo4 may be an important therapeutic target in HSC transplantation therapy

In summary, a newly discovered molecule, called Robo4, has been found in hematopoietic stem cell (HSC)-niche interactions that is involved in HSC engraftment and mobilization and does so in cooperation with Cxcr4 to guide stem cells to and secure them in the niche. Development of new therapeutics to enhance bone marrow transplants may use Robo4 as a target opportunity.

Full-size image

Friday, January 7, 2011

Obese America: Nine States Now Over 30 Per Cent Obese, Triple Numbers In One Year

American society has become "obesogenic" according to the US Centers for Disease Control and Prevention (CDC). Their latest report shows that nine states now report more than 30 per cent of adults are obese, yet it was only ten years ago that no state had a 30 per cent or more rate of obesity in its adult population.

Nine states now surpass the 30 per cent obesity rate: Alabama, Arkansas, Kentucky, Louisiana, Mississippi, Missouri, Oklahoma, Tennessee, and West Virginia. The CDC describes American society as "obesogenic", where people live in environments that promote over-eating, unhealthy food, and physical inactivity. 

The latest evidence in support of this conclusion: in just one year, since 2009, the number of states with an obesity prevalence of 30 per cent or more has tripled to nine. Further, not one state has met the Healthy People 2010 national goal of 15 per cent adult obesity prevalence, and only two, the state of Colorado and the District of Columbia report an obesity prevalence under 20 per cent (18. and 19.7 per cent respectively).

If we don't address this with intensive and comprehensive efforts, we will see more and more people becoming ill and dying from obesity-related causes such as heart disease, stroke, type 2 diabetes, and certain types of cancer, some of the leading causes of death, and a serious drag on our health care system and economy.

Wednesday, January 5, 2011

Stem Cells But Not Progenitor Cells Active In Male Pattern Baldness

A new study shows that androgenetic alopecia (AGA), also known as common male baldness, is characterized by a marked decrease in hair follicle size that is related to the loss of hair follicle progenitor cells. Dr. George Cotsarelis and his team at the Department of Dermatology at the University of Pennsylvania School of Medicine, report in the Journal of Clinical Investigation, that they analyzed bald and non-bald scalp from AGA individuals for the presence of hair follicle stem and progenitor cells. Cells expressing cytokeratin15 (KRT15), CD200, CD34, and integrin, α6 (ITGA6) were quantified using flow cytometry. High levels of KRT15 expression correlated with stem cell properties of small cell size and quiescence. These KRT15hi stem cells were maintained in bald scalp samples. However, CD200hiITGA6hi and CD34hi cell populations were shown to possess a progenitor phenotype given that they localized closely to the stem cell–rich bulge area but were larger and more proliferative than the KRT15hi stem cells and were markedly diminished. In functional assays, analogous CD200hiItga6hi cells from murine hair follicles were multipotent and generated new hair follicles in skin reconstitution assays.

These findings suggest that a defect in conversion of hair follicle stem cells to progenitor cells plays a role in the pathogenesis of AGA, and further suggests that this condition may be reversible by means that activate the stem cells to produce the required set of progenitor cells for hair growth.

Tuesday, January 4, 2011

Farm Raised Tilapia May Be A Killer

Farm-raised tilapia, one of the most highly consumed fish in America, has very low levels of beneficial omega-3 fatty acids and, perhaps worse, very high levels of omega-6 fatty acids. The combination could be a potentially dangerous food source for some patients with heart disease, arthritis, dry eye, glaucoma, asthma and other allergic and auto-immune diseases that are particularly vulnerable to an “exaggerated inflammatory response.” Inflammation is known to cause damage to blood vessels, the heart, lung and joint tissues, eye, skin, and the digestive tract.

In the United States, tilapia has shown the biggest gains in popularity among seafood, and this trend is expected to continue as consumption is projected to increase 67% from 1.5 million tons in 2003 to 2.5 million tons by 2010. Farm-raised tilapia, as well as farmed catfish, have several fatty acid characteristics that are considered by the scientific community as detrimental. Tilapia has higher levels of potentially detrimental long-chain omega-6 fatty acids than 80-percent-lean hamburger, doughnuts, and pork bacon. For individuals who are eating fish as a method to control inflammatory diseases such as heart disease, it is clear from these numbers that tilapia is a bad choice. Aside from other nutritional considerations, the inflammatory potential of hamburger and pork bacon is lower than the average serving of farm raised tilapia.
Omega-3 fatty acids, known scientifically as “long-chain n-3 polyunsaturated fatty acids” (PUFAs), have been well studied. Considering these studies, the American Heart Association now recommends that everyone eat at least two servings of fish per week, and that heart patients consume at least 1 gram a day of the two most critical omega-3 fatty acids, known as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid).  However the recommendation by the medical community for people to eat more fish has resulted in consumption of increasing quantities of fish such as tilapia that may do more harm than good, because farm-raised tilapia contains high levels of omega-6 fatty acids, also called n-6 PUFAs, such as arachidonic acid.
The ratio of arachidonic acid (AA) to very long-chain n-3 PUFAs (EPA and DHA) in diets of human beings appears to be an important factor that dictates the anti-inflammatory effects of fish oils. One recent study predicts “that changes in arachidonic acid to EPA or DHA ratios shift the balance from pro-inflammatory agents to protective chemical mediators … which are proposed to play a pivotal role in resolving inflammatory response.
The researchers found that farmed tilapia contained small amounts of omega-3 fatty acids, less than half a gram per 100 grams of fish, similar to that found in flounder and swordfish. Farmed salmon and trout, by contrast, had nearly 3 and 4 grams, respectively. And wild fish will contain even more. However, the tilapia had much higher amounts of omega-6 acids generally and AA specifically than both salmon and trout.  Ratios of omega-6 to omega-3 in tilapia averaged about 11:1, compared to much less than 1:1 (indicating more EPA than AA) in both salmon and trout. Decades of studies show that arachidonic acid is the substrate for all pro-inflammatory lipid mediators, and animal studies demonstrate unequivocally that if you feed arachidonic acid to animals, they quickly show signs of inflammation and become sick. Further, a New England Journal of Medicine article several years ago reported if you had heart disease combined with certain genomic characteristics, and you ingested arachidonic acid, the diameter of your coronary artery was smaller, which is a major risk factor for a heart attack.
Tilapia is easily farmed using inexpensive corn-based feeds, which contain short chain omega-6s that the fish very efficiently convert to AA and place in their tissues. This ability to feed the fish inexpensive foods, together with their capacity to grow under almost any condition, keeps the market price for the fish so low that it is rapidly becoming a staple in low-income diets. Moreover, tilapia sourced from some places, including China, is often contaminated with other chemicals and heavy metals.
If your cardiologists recommends eating fish, your best choices are fish such as wild salmon and tuna, and your poorest choice is farm raised tilapia.