The Global Fool

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Environmental Toxins and Damage to the Immune System: Transgenerational Effects
Dec05

Environmental Toxins and Damage to the Immune System: Transgenerational Effects

By Roberta Attanasio The hypothesis of the Developmental Origins of Health and Disease (DOHaD), also called “Barker’s hypothesis”, was formulated a few decades ago and stimulated interest in the fetal origins of adult disorders. Subsequent research by Mohan Manikkam and Michael Skinner helped establish the principle of transgenerational toxicity by showing that the effects of toxic chemicals can extend even to the third generation of offspring. Photo by Liv Bruce on Unsplash Indeed, it is now clear that early life development is a critical and unique window of vulnerability during which environmental exposures influence cellular programming in ways that shape health and disease later in life. While most research on the transgenerational effects of environmental chemicals focuses on the reproductive, nervous, or endocrine systems, results from a recently published study show that environmental toxins may also impair the immune system. Paige Lawrence, senior author of the study, said in a press release: “The old adage ‘you are what you eat’ is a touchstone for many aspects of human health. But in terms of the body’s ability to fights off infections, this study suggests that, to a certain extent, you may also be what your great-grandmother ate.” To carry out the study, researchers exposed pregnant mice to dioxin, a common by-product of industrial production and waste incineration which is also found in some consumer products. Thus, dioxins are environmental pollutants. They belong to the so-called “dirty dozen”—a group of dangerous chemicals known as persistent organic pollutants (POPs). Dioxins are of concern because of their highly toxic potential. In the environment, dioxins tend to accumulate in the food chain. The higher an animal is in the food chain, the higher the concentration of dioxins. Therefore, dioxins are found in greater concentrations in animal-based food products. Once dioxins enter the body, they last a long time because of their chemical stability and their ability to be absorbed by fat tissue, where they are then stored. Their half-life in the body is estimated to be 7 to 11 years.  After exposing pregnant mothers to dioxin, they assessed the production and function of cytotoxic T cells in the offspring. To do so, they infected the mice with influenza A virus, and found that exposure of the pregnant mothers to dioxin resulted in an impaired cytotoxic T cell response of the offspring against the influenza A virus. The impaired cytotoxic T cell response was observed not only in the offspring of the mice whose mothers where exposed to dioxin, but also in subsequent generations, up to the rodent equivalent of great-grandchildren.   Lawrence said: “When you are infected or receive a flu vaccine, the immune system ramps up production of...

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As coal mining declines, community mental health problems linger
Aug02

As coal mining declines, community mental health problems linger

By Roberta Attanasio The U.S. coal industry is in rapid decline, a shift marked not only by the bankruptcy of many mine operators in coal-rich Appalachia but also by a legacy of potential environmental and social disasters. As mines close, states, the federal government and taxpayers are left wondering about the costs of cleaning up the abandoned land, especially at mountaintop removal sites, the most destructive type of mining. As coal companies go bankrupt, this has left states concerned taxpayers may have to pick up the environmental cleanup costs. But there are also societal costs related to mountaintop removal mining’s impact on health and mental health. As an immunologist, I reviewed the research literature for specific effects of mountaintop removal mining on the immune system. I did not identify any pertinent information. However, I did find plenty of clues suggesting that health and mental health issues will pose enormous challenges to the affected coal communities, and will linger for decades. Environmental contaminants The communities that reside in proximity to the devastated lands where mountaintop removal mining occurs – some of the poorest in the nation – are concentrated in a 65-county area in southern West Virginia, eastern Kentucky, southwestern Virginia and northeastern Tennessee. They are also hit by the economic downturn caused by the decline of the local coal industry. Healthwise, Appalachian populations suffer disproportionately higher morbidity and mortality compared with the nation as a whole. A study that examined the elevated mortality rates in Appalachian coal mining areas for 1979-2005 linked coal mining to “socioeconomic disadvantages” and concluded that the human cost of the Appalachian coal mining economy outweighed its economic benefits. Results from research published in 2011 show that mountaintop mining areas, in particular, are associated with the lowest health-related quality of life even in comparison to counties with other forms of coal mining. So, what makes mountaintop removal mining such a scourge for human health? To remove the top of the mountains, coal companies use destructive processes. In order to extract the underlying coal seams, a peak’s forest and brush are clear-cut and the topsoil is scraped away. The resulting debris is often set on fire. Then, explosives are poured into huge holes to literally blast off up to 800 to 1,000 feet of mountaintops. Draglines – huge machines able to scoop up to 100 tons in a single load – push rock and dirt into nearby streams and valleys, damaging waterways and life associated with them. The result is not only a devastated landscape and the crushing of entire ecosystems, but also the dispersion in the environment of toxic pollutants. To learn more about the...

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Farmed Salmon Develop Ear Deformities All Around the World
May31

Farmed Salmon Develop Ear Deformities All Around the World

By Roberta Attanasio Salmon farming is the fastest growing food production system in the world—accounting for 70 percent (2.4 million metric tons) of the market. Increasing demand is leading to the gradual development of responsible practices to minimize its negative impacts on the environment. Indeed, salmon farming is known to pollute the oceans, use toxic pesticides to control the spread of sea lice, foster diseases caused by viruses and bacteria, allow escapees, and deplete the stocks of forage fish—depending on the production region, 1.5 – 8 kilograms of wild fish are needed to produce one kilogram of farmed salmon. However, despite the development of the open and transparent production practices encouraged by the WWF in 2004, and currently managed by the Aquaculture Stewardship Council (ASC), salmon farming is plagued by numerous problems. A deadly algal bloom is killing millions of farmed fish salmon in Chile, causing a drop of 35% to 45% in exports this year. In addition, the recent research finding that farmed Atlantic salmon from Norway, Australia, Scotland, Canada and Chile are going deaf is both surprising and alarming, raising questions about animal welfare and conservation efforts. Farmed salmon have deformed otoliths (or fish earbones) and, as a result, poorer hearing. Otoliths are located behind a fish’s brain and are essential for hearing and balance, much like the inner ears of humans and other mammals. The typical structure of healthy otoliths is made up of calcium carbonate. However, in most farmed Atlantic salmon, the calcium carbonate is present in the otoliths in a different crystal form, leading to larger, lighter and more brittle structures. This deformity is very uncommon in wild fish. The researchers point out that the deformed earbones could be responsible for the low efficiency of conservation programs, thus explaining the origins of what, in the field, is considered a long-standing mystery. Every year, billions of captive-bred juvenile salmon are released into rivers worldwide to boost wild populations, but their survival is 10-20 times lower than that of wild salmon. The new finding may help explain this low survival rate. Hearing loss could prevent fish from detecting predators, and restrict their ability to navigate back to their home stream to breed. Researchers do not know what the triggering factor for earbone deformity is—they speculate it could be something in the fish’s diet, or a genetic component unique to the salmon selected to be farmed, or it could be related to their abnormally rapid growth rate. Salmon farming is a work in progress. Knowledge and experience, along with commitment to sustainable practices, are necessary for successful production. The unexpected finding of hearing loss in farmed salmon...

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Pharmaceuticals in Drinking Water?
Apr25

Pharmaceuticals in Drinking Water?

By Roberta Attanasio The problem of contaminated tap water in the U.S. goes well beyond Flint—and also beyond lead. There are many more toxic chemicals in our drinking water that we like to believe. Communities in New York, New Hampshire and Vermont recently found elevated levels of PFOA, a suspected carcinogen, in their water supplies. PFOA, or perfluorooctanoic acid, is a synthetic perfluoroalkyl chemical used to manufacture nonstick pan coatings and water-resistant clothing. And, even more recent is the finding that water discharged from Burlington’s wastewater treatment plant into Lake Champlain—the source of drinking water for tens of thousands of people in the Burlington area—contains concentrations of pharmaceuticals high enough to reflect demographic shifts in the city. The presence of pharmaceuticals in drinking water from different U.S. areas has been know for more than a few years. A report publicly released in 2011 by the U.S. Government Accountability Office revealed that drinking water in some metropolitan areas contains pharmaceuticals, and raised concerns about their potential impact on human health. According to the World Health Organization “Pharmaceuticals are synthetic or natural chemicals that can be found in prescription medicines, over-the-counter therapeutic drugs and veterinary drugs. Pharmaceuticals contain active ingredients that have been designed to have pharmacological effects and confer significant benefits to society. Pharmaceuticals can be introduced into water sources through sewage, which carries the excreta of individuals and patients who have used these chemicals, from uncontrolled drug disposal (e.g. discarding drugs into toilets) and from agricultural runoff comprising livestock manure. They have become chemicals of emerging concern to the public because of their potential to reach drinking-water.” Emma Rosi-Marshall, a scientist at the Cary Institute of Ecosystem Studies and lead author of a study published in 2013 on the effects of pharmaceutical pollution on aquatic life and water quality, said in a press release: “Pharmaceutical pollution is now detected in waters throughout the world. Causes include aging infrastructure, sewage overflows, and agricultural runoff. Even when waste water makes it to sewage treatment facilities, they aren’t equipped to remove pharmaceuticals. As a result, our streams and rivers are exposed to a cocktail of synthetic compounds, from stimulants and antibiotics to analgesics and antihistamines.” Results from a study published this year in the journal Science of the Total Environment show that water samples from private wells on Cape Cod are contaminated not only by perfluoroalkyl chemicals and flame retardants, but also by a dozen different pharmaceuticals. The researchers found that sulfamethoxazole, an antibiotic used to treat urinary tract infections, and carbamazepine, a drug used to treat seizures, nerve pain, and bipolar disorder, were among the most common pharmaceuticals detected. The researchers also found that...

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Climate Change, Parasite Infections, and Immune Responses
Mar06

Climate Change, Parasite Infections, and Immune Responses

By Roberta Attanasio Global climate change noticeably impacts human health—safe drinking water, sufficient food, and secure shelter are threatened by rising sea levels and severe weather events. Heat waves dramatically increase death rates not only from heat strokes, but also from complications arising from cardiovascular, respiratory, and cerebrovascular diseases. Although global warming may bring some localized benefits, such as fewer winter deaths in temperate climates and increased food production in certain areas, the overall health effects of a changing climate are likely to be overwhelmingly negative. For example, climate warming is predicted to increase the transmission of parasite infections. Now, results from a recent study show that host immunity can influence the impact of warming on host–parasite interactions and mitigate its long-term effects. For the study (Host immunity shapes the impact of climate changes on the dynamics of parasite infections), researchers focused on soil-transmitted gastrointestinal helminths, also known as parasitic worms. In humans, these worms cause some of the most common parasitic infections worldwide. According to the World Health Organization (WHO), approximately 2 billion people are infected with soil-transmitted helminths globally, mostly in the poorest and most deprived communities. They are transmitted by eggs present in human feces, which in turn contaminate soil in areas where sanitation is poor. However, the researchers focused on two parasitic worms of rabbits, Trichostrongylus retortaeformis and Graphidum strigosum. In previous studies, the researchers found that, in rabbits, infections from one of the parasites are controlled by the immune response, whereas infections from the other parasite species are not controlled, even though the rabbits do mount an immune response to the parasite. Therefore, the researchers designed the new study to understand the contribution of climate change and immunity on the long-term and seasonal dynamics of infections caused by the two rabbit parasitic worms. They examined samples collected monthly between 1977 and 2002 in Scotland. The study results show that climate warming—rising temperature and humidity—increases the availability in pastures of the infective stages of both intestinal worms. The intensity of infection increases for the worm not regulated by immunity. In contrast, there is no significant long-term positive trend in the intensity for the immune-controlled worm. Specifically, G. strigosum infection is not controlled by the rabbit immune response. Therefore, the intensity of the parasite infection increases with warming, leading to significant accumulation of G. strigosum in rabbits, mostly in adult rabbits. Why? The rabbits aren’t able to clear the infection caused by G. strigosum with their immune response; therefore, the rabbits accumulate more and more parasites as they age—the result is that older individuals carry most of the infection in the population. However, because T. retortaeformis infection is...

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