Emergency response system for blood formation recently identified within body

Rendering of red blood cells.

Credit: © yodiyim / Fotolia

Scientists at the Children's eye analysis Institute at UT Southwestern (CRI) have determined however the body responds throughout times of emergency once it wants additional blood cells. in an exceedingly study revealed in Nature, researchers report that once tissue harm happens, in times of excessive harm, or throughout physiological state, a secondary, emergency blood-formation system is activated within the spleen.

"Blood-forming,or Hematopoietic, stem cells reside mainly in the bone marrow, and most new blood cell formation occurs within the bone marrow under normal circumstances. But when there is hematopoietic stress, blood cell formation expands to the spleen," said Dr. Sean Morrison, CRI Director and Mary McDermott Cook Chair in Pediatric Genetics at UT Southwestern Medical Center. "Blood-forming stem cells migrate from the bone marrow to the spleen, which becomes a hematopoietic organ where blood formation then occurs."

Normally, there are very few blood-forming stem cells in the spleen. But the cells that create the supporting environment for these stem cells are present in the spleen, ready to respond during times of hematopoietic stress and to receive an influx of blood-forming stem cells from the bone marrow.

In characterizing the micro-environment, or niche, which supports blood formation in the spleen, the CRI research team used mouse models to examine the expression patterns of two known niche cell factors, stem cell factor (SCF) and CXCL12. The researchers found that the blood-forming microenvironment in the spleen is found near sinusoidal blood vessels and is created by endothelial cells and perivascular stromal cells -- just like the micro-environment in the bone marrow.

"Under emergency conditions, the endothelial cells and perivascular stromal cells that reside in the spleen are induced to proliferate, so they can sustain all the new blood-forming stem cells that migrate into the spleen," said Dr. Morrison, who is also a CPRIT Scholar in Cancer Research and a Howard Hughes Medical Institute Investigator. "We determined that this process in the spleen is physiologically important for responding to hematopoietic stress without it, the mice we studied could not maintain normal blood cell counts during pregnancy or quickly regenerate blood cell counts after bleeding or chemotherapy."

Based on this new information about the spleen's emergency backup role for blood cell formation, therapeutic interventions could be developed in the future to enhance blood formation following chemotherapy or bone marrow transplantation and thus accelerate the recovery of blood cell counts.

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The above post is reprinted from materials provided by UT Southwestern Medical Center. Note: Materials may be edited for content and length.

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Blood sugar levels in response to foods are highly individual

Amazingly different responses to Same foods. In a Research based Study, 445 participant  (top), blood sugar levels rose sharply after eating bananas but not after cookies of the same amount of calories. The opposite occurred in participant 644 (bottom).

Credit: Weizmann Institute of Science

Which is more likely to raise blood sugar levels: sushi or ice cream? According to a Weizmann Institute of Science study reported in the November 19 issue of the journal Cell, the answer varies from one person to another. The study, which continuously monitored blood sugar levels in 800 people for a week, revealed that the bodily response to all foods was highly individual.

The study, called the Personalized Nutrition Project, was conducted by the groups of Prof. Eran Segal of the Department of Computer Science and Applied Mathematics and Dr. Eran Elinav of the Department of Immunology. Prof. Segal said: "We chose to focus on blood sugar because elevated levels are a major risk factor for diabetes, obesity, and metabolic syndrome. The huge differences that we found in the rise of blood sugar levels among different people who consumed identical meals highlights why personalized eating choices are more likely to help people stay healthy than universal dietary advice."

Indeed, the scientists found that different people responded very differently to both simple and complex meals. For example, a large number of the participants' blood sugar levels rose sharply after they consumed a standardized glucose meal, but in many others, blood glucose levels rose sharply after they ate white bread, but not after glucose. "Our aim in this study was to find factors that underlie personalized blood glucose responses to food," said Dr. Elinav. "We used that information to develop personal dietary recommendations that can help prevent and treat obesity and diabetes, which are among the most severe epidemics in human history."

David Zeevi and Tal Korem, PhD students in Prof. Segal's lab, led the study. They collaborated with Dr. Niv Zmora, a physician conducting PhD studies in Dr. Elinav's lab, and with PhD student Daphna Rothschild and research associate Dr. Adina Weinberger from Prof. Segal's lab. The study was unique in its scale and in the inclusion of the analysis of gut microbes, collectively known as the microbiome, which had recently been shown to play an important role in human health and disease. Study participants were outfitted with small monitors that continuously measured their blood sugar levels and were asked to record everything they ate, as well as such lifestyle factors as sleep and physical activity. Overall, the researchers assessed the responses of different people to more than 46,000 meals.

Taking these multiple factors into account, the scientists generated an algorithm for predicting individualized response to food based on the person's lifestyle, medical background, and the composition and function of his or her microbiome. In a follow-up study of another 100 volunteers, the algorithm successfully predicted the rise in blood sugar in response to different foods, demonstrating that it could be applied to new participants. The scientists were able to show that lifestyle also mattered: The same food affected blood sugar levels differently in the same person, depending, for example, on whether its consumption had been preceded by exercise or sleep.

In the final stage of the study, the scientists designed a dietary intervention based on their algorithm; this was a test of their ability to prescribe personal dietary recommendations for lowering blood-glucose-level responses to food. Volunteers were assigned a personalized "good" diet for one week, and a "bad" diet -- also personalized -- for another. Both good and bad diets were designed to have the same number of calories, but the diets differed between participants. Thus, certain foods in one person's "good" diet were part of another's "bad" diet. The "good" diets indeed helped to keep blood sugar at steadily healthy levels, whereas the "bad" diets often induced spikes in glucose levels -- all within just one week of intervention. Moreover, as a result of the "good" diets, the volunteers experienced consistent changes in the composition of their gut microbes, suggesting that the microbiome may be influenced by the personalized diets while also playing a role in participants' blood sugar responses.

A video animation describing the study: www.youtube.com/watch?v=Ryc5M3Ciytg&feature=youtu.be

The scientists are currently enrolling Israeli volunteers for a longer-term follow-up dietary intervention study that will focus on people with consistently high blood sugar levels -- and thus are at risk of developing diabetes -- with the aim of preventing or delaying this disease.

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The above post is reprinted from materials provided by Weizmann Institute of Science. Note: Materials may be edited for content and length.

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Just one energy drink may boost heart disease risk in young adults

Drinking one 16-ounce energy drink boosts blood pressure and stress hormone responses in young, healthy adults, according to a study presented at the American Heart Association's Scientific Sessions 2015. These changes could conceivably trigger new cardiovascular events.

Researchers studied 25 healthy young adults with no known cardiovascular risk factors. Each drank one 16-ounce can of a commercially available energy drink or a sham drink in random order on two separate days. Researchers measured participants' blood pressure and blood levels of norepinephrine before and 30 minutes after drink consumption. Norepinephrine is a "fight or flight" chemical that increases blood pressure and the heart's ability to contract and it modulates heart rate and breathing in response to perceived stress.

Researchers found that in addition to increases in blood pressure after consuming the energy drink, participants' norepinephrine levels increased more than twice as much when compared to those who drank the sham drink. Specifically, norepinephrine levels increased by almost 74 percent after the energy drink consumption, versus by 30 percent after the sham drink.

Researchers said their findings suggest increases in blood pressure and stress hormones could predispose otherwise healthy, young adults to increased cardiovascular risk.

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Source: Science Daily

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The above post is reprinted from materials provided by American Heart Association. Note: Materials may be edited for content and length.

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