Even the best hospital intensive care units may be helpless to save patients stricken by severe sepsis. According to a 2003 study by Emory University and the Centers for Disease Control and Prevention, sepsis killed 120,491 hospitalized people in 2000. The same study found cases of sepsis in the U.S. have risen dramatically in recent decades, nearly tripling from 82.7 cases out of every 100,000 Americans in 1979 to 240.4 cases per 100,000 in 2000. Muppets creator Jim Henson died of the disease in 1990 at age 53.
Epidemiologists blame this large increase on the explosive rise in antibiotic-resistant bacteria caused by overuse of antibiotics as well as on the increasing numbers of people living with immune systems weakened by HIV, using immune-suppressive therapy for organ and bone marrow transplants, and receiving high-dose chemotherapy for cancer. Young children and elderly people are also at a higher risk for the condition because of their weaker immune systems.
Now, Assistant Professor Kota V. Ramana and Professor Satish Srivastava of the University of Texas Medical Branch at Galveston (UTMB) and their collaborators have discovered that in laboratory mice, blocking the activity of a single enzyme known as aldose reductase can short-circuit sepsis, protecting heart function and greatly reducing sepsis deaths. Moreover, the scientists have accomplished this feat using a chemical compound very similar to a diabetes drug already in stage three clinical trials in the United States, the final level of human experimentation before a drug is considered for federal licensing approval.
If those diabetes trials prove successful and the drug is approved for use in diabetics, it's possible that such an "aldose reductase inhibitor" could be used by physicians relatively quickly for "off-label" emergency use against sepsis in humans, the scientists said. When a drug is approved for one human use, individual doctors may try it out against other conditions where it appears warranted.
Srivastastava, senior author of a paper on the sepsis discovery to be published online Oct. 9 in the journal Circulation, explained that in this disease, "You can treat an infection and kill off all the bacteria, but there are still two things causing damage -- the inflammatory proteins released by the body's natural defenses, and the outer membranes of the dead bacteria, mainly composed of large toxic molecules called lipopolysaccharides, which go on inducing more inflammatory immune response even though the bacteria themselves are dead."
"This inflammatory response causes significant problems with cardiac contractility," Srivastava added, "and so instead of pumping blood properly, the heart just flutters, a condition leading to cardiomyopathy."
The drastic drop in the heart's ability to pump blood is dangerous in itself, the researcher continued, and it can also have disastrous effects on the lungs and kidneys, which depend on efficient blood circulation.
Srivastava, lead author Ramana and their collaborators injected mice with lipopolysaccharide (LPS) to produce the conditions of severe sepsis, leading to major declines in heart function and substantial increases in heart-damaging inflammatory signaling molecules. But when they treated the mice with an aldose reductase inhibitor, they found that blocking the enzyme's activity restored the heart's ability to pump blood normally and allowed mice injected with otherwise lethal levels of LPS to survive.
Other experiments conducted in cell cultures traced the specific biochemical pathways by which LPS triggers an inflammatory cycle that damages the cells of the heart. By blocking aldose reductase activity with pharmacological inhibitors or using small interfering RNAs (pieces of genetic material that specifically stop the production of particular cellular proteins) to prevent the cells from producing the enzyme in the first place, the researchers demonstrated that aldose reductase is essential to that cycle.
Previous work by Srivastava and his UTMB collaborators (including research described in a paper published Oct. 1 in Cancer Research) has demonstrated that blocking aldose reductase similarly can dramatically reduce the inflammation-driven processes of colorectal cancer and complications of diabetes.
"There are so many inflammatory signaling processes that depend on this enzyme, and so it made sense to look into with regard to sepsis, which we knew was a runaway inflammatory process," Srivastava said. "We're hoping that when an aldose reductase inhibitor is approved as a drug in the U.S. -- one is already in use in Japan for diabetes, by the way -- we can interest clinicians in studying its use against sepsis."
Jim Kelly | EurekAlert!
Oxygen can wake up dormant bacteria for antibiotic attacks
08.12.2016 | Penn State
NTU scientists build new ultrasound device using 3-D printing technology
07.12.2016 | Nanyang Technological University
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
08.12.2016 | Life Sciences
08.12.2016 | Physics and Astronomy
08.12.2016 | Materials Sciences