Featured Research

from universities, journals, and other organizations

Immune cells may heal an injured heart

Date:
January 16, 2014
Source:
Washington University in St. Louis
Summary:
The immune system plays an important role in the heart’s response to injury. Now, researchers have shown that two major pools of immune cells are at work in the heart. Both belong to a class of cells known as macrophages. One appears to promote healing, while the other likely drives inflammation, which is detrimental to long-term heart function.

Studying mice, new research suggests that embryonic macrophages in the heart promote healing after injury.
Credit: Slava Epelman, MD, PhD

The immune system plays an important role in the heart's response to injury. But until recently, confusing data made it difficult to distinguish the immune factors that encourage the heart to heal following a heart attack, for example, from those that lead to further damage.

Now, researchers at Washington University School of Medicine in St. Louis have shown that two major pools of immune cells are at work in the heart. Both belong to a class of cells known as macrophages. One appears to promote healing, while the other likely drives inflammation, which is detrimental to long-term heart function.

The study, in mice, is published Jan. 16 in the journal Immunity.

"Macrophages have long been thought of as a single type of cell," said first author Slava Epelman, MD, PhD, instructor in medicine. "Our study shows there actually are many different types of macrophages that originate in different places in the body. Some are protective and can help blood vessels grow and regenerate tissue. Others are inflammatory and can contribute to damage."

Macrophages play multiple roles in the body, from digesting dead cells to activating other immune cells against foreign invaders. It was long assumed that all macrophages originate in the bone marrow and circulate in the bloodstream, populating different tissues and responding to threats as necessary.

"Now we know it's more complicated," Epelman said. "We found that the heart is one of the few organs with a pool of macrophages formed in the embryo and maintained into adulthood. The heart, brain and liver are the only organs that contain large numbers of macrophages that originated in the yolk sac, in very early stages of development, and we think these macrophages tend to be protective."

Studying mice, Epelman and his colleagues showed that healthy hearts maintain this population of embryonic macrophages, as well as a smaller pool of adult macrophages derived from the blood. But during cardiac stress such as high blood pressure, not only were more adult macrophages recruited from the blood and brought to the heart, they actually replaced the embryonic macrophages.

"Now that we can tell the difference between these two types of macrophages, we can try targeting one but not the other," Epelman said. "We want to try blocking the adult macrophages from the blood, which appear to be more inflammatory. And we want to encourage the embryonic macrophages that are already in the heart to proliferate in response to stress because they do things that are beneficial, helping the heart regenerate."

Epelman points out a developmental reason that embryonic macrophages might encourage healing.

"Since they originate in the embryo, it makes sense that these macrophages appear to do things that are good for the developing embryo -- helping growth, blood vessel formation, organization and structure, and eating up dead and dying cells," Epelman said.

It follows then that adult macrophages originating in the bone marrow and circulating in the blood might be better equipped to respond to infection, and therefore specialize in triggering an inflammatory response.

The complex interplay between these immune cells in the heart may provide an explanation for why some people experience healing following a heart attack but others don't. Patients with diabetes, for example, don't heal well following injury to the heart.

"We know there's a link between diabetes and poor recovery of heart function," Epelman said. "And a link between diabetes and altered function of macrophages. We knew these links existed, we just haven't been able to put it all together. We want to know what happens to macrophages in times of cardiac stress, how this changes the balance between the cell types and whether we can influence that balance."

While this research is still in the early stages, the current study is a starting point for finding ways to improve treatment for chronic heart problems.

"Long-established heart failure doesn't recover," Epelman said. "But in the first few months after injury, there's a real potential to impact the heart's recovery."


Story Source:

The above story is based on materials provided by Washington University in St. Louis. The original article was written by Julia Evangelou Strait. Note: Materials may be edited for content and length.


Journal Reference:

  1. Epelman S, Lavine KJ, Beaudin AE, Sojka DK, Carrero JA, Calderon B, Brija T, Gautier EL, Ivanov S, Satpathy AT, Schilling JD, Schwendener R, Sergin I, Razani B, Forsberg EC, Yokoyama W, Unanue ER, Colonna M, Randolph GJ, Mann DL. Embryonic and adult-derived resident cardiac macrophages are maintained through distinct mechanisms at steady state and during inflammation. Immunity, January 2014

Cite This Page:

Washington University in St. Louis. "Immune cells may heal an injured heart." ScienceDaily. ScienceDaily, 16 January 2014. <www.sciencedaily.com/releases/2014/01/140116130445.htm>.
Washington University in St. Louis. (2014, January 16). Immune cells may heal an injured heart. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2014/01/140116130445.htm
Washington University in St. Louis. "Immune cells may heal an injured heart." ScienceDaily. www.sciencedaily.com/releases/2014/01/140116130445.htm (accessed July 31, 2014).

Share This




More Health & Medicine News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
At Least 20 Chikungunya Cases in New Jersey

At Least 20 Chikungunya Cases in New Jersey

AP (July 30, 2014) At least 20 New Jersey residents have tested positive for chikungunya, a mosquito-borne virus that has spread through the Caribbean. (July 30) Video provided by AP
Powered by NewsLook.com
Xtreme Eating: Your Daily Caloric Intake All On One Plate

Xtreme Eating: Your Daily Caloric Intake All On One Plate

Newsy (July 30, 2014) The Center for Science in the Public Interest released its 2014 list of single meals with whopping calorie counts. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



      Save/Print:
      Share:

      Free Subscriptions


      Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

      Get Social & Mobile


      Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

      Have Feedback?


      Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
      Mobile: iPhone Android Web
      Follow: Facebook Twitter Google+
      Subscribe: RSS Feeds Email Newsletters
      Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins