Intestinal Bacteria: A Delicate Balance

by Brian Thomas, M.S. *

Certain intestinal bacteria can spur an imbalance in immune system cells, leading to an inflammation of the digestive tract, according to a new study out of New York University.

“Inflammatory bowel disease (IBD)…is one of the most prevalent gastrointestinal diseases in the United States”¹ and involves redness, swelling, and pain in the affected area. Mammalian intestinal lining contains cells that specialize in either promoting or calming inflammation. More inflammation-promoting T-helper 17 cells (Th17) are produced when the body needs protection, and the pacifying T cells (Treg cells) dominate when it does not.

In a healthy immune system, the Th17 and Treg cells balance each other. When too many Th17 are produced, IBD can result. Researchers at NYU Langone Medical Center, whose work appeared in the journal Cell Host & Microbe, tested mice and discovered that certain kinds of bacteria regulated the Th17:Treg balance.²

The exact bacterial species responsible for instigating Th17, and therefore inflammation, in the mouse digestive systems has not been identified, but it belongs to the broad “cytophaga-flavobacter-bacteroidetes” group, which includes bacteria that help digestion and immunity function properly. Targeting the precise species promises to be difficult, but it is the necessary next step in finding new treatments for IBD and other gastrointestinal diseases.

The digestive processes that convert food into fuel involve intricate interactions between the body’s organs and their resident bacteria. The fact that imbalances occur is an indication that such systems must be well-tuned in order to function properly. Skeptics often argue that imperfections in nature mean that God cannot exist. The presence of unbalanced systems, however, is entirely consistent with Scripture, which describes “this present evil world”³ as fallen and in need of restoration.

The created world we live in still retains so much of its former “perfection” that, even with its imbalances, it must have been emplaced by a wise Creator. After all, imbalance implies balance, and balance implies design. “Or speak to the earth, and it shall teach thee: and the fishes of the sea shall declare unto thee. Who knoweth not in all these that the hand of the Lord hath wrought this?”⁴

References

1. Bugs in the Gut Trigger Production of Important Immune Cells, NYU Study Finds. NYU Langone Medical Center press release, October 15, 2008.
2. Ivaylo, I. I. et al. 2008. Specific Microbiota Direct the Differentiation of IL-17-Producing T-Helper Cells in the Mucosa of the Small Intestine. Cell Host & Microbe. 4 (4): 337-349.
3. Galatians 1:4.
4. Job 12:8-9.

* Mr. Thomas is Science Writer.

Article posted on October 24, 2008.