Inflammation. The word typically has a negative connotation. Arthritis … infection … numerous maladies come to mind.
But a Kansas State University researcher found that inflammation that
occurs naturally in dairy cows the first few days after giving birth
may play a surprisingly beneficial role in the complex process of going
from late pregnancy to lactation.
"We know that during the first several days after giving birth and
going into the lactating phase, dairy cows naturally experience some
degree of inflammation," said Barry Bradford, associate professor in the
university's department of animal sciences and industry. "We also know
that many disorders, including metabolic diseases such as ketosis and
fatty liver, occur during this time of transition."
He, along with a team of researchers from Kansas State University,
Iowa State University and Michigan State University, wondered if
inflammation actually causes the metabolic problems.
Thinking that reducing inflammation during this period might be
beneficial for the cow's transition from gestation to lactation, plus
limit metabolic disease, Bradford and the team conducted a study. The
objective was to determine if using an anti-inflammatory drug (sodium
salicylate or SS) for the first seven days of lactation would prevent
liver fat accumulation, improve the supply of glucose for lactation, and
limit metabolic disease in dairy cows entering lactation. SS was
delivered to the animals in a controlled way to their drinking water.
The team did not get the result they expected.
"Our findings suggest that mild inflammation may be a necessary part of a cow's adaptation to lactation," Bradford said.
Among the significant findings, the research showed that rather than
preventing fatty liver by blocking the inflammation, liver fat content
was actually increased in the first week of lactation. Similarly,
anti-inflammatory treatment led to a dramatic drop in plasma glucose
concentration in mature cows. Both of these responses are often
associated with metabolic disease in early lactation cows.
"The study improved our understanding of the re-prioritization
process by suggesting that inflammatory pathways promote a temporary
state of insulin resistance in dairy cows, resulting in conservation of
glucose for use by the mammary gland," Bradford said.
The results of the study, which was funded by the U.S. Department of
Agriculture's National Institute of Food and Agriculture, indicate that
inflammation-induced insulin resistance is in some cases an adaptive,
rather than pathological, phenomenon. It may help clarify why the links
between inflammation and metabolism have survived the evolution process,
he said.
And it's not just cattle that experience the shift in demands on the
body: "Many species experience these dramatic shifts," Bradford said.
"The role of inflammation in this process has not been studied very
much. We are missing some information about why our bodies are wired the
way they are -- even after evolutionary refinement of the immune
system, there seems to be a role for inflammation in metabolic
function."
The research team's findings have been published by the American Journal of Physiology.
"Our findings suggest that we want some degree of inflammation at
this time because it helps the animal shift gears," Bradford said.
"Rather than thinking of mild inflammation as a disease-inducing factor,
we think there may be times during life where some inflammation is
advantageous or necessary."
The research team plans to delve into the topic further and is
seeking funding to find evidence of the phenomenon in other species.
