Laminar chemokine mRNA concentrations in horses with carbohydrate overload-induced laminitis.

This study examined the role of chemokines, substances that trigger leukocyte activity, in horses suffering from laminitis induced by carbohydrate overload. It found that chemokine levels increase before peak leukocyte activity and this may be why lameness develops.

Research Purpose and Methodology

• The aim of this study was to investigate the pattern of laminar chemokine expression in horses suffering from carbohydrate overload (CHO)-induced laminitis. Laminitis is a painful and debilitating disease which commonly occurs in horses due to excess consumption of carbohydrates.
• For the experiment, laminar samples were taken from a control group of horses (CON) and from horses that were induced to laminitis (DEV and LAM groups).
• The samples were taken 24 hours after water was given to the CON group and at the onset of fever and lameness in the DEV and LAM groups.
• These samples were then subjected to a Real time quantitative PCR, a method used for measuring specific genetic material, to determine the concentration of various chemokines.

Results and Findings

• The study found that all CXC chemokines (CXCL1, CXCL6, CXCL8) were increased at both the DEV and LAM stages as compared to the control horses.
• In the case of the CC chemokines (CCL2 [MCP-1], CCL3 [MIP-1α], and CCL8 [MCP-2]), they were only increased in the LAM horses as compared to the controls and the DEV horses.
• This suggests that the increase in chemokines precedes the peak accumulation of leukocytes, white blood cells that play an essential role in the body’s immune response.
• The increased expression of CCL2 and CCL8 aligns with previous research, suggesting that monocyte/macrophage accumulation occurs in the affected laminae. Monocytes/macrophages are types of white blood cells involved in engulfing and digesting harmful organisms in the body.

Implications and Conclusion

• The study’s findings demonstrated that an increase in laminar CXC chemokine expression consistently occurs before peak leukocyte accumulation and the onset of lameness in horses suffering from CHO-induced laminitis.
• This suggests that chemokines function as a trigger for the excessive immune response seen in laminitis, potentially causing the painful symptoms seen in horses affected by the condition.
• Using chemokine antagonists, substances that inhibit the activity of chemokines, could therefore be a possible therapeutic target to reduce the influx of leukocytes during the development of laminitis, potentially reducing the severity of the disease in horses.