Plasma fructosamine concentrations in horses with pituitary pars intermedia dysfunction with and without laminitis.

The research investigates whether plasma fructosamine concentrations, which reflect average blood glucose levels, are higher in horses with both Pituitary Pars Intermedia Dysfunction (PPID) and active laminitis when compared to normal horses or those with PPID but no laminitis. The study found that plasma fructosamine was not higher in PPID horses overall when compared to normal animals, but in PPID cases, significantly higher concentrations were found in those with active laminitis.

Hypotheses and Methodology

• The scientists postulated that plasma fructosamine concentrations, which are indicative of medium-term average blood sugar levels, would be higher in PPID horses than in healthy ones. They also hypothesized that the levels would be higher within PPID cases suffering from active laminitis compared to PPID cases without laminitis.
• To test this, an observational, case-control/cross-sectional study was performed, involving normal horses and those with PPID. The fructosamine levels were measured, a normal range calculated, and these values were then compared between the two groups, as well as amongst PPID cases with and without active laminitis.

Results

• The data indicated that in normal animals, the mean plasma fructosamine level was 248.7 μmol/l, with a normal range between 195.5-301.9 μmol/l.
• Contrary to the original hypothesis, plasma fructosamine was not found to be higher in all PPID cases compared to the normal animals. This means that having PPID alone does not necessarily result in heightened average blood glucose levels.
• The research did however support the second hypothesis, with fructosamine levels in PPID horses with active laminitis significantly higher (mean ± s.d. 261.2 ± 39.2 μmol/l) compared to those without active laminitis (234.5 ± 32.9 μmol/l).
• The study found no significant difference in fructosamine concentrations between horses with PPID that had been affected by active laminitis in the past year and those that had not.

Conclusions

• While this study found that plasma fructosamine is higher in PPID horses with active laminitis compared to those without it, the use of fructosamine to gauge laminitis risk in clinical practice has limitations due to overlap with the normal range.
• Given these findings, the authors recommend further research into glucose and protein metabolism in PPID cases to improve understanding of the disease and its relationships with blood sugar and laminitis.