Acute phase proteins in cats: Diagnostic and prognostic role, future directions, and analytical challenges

While clinical studies on acute phase proteins (APPs) have significantly increased in the last decade, and most commercial labs are now offering major APPs in their biochemical profiles, APP testing has not been widely adopted by veterinary clinical pathologists and veterinarians. Measurement of APP concentration is a useful marker for detecting the presence or absence of inflammation in cats with various diseases. APPs can also be reliably measured in different biological fluids (eg, effusions and urine) to improve their diagnostic utility. Measurement of APPs can be extremely beneficial in cats with feline infectious peritonitis (FIP) to discriminate between FIP and non-FIP cats with similar clinical presentations. Additional benefits come from multiple and sequential measurements of APPs, particularly in the assessment of therapeutic efficacy. APPs are more sensitive than WBC counts for early detection of inflammation and to demonstrate an early remission or recurrence of the diseases. Given the potential utility of APPs, more studies are warranted, with a particular focus on the applications of APPs to guide the length of antimicrobial therapies, as suggested by the antimicrobial stewardship policy. New inflammatory markers have been discovered in human medicine, with a higher specificity for distinguishing between septic versus nonseptic inflammatory diseases. It is desirable that these new markers be investigated in veterinary medicine, to further test the power of APPs in diagnostic setting.

Serum Insulin-like Growth Factor-1 Is a Biomarker of Testosterone Production and Intact Acrosome in Asian Elephants (Elephas maximus)

Simple Summary

In Thailand, the low fertility rate of Asian elephants has been identified. Factors contributing to poor semen quality in the elephants are not fully understood. Insulin-like growth factor-1 (IGF-1) is related to male infertility. It plays an essential role in testicular development by stimulating cell proliferation, differentiation, and steroidogenesis. In addition, there is increasing evidence that IGF-1 plays a critical role in spermatogenesis. This may be conducive to finding the causes of poor sperm quality in Asian elephants (Elephas maximus). In the present study, we investigated the relationships among serum IGF-1, serum testosterone level, and semen parameters in seven elephant bulls. The findings suggest that serum IGF-1 concentration is likely to predict sperm quality like acrosome integrity. The further mechanism by which IGF-1 affects sperm quality requires further investigation.

Abstract

The objective of this study was to find relationships among serum IGF-1, serum testosterone, seminal plasma IGF-1 concentrations and semen parameters in Asian elephants (Elephas maximus). A total of 17 ejaculates (one to three ejaculates/bull) were collected from seven captive elephant bulls by performing rectal massage. Before each ejaculation, blood samples were obtained for serum IGF-1 and testosterone assays. Subsequently, the semen characteristics of each ejaculate were evaluated. Mean serum IGF-1 concentration of elephant bulls was estimated as 326.3 ± 114.6 ng/mL (median, 286.2 ng/mL; range, 167.4–542.7 ng/mL). An increase in serum IGF-1 concentration was found to correlate with the percentage of spermatozoa with intact acrosomes. In addition, IGF-1 concentration was positively correlated with testosterone level. However, seminal IGF-1 concentrations could not be detected. In conclusion, our findings suggest that serum IGF-1 concentration is likely a biomarker of normal testicular functions, particularly spermatogenesis in elephants. Moreover, this commercial IGF-1 ELISA is eligible for analyzing serum IGF-1 concentration in Asian elephants.

Serum haptoglobin concentrations in feline inflammatory bowel disease and small-cell alimentary lymphoma: a potential biomarker for feline chronic enteropathies

OBJECTIVES

The aim of this study was to evaluate serum haptoglobin as a biomarker to differentiate between small-cell alimentary lymphoma and inflammatory bowel disease in cats.

METHODS

Client-owned domestic cats with and without chronic gastrointestinal signs were enrolled in the study. Serum was collected from each patient and serum haptoglobin levels were measured using ELISA. In cats with gastrointestinal signs, histopathologic evaluation of endoscopic biopsies harvested from the intestinal tract was used to separate them into inflammatory bowel disease and small-cell lymphoma cohorts. Serum haptoglobin levels were statistically analyzed and compared among the three groups: healthy cats; cats with inflammatory bowel disease; and cats with small-cell alimentary lymphoma.

RESULTS

Sixty-two cats were enrolled in the study, including 20 clinically normal cats, 14 cats with small-cell alimentary lymphoma and 28 cats with inflammatory bowel disease. The mean ± SD serum haptoglobin was 73.2 ± 39.1 mg/dl in normal cats, 115.3 ± 72.8 mg/dl in cats with inflammatory bowel disease and 133.1 ± 86.1 mg/dl in cats with small-cell alimentary lymphoma. Cats with inflammatory bowel disease and lymphoma had significantly higher serum haptoglobin than controls, with P values of 0.0382 and 0.0138, respectively. There was no statistical difference between the inflammatory bowel disease and lymphoma cohorts (P = 0.4235). For every one unit increase in serum haptoglobin, the odds of gastrointestinal inflammatory disease (inflammatory bowel disease or small-cell alimentary lymphoma) increased by 1.41% (P = 0.0165).

CONCLUSIONS AND RELEVANCE

Serum haptoglobin is a useful biomarker for distinguishing between normal cats and those with gastrointestinal inflammatory disease, but it could not significantly differentiate between inflammatory bowel disease and lymphoma. Additional studies may be beneficial in determining the prognostic significance of serum haptoglobin as it may relate to the severity of gastrointestinal inflammation.

Acute-phase proteins in pregnant goats: a longitudinal study

We documented changes in serum amyloid A (SAA) and haptoglobin (Hp) concentration in goats during pregnancy, as measured by competitive ELISAs. Fifteen does (pregnant group) and 20 castrated males (control group) were enrolled in the study. Blood samples were collected on the same day from all 35 goats, 7 times throughout the study period: at mating, then once every month, during the week preceding kidding, and 1 mo after kidding. Baseline SAA and Hp concentrations at mating were identical in the 2 groups. In the pregnant group, SAA concentration rose significantly in the second month and remained elevated until the end of pregnancy, with the peak concentration at kidding. In the control group, SAA concentration remained unchanged compared to the baseline concentration throughout the study. SAA concentration was significantly higher in the pregnant than control group only at the end of the fourth month of pregnancy and at kidding. Hp concentration did not change during pregnancy or between groups. SAA concentration at kidding was affected only by parity of does – it was highest in does in the third and fourth pregnancy and gradually lower in older does.