Validation of an enzyme-linked immunosorbent assay (ELISA) for the measurement of canine S100A12

The companion dog as a model for inflammaging: a cross-sectional pilot study

Inflammaging, the chronic, progressive proinflammatory state associated with aging, has been associated with multiple negative health outcomes in humans. The pathophysiology of inflammaging is complex; however, it is often characterized by high serum concentrations of inflammatory mediators such as tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, and C-reactive protein (CRP). Few studies have evaluated the effects of age on inflammatory cytokines in companion dogs, and most of these studies included dogs of a single breed. In this cross-sectional study, we measured multiple circulating inflammatory markers and hematological parameters in banked serum samples from 47 healthy companion dogs of various breeds enrolled in the Dog Aging Project. Using univariate linear models, we investigated the association of each of these markers with age, sex, body weight, and body condition score (BCS), a measure of obesity in the dog. Serum IL-6, IL-8, and TNF-α concentrations were all positively associated with age. Lymphocyte count was negatively associated with age. Platelet count had a negative association with body weight. IL-2, albumin, cholesterol, triglyceride, bilirubin, S100A12, and NMH concentrations were not associated with age, weight, BCS, or sex after adjustment for multiple comparisons. Our findings replicate previous findings in humans, including increases in IL-6 and TNF-α with age, giving more evidence to the strength of the companion dog as a model for human aging.

Tissue S100/calgranulin expression and blood neutrophil-to-lymphocyte ratio (NLR) in prostatic disorders in dogs

BACKGROUND

Prostatic carcinoma (PCA) is a rare but severe condition in dogs that is similar to the androgen-independent form of PCA in men. In contrast to humans, PCA is difficult to diagnose in dogs as reliable biomarkers, available for PCA screening in human medicine, are currently lacking in small animal oncology. Calprotectin (S100A8/A9) and S100A12 are Ca2+-binding proteins of the innate immune system with promising potential to distinguish malignant from benign urogenital tract conditions, similar to the blood neutrophil-to-lymphocyte-ratio (NLR). However, both have not yet been extensively investigated in dogs with PCA. Thus, this study aimed to evaluate the expression of the S100/calgranulins (calprotectin, S100A12, and their ratio [Cal-ratio]) in prostatic biopsies from nine dogs with PCA and compare them to those in dogs with benign prostatic lesions (eight dogs with prostatitis and ten dogs with benign prostatic hyperplasia [BPH]) as well as five healthy controls. In addition, blood NLRs were investigated in twelve dogs with PCA and 22 dogs with benign prostatic conditions.

RESULTS

Tissue S100A8/A9+ cell counts did not differ significantly between tissue from PCA and prostatitis cases (P = 0.0659) but were significantly higher in dogs with prostatitis than BPH (P = 0.0013) or controls (P = 0.0033). S100A12+ cell counts were significantly lower in PCA tissues than in prostatitis tissue (P = 0.0458) but did not differ compared to BPH tissue (P = 0.6499) or tissue from controls (P = 0.0622). Cal-ratios did not differ significantly among the groups but were highest in prostatitis tissues and significantly higher in those dogs with poor prostatitis outcomes than in patients that were still alive at the end of the study (P = 0.0455). Blood NLR strongly correlated with prostatic tissue S100A8/A9+ cell counts in dogs with PCA (ρ = 0.81, P = 0.0499) but did not differ among the disease groups of dogs.

CONCLUSIONS

This study suggests that the S100/calgranulins play a role in malignant (PCA) and benign (prostatic inflammation) prostatic conditions and supports previous results in lower urinary tract conditions in dogs. These molecules might be linked to the inflammatory environment with potential effects on the inflammasome. The blood NLR does not appear to aid in distinguishing prostatic conditions in dogs. Further investigation of the S100/calgranulin pathways and their role in modulation of tumor development, progression, and metastasis in PCA is warranted.

High-Dose Hydrocortisone Treatment Does Not Affect Serum C-Reactive Protein (CRP) Concentrations in Healthy Dogs

Measuring C-reactive protein (CRP) in serum is a useful surrogate marker for assessing disease progression and treatment response in dogs with autoinflammatory diseases. Affected dogs often receive high-dose glucocorticoid treatment, but the effect of such treatment alone on serum CRP concentrations is unknown. We evaluated serum CRP concentrations via immunoassay (sandwich enzyme-linked immunosorbent assay and particle-enhanced turbidimetric immunoassay) in 12 healthy beagle dogs administered high-dose hydrocortisone (8 mg/kg q12 h) per os vs. placebo over 28 days (days 0, 1, 5, and 28) in a randomized parallel study design. Serum CRP concentrations slightly decreased during treatment or placebo but without a significant association with hydrocortisone administration (p = 0.761). Compared to baseline, serum CRP concentrations were decreased by >2.7-fold (minimum critical difference) in three hydrocortisone-treated dogs and two dogs in the placebo group on day 28, whereas an increase to >2.7-fold was seen in one dog receiving placebo. These results suggest a lack of confounding effects of high-dose hydrocortisone administration on serum CRP concentrations in healthy dogs. This might also hold in dogs with autoinflammatory conditions and/or administration of other high-dose corticosteroids, suggesting that CRP presents a suitable biomarker to monitor inflammatory disease processes. However, this needs confirmation by further studies evaluating corticosteroid-induced cellular (e.g., hepatic) transcriptome and proteome changes.

S-100 Proteins: Basics and Applications as Biomarkers in Animals with Special Focus on Calgranulins (S100A8, A9, and A12)

S100 proteins are a group of calcium-binding proteins which received this name because of their solubility in a 100% saturated solution of ammonium sulphate. They have a similar molecular mass of 10-12 KDa and share 25-65% similarity in their amino acid sequence. They are expressed in many tissues, and to date 25 different types of S100 proteins have been identified. This review aims to provide updated information about S100 proteins and their use as biomarkers in veterinary science, with special emphasis on the family of calgranulins that includes S100A8 (calgranulin A; myeloid-related protein 8, MRP8), S100A9 (calgranulin B; MRP14), and S100A12 (calgranulin C). The proteins SA100A8 and S100A9 can be linked, forming a heterodimer which is known as calprotectin. Calgranulins are related to the activation of inflammation and the immune system and increase in gastrointestinal diseases, inflammation and sepsis, immunomediated diseases, and obesity and endocrine disorders in different animal species. This review reflects the current knowledge about calgranulins in veterinary science, which should increase in the future to clarify their role in different diseases and potential as biomarkers and therapeutic targets, as well as the practical use of their measurement in non-invasive samples such as saliva or feces.

Fecal S100A12 concentrations in cats with chronic enteropathies

OBJECTIVES

The aim of this study was to compare fecal S100A12 concentrations in cats diagnosed with chronic enteropathy (CE) with healthy control cats.

METHODS

This was a prospective, cross-sectional study. Forty-nine cats that had gastrointestinal signs for >3 weeks and a complete diagnostic work-up, including bloodwork, abdominal ultrasound and upper and/or lower gastrointestinal endoscopic biopsies, were enrolled into the CE group. Nineteen cats from the CE group were diagnosed with inflammatory bowel disease (IBD) or chronic inflammatory enteropathy (CIE) and 30 with alimentary lymphoma (LSA), based on histopathology results and additional testing with immunohistochemistry or molecular clonality testing with PCR if indicated. Nineteen apparently healthy control cats were included in the study. One fecal sample was collected from each cat and S100A12 concentrations were quantified by an analytically validated in-house ELISA.

RESULTS

Fecal S100A12 concentrations differed between cats with LSA (median 110 ng/g; interquartile range [IQR] 18-548) and control cats (median 4 ng/g; IQR 2-25 [P <0.001]) and between cats with IBD (median 34 ng/g; IQR 15-973) and control cats (P <0.003). S100A12 concentrations in CE cats (median 94 ng/g; IQR 16-548) were statistically significantly higher compared with control cats (P <0.001). The area under the receiver operating characteristic curve (AUROC) to separate healthy cats from CE cats was 0.81 (95% confidence interval [CI] 0.70-0.92) and was statistically significant (P <0.001). The AUROC to separate cats with IBD from cats with LSA was 0.51 (95% CI 0.34-0.68) and was not statistically significant (P = 0.9).

CONCLUSIONS AND RELEVANCE

Fecal S100A12 concentrations at the time of diagnostic investigation were higher in cats with CIE and LSA than in healthy controls but did not differ between cats with LSA and those with CIE/IBD. This study is an initial step toward evaluating a novel non-invasive marker of feline CIE. Further studies are needed to determine the diagnostic utility of fecal S100A12 concentrations in cats with CE, including comparing cats with IBD/CIE and LSA, and to compare them with cats with extra-gastrointestinal disease.

Tissue S100/calgranulin expression and blood neutrophil-to-lymphocyte ratio (NLR) in dogs with lower urinary tract urothelial carcinoma

BACKGROUND

Urothelial carcinoma (UC) is the most common neoplasm of the canine lower urinary tract, affecting approximately 2% of dogs. Elderly female patients of certain breeds are predisposed, and clinical signs of UC can easily be confused with urinary tract infection or urolithiasis. Diagnosis and treatment are challenging given the lack of disease-specific markers and treatments. The S100A8/A9 complex and S100A12 protein are Ca²⁺-binding proteins expressed by cells of the innate immune system and have shown promise as urinary screening markers for UC. The neutrophil-to-lymphocyte ratio (NLR) can also aid in distinguishing certain neoplastic from inflammatory conditions. Our study aimed to evaluate the tissue expression of S100/calgranulins and the blood NLR in dogs with UC. Urinary bladder and/or urethral tissue samples from dogs with UC (n = 10), non-neoplastic inflammatory lesions (NNUTD; n = 6), and no histologic changes (n = 11) were evaluated using immunohistochemistry. Blood NLRs were analyzed in dogs with UC (n = 22) or NNUTD (n = 26).

RESULTS

Tissue S100A12-positive cell counts were significantly higher in dogs with lower urinary tract disease than healthy controls (P = 0.0267 for UC, P = 0.0049 for NNUTD), with no significant difference between UC and NNUTD patients. Tissue S100A8/A9-positivity appeared to be higher with NNUTD than UC, but this difference did not reach statistical significance. The S100A8/A9⁺-to-S100A12⁺ ratio was significantly decreased in neoplastic and inflamed lower urinary tract tissue compared to histologically normal specimens (P = 0.0062 for UC, P = 0.0030 for NNUTD). NLRs were significantly higher in dogs with UC than in dogs with NNUTD, and a cut-off NLR of ≤ 2.83 distinguished UC from NNUTD with 41% sensitivity and 100% specificity. Higher NLRs were also associated with a poor overall survival time (P = 0.0417).

CONCLUSIONS

These results confirm that the S100/calgranulins play a role in the immune response to inflammatory and neoplastic lower urinary tract diseases in dogs, but the tissue expression of these proteins appears to differ from their concentrations reported in urine samples. Further investigations of the S100/calgranulin pathways in UC and their potential as diagnostic or prognostic tools and potential therapeutic targets are warranted. The NLR as a routinely available marker might be a useful surrogate to distinguish UC from inflammatory conditions.

Canine chronic enteropathy—Current state-of-the-art and emerging concepts

Over the last decade, chronic inflammatory enteropathies (CIE) in dogs have received great attention in the basic and clinical research arena. The 2010 ACVIM Consensus Statement, including guidelines for the diagnostic criteria for canine and feline CIE, was an important milestone to a more standardized approach to patients suspected of a CIE diagnosis. Great strides have been made since understanding the pathogenesis and classification of CIE in dogs, and novel diagnostic and treatment options have evolved. New concepts in the microbiome-host-interaction, metabolic pathways, crosstalk within the mucosal immune system, and extension to the gut-brain axis have emerged. Novel diagnostics have been developed, the clinical utility of which remains to be critically evaluated in the next coming years. New directions are also expected to lead to a larger spectrum of treatment options tailored to the individual patient. This review offers insights into emerging concepts and future directions proposed for further CIE research in dogs for the next decade to come.

Effects of Canine-Obtained Lactic-Acid Bacteria on the Fecal Microbiota and Inflammatory Markers in Dogs Receiving Non-Steroidal Anti-Inflammatory Treatment

Non-steroidal anti-inflammatory drugs (NSAIDs) may cause enteropathy in dogs and probiotics may be one option to prevent this. The objective of this study was to determine whether the administration of canine-obtained lactic acid bacteria (LAB) has an effect on the frequency of diarrhea, the composition of the fecal microbiota, and/or markers of gastrointestinal inflammation in dogs receiving NSAIDs when compared to dogs given NSAIDs and a placebo. A total of 22 dogs treated with NSAIDs for various clinical indications were enrolled in a seven-day randomized, double-blinded placebo-controlled interventional study. Dogs were randomized to receive either placebo or LAB, a product containing Limosilactobacillus fermentum, Lacticaseibacillus rhamnosus, and Lactiplantibacillus plantarum. Fecal samples were collected on days one and seven. The fecal microbiota was evaluated using the fecal dysbiosis index (DI) and individual bacterial taxa. Fecal calprotectin (CP) and S100A12/Calgranulin C concentrations were used as markers of gastrointestinal inflammation. There was a difference in frequency of diarrhea between groups, with it affecting 4/12 dogs (33%) in the placebo group and 1/10 dogs (10%) in the LAB group, but this difference did not reach statistical significance (p = 0.32). There was a correlation between S100A12 and CP (p < 0.001), and Clostridium perfringens correlated with S100A12 (p < 0.015). Neither treatment significantly affected S100A12 (p = 0.37), CP (p = 0.12), or fecal DI (p = 0.65). This study suggests that LAB is a safe supplement to use for short-term treatment in NSAID-treated dogs, but further studies are needed to determine its potential to prevent NSAID-induced enteropathy in dogs.

Intestinal S100/Calgranulin Expression in Cats with Chronic Inflammatory Enteropathy and Intestinal Lymphoma

Diagnosing chronic inflammatory enteropathies (CIE) in cats and differentiation from intestinal lymphoma (IL) using currently available diagnostics is challenging. Intestinally expressed S100/calgranulins, measured in fecal samples, appear to be useful non-invasive biomarkers for canine CIE but have not been evaluated in cats. We hypothesized S100/calgranulins to play a role in the pathogenesis of feline chronic enteropathies (FCE) and to correlate with clinical and/or histologic disease severity. This retrospective case-control study included patient data and gastrointestinal (GI) tissues from 16 cats with CIE, 8 cats with IL, and 16 controls with no clinical signs of GI disease. GI tissue biopsies were immunohistochemically stained using polyclonal α-S100A8/A9 and α-S100A12 antibodies. S100A8/A9+ and S100A12+ cells were detected in all GI segments, with few significant differences between CIE, IL, and controls and no difference between diseased groups. Segmental inflammatory lesions were moderately to strongly correlated with increased S100/calgranulin-positive cell counts. Clinical disease severity correlated with S100A12+ cell counts in cats with IL (ρ = 0.69, p = 0.042) and more severe diarrhea with colonic lamina propria S100A12+ cells with CIE (ρ = 0.78, p = 0.021) and duodenal S100A8/A9+ cells with IL (ρ = 0.71, p = 0.032). These findings suggest a role of the S100/calgranulins in the pathogenesis of the spectrum of FCE, including CIE and IL.

Differences in Metabolic Profiles of Healthy Dogs Fed a High-Fat vs. a High-Starch Diet

Obesity is a common problem in dogs and overconsumption of energy-rich foods is a key factor. This study compared the inflammatory response and fecal metabolome of dogs fed a high-fat vs. a high-starch diet. Ten healthy lean adult beagles were equally allocated into two groups in a cross-over design. Each group received two diets in which fat (horse fat) and starch (pregelatinized corn starch) were exchanged in an isocaloric way to compare high fat vs. high starch. There was a tendency to increase the glucose and glycine concentrations and the glucose/insulin ratio in the blood in dogs fed with the high-fat diet, whereas there was a decrease in the level of Non-esterified fatty acids and a tendency to decrease the alanine level in dogs fed with the high-starch diet. Untargeted analysis of the fecal metabolome revealed 10 annotated metabolites of interest, including L-methionine, which showed a higher abundance in dogs fed the high-starch diet. Five other metabolites were upregulated in dogs fed the high-fat diet, but could not be annotated. The obtained results indicate that a high-starch diet, compared to a high-fat diet, may promote lipid metabolism, anti-oxidative effects, protein biosynthesis and catabolism, mucosal barrier function, and immunomodulation in healthy lean dogs.

From Bench Top to Clinics: How New Tests Can Be Helpful in Diagnosis and Management of Dogs with Chronic Enteropathies

In this article, we review different tests that have been researched in dogs with chronic enteropathy. The usefulness of these tests either to assess etiology, to differentiate between treatment response, or to monitor treatment response is discussed. The tests are divided in those that are commercially available and those that hold promises for further development.

Association of clinical characteristics and lifestyle factors with fecal S100/calgranulin concentrations in healthy dogs

Background

Fecal S100/calgranulin (S100A12 and calprotectin) concentrations are useful markers of gastrointestinal inflammation in dogs. In people, fecal S100/calgranulin concentrations are affected by age, obesity, diet and other lifestyle factors. Knowledge about the effects of such factors on fecal S100/calgranulin concentrations in dogs is currently scarce.

Objective

To evaluate the association between several factors and fecal S100/calgranulin concentrations in a large cohort of healthy adult dogs.

Methods

Single‐spot fecal samples from 181 healthy pet dogs and data derived from a standard questionnaire served to evaluate the effect of age, sex, reproductive status, body weight and body condition, breed type and size, vaccination, endoparasite treatment, diet, environment and travel history on fecal S100/calgranulin concentrations and the fecal calgranulin ratio (fCalR).

Results

Univariate analysis showed a significant association of reproductive status (in female dogs) and breed size with fecal S100A12, fecal calprotectin and fCalR. Breed type was linked to fecal S100A12 concentrations and fCalR; recent vaccination (particularly with a vaccine against canine parvovirus) to fCalR. In multivariate models, breed size was linked to fecal S100A12 and calprotectin concentrations, and recent vaccination affected S100A12 concentrations.

Conclusions

Breed size, recent vaccination and reproductive status in female dogs can affect fecal S100/calgranulin concentrations, and these biomarkers should be interpreted in light of those confounding factors. The utility of reference intervals for fecal canine S100/calgranulin concentrations might be improved through stratification by sex/reproductive status and breed size. Fecal canine S100/calgranulin concentrations are not confounded by age, body condition, deworming, diet, environment or travel history.

Blood neutrophil-to-lymphocyte ratio (NLR) as a diagnostic marker in dogs with chronic enteropathy

Few routinely available biomarkers are clinically useful in assessing dogs with chronic enteropathy (CE) and aid in CE subclassification. The diagnostic potential of the blood neutrophil-to-lymphocyte ratio (NLR) has not been evaluated in canine CE. We evaluated the NLR in 93 dogs with CE (no steroid treatment for ≥2 wk prior) and tested for an association with clinical, clinicopathologic, and histologic characteristics and also with CE subclassification. NLR was significantly higher in CE dogs with severe clinical disease than dogs with mild clinical disease (p = 0.047). Hypoalbuminemia (p < 0.001), but not hypocobalaminemia, was associated with higher NLRs. NLR was correlated with fecal alpha₁-proteinase inhibitor concentrations (ρ = 0.47) and the serum-to-fecal alpha₁-proteinase inhibitor ratio (ρ = -0.48; both p < 0.001) but not with serum or fecal inflammatory markers nor with the overall histologic score (all p > 0.05). Dogs with steroid- or other immunosuppressant-responsive (IRE) or nonresponsive enteropathy (NRE) had significantly higher NLRs (median: 7.3) than dogs with food-responsive enteropathy (FRE; median: 3.0; p = 0.003), and a NLR ≥5.5 best distinguished both groups of dogs. No difference in NLR was detected between dogs with IRE and dogs diagnosed with NRE. These findings suggest that leukogram changes (i.e., NLR) could be clinically useful in canine CE, and that neutrophils might play a role in the systemic inflammatory response associated with canine CE. The NLR can be easily assessed on routine hematology and can potentially aid in the subclassification of dogs with CE based on the response to treatment.

Increased IL-33 and IL-17 in Colorectal Carcinoma Patients with Severe Disease

Colorectal cancer (CRC) represents one of the most common cancers. It is frequently diagnosed at advanced stages, indicating on need for new diagnostic markers. The aim of this study was to determine systemic and fecal values of IL-17 and IL-33 in patients with CRC and the relationship with clinicopathological aspects of disease.

The blood samples and feces liquid fraction of 50 patients with CRC were analyzed. Serum and fecal levels of IL-33 and IL-17 were measured using sensitive enzyme-linked immunosorbent assay (ELISA) kits.

Fecal levels of Il-33 and IL-17 were increased in CRC patients with poor tumor tissue differentiation. Serum IL-33 and fecal IL-17 were increased in patients with presence of lung/liver metastasis or peritoneal carcinomatosis, respectively, while enhanced fecal IL-33 was detected only in patients with peritoneal carcinomatosis.

Positive correlation between IL-33 and IL-17 values in sera and feces, respectively was also observed.

We believe that increased local values of IL-33 and IL-17, reflected trough higher fecal concentration, in CRC patients with poor tumor tissue differentiation and with presence of lung/liver metastasis or peritoneal carcinomatosis may be considered as a sign of the tumor’s malignant progression and, consequently, of a poor prognosis for patients.

Association between serum soluble receptor for advanced glycation end-products (RAGE) deficiency and severity of clinicopathologic evidence of canine chronic inflammatory enteropathy

Innate immunity plays a central role in the pathogenesis of chronic inflammatory enteropathies (CIE) in dogs, and further evaluation of the innate immune receptor for advanced glycation end-products (RAGE) is warranted. We measured serum concentrations of decoy receptor soluble RAGE (sRAGE) in 102 dogs diagnosed with CIE, and evaluated relationships with clinical disease severity, histologic lesion severity, concentrations of serum C-reactive protein (CRP), and serum and fecal calprotectin, S100A12, and alpha₁-proteinase inhibitor (α₁PI). Serum sRAGE levels were not associated with clinical disease activity, serum CRP, serum and fecal α₁PI, calprotectin, or S100A12 concentrations. Microscopic lesions in the duodenum were more severe in dogs with serum sRAGE concentration ≤ 340 ng/L (p = 0.013). Serum sRAGE levels were weakly and inversely correlated with the severity of lymphoplasmacytic infiltration in the gastric antrum and duodenum, and with crypt dilation and the neutrophilic infiltrate in the duodenum, in univariate analysis (all p < 0.05), but none of the correlations remained statistically significant after correction for multiple comparisons. Our study confirms that CIE in dogs is associated with decreased serum sRAGE concentrations, suggesting a dysregulated sRAGE/RAGE axis.

Analytical validation of an enzyme-linked immunosorbent assay for the quantification of S100A12 in the serum and feces of cats

BACKGROUND

Measuring S100A12 concentrations in serum and feces is a sensitive and specific marker of inflammation, such as seen with chronic gastrointestinal inflammation in people and dogs. Biomarkers of inflammation in cats are currently lacking.

OBJECTIVES

We aimed to analytically cross-validate the canine S100A12-ELISA for the measurement of S100A12 in feline specimens.

METHODS

The ELISA was analytically validated by assessing dilutional linearity, spiking/recovery, intra- and inter-assay variability. Reference intervals for serum and fecal feline S100A12 concentrations were calculated using samples from healthy cats, and the short-term biological variation of fecal S100A12 was assessed.

RESULTS

Observed-to-expected ratios (O/E) for serial dilutions of serum and fecal extracts ranged from 91%-159% (mean, 120%) and 100%-128% (mean, 114%), and for the spiking/recovery method ranged from 106%-263% (mean, 154%) and 52%-171% (mean, 112%). Intra- and inter-assay CV% for serum were ≤5.6% and ≤14.0%, and for fecal extracts were ≤3.8% and ≤19.1%, repsectively. RIs for feline serum and fecal S100A12 concentrations were <43 µg/L and < 20 ng/g, respectively. A mild short-term biologic variation, but large individuality were detected when measuring fecal S100A12 concentrations in healthy cats.

CONCLUSIONS

The canine S100A12-ELISA is accurate, reproducible, and sufficiently linear and precise for the measurement of S100A12 in feline serum and fecal samples. The use of this assay is a reasonable option for the measurement of S100A12 concentrations in feline specimens and provides a basis for the further evaluation of  S100A12 in cats with gastrointestinal disease. Using a population-based RI for fecal feline S100A12 appears to be of limited value.

Prospective evaluation of S100A12 and S100A8/A9 (calprotectin) in dogs with sepsis or the systemic inflammatory response syndrome

Pattern recognition receptors (e.g., S100A12 or S100A8/A9) hold promise as inflammatory biomarkers. We prospectively determined and compared serum S100A12 and S100A8/A9 concentrations in dogs with sepsis (n = 11) or systemic inflammatory response syndrome (SIRS; n = 8) over a 3-d period with each other, healthy controls (n = 50), and other clinical and clinicopathologic variables. Serum S100A12 and S100A8/A9 concentrations were significantly higher in dogs with sepsis or SIRS (all p < 0.05) at the time of hospital admission (day 1) compared to healthy controls, with no differences between patient groups. However, septic dogs had significantly lower serum S100A12 concentrations on day 2 and day 3 (both p < 0.05) compared to dogs with SIRS. Likewise, dogs with sepsis had significantly lower S100A8/A9 concentrations on day 2 (p < 0.05). Neither serum S100A12 nor S100A8/A9 concentrations were associated with survival to discharge. Our results suggest a differential expression of the S100/calgranulins between dogs with sepsis and those with SIRS. Serum S100A12 or S100A8/A9 concentration at the time of hospital admission did not differentiate dogs with sepsis from those with SIRS, but the trend of S100/calgranulin concentrations during the following 24-48 h may be a useful surrogate marker for differentiating sepsis from SIRS.

Mucosal expression of S100A12 (calgranulin C) and S100A8/A9 (calprotectin) and correlation with serum and fecal concentrations in dogs with chronic inflammatory enteropathy

S100A12 and S100A8/A9 (calprotectin) are released from activated mononuclear cells and belong to the group of damage associated molecular patterns. Fecal S100A12 and S100A8/A9 concentrations have been suggested as biomarkers of intestinal inflammation in dogs with chronic inflammatory enteropathies (CIE). However, the mucosal cellular infiltrate in dogs with CIE is primarily lymphocytic-plasmacytic. Whether fecal S100A12 and S100A8/A9 levels reflect the number and/or activity of intestinal mucosal mononuclear cells, or whether these proteins are also produced by other cells has not been investigated. Thus, the aim of this study was to evaluate intestinal mucosal S100A12 and S100A8/A9 positivity and a potential relationship with the respective protein concentrations in serum and fecal samples in dogs with CIE. Serum (single sample), fecal samples (from 3 consecutive days), and gastrointestinal tissue biopsies (i.e., stomach, duodenum, ileum, and colon) were evaluated from 21 dogs with CIE. Serum and fecal S100A12 and S100A8/A9 concentrations were measured by analytically validated in-house ELISAs. Tissue biopsies underwent routine histopathology and immunohistochemical evaluation for S100A12 and S100A8/A9 positivity (S100A12⁺ and S100A8/A9⁺, each recorded as positive cells/mm²). S100A12⁺ and S100A8/A9⁺ cells were identified in all segments of the gastrointestinal tract, but were predominantly localized in the lamina propria (LP). Duodenal LP S100A12 positivity correlated statistically significantly with that in the stomach and ileum (ρ = 0.66 and 0.69, both p < 0.01), but was inversely correlated with the severity of macrophage infiltration in the duodenum (ρ=-0.47, p = 0.042). Ileal LP S100A8/A9 positivity correlated positively with the extent of ileal neutrophil and macrophage infiltration (ρ=0.61, p = 0.047). Fecal S100A12 concentrations strongly correlated with the number of S100A12⁺ cells along the entire gastrointestinal tract (ρ = 0.76, p = 0.028), whereas serum S100A12 concentrations were inversely correlated to colonic S100A12⁺ cell counts (ρ=-0.50, p = 0.043). Mucosal S100A8/A9⁺ cell counts were not associated with the corresponding fecal or serum S100A8/A9 concentrations. These results suggest that the intestinal mucosa in dogs with CIE contains an increased number of activated (pro-inflammatory) phagocytes expressing and secreting the S100A12 protein, but the macrophage population seen on routine histopathology is predominantly mature (anti-inflammatory) with a reduced or absent expression of S100A12 and a normal or increased expression of S100A8/A9. However, the distribution of intestinal S100A8/A9 expression requires further study.

Clinical utility of currently available biomarkers in inflammatory enteropathies of dogs

Chronic inflammatory enteropathies (CIE) in dogs are a group of disorders that are characterized by chronic persistent or recurrent signs of gastrointestinal disease and histologic evidence of mucosal inflammation. These CIEs are classified as either food-responsive, antibiotic-responsive, or immunosuppressant-responsive enteropathy. Patients not clinically responding to immunomodulatory treatment are grouped as nonresponsive enteropathy and dogs with intestinal protein loss as protein-losing enteropathy. Disease-independent clinical scoring systems were established in dogs for assessment of clinical disease severity and patient monitoring during treatment. Histopathologic and routine clinicopathologic findings are usually not able to distinguish the subgroups of CIE. Treatment trials are often lengthy and further diagnostic tests are usually at least minimally invasive. Biomarkers that can aid in defining the presence of disease, site of origin, severity of the disease process, response to treatment, or a combination of these would be clinically useful in dogs with CIE. This article summarizes the following biomarkers that have been evaluated in dogs with CIE during the last decade, and critically evaluates their potential clinical utility in dogs with CIE: functional biomarkers (cobalamin, methylmalonic acid, folate, α1 -proteinase inhibitor, immunoglobulin A), biochemical biomarkers (C-reactive protein, perinuclear anti-neutrophilic cytoplasmic antibodies, 3-bromotyrosine, N-methylhistamine, calprotectin, S100A12, soluble receptor of advanced glycation end products, cytokines and chemokines, alkaline phosphatase), microbiomic biomarkers (microbiome changes, dysbiosis index), metabolomic biomarkers (serum metabolome), genetic biomarkers (genomic markers, gene expression changes), and cellular biomarkers (regulatory T cells). In addition, important performance criteria of diagnostic tests are briefly reviewed.

S100A12 concentrations and myeloperoxidase activities are increased in the intestinal mucosa of dogs with chronic enteropathies

Background

Intestinal mucosal S100A12 and myeloperoxidase (MPO) are inflammatory biomarkers in humans with inflammatory bowel disease (IBD). However, these biomarkers have not been studied in the intestinal mucosa of dogs with chronic enteropathies (CE), even though dogs with CE have increased S100A12 concentrations in feces and serum. This study investigated mucosal S100A12 concentrations and MPO activities in both dogs with CE and healthy Beagles. ELISA (S100A12 concentrations) and spectrophotometric methods (MPO activity) were used. The associations of both biomarkers with canine IBD activity index (CIBDAI), histopathologic findings, clinical outcome, and serum albumin concentrations were also investigated. We studied intestinal mucosal samples originating from different intestinal regions of 40 dogs with CE and 18 healthy Beagle dogs (duodenum, ileum, colon, and cecum).

Results

Compared with healthy Beagles, mucosal S100A12 concentrations in dogs with CE were significantly higher in the duodenum (p < 0.0001) and colon (p = 0.0011), but not in the ileum (p = 0.2725) and cecum (p = 0.2194). Mucosal MPO activity of dogs with CE was significantly higher in the duodenum (p < 0.0001), ileum (p = 0.0083), colon (p < 0.0001), and cecum (p = 0.0474). Mucosal S100A12 concentrations in the duodenum were significantly higher if the inflammatory infiltrate consisted mainly of neutrophils (p = 0.0439) or macrophages (p = 0.037). Mucosal S100A12 concentrations also showed a significant association with the severity of total histopathological injury and epithelial injury in the colon (p < 0.05). Mucosal MPO activity showed a significant association (p < 0.05) with the severity of total histopathological injury, epithelial injury, and eosinophil infiltration in the duodenum. There was no significant association of both biomarkers with CIBDAI or clinical outcome.

Conclusions

This study showed that both mucosal S100A12 concentrations and MPO activities are significantly increased in the duodenum and colon of dogs with CE; mucosal MPO was also increased in the ileum and cecum. Future research should focus on assessing the clinical utility of S100A12 and MPO as diagnostic markers in dogs with CE.

Fecal Galectin-3: A New Promising Biomarker for Severity and Progression of Colorectal Carcinoma

Background and Objectives

The aim of the study was to determine systemic and fecal values of galectin-3 and pro- and anti-inflammatory cytokines in patients with CRC and the relationship with clinicopathological aspects.

Methods

Concentrations of galectin-3, TNF-α, TGF-β, IL-10, and IL-1β were analyzed in samples of blood and stool of 60 patients with CRC.

Results

Systemic concentration of TNF-α was significantly lower in patients with severe diseases (advanced TNM stage, nuclear grade, and poor histological differentiation) as in patients with more progressive CRC (lymph and blood vessel invasion, presence of metastasis). Fecal values of anti-inflammatory cytokines TGF-β and IL-10 were increased in patients with severe stadium of CRC. Fecal concentration of Gal-3 was enhanced in CRC patients with higher nuclear grade, poor tumor tissue differentiation, advanced TNM stage, and metastatic disease. Gal-3/TNF-α ratio in sera and feces had a higher trend in patients with severe and advanced diseases. Positive correlation between fecal Gal-3 and disease severity, tumor progression, and biomarkers AFP and CEA, respectively, was also observed.

Conclusions

Predomination of Gal-3 in patients with advanced diseases may implicate on its role in limiting ongoing proinflammatory processes. The fecal values of Gal-3 can be used as a valuable marker for CRC severity and progression.

Molecular aspects of uterine diseases in dogs

Uterine diseases are common in dogs, particularly in countries where elective spaying is not usually performed. The associated clinical illnesses may be of varying degree ranging from merely decreased fertility to a critical pyometra requiring intensive care to survive. The diagnosis of some uterine diseases is generally uncomplicated, such as in a classic pyometra presenting with enlarged, fluid-filled uterus, purulent vaginal discharge and characteristic signs of illness or in other disorders associated with uterine enlargement. However, it can be more puzzling in diseases with normal uterine size and very mild or obscure clinical signs. It is important to recognize the uterine diseases early because of the risk of potentially life-threatening complications such as sepsis developing if treatment is delayed in cases where bacterial infection is present. In breeding bitches, an early diagnosis, that is when the disease has not developed extensively, will increase the possibility of non-surgical treatment options without increased risk and thereby also increasing chances of maintained fertility. Early diagnosis and treatment initiation are thus favourable for complete recovery, also in less severe uterine diseases and those without infection. Molecular markers are molecules in biological samples that can be measured for diagnostic purposes, outcome prediction, and for gaining more information about different physiological and pathological conditions. Examples of commonly evaluated markers include laboratory variables analysed in blood, urine, cytological or tissue biopsy samples. Regarding the genetic pre-disposition for different uterine diseases in dogs, information is lacking. Recently, the global gene expression in uterine tissue in dogs has been investigated more closely, and newly developed technologies provide excellent opportunities for identifying molecular markers worth exploring further. The focus of this review article is to highlight findings on markers relevant for diagnosis, prediction of prognosis and treatment outcome in the most common uterine diseases in dogs.

Association of fecal calprotectin concentrations with disease severity, response to treatment, and other biomarkers in dogs with chronic inflammatory enteropathies

BACKGROUND

Calprotectin is a marker of inflammation, but its clinical utility in dogs with chronic inflammatory enteropathies (CIE) is unknown.

OBJECTIVE

Evaluation of fecal calprotectin in dogs with biopsy-confirmed CIE.

ANIMALS

127 dogs.

METHODS

Prospective case-control study. Dogs were assigned a canine chronic enteropathy clinical activity index (CCECAI) score, and histologic lesions severity was assessed. Fecal calprotectin, fecal S100A12, and serum C-reactive protein (CRP) were measured. Food- or antibiotic-responsive cases (FRE/ARE, n = 13) were distinguished from steroid-/immunosuppressant-responsive or -refractory cases (SRE/IRE, n = 20). Clinical response to treatment in SRE/IRE dogs was classified as complete remission (CR), partial response (PR), or no response (NR).

RESULTS

Fecal calprotectin correlated with CCECAI (ρ = 0.27, P = .0065) and fecal S100A12 (ρ = 0.90, P < .0001), some inflammatory criteria, and cumulative inflammation scores, but not serum CRP (ρ = 0.16, P = .12). Dogs with SRE/IRE had higher fecal calprotectin concentrations (median: 2.0 μg/g) than FRE/ARE dogs (median: 1.4 μg/g), and within the SRE/IRE group, dogs with PR/NR had higher fecal calprotectin (median: 37.0 μg/g) than dogs with CR (median: 1.6 μg/g). However, both differences did not reach statistical significance (both P = .10). A fecal calprotectin ≥15.2 μg/g separated both groups with 80% sensitivity (95% confidence interval [95%CI]: 28%-100%) and 75% specificity (95%CI: 43%-95%).

CONCLUSIONS AND CLINICAL IMPORTANCE

Fecal calprotectin could be a useful surrogate marker of disease severity in dogs with CIE, but larger longitudinal studies are needed to evaluate its utility in predicting the response to treatment.

Serum C-reactive protein and S100A12 concentrations in dogs with hepatic disease

OBJECTIVES

To describe serum C-reactive protein and S100A12 concentrations in dogs with hepatic disease and to determine whether there is a relationship between the concentration of either and the severity of hepatic necroinflammation.

METHODS

Serum C-reactive protein and S100A12 concentrations were measured in 46 dogs undergoing hepatic biopsy. Dogs were divided into three groups: congenital portosystemic shunts, chronic hepatitis and hepatic neoplasia. The histological severity of hepatic necroinflammation was scored.

RESULTS

C-reactive protein and S100A12 concentrations were greater than the upper limit of the reference intervals in 39 and 26% of dogs, respectively. There was no association of disease group with C-reactive protein (P=0·1733) or S100A12 (P=0·1513) concentrations. There was a positive correlation between serum C-reactive protein concentration and hepatic necroinflammatory activity (rs =0·428, P=0·006).

CLINICAL SIGNIFICANCE

Increased serum C-reactive protein and S100A12 concentrations were observed in a subpopulation of dogs with various types of hepatic diseases, suggesting acute-phase inflammation and activation of phagocytic cells, respectively. Dogs with higher hepatic necroinflammatory activity scores tended to have higher serum C-reactive protein concentrations. Further studies are needed to confirm this finding in a larger group of dogs.

Role of serum S100A12 in diagnosis and evaluation of ulcerative colitis

AIM: To determine serum levels of S100A12 in patients with ulcerative colitis (UC) and to explore its potential role in the diagnosis of UC and evaluation of disease development.

METHODS: Serum samples were collected from 66 patients with active UC (A-UC), 24 patients with UC in remission (R-UC) and 20 healthy controls. S100A12 levels were determined by ELISA. The role of S100A12 in the diagnosis and evaluation of disease development was then investigated.

RESULTS: The levels of serum S100A12 were significantly higher in patients with A-UC (725.6 pg/mL ± 239.6 pg/mL) compared with R-UC patients (311.2 pg/mL ± 87.5 pg/mL) and healthy controls (218.6 pg/mL ± 76.8 pg/mL) (P < 0.001). S100A12 was found to be markedly increased in severe UC patients compared with mild and moderate UC patients (P < 0.05). S100A12 was positively correlated with serum C-reactive protein (CRP) in UC patients. Moreover, S100A12 was found to be markedly decreased in UC patients after receiving effective treatment compared with that before treatment (P< 0.05).

CONCLUSION: S100A12 is markedly increased in the sera of UC patients. It can be used to diagnose the disease and predict the disease progression, suggesting that S100A12 is a useful marker for the prediction of UC.

Fecal S100A12 concentration predicts a lack of response to treatment in dogs affected with chronic enteropathy

S100A12 is a potential biomarker of gastrointestinal inflammation in dogs and fecal S100A12 concentrations are correlated with disease severity and outcome. The aim of the present study was to investigate whether there was any association between pre-treatment fecal S100A12 concentrations in dogs affected with chronic enteropathy (CE) and the response to treatment. Dogs affected with CE were recruited into the study and were classified as antibiotic-responsive diarrhea (ARD; n = 9), food-responsive diarrhea (FRD; n = 30) or idiopathic inflammatory bowel disease (IBD; n = 25). They were also grouped based on their response to treatment as complete remission (n = 35), partial response (n = 25) or no response (n = 4). Fecal S100A12 concentrations, measured by ELISA, were elevated in dogs affected with IBD compared with those from dogs affected with FRD (P = 0.010) or ARD (P = 0.025). Dogs with IBD that did not respond to treatment (n = 4) had significantly greater fecal S100A12 concentrations than dogs in complete remission (P = 0.009). Measurement of fecal S100A12 at the time of diagnosis discriminated between dogs with IBD that were refractory to therapy (≥2700 ng/g fecal S100A12) from those with at least a partial response (<2700 ng/g fecal S100A12), with a sensitivity of 100% and a specificity of 76%. These preliminary results suggest that testing of fecal S100A12 may be useful for predicting the lack of response to treatment in dogs affected with CE. The utility of serial fecal S100A12 measurements for monitoring dogs undergoing treatment for CE warrants further investigation.