Elevation of serum thymidine kinase 1 in a bacterial infection: Canine pyometra

A monoclonal antibody-based sandwich ELISA for measuring canine Thymidine kinase 1 protein and its role as biomarker in canine lymphoma

Introduction

Dogs play an important role in society, which increased during the covid epidemics. This has led to a much higher workload for the veterinarians. Therefore, there is a need for efficient diagnostic tools to identify risk of malignant diseases. Here the development of a new test that can solve some of these problems is presented. It is based on serum Thymidine Kinase 1 (TK1), which is a biomarker for cell proliferation and cell lysis.

Methods

Anti-TK1 monoclonal antibodies were produced against two different epitopes, the active site of the TK1 protein and the C-terminal region of canine TK1. The antibodies were developed with hybridoma technology and validated using dot blot, Quartz Crystal Microbalance (QCM) technology, western blots, immunoprecipitation (IP), and enzyme-linked immunosorbent assay (ELISA). Clinical evaluation of Canine TK1 ELISA was done by using sera from 131 healthy dogs and 93 dogs with lymphoma. The two selected Anti-TK1 monoclonal antibodies have Kd values in the range of 10-9 M and further analysis with dot and western blots confirmed the high affinity binding of these antibodies. A sandwich Canine TK1 ELISA was developed using the anti-TK1 antibodies, and TK1 concentrations in serum samples were determined using dog recombinant TK1 as a standard.

Results

Serum TK1 protein levels were significantly higher in dogs with lymphoma compared to those in healthy dogs (p < 0.0001). Receiver operating curve analysis showed that the canine TK1-ELISA obtain a sensitivity of 0.80, at a specificity of 0.95. Moreover, the Canine TK1 ELISA has a positive predictive value (PPV) of 97%, and the negative predictive value (NPV) of 83%, reflecting the proportion of test results that are truly positive and negative. Furthermore, Canine TK1 ELISA had significantly higher capacity to differentiate dogs with T-cell lymphoma from those with B-cell lymphoma compared to earlier used TK1 activity assays.

Discussion

These results demonstrate that the Canine TK1 ELISA can serve as an efficient tool in the diagnosis and management of dogs with lymphomas.

The assessment of haematologic and serum chemistry parameters in canine pyometra: a systematic review and meta-analysis

OBJECTIVES

Pyometra is common in non-spayed adult female dogs requiring early diagnosis and treatment to increase the survival rate. The diagnosis of pyometra is mainly based on clinical examination and anamnesis. Radiography, ultrasonography and laboratory analyses are recommended to support a diagnosis. The aim of this study was to assess blood parameters associated with pyometra by performing a systematic review and meta-analysis.

MATERIALS AND METHODS

The review was conducted in accordance with PRISMA guidelines. A search of three databases (PubMed, Google Scholar and CAB abstracts) was performed in July 2022. Studies providing information about laboratory parameters for both the pyometra group and healthy control group dogs were eligible for inclusion. Data extraction included the first author's name, publication year, country, number of participants in both groups, mean values of selected studies, standard deviation values, and blood parameters. The risk of bias for each study was evaluated, and a random-effects meta-analysis was performed.

RESULTS

We included 44 studies which investigated 12 blood parameters. High heterogeneity was detected in all parameters in these meta-analyses. The following blood parameters were increased in dogs with pyometra: white blood cell (mean=27.75×109  L-1 , mean difference (MD)=17.16, 95% confidence interval (CI) 14.85 to 19.47), monocytes (mean=2.06×1012 /L, MD=1.37, 95% CI 0.99 to 1.74), blood urea nitrogen (mean=41.42 mg/dL MD=18.06, 95% CI 12.26 to 23.85), alkaline phosphatase (mean=212.78 IU/L, MD=137.51, 95% CI 81.81 to 88.62), and aspartate aminotransferase (mean=48.31 IU/L, MD=16.96, 95% CI 10.61 to 23.30). The following parameters were reduced: red blood cell (mean=5.42 1012 /L, MD=-1.37, 95% CI -1.68 to -1.05), haemoglobin (mean=121.20 g/L, MD=-30.57, 95% CI -39.70 to 21.45), albumin (mean=23.71 g/L, MD = -8.16, 95% CI -11.46 to -4.86). Lymphocyte, creatinine, urea, and alanine transaminase parameters were increased in some studies and decreased in others.

CLINICAL SIGNIFICANCE

In canine pyometra, some blood parameters are consistently increased, some consistently decreased, and some increased or decreased depending on the study.

Feline thymidine kinase 1: molecular characterization and evaluation of its serum form as a diagnostic biomarker

BACKGROUND

Thymidine kinase 1 (TK1) catalyzes the initial phosphorylation of thymidine in the salvage pathway synthesis of dTTP, an essential building block of DNA. TK1 is a cytosolic enzyme with its highest level during the S-phase of the cell cycle. In cancer cells TK1 is upregulated and excess TK1 is leaked into the blood. Therefore, serum TK1 has been used as biomarker for cancer diagnosis and prognosis in human medicine. Feline TK1 shows high sequence similarity to TK1 from other species. The aim of this study was to characterize feline TK1 and evaluate if serum TK1 can be used as a diagnostic biomarker.

RESULTS

Feline TK1 was cloned, expressed and affinity purified. The purified feline TK1 phosphorylated not only pyrimidine deoxyribonucleosides but also pyrimidine ribonucleosides and to some extent purine deoxynucleosides. A number of anticancer and antiviral nucleoside analogs also served as substrates with fairly high efficiency. ATP and dATP were the preferred phosphate donor. Serum TK1 activity in felines with malignant diseases was significantly higher than that in healthy individuals. ROC analysis revealed an area under the curve (AUC) of 0.98 with a sensitivity of 0.83 and a specificity of 0.95 for felines with lymphoma. Serum TK1 activity in felines with IBD or inflammatory disease was within the same range as healthy ones. Furthermore, in felines with lymphoma serum TK1 activity returned to normal levels in response to treatment.

CONCLUSION

Feline TK1 has high specific activity and a broader substrate specificity in comparison with TK1 from other species. Serum TK1 activity in felines with malignant diseases is significantly higher than that in normal felines and in felines with inflammatory diseases. These results suggest that serum TK1 may be a promising biomarker for the diagnosis and monitoring of malignant diseases and for the differential diagnosis of certain inflammatory disease.

Thymidine kinase 1 through the ages: a comprehensive review

Proliferation markers, such as proliferating cell nuclear antigen (PCNA), Ki-67, and thymidine kinase 1 (TK1), have potential as diagnostic tools and as prognostic factors in assessing cancer treatment and disease progression. TK1 is involved in cellular proliferation through the recovery of the nucleotide thymidine in the DNA salvage pathway. TK1 upregulation has been found to be an early event in cancer development. In addition, serum levels of TK1 have been shown to be tied to cancer stage, so that higher levels of TK1 indicate a more serious prognosis. As a result of these findings and others, TK1 is not only a potentially viable biomarker for cancer recurrence, treatment monitoring, and survival, but is potentially more advantageous than current biomarkers. Compared to other proliferation markers, TK1 levels during S phase more accurately determine the rate of DNA synthesis in actively dividing tumors. Several reviews of TK1 elaborate on various assays that have been developed to measure levels in the serum of cancer patients in clinical settings. In this review, we include a brief history of important TK1 discoveries and findings, a comprehensive overview of TK1 regulation at DNA to protein levels, and recent findings that indicate TK1’s potential role in cancer pathogenesis and its growing potential as a tumor biomarker and therapeutic target.

The endometrium histopathology and cell ultrastructure in bitches with pyometra induced using progesterone and Escherichia coli

BACKGROUND

We investigated uterine histopathological and ultrastructural changes in female dogs with pyometra induced by Escherichia coli (E. coli) inoculation using progesterone and/or estradiol.

METHODS

Dogs were ovariectomized and classified into six groups: Groups 1-6 corresponding to estradiol treatment followed by progesterone supplementation, progesterone supplementation only, estradiol supplementation only, simultaneous treatment using estradiol and progesterone, similar to Group 1 but with a double dose, and control group, respectively.

RESULTS

Pyometra was successfully induced in Groups 1, 2, 4, and 5, but not in Group 3. An uneven endometrial surface was observed, along with a purulent discharge, bleeding, inflammatory lesions, cystic endometrial hyperplasia (CEH) or cystic endometrial atrophy. Endometrial thickness percentage, uterine wall thickness, and the percentage of endometrial cyst area increased. Endometrial epithelial mushroom-like hyperplasia and the honeycomb-like structure exposed under the epithelium after flaky exfoliation were found, and the glandular epithelial villi became longer or shorter. Mitochondria expansion and increased lysosome were observed. Endoplasmic reticulum dilation and swelling and many inflammatory cells, especially plasma cell infiltration in the stroma, were found.

CONCLUSIONS

Endometrial histopathology and ultrastructural changes in affected dogs were accompanied by induction of pyometra, and they were affected by different hormonal patterns and E. coli.

Changed Expression of Cytoskeleton Proteins During Lung Injury in a Mouse Model of Streptococcus pneumoniae Infection

Infections by Streptococcus pneumoniae are a major cause of morbidity and mortality worldwide, often causing community-acquired pneumonia, otitis media and also bacteremia and meningitis. Studies on S. pneumoniae are mainly focused on its virulence or capacity to evade the host immune system, but little is known about the injury caused in lungs during a pneumococcal infection. Herein we investigated this issue comparing the proteome profile of lungs from S. pneumoniae-infected mice with control mice by means of difference gel electrophoresis (DIGE) technology. In order to obtain reliable results three biological replicas were used, and four technical replicas were carried out in each biological replica. Proteomic comparison was performed at two time points: 24 and 48 h post infection. A total of 91 proteins were identified with different abundance. We found important changes in the protein profiles during pneumococcal infection mainly associated with regulation of vesicle-mediated transport, wound healing, and cytoskeleton organization. In conclusion, the results obtained show that the cytoskeleton of the host cell is modified in S. pneumoniae infection.

Serum insulin-like growth factor-1 and C-reactive protein concentrations before and after ovariohysterectomy in bitches with pyometra

Pyometra is one of the most common diseases of the reproductive system in bitches. The inflammatory processes occurring in the uterus result in changes in concentrations of numerous serum biomarkers, which are used for monitoring the postoperative period. The aim of the present report was to study the evolution of serum levels of insulin-like growth factor-1 (IGF-1) and C-reactive protein (CRP) in bitches suffered from pyometra and after ovariohysterectomy in comparison with the control group of healthy dogs submitted to the surgery. Our results indicate that the serum level of IGF-1 is decreased (101.6 ng/mL [73.8-177.8 ng/mL]), whereas CRP is increased (114.6 μg/mL [95.3-131.6 μg/mL]) during severe inflammation. When inflammation caused by pyometra and surgery is resolved, the level of IGF-1 is increased (186.0 ng/mL [94.6-344.3 ng/mL], P < 0.05) and CRP decreased (23.3 μg/mL [9.9-77.0 μg/mL], P < 0.01), suggesting that these markers could be useful for assessment of the postoperative period in bitches.

Cancer screening tests for small animals

Cancer is increasingly more common. Several tests for the diagnosis and treatment of cancer in companion animals have been developed. Screening tests discussed include those for lymphoid neoplasia, hemangiosarcoma, and transitional cell carcinoma of the bladder. None of these tests should be used in isolation for diagnosis. Vincristine and doxorubicin are mainstays in the treatment of canine lymphoma. However, it is important and accepted practice to test individuals of predisposed breeds for this mutation before administering these drugs in a lymphoma protocol.

Microarray Analysis of Antigen-Dependent B-Cell Activation Gene Expression in Bitches with Pyometra

Canine pyometra is defined as a complex disease associated with activation and proliferation of immune specific cells, B and T cells, as well as synthesis and activation of immune and pro-inflammatory molecules. Although all of these mechanisms are well recognized in several human immune diseases and cancers, the possible role or dysfunction of these molecules in dogs with pyometra still requires investigation. This study was aimed to examine antigen-dependent B-cell activation gene expression (CD4, CD28, CD40, CD80, Fas, HLA-DRB1 and IL10) in a total of 24 mixed-breed bitch uteri with pyometra and 20 healthy controls. Using canine RNA microarray assays (Affymetrix) altogether 17,138 different transcripts were analyzed. A significant increase was found of CD28, CD40, HLA-DRB1 (P<0.001), and CD4, CD80, Fas and IL10 (P<0.01) in the group of bitches with pyometra, as compared to controls. In the affected group an increased share of CD4, CD28, CD40, CD80, Fas, HLA-DRB1 and IL10, (13.6-, 2.8-, 2.9-, 5.6-, 3.3-, 4.4-, and 6.5-fold increase, respectively) was also detected. It is suggested that an increased expression of B cell-specific immune response molecules may be associated with recruitment of immunologically specific cells in bitches with pyometra as well as with activation of pro-inflammatory proteins as a consequence of exposure to foreign antigens due to bacterial infection.