Long-term effect of neutering on plasma luteinising hormone concentration in cats

Somatic GNAQ, CTNNB1, and CACNA1C Mutations in Cat Aldosterone-Secreting Tumors

BACKGROUND

Primary aldosteronism (PA) is a common cause of human hypertension. Somatic mutations in KCNJ5, CACNA1D, ATP1A1, and ATP2B3 are found in at least 80% of aldosterone-producing adenomas, which cause unilateral PA in humans. Somatic mutations have been identified infrequently in 7 other genes; few of these were known to play a role in aldosterone secretion before the discovery of their mutations. Interrogating somatic mutations in the domestic cat, in which spontaneous PA is also known to occur, might improve the understanding of normal adrenal gland physiology and the pathophysiology of PA.

METHODS

DNA and RNA extracted from tissue from 13 cats with unilateral aldosterone-secreting tumors, including 8 carcinomas and 5 adenomas, underwent whole genome sequencing, targeted Sanger sequencing, and RNA sequencing. Single-nucleotide substitution variants were filtered to select those with a predicted deleterious effect on protein function and a suspected role in aldosterone secretion.

RESULTS

Probable functional somatic single-nucleotide polymorphisms (n=8) were found in 3 adenomas and 2 carcinomas. Mutations with predicted significant effects were identified in 2 genes also mutated in human PA; GNAQ and CTNNB1, and in a residue of CACNA1C analogous to a common CACNA1D mutation. In contrast to humans, CACNA1C expression was much greater than CACNA1D in both feline tumor and nontumor adrenal tissue. No mutations were identified in KCNJ5, CACNA1D, ATP1A1, or ATP2B3.

CONCLUSIONS

Similar mutations were identified in cats to those found in humans. It is, therefore, likely that both species have shared underlying selection pressures for mutations that increase aldosterone secretion.

Antibody fragments targeting the extracellular domain of follicular stimulating hormone receptor for contraception in male dogs and cats

The increased LH levels resulting from the absence of negative feedback after castration has been linked to long-term health issues. A need exists for an alternative contraceptive agent that functions without interfering the LH pathways. This study aimed to develop antibody fragments against the follicular-stimulating hormone receptor (anti-FSHr) using phage-display technology and evaluate its effects on Sertoli cell functions. Phage clones against the extracellular domain of dog and cat FSHr selected from an antibody fragment phagemid library were analyzed for binding kinetics by surface plasmon resonance. Sertoli cells were isolated from testes of adult animals (five dogs and five cats). Efficacy test was performed by treating Sertoli cell cultures (SCCs) with anti-FSHr antibody fragments compared with untreated in triplicates. Expressions of androgen binding protein (ABP), inhibin subunit beta B (IHBB) and vascular endothelial growth factor A (VEGFA) mRNA in SCCs were quantified by RT-qPCR. The results demonstrated that the molecular weight of the purified dog and cat anti-FSHr antibody fragment was 25 kDa and 15 kDa, respectively. Based on protein molecular weight, the antibody fragment of dogs and cats was therefore, so-called single-chain variable fragments (scFv) and nanobody (nb), respectively. The binding affinity with dissociation constant (KD) was 2.32 × 10-7 M and 2.83 × 10-9 M for dog and cat anti-FSHr antibody fragments, respectively. The cross-binding kinetic interactions between the dog anti-FSHr scFv and the cat ECD of FSHr could not be fitted to the curves to determine the binding kinetics. However, the cross-binding affinity KD between the cat anti-FSHr nb and the dog ECD FSHr was 1.75 × 10-4 M. The mRNA expression of ABP, IHBB and VEGFA in SCCs was less (P < 0.05) in both dogs (12.26, 4.07 and 5.11 folds, respectively) and cats (39.53, 14.07 and 20.29 folds, respectively) treated with anti-FSHr antibody fragments, indicating the Sertoli cell functions were suppressed. In conclusion, this study demonstrated the establishment of species-specific antibody fragments against FSHr in SCCs for dogs and cats. The fragment proteins illustrate potential to be developed as non-surgical contraceptive agent targeting FSHr in companion animals.

Clinical Characterisation of Caudal Traumatic Malocclusions and Treatment Outcomes in Cats (2018-2022)

Caudal malocclusions in cats may result in a variety of traumatic lesions affecting the soft tissues of the ipsilateral mandible such as fovea, gingival cleft, and proliferative lesions. Fifty-one cats diagnosed with a traumatic caudal malocclusion were compared with a control hospital population and evaluated for prevalence with respect to breed and sex. Twenty-two cats that were treated had radiographic, clinical findings, and the outcome of treatment (extraction or odontoplasty) recorded. Maine Coon, Persian, and male neutered cats were overrepresented while Domestic Shorthairs were underrepresented within the study population. Radiographically, 50% of the fovea lesions had an area of decreased bone density in the region of the lesion and none of these had evidence of periodontal disease. All gingival cleft lesions had radiographic changes consistent with periodontal disease. 15.4% of proliferative lesions presented with radiographic changes, with only half of those presenting with both radiographic and clinical evidence of periodontal disease. Eleven cats were treated by odontoplasty and eleven by extraction. One cat treated by odontoplasty developed new lesions caudally, and another had persistence of the initial lesions. Two cats in the extraction group developed new lesions rostral to the extracted teeth. In most instances, odontoplasty or extraction resulted in successful soft tissue lesion resolution. In rare cases, additional treatment was necessary due to either persistence or development of new lesions.