Prevalence of hypersomatotropism and hyperthyroidism in cats with diabetes mellitus from referral centers in Buenos Aires (2020-2022).

OBJECTIVES: The aim of this study was to estimate the prevalence of hypersomatotropism (HST) and hyperthyroidism in cats with diabetes mellitus (DM) from referral centers in Buenos Aires, Argentina. METHODS: This was a prospective study. Systematic screening of serum insulin-like growth factor 1 (IGF-1) and total thyroxine was performed in all cats diagnosed with DM at referral centers in Buenos Aires between February 2020 and February 2022. RESULTS: In total, 154 diabetic cats were evaluated (99 males and 55 females; median age 12 years [range 3-21]; mean body weight 5 kg [range 2-12]). Altogether, there were 115 (75%) domestic shorthairs and one domestic longhair; the remaining 38 cats were purebred (mainly Siamese, n = 25 [16%]). Twenty (12.9%) cats had IGF-1 concentrations >1000 ng/ml, and three (1.9%) had IGF-1 concentrations between 800 and 1000 ng/ml along with pituitary enlargement on CT, resulting in a 14.9% HST prevalence rate in diabetic cats. Intracranial imaging was performed in all cats with HST; median pituitary dorsoventral height was 5.8 mm (range 3.1-9.5). Fourteen of 23 (61%) cats had phenotypic changes consistent with acromegaly at the time of diagnosis of HST. Four of 154 (2.5%) cats had concurrent hyperthyroidism. CONCLUSIONS AND RELEVANCE: To date, this is the first study outside of Europe to have evaluated the prevalence of HST and hyperthyroidism in cats with DM. In Buenos Aires referral centers, feline HST is the most common concurrent endocrinopathy in cats with DM but with a lower prevalence than has previously been reported. Hyperthyroidism is a rare concurrent endocrinopathy in diabetic cats from referral centers in Buenos Aires.

Therapy for feline secondary hypertriglyceridemia with fenofibrate.

OBJECTIVES: The aim of this study was to assess the short-term safety and efficacy of fenofibrate in controlling secondary hypertriglyceridemia in cats. METHODS: This was a prospective cohort study. Seventeen adult cats with hypertriglyceridemia (serum triglycerides [TG] >160 mg/dl) were enrolled. Cats received a median dose of 5 mg/kg (range 3.2-6) fenofibrate (q24h PO) for 1 month. Serum TG, total cholesterol (TC), creatine kinase and liver enzymes (alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase) were evaluated before (t0) and after 1 month (t1) of fenofibrate treatment. RESULTS: The causes of secondary hypertriglyceridemia were diabetes mellitus (DM; 29.4%), obesity (29.4%), hyperadrenocorticism (HAC) and DM (11.7%), HAC without DM (5.9%), hypersomatotropism (HST) and DM (5.9%), hypothyroidism (5.9%), long-term treatment with glucocorticoids (5.9%) and chylothorax (5.9%). Serum TG (t0 median 920 mg/dl [range 237-1780]; t1 median 51 mg/dl [range 21-1001]; P = 0.0002) and TC (t0 median 278 mg/dl [range 103-502]; t1 median 156 mg/dl [range 66-244]; P = 0.0001) concentrations showed a significant decrease after 1 month of fenofibrate treatment. Fifteen cats normalized their TG concentration at t1 (88.2%). Of the eight cats that were hypercholesterolemic at t0, six (75%) normalized their TC concentrations at t1. One of 17 cats (5.9 %) presented with diarrhea; the remaining 16 did not show any adverse effects. CONCLUSIONS AND RELEVANCE: DM and obesity are the most common endocrine causes of secondary hyperlipidemia, although it can also be found in cats with HAC, HST or hypothyroidism. This study suggests that fenofibrate treatment was associated with reduction and normalization of TG and TC concentrations in cats with moderate and severe hypertriglyceridemia, regardless of the cause of secondary hypertriglyceridemia. Further work should focus on controlled studies with a greater number of cases.

Quality of life and response to treatment in cats with hypersomatotropism: the owners' point of view.

OBJECTIVES: The aim of this study was to collect clinical information from owners of cats with hypersomatotropism (HS) distributed worldwide, assessing the impact of HS and its treatments on cats' quality of life (QoL) and survival time. METHODS: A survey focused on clinical presentation, diagnostic procedures, treatments, cats' QoL and disease progression was distributed worldwide to owners of cats with HS. The owner's perception of the cats' QoL before and after or during treatment was defined using a score ranging from 1 (poor) to 5 (excellent). Improvement following treatment (IFT) was quantified using a score ranging from 1 (absent) to 5 (obvious). Different treatment groups, including at least five cases, were compared. RESULTS: A total of 127 cats were included from at least 11 different countries. Among these, 120 (95%) were diabetic and 7 (5%) were not. Out of 120 diabetic cats, 55 (46%) were treated with insulin as a single treatment (INS). Other treatments were not mentioned to owners in 35/120 (29%) cases. The median QoL score at diagnosis was 2 (range 1-5) and improved after treatment in all groups. Cabergoline (4; range 1-5), radiotherapy (4; range 2-5) and hypophysectomy (5; range 4-5) showed better median IFT scores compared with INS (3; range 1-5) (P = 0.046, P <0.002 and P <0.0001, respectively). Hypophysectomy IFT proved superior to cabergoline (P = 0.047) and was equal to radiotherapy IFT (P = 0.32). No difference was found between cabergoline and radiotherapy IFT (P = 0.99). The median survival time (MST) was 24 months (range 0-75 months). Cats treated with INS showed shorter MST (22 months; range 0-69 months) compared with cats treated with causal treatments combined (36 months; range 3-75 months) (P = 0.04). CONCLUSIONS AND RELEVANCE: Not all cats with HS will have diabetes mellitus. Causal treatments seem associated with the greatest improvements in perceived cats' QoL and survival; such treatments should therefore be discussed with owners. Cabergoline could be an effective alternative management option.

Cabergoline treatment in cats with diabetes mellitus and hypersomatotropism.

OBJECTIVES: The aim of this study was to evaluate the safety and efficacy of cabergoline to control hypersomatotropism (HST) and diabetes mellitus (DM) in cats. METHODS: This was a prospective cohort study. Twenty-three cats with HST and concurrent DM were enrolled. Cats received a dose of 10 µg/kg cabergoline q48h PO for 6 months. Serum insulin-like growth factor 1 (IGF-1) and fructosamine concentrations, insulin dose and Insulin Resistance Index (IRI) were measured at the time of diagnosis of HST and at the start of cabergoline treatment (t0), and 3 months (t1) and 6 months (t2) during cabergoline treatment. RESULTS: A decrease and normalization of serum IGF-1 concentration was observed in 35% and 26% of cats, respectively. Median IGF-1 (t0: 1350 ng/ml [range 832-1501]; t1: 1284 ng/ml [range 365-1501]; t2: 1240 ng/ml [range 263-1501]; P = 0.016) decreased significantly. Twelve cats underwent diagnostic imaging of the pituitary area. The median pituitary height at t0 of cats that experienced an IGF-1 reduction (n = 5/12) was significantly lower compared with those that did not experience an IGF-1 reduction (n = 7/12) (3.2 mm [range 3.1-3.7] vs 6 mm [range 3.5-9.5]; P = 0.011). Median fructosamine (t0: 628 µmol/l [range 400-963]; t1: 404 µmol/l [range 249-780]; t2: 400 µmol/l [range 260-815]; P <0.0001), insulin dose (t0: 1.3 IU/kg [range 0.5-4.6]; t0: 0.5 IU/kg [range 0-2.3]; t2: 0.4 IU/kg [range 0-2.1]; P <0.0001) and IRI (t0: 800 µmolIU/kgl [range 257-2700]; t1: 300 µmolIU/kgl [range 0-1498]; t2: 250 µmolIU/kgl [range 0-1498]; P <0.0001) decreased significantly during cabergoline treatment. Eight cats achieved diabetic remission between months 1 and 6 of cabergoline treatment (median time to achieve remission: 3 months [range 1-6]). Three cats experienced asymptomatic hypoglycemia. CONCLUSIONS AND RELEVANCE: Cabergoline was effective in normalizing IGF-1 concentration in 26% of cats. Cabergoline improved diabetes control and was associated with remission of DM in 35% of cases. Cabergoline could be a treatment option for cats with HST and DM, especially in those cases with a relatively small pituitary tumor.

Diabetes mellitus remission in a cat with hyperadrenocorticism after cabergoline treatment.

CASE SUMMARY: A 7-year-old spayed female domestic shorthair cat weighing 5 kg was referred with polyuria, polydipsia, lethargy, abdominal distension and dermatologic abnormalities. Diabetes mellitus was diagnosed and treatment was started with a diet for diabetic cats and insulin glargine (1 IU q12h SC). Hyperadrenocorticism (HAC) was suspected and diagnosed based on clinical signs, increased urinary cortisol:creatinine ratio, lack of suppression on low-dose dexamethasone suppression test and abdominal ultrasonography demonstrating bilateral adrenal enlargement. Oral cabergoline (10 µg/kg every other day) was initiated. After the second administration of cabergoline, the cat suffered from clinical hypoglycemia and no longer required insulin. One month after insulin withdrawal, blood work and urine analysis results showed normoglycemia, a normal serum fructosamine concentration (244 µmol/l) and normal urine analysis without glycosuria. Diabetic remission persisted until its death 7 months later. In addition, cabergoline treatment was associated with improvement in clinical signs such as lethargy, seborrhea, alopecia and abdominal distension. RELEVANCE AND NOVEL INFORMATION: To our knowledge, this is the first reported case of the use of cabergoline in a cat with HAC, as well as the first reported case of diabetic remission in a cat with HAC after cabergoline treatment. Cabergoline could be an alternative treatment for diabetic cats with pituitary-dependent HAC. Further work should focus on different protocols with greater number of cases.

Adrenal cortex stimulation with hCG in spayed female dogs with Cushing's syndrome: Is the LH-dependent variant possible?

Background: The expression and overexpression of luteinizing hormone (LH) receptors in the canine adrenal gland cortex have been reported. Therefore, it was hypothesized that a LH-dependent form of Cushing's syndrome (CS) could exist in dogs. Aim: To assess whether the adrenal gland post-ovariectomy (OVx) exhibits a greater response to adrenocorticotrophin (ACTH) stimulation; to evaluate whether the adrenal gland responds to human chorionic gonadotropin (hCG) stimulation by increasing the release of cortisol; and to consider whether hCG stimulus testing would be useful as a diagnosis for possible cases of LH-dependent CS. Methods: Cortisol concentrations were measured from healthy female dogs (n=16) at baseline and following ACTH stimulation before and 2 months after gonadectomy (OVx). Cortisol concentrations were also measured for female dogs with CS (n = 14) following administration of hCG (5000 IU). A post-hCG cortisol concentration greater than 140 nmol/l was used to define dogs with LH-dependent Cushing's syndrome. Results: In normal female dogs, both pre- and post-stimulation cortisol concentrations increased following OVx (p = 0.002 and p = 0.0003, respectively). In female dogs with CS, cortisol concentrations increased following stimulation with hCG in 57% (8/14; p = 0.002). Age at the time of OVx was associated (p = 0.015) with the cortisol response to hCG [8 (5-9) years vs. 3.5 (2-6) years, p = 0.0013). Conclusion: Based on these results, an LH-dependent form of CS occurs in spayed female dogs, and that it is more likely to occur when female dogs are spayed later in life.

Diabetes mellitus remission in three cats with hypersomatotropism after cabergoline treatment.

CASE SUMMARY: Three diabetic cats presented with polyuria, polydipsia, polyphagia and poor glycemic control. Cat 1 displayed prognathia inferior and had a body condition score (BCS) of 4/5; cat 2 had a BCS of 5/5; and cat 3 had broad facial features. Serum insulin-like growth factor 1 concentrations were compatible with hypersomatotropism in cat 1 and cat 2 (>1500 ng/ml and 1200 ng/ml, respectively) and just below the cut-off of 1000 ng/ml (947 ng/ml) in cat 3; in this last cat diagnosis was further supported by the presence of pituitary enlargement on MRI. Oral cabergoline (10 µg/kg q48h) was initiated. Insulin requirements progressively reduced, as evidenced by daily blood glucose monitoring and weekly blood glucose curves. Diabetic remission occurred in all three cats between the second and third months of cabergoline treatment. At the time of writing, remission has persisted thus far (cat 1: 23 months; cat 2: 14 months; cat 3: 38 months). RELEVANCE AND NOVEL INFORMATION: To our knowledge, these are the first reported cases of diabetic remission in cats with hypersomatotropism after cabergoline treatment, despite previous reports of this being an ineffective treatment. Further work is indicated to determine why some cats do, and others do not, respond to this treatment.

Decrease of nitric oxide and increase in diastolic blood pressure are two events that affect renal function in dogs with pituitary dependent hyperadrenocorticism.

Hyperadrenocorticism is a frequent disease in dogs. The excess of circulating cortisol affects different organs and metabolic pathways, producing severe adverse effects that endanger the animal's life. Among these effects, hypertension and renal damage can be mentioned. A group of 20 dogs with pituitary dependent hyperadrenocorticism (PDH) and 12 control dogs were used to study the following parameters: cortisol and nitric oxide (NO nit/nit) concentrations, diastolic and systolic blood pressure, renal artery resistance index by Doppler ultrasound, the rate of glomerular filtration by radio-renogram excretion and the presence of proteins in urine. Dogs with PDH showed a significantly lower NO nit/nit (P<0.0001) than the controls and this correlated with high values of diastolic and systolic pressure (r = -0.87; P<0.0001 and r = -0.81; P<0.0001 respectively). Most dogs (80%) are hypertensive mainly due to an increase in diastolic pressure, which correlated positively with the UPC (r = 0.8; P<0.001) and negatively with the glomerular rate of filtration (r = -0.58; P=0.007). Systolic pressure only increased in 60% of the cases and did not correlate with the mentioned variables. In PDH the decrease of NO affects blood pressure. The diastolic pressure would seem to have the greatest impact on the kidneys, therefore its evaluation and control are important to avoid and/or control renal damage.