Prednisolone-induced diabetes mellitus in the cat: a historical cohort

Remission of diabetes mellitus induced by prednisolone in combination with cyclosporine toxicity in a cat

A 6-year-old spayed female domestic short-hair cat was presented for primary complaints of anorexia and lethargy. The cat was being treated with cyclosporine (25 mg/cat, PO q24h) and prednisolone (1 mg/kg, PO q12h) for feline hypersensitivity dermatitis and inflammatory bowel disease for 1 year, wherein prednisolone was withdrawn 2 weeks prior to presentation. At presentation, dehydration, hyperglycaemia, ketonaemia, increased fructosamine, glucosuria, ketonuria and metabolic acidosis were observed. The cat was diagnosed with diabetic ketoacidosis (DKA). Immediate treatments with insulin continuous-rate infusion and intravenous fluid therapy were initiated. A serum cyclosporine concentration was >2100 ng/mL, indicating cyclosporine toxicity. Cyclosporine was discontinued immediately. The cat's acidosis and ketonaemia were resolved within a week, allowing a switch from insulin continuous-rate infusion to subcutaneous glargine (1 IU/cat), which was eventually discontinued due to persistent normoglycaemia 12 days after initial presentation. Hyperglycaemia was not observed for 28 days thereafter without insulin, indicating remission of diabetes mellitus. This report suggests that using prednisolone, particularly immune suppressive doses, could be problematic in cats receiving long-term cyclosporine therapy. Additionally, diabetic cats receiving immune-suppressive agents can possibly achieve diabetic remission after surviving DKA through regular monitoring of blood glucose concentration, elimination of prednisolone and intensive blood glucose management.

Phenotypes of streptozotocin-induced gestational diabetes mellitus in mice

Gestational diabetes mellitus (GDM) in human patients disrupts glucose metabolism post-pregnancy, affecting fetal development. Although obesity and genetic factors increase GDM risk, a lack of suitable models impedes a comprehensive understanding of its pathology. To address this, we administered streptozotocin (STZ, 75 mg/kg) to C57BL/6N mice for two days before pregnancy, establishing a convenient GDM model. Pregnant mice exposed to STZ (STZ-pregnant) were compared with STZ-injected virgin mice (STZ-virgin), citrate buffer-injected virgin mice (CB-virgin), and pregnant mice injected with citrate buffer (CB-pregnant). STZ-pregnant non-obese mice exhibited elevated blood glucose levels on gestational day 15.5 and impaired glucose tolerance. They also showed fewer normal fetuses compared to CB-pregnant mice. Additionally, STZ-pregnant mice had the highest plasma C-peptide levels, with decreased pancreatic islets or increased alpha cells compared to CB-pregnant mice. Kidneys isolated from STZ-pregnant mice did not display histological alterations or changes in gene expression for the principal glucose transporters (GLUT2 and SGLT2) and renal injury-associated markers. Notably, STZ-pregnant mice displayed decreased gene expression of insulin-receiving molecules (ISNR and IGFR1), indicating heightened insulin resistance. Liver histology in STZ-pregnant mice remained unchanged except for a pregnancy-related increase in lipid droplets within hepatocytes. Furthermore, the duodenum of STZ-pregnant mice exhibited increased gene expression of ligand-degradable IGFR2 and decreased expression of GLUT5 and GLUT12 (fructose and glucose transporters, respectively) compared to STZ-virgin mice. Thus, STZ-pregnant mice displayed GDM-like symptoms, including fetal abnormalities, while organs adapted to impaired glucose metabolism by altering glucose transport and insulin reception without histopathological changes. STZ-pregnant mice offer a novel model for studying mild onset non-obese GDM and species-specific differences in GDM features between humans and animals.

Ionized hypercalcemia can resolve with nutritional modification in cats with idiopathic hypercalcemia or chronic kidney disease

CASE SERIES SUMMARY

Cats with ionized hypercalcemia that were fed diets with either more than 200 mg calcium per 100 kilocalories (kcal), a calcium:phosphorus (Ca:P) ratio greater than 1.4:1 or both, based on diet history, were included in this case series. Ionized hypercalcemia was documented at least twice in all cats before enrollment. Cats were referred for evaluation of ionized hypercalcemia (n = 5) or were incidentally found to have ionized hypercalcemia (n = 5). After medical workups, cats were diagnosed with either idiopathic hypercalcemia (IHC; n = 7) or chronic kidney disease (n = 3). Cats receiving medications to treat IHC (eg, alendronate, corticosteroids) were excluded. Nutritional recommendations were made to transition the cats to diets with less thn 200 mg calcium per 100 kcal and a Ca:P ratio less than 1.4:1. Ionized calcium (iCa) concentrations were rechecked in all cats, with a median recheck time of 9 weeks (range 3-20). Of the 10 cats, nine (90%) had a decrease in iCa. Of the 10 cats, six (60%) became normocalcemic after the diet change, three (30%) had a partial response and one (10%) did not respond. Of the four cats that did not achieve normocalcemia with a change in diet, two (50%) received chia seeds (1-2 g per day), and at the next recheck, both cats' iCa concentrations had normalized. Three cats had a long-term follow-up. Ionized normocalcemia was maintained for at least two consecutive follow-up visits over a median follow-up period of 33 weeks (range 12-34).

RELEVANCE AND NOVEL INFORMATION

Dietary calcium concentrations and the dietary Ca:P ratio appear to be important variables in considering nutritional approaches for hypercalcemic cats.

Reactions to environmental allergens in cats with feline lower airway disease

Objectives

Aeroallergens have been discussed as potential triggers for feline asthma (FA), which can be induced experimentally by allergen sensitization. To date, only few studies have investigated reactions to environmental allergens in cats with naturally occurring feline lower airway disease (FLAD). The aim of the study was to compare results of intradermal testing (IDT) and serum allergen-specific immunoglobulin E-(IgE) testing (SAT) in cats with FLAD, and to investigate possible associations with allergen exposure.

Material and methods

Eight cats with eosinophilic airway inflammation (EI), ten cats with mixed inflammation (MI), six with neutrophilic inflammation (NI), and 24 healthy cats (HC) were included. Cats diagnosed with FLAD were assigned to the different inflammatory groups based on bronchoalveolar lavage fluid (BLAF) cytology. SAT was performed in all cats; IDT was only carried out in cats with FLAD. Information about the cats' environment and potential allergen exposure was obtained using an owner questionnaire.

Results

In comparison to 83% of HC with positive reactions on SAT only 52% of cats with FLAD had positive responses (p = 0.051). Significantly more positive reactions per cat were detected on IDT than on SAT (p = 0.001). No significant difference was found for positive reactions per cat on SAT when compared between HC, NI, EI, and MI (p = 0.377). Only "slight" agreement was found for most allergens when reactions obtained in both tests in cats with FLAD were compared, except for "moderate" agreement for English plantain (k = 0.504) and Alternaria alternata (k = 0.488). Overall, no clear association between the cats' environment and allergen reactions were detected.

Conclusions and clinical importance

Interpretation of allergy test results in cats with FLAD should be done in the context of clinical signs and individual factors.

Assessment of glucocorticoid and antibiotic exposure as risk factors for diabetes mellitus in selected dog breeds attending UK primary-care clinics

BACKGROUND

Diabetes mellitus (DM) is an important endocrine disorder in dogs. This study explored prior exposure to glucocorticoids or antibiotic treatment as risk factors for developing DM in dogs attending primary-care VetCompass clinics in the UK.

METHODS

A breed frequency matched case-control study nested in a cohort of dogs (n = 480,469) aged 3 years or over was used to explore associations between glucocorticoid and antibiotic exposure and the odds of developing DM.

RESULTS

A total of 565 cases and 2179 controls were included. Dogs with DM had over four times the odds of exposure to glucocorticoids within 6 weeks prior to diagnosis (odds ratio [OR] 4.07, 95% confidence interval [CI] 2.41-6.89, p < 0.001) compared to controls within 6 weeks prior to a randomly selected quasi-date of diagnosis. Dogs that had only one unique documented antibiotic course had a decreased odds of developing DM (OR 0.65, 95% CI 0.46-0.91, p = 0.012) compared to dogs that had no documented courses of antibiotics.

LIMITATIONS

This study only included selected breeds, so the results may not be generalisable to all dog breeds.

CONCLUSIONS

Exposure to glucocorticoids is associated with a substantial increase in the risk of developing DM for the dog breeds included in this analysis.

Pathophysiology of Prediabetes, Diabetes, and Diabetic Remission in Cats

Diabetes mellitus (DM) has a heterogenous cause, and the exact pathogenesis differs between patients. Most diabetic cats have a cause similar to human type 2 DM but, in some, DM is associated with underlying conditions, such as hypersomatotropism, hyperadrenocorticism, or administration of diabetogenic drugs. Predisposing factors for feline DM include obesity, reduced physical activity, male sex, and increasing age. Gluco(lipo)toxicity and genetic predisposition also likely play roles in pathogenesis. Prediabetes cannot be accurately diagnosed in cats at the current time. Diabetic cats can enter remission, but relapses are common, as these cats might have ongoing, abnormal glucose homeostasis.

Histopathological evaluation of the adrenal glands in a cat with primary hypoadrenocorticism and multiple endocrine disease

Case summary

A 6-year-old male neutered domestic longhair cat was referred for investigation of weight loss, hyporexia, vomiting and diarrhoea. The cat was diagnosed with primary hypoadrenocorticism, exocrine pancreatic insufficiency, cobalamin deficiency and a chronic enteropathy, and started on therapeutic treatment. Diabetes mellitus developed 4.5 months later, and the cat was started on insulin therapy. The cat was euthanased 10 months following the diagnosis of hypoadrenocorticism due to the development of status epilepticus, which was not associated with glucose or electrolyte abnormalities. Histopathological assessment of the adrenal glands at post-mortem examination documented lymphoplasmacytic adrenalitis, with the lymphocytic population being predominant. Immunohistochemical staining classified the lymphocytic infiltrate as T-cell rich, supportive of the cat's hypoadrenocorticism being due to autoimmune disease.

Relevance and novel information

This case documents the novel use of immunohistochemical staining in combination with histopathology to further assess the adrenal glands in non-neoplastic-associated primary hypoadrenocorticism in a cat. This identified similar pathological changes to those previously described in dogs with autoimmune primary hypoadrenocorticism. Additionally, this is the first report of a cat with multiple endocrine disease that included primary hypoadrenocorticism and highlights that monitoring for the development of additional endocrine disease should be advised in these cases.

Prevalence of bacteriuria in cats with neurogenic bladder

Urinary tract infections are defined as the adherence, multiplication, and persistence of an infectious agent within the urogenital system, causing an associated inflammatory response and clinical signs; instead, the presence of bacteria in urine as determined by positive bacterial culture (PUC) from a properly collected urine specimen, in the absence of clinical signs, is defined subclinical bacteriuria. Limited information on the prevalence of PUC in spinal cord injury cats affected by neurogenic bladder (NB) is available. On contrary, in NB dogs and humans the prevalence of bacteriuria is well documented. Moreover, while in humans information about bacteriemia associated with NB is already available, this aspect has never been studied in NB cats. The aim of this prospective study was to determine the prevalence of PUC in cats with NB, compared to animals affected by chronic kidney disease (CKD) and healthy cats. Furthermore, the prevalence of bacteriemia in cats with NB was evaluated. Fifty-one cats met the inclusion criteria: 12 cats were affected by NB, 22 had CKD and 17 were healthy. The prevalence of PUC was 58.33% and 18% in NB and CKD cat populations, respectively. All blood cultures were negative. The incomplete bladder emptying and the decreased resistance in the bladder wall could be considered predisposing elements to PUC in the NB feline population. The results of this study highlight, for the first time, an high prevalence of PUC in cats affected by NB, which was not found to be associated with bacteriemia.

Is methylprednisolone acetate-related insulin resistance preventable in cats?

Methylprednisolone acetate (MPA) is often prescribed to cats despite being recognized eventually as diabetogenic. To assess MPA-related insulin resistance and evaluate the efficacy of metformin or an obesity and diabetes mellitus (O&D) adjuvant diet as protective factors, a randomized clinical trial was conducted with 28 owned cats undergoing glucocorticoid therapy. A single MPA dose of 20 mg intramuscularly was administered to each cat. Controls (n=10) received only MPA. In the diet group (n=9), replacement of their habitual diet by ad-libitum feeding of a feline commercial O&D diet (Equilíbrio O&D, Total Alimentos ADM) was made. In the metformin group (n=9), metformin chlorhydrate 25mg/cat PO/q24h was administered for 30 days. All patients were clinically evaluated at baseline (T0), day 15 (T15), and day 30 (T30) and blood draw for complete blood count, serum biochemistry, and determination of insulin concentrations. Fasting Insulin Sensitivity Index (SI), Amended Insulin to Glucose Ratio (AIGR), Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), and Homeostatic Model Assessment of beta-cell function (HOMA-B) were calculated based on fasting glycemia and insulinemia. All groups showed significantly higher levels (p < 0.05) of neutrophils, albumin, glucose, cholesterol, triglycerides, and serum insulin at T15. Patients in the metformin group showed also higher SI, AIGR, and HOMA-IR results at T15. Also, at T15, reduced levels (p < 0.05) of eosinophils, lymphocytes, and creatinine were documented in all groups. An MPA single dose induced changes in insulin sensitivity in cats; however, neither metformin nor O&D feeding used in this study was effective as protective factors against MPA-related insulin resistance.

Oral dexamethasone sodium phosphate solution significantly reduces pruritus and clinical lesions in feline hypersensitivity dermatitis: an open-label study

BACKGROUND

There are no liquid oral glucocorticoids labelled for management of pruritus and clinical lesions of feline hypersensitivity dermatitis (feline HD).

HYPOTHESIS

First, to demonstrate that dexamethasone sodium phosphate (DexSP, DexajectSP, Henry Schein; Dublin, OH, USA; 4 mg/mL), an intravenous glucocorticoid, can be absorbed by healthy cats when administered orally. Second, to demonstrate the efficacy of orally administered DexSP for reducing pruritus and clinical lesions in patients with feline HD.

ANIMALS

Seven healthy and 12 client-owned cats with HD.

METHODS AND MATERIALS

Healthy cats were administered a single dose of 0.2 mg/kg DexSP p.o. and serum concentrations were measured using enzyme-linked immunosorbent assay (ELISA). Feline HD patients were assessed with SCORing Feline Allergic Dermatitis (SCORFAD) and pruritus Visual Analog Scale (pVAS) at Visit 1 (V1) and after 20-31 days of receiving 0.2 mg/kg/day DexSP p.o. (V2). Complete blood cell counts, serum chemistry profile, and urinalysis were performed in 50% of feline HD patients at both visits.

RESULTS

Healthy cats had detectable serum concentrations of DexSP following oral administration; concentrations ranged from 0.7 to 92.3 ng/mL. Feline HD patients showed significant decreases in SCORFAD and pVAS scores from V1 to V2.

CONCLUSIONS

DexSP was absorbed when administered orally to healthy cats and 0.2 mg/kg/day DexSP is an efficacious dose to rapidly improve the pruritus and clinical lesions associated with feline HD.

Altered Renal Pathology in an Autoimmune Disease Mouse Model After Induction of Diabetes Mellitus

Diabetes mellitus (DM) is a predisposing factor for renal disorder progression and is referred to as diabetic kidney disease (DKD). However, there are no reports of DKD with an underlying autoimmune disorder. In this study, we compared the pathophysiological changes caused by DM induction after streptozotocin (STZ) injection in comparison with that in a control group receiving citrate buffer (CB) in the autoimmune disease model mice “BXSB/MpJ-Yaa” (Yaa) and the wild-type strain BXSB/MpJ. Both strains showed hyperglycemia after 12 weeks of STZ injection. Interestingly, the Yaa group developed membranous and proliferative glomerulonephritis, which tended to be milder glomerular lesions in the STZ group than in the CB group, as indicated by a decreased mesangial area and ameliorated albuminuria. Statistically, the indices for hyperglycemia and autoimmune abnormalities were negatively and positively correlated with the histopathological parameters for mesangial matrix production and glomerular proliferative lesions, respectively. STZ treatment induced renal tubular anisonucleosis and dilations in both strains, and they were more severe in Yaa. Significantly decreased cellular infiltration was observed in the Yaa group compared to the CB group. Thus, in DKD related to autoimmune nephritis, hyperglycemia modifies its pathology by decreasing the mesangial area and interstitial inflammation and aggravating renal tubular injury.