Recovery of insulin sensitivity in mature horses after a 3 week course of dexamethasone therapy

Effect of 5'-adenosine monophosphate-activated protein kinase agonists on insulin and glucose dynamics in experimentally induced insulin dysregulation in horses

BACKGROUND

5'-adenosine monophosphate-activated protein kinase (AMPK) agonists, particularly resveratrol (RES), have not been extensively evaluated for their effect on insulin dysregulation (ID) in horses.

OBJECTIVES

Evaluate the effects of treatment with RES (10 mg/kg PO q12h), metformin (MET; 30 mg/kg PO q12h), and aspirin (ASP; 20 mg/kg PO q24h) on experimentally induced ID.

ANIMALS

Thirty-three healthy, adult, light-breed horses.

METHODS

Unblinded, placebo-controlled, experimental trial evaluating effects of AMPK agonists (RES, MET, and ASP) on experimentally induced ID. Horses were randomly assigned to a treatment group (RES, MET/ASP, RES/ASP, RES/MET/ASP, or placebo [CON]) after induction of ID with dexamethasone (0.08 mg/kg PO q24h for 7 days). Frequently sampled insulin-modified IV glucose tolerance tests (FSIGTT) and oral sugar tests (OST) were performed at baseline, 7 days after ID, and ID plus 7 days of treatment. Minimal model and OST variables were compared between (1-way ANOVA) and within (1-way ANOVA for repeated measures) groups over time to determine effects of treatment on ID.

RESULTS

Administration of dexamethasone for 14 days resulted in significantly altered insulin and glucose dynamics (SI, DI, basal [glucose], and [insulin]) and produced clinical signs of laminitis in 5 out of 33 (15%) of horses included in the study. Combination therapy with RES, MET, and ASP did not significantly improve insulin and glucose dynamics in horses with experimentally induced ID.

CONCLUSIONS AND CLINICAL IMPORTANCE

Metabolic testing before glucocorticoid administration should be considered in horses with clinical signs of metabolic syndrome.

Nebulized glycosylated caffeic acid phenylether ester attenuation of environmental particulate-induced airway inflammation in horses

The objective of this study was to determine the extent that nebulized glycosylated caffeic acid phenylether ester-4-O-alpha-D-glucopyranoside (G-CAPE) attenuates particulate-induced airway inflammation in healthy horses. Our hypothesis was that nebulization with G-CAPE would result in improved respiratory scores, higher arterial oxygen partial pressure, and less inflammatory airway infiltrates in horses with induced airway inflammation, compared with untreated controls. Five healthy adult horses were housed inside a climate controlled, closed barn on straw bedding and fed ad lib moldy grass hay for 16 days to induce airway inflammation. An experimental crossover study was performed in which animals were treated with 200 mg G-CAPE dissolved in 45 mL of 10% triethanolamine (G-CAPE group) or 45 mL of 10% triethanolamine (CONTROL group), and clinical respiratory scoring, arterial blood gases, and bronchoalveolar lavages (BALs) were collected at predetermined time points up to 24 h post nebulization. While the mean neutrophil percentage decreased in treated horses compared to controls (9.3 ± 2.0 and 16.9 ± 2.4, respectively) at 6 hours post treatment (t = 6 h), the difference did not achieve statistical significance (p = 0.1154). Blood gas analysis did not differ significantly between groups. There was a significant difference in the mean respiratory scores of G-CAPE-treated horses between baseline and at 1-h post treatment (from 3.2 ± 0.7 to 1.6 ± 0.7, p = 0.0013). This study demonstrates that a single nebulized dose of G-CAPE decreased clinical respiratory scores 1 h post administration and decreased BAL percentage of neutrophils 6 h post administration in horses with particulate induced airway inflammation. This compound shows promise as an anti-inflammatory and warrants further investigation.

Glucocorticoid treatment in horses with asthma: A narrative review

Despite substantial research efforts to improve the treatment and outcome of horses with asthma, glucocorticoids (GC) remain the cornerstone of drug treatment of this prevalent disease. The high efficacy of GC to relieve airway obstruction explains their extensive use despite potential deleterious effects. However, much is yet to be uncovered concerning GC use in horses with asthma, including the comparative efficacy of the different drugs, the determination of minimal effective doses and the mechanisms underlying their variable modulation of airway inflammation. The objectives of this structured review were to report and compare the plethora of effects of the various GC used in asthmatic horses with a focus on impact on lung function, airway inflammation, and bronchial remodeling. Adverse effects are also briefly described, with an emphasis on those that have been specifically reported in horses with asthma. Ultimately, we aimed to highlight gaps in the literature and to identify future research areas.

Influence of endocrine disease on l-lactate concentrations in blood of ponies

Background

Blood l‐lactate concentrations are higher in people with developing or established diabetes mellitus and insulin resistance.

Objectives

To investigate whether blood l‐lactate concentrations are positively correlated with measures of insulin dysregulation (ID) or increased autumnal ACTH concentrations in ponies.

Animals

Systemically healthy client‐owned ponies (n = 101).

Methods

Prospective case‐control study. Blood samples were obtained from 101 clinically healthy ponies. Breed, weight, height, and subjective and objective measures of body condition were recorded. Blood l‐lactate, glucose, triglyceride, total adiponectin, and ACTH concentrations were measured and an oral sugar test (OST) was carried out. Correlations between blood l‐lactate and variables of endocrine health were determined.

Results

Using a seasonal cutoff point of ACTH concentrations ≥47 pg/mL, 55 ponies had increased autumnal ACTH concentrations and 45 did not. Using a basal insulin concentration of >50 μiU/mL, 42 ponies were diagnosed with ID and 58 were not. Using a 60 minutes after OST cutoff point of >45 μiU/mL, 57 ponies had ID and 37 did not. Blood l‐lactate concentrations were significantly lower in obese (average body condition score ≥ 7/9) compared to nonobese ponies (0.6 mmol/L; range, 0.0‐1.9 mmol/L vs 0.8 mmol/L; range, 0.3‐2.7 mmol/L; P = .01). No other significant correlations were detected. No differences were detected between ponies with and without increased autumnal ACTH concentrations (0.7 mmol/L; range, 0.0‐2.7 mmol/L vs 0.7 mmol/L; range, 0.3‐1.8 mmol/L; P = .84) and with and without ID (0.7 mmol/L; range, 0.3‐2.7 mmol/L vs 0.8 mmol/L; range, 0.0‐1.6 mmol/L; P = .63).

Conclusions and Clinical Importance

Results do not support an effect of endocrine status on l‐lactate concentrations in blood of ponies.

[Therapy of bullous pemphigoid in a Warmblood gelding]

A 15-year-old Warmblood gelding was presented with multiple large, ulcerative, and crusty dermal lesions that had been existing for 4 years. Histopathology of a skin biopsy revealed cleft formation at the dermal-epidermal junction beneath the basal cells and above the basement membrane leading to the diagnosis of bullous pemphigoid. Immunosuppressive therapy with dexamethasone and azathioprine was initiated and after 14 weeks full remission of the ulcers was achieved. Scar tissue formation was evident in the areas of the formerly affected lesions. Following medication tapering over a period of 5 months, long-term therapy was continued with a maintenance dose of 0.5 mg/kg azathioprine daily. The ulcerative lesions recurred after 63 weeks of disease stabilization. Additionally, adverse drug reactions (acute laminitis and increased susceptibility to infections) were evident and the gelding was euthanized due to animal welfare considerations.

Correlation between l-lactate and glucose concentrations and body condition score in healthy horses and ponies

Background

Blood l‐lactate and glucose concentrations were higher in ponies with gastrointestinal disease than in horses, possibly because of differences in body condition (BC).

Objectives

To investigate whether l‐lactate and glucose concentrations correlate with BC and differ between healthy horses and ponies.

Animals

Systemically healthy client‐owned ponies (n = 101) and horses (n = 51).

Methods

Prospective observational study. Breed, weight, height, and subjective and objective measures of BC were recorded and l‐lactate and glucose concentrations were measured. Correlations between l‐lactate and glucose concentrations and BC were established. The association between l‐lactate concentrations, equid type (pony or horse), BC, age, and glucose concentrations was investigated using a multivariable model.

Results

Weak but significant (P = .001) negative correlations were detected between l‐lactate concentration and average BC score (r = −0.29), heart girth:height ratio (r = −0.27), and age (r = −0.27). Glucose concentrations were significantly (P < .001) positively correlated with neck length:heart girth ratio (r = 0.37) and heart girth:height ratio (r = 0.31). l‐lactate and glucose concentrations were weakly correlated (r = 0.15; P = .04). In the final multivariable model, age (−0.02 ± 0.006; P = .001) and heart girth:height ratio (−1.74 ± 0.53; P = .001) were significantly associated with the natural logarithm of l‐lactate concentration (Lnl‐Lactate). This represents a 2% decrease in l‐lactate concentration per year increase in age and 10% decrease in l‐lactate concentration per 0.06 unit increase in heart girth:height ratio.

Conclusions and Clinical Importance

In healthy horses and ponies, age and BC significantly influence l‐lactate concentrations.

Metabolic and inflammatory responses to the common sweetener stevioside and a glycemic challenge in horses with equine metabolic syndrome

Extracts derived from the leaves of the stevia plant (stevioside) are commonly used as sweeteners for humans and horses. Stevioside appears to be safe for human consumption, including for individuals with insulin dysregulation. In the horse, the safety or metabolic effects of stevioside on normal animals or on those with metabolic dysfunction are unknown. Furthermore, the inflammatory response to a glycemic challenge or to stevioside in horses is not well defined. Therefore, the objective of this study was to measure the effects of stevioside and a glycemic challenge on insulin, glucose, and inflammatory responses in horses with a common metabolic dysfunction (equine metabolic syndrome or EMS) compared with non-EMS controls. To accomplish this, 15 horses were selected; 8 EMS and 7 age-matched controls. An oral sugar test was performed using Karo corn syrup (karo) or stevioside in a random crossover design. Horses were given 0.15 mL/kg body weight of karo or its equivalent grams of sugar in stevia dissolved in water. Blood samples were collected by jugular venipuncture before administration of either stevia or karo and at 60 and 240 min after administration. Serum was used for glucose and insulin determination and plasma for isolation of peripheral blood mononuclear cells (PBMCs) for inflammatory cytokine analysis via flow cytometry and reverse transcription PCR (RT-PCR). Stevia appeared to stimulate lower glycemic and insulinemic responses when compared to karo, in particular in EMS horses. EMS and control horses had inverse inflammatory responses to administration of either stevia or karo with EMS horses having a proinflammatory response (P ≤ 0.05). These data provide evidence as to why horses with EMS may be predisposed to developing laminitis, potentially as a result of an exaggerated inflammatory response to glycemic and insulinemic responses. Furthermore, the data provide new avenues for exploring mechanisms behind the syndrome, in particular when using a glycemic challenge.

Effect of ATorvastatin On Chronic subdural Hematoma (ATOCH): a study protocol for a randomized controlled trial

Background

Chronic subdural hematoma (CSDH) is a common disease that is more prevalent in older people. Surgical intervention is a safe treatment of choice. However, the recurrence rate is relatively high and the outcome is not always satisfactory among surgically treated patients. It is believed that aberrant angiogenesis and intracapsular inflammation contribute to the development of CSDH. Atorvastatin is reported to promote angiogenesis and suppress inflammation. We have recently shown that atorvastatin is effective to non-surgically reduce and eliminate CSDH with minimal side effects. Here, we report a clinical research trial protocol that is designed to evaluate the therapeutic effects of atorvastatin on CSDH.

Methods/Design

We have designed a multi-center, randomized, placebo-controlled, double blind clinical trial for evaluating the efficacy of oral atorvastatin in reducing CSDH. We have so far recruited 96 patients with CT-confirmed or MRI-confirmed CSDHs from 16 medical centers in China. These patients were originally recruited for the Oriental Neurosurgical Evidence-based Study Team (ONET) study. After informed consent is provided, patients are randomized to receive either atorvastatin (oral 20 mg/night for 8 weeks) or placebo (dextrin for 8 weeks); and followed for 16 weeks after the treatment. The primary outcome is the change in hematoma volume at the end of 8-week treatment. Secondary outcomes include: changes in 1) the hematoma volume at the 4^th, 12^th, and 24^th weeks; 2) Markwalder’s Grading Scale and Glasgow Coma Scale (MGS-GCS); 3) Glasgow Outcome Score (GOS) and 4) Activities of Daily Life – the Barthel Index scale (ADL-BI). Safety will be assessed during the study by monitoring adverse events, laboratory tests, electrocardiography (ECG), measurements of vital signs (temperature, pulse, and blood pressure) and body weight.

Discussion

Results of this trial will provide critical information regarding whether atorvastatin is an effective and safe alternative to surgical treatment of CSDH.

Trial registration

ClinicalTrials.gov Identifier – NCT02024373

The date of trial registration: 7 August 2013

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-015-1045-y) contains supplementary material, which is available to authorized users.