Kris Gommeren

Oligofructose and inulin modulate glucose and amino acid metabolism through propionate production in normal-weight and obese cats

The effect of dietary oligofructose and inulin supplementation on glucose metabolism in obese and non-obese cats was assessed. Two diets were tested in a crossover design; a control diet high in protein (46 % on DM basis), moderate in fat (15 %), low in carbohydrates (27 %), but no soluble fibres added; and a prebiotic diet, with 2.5 % of a mixture of oligofructose and inulin added to the control diet. Eight non-obese and eight obese cats were allotted to each of two diets in random order at intervals of 4 weeks. At the end of each testing period, intravenous glucose tolerance tests were performed. Area under the glucose curve (AUCgluc) was increased (P = 0.022) and the second insulin peak was delayed (P = 0.009) in obese compared to non-obese cats. Diets did not affect fasting plasma glucose concentrations, blood glucose response at each glucose time-point after glucose administration, AUCgluc, fasting serum insulin concentrations, area under the insulin curve, and height and appearance time of insulin response. Yet, analysis of acylcarnitines revealed higher propionylcarnitine concentrations (P = 0.03) when fed the prebiotic diet, suggesting colonic fermentation and propionate absorption. Prebiotic supplementation reduced methylmalonylcarnitine (P = 0.072) and aspartate aminotransferase concentrations (P = 0.025), both indicating reduced gluconeogenesis from amino acids. This trial evidenced impaired glucose tolerance and altered insulin response to glucose administration in obese compared to non-obese cats, regardless of dietary intervention; yet modulation of glucose metabolism by enhancing gluconeogenesis from propionate and inhibition of amino acid catabolism can be suggested.

Effect of Thyroxine Supplementation on Glomerular Filtration Rate in Hypothyroid Dogs

BACKGROUNDnGlomerular filtration rate (GFR) is decreased in humans with hypothyroidism, but information about kidney function in dogs with hypothyroidism is lacking.nnnHYPOTHESISnHypothyroidism influences GFR in dogs. The objective of this study was to assess GFR in hypothyroid dogs before implementation of thyroxine supplementation and after re-establishing euthyroidism.nnnANIMALSnFourteen hypothyroid dogs without abnormalities on renal ultrasound examination or urinalysis.nnnMETHODSnBlood pressure and GFR (measured by exogenous creatinine clearance) were measured before treatment (T0, n=14) and at 1 month (T1, n=14) and at 6 months (T6, n=11) after beginning levothyroxine supplementation therapy (20 microg/kg/d, PO). The response to therapy was monitored at T1 by measuring serum total thyroxine and thyroid stimulating hormone concentrations. If needed, levothyroxine dosage was adjusted and reassessed after 1 month. Statistical analysis was performed using a general linear model. Results are expressed as mean+/-standard deviation.nnnRESULTSnAt T0, the average age of dogs in the study group was 6.3+/-1.4 years. Their average body weight decreased from 35+/-18 kg at T0 to 27+/-14 kg at T6 (P<.05). All dogs remained normotensive throughout the study. GFR increased significantly with levothyroxine supplementation; the corresponding results were 1.6+/-0.4 mL/min/kg at T0, 2.1+/-0.4 at T1, and 2.0+/-0.4 at T6 (P<.01).nnnCONCLUSIONnGFR was <2 mL/min/kg in untreated hypothyroid dogs. Re-establishment of a euthyroid state increased GFR significantly.

The glucose and insulin response to isoenergetic reduction of dietary energy sources in a true carnivore: the domestic cat ( Felis catus )

The present study assessed the effect of separate reduction of each energy-delivering nutrient - protein, fat and carbohydrate - on glucose tolerance and insulin response in a strict carnivore: the domestic cat (Felis catus). Three isoenergetic, home-made diets with the following energetic distribution, low protein (LP): protein 28 % of metabolisable energy; fat 43 %; nitrogen-free extract 29 %; low fat: 47, 27 and 25 %; low carbohydrate (LC): 45, 48 and 7 %, were tested in a 3 x 3 Latin square design. Nine healthy normal-weight cats were randomly assigned to each of the diets in a random order at intervals of 3 weeks. At the end of each testing period, intravenous glucose tolerance tests were performed. Plasma glucose concentrations and area under the glucose curve showed no differences. Area under the insulin curve was lower when cats were fed the LP diet, and the second insulin peak tended to be delayed when the LC diet was fed. In contrast to other studies, in which energy sources were elevated instead of being reduced, the present trial contradicts the often suggested negative impact of carbohydrates on insulin sensitivity in carnivores, and shows that reducing the dietary carbohydrate content below common amounts for commercial foods evokes an insulin-resistant state, which can be explained by the cats strict carnivorous nature. It even points to a negative effect of protein on insulin sensitivity, a finding that corresponds with the highly gluconeogenic nature of amino acids in strict carnivores.

Effect of recombinant human thyroid stimulating hormone on serum thyroxin and thyroid scintigraphy in euthyroid cats

This study investigated the thyroidal response to administration of recombinant human thyroid stimulating hormone (rhTSH) by means of serum total thyroxine (TT4) concentration and pertechnetate uptake by the thyroid gland in six healthy euthyroid spayed female cats. A pertechnetate scan was performed on day 1 to calculate thyroid/salivary gland (T/S) uptake ratio. On day 3, 25 μg rhTSH was injected intravenously. Six hours later the thyroid scan was repeated as on day 1. Blood was drawn for serum TT4 measurement prior to injection of rhTSH and performance of the pertechnetate scan. Statistically significant differences in mean serum TT4 concentration, T/S uptake ratio before and 6 h after rhTSH administration and T/S uptake ratio between left and right lobes were noted. We can conclude that 25 μg rhTSH increases pertechnetate uptake in the thyroid glands of cats, this should be taken into account when thyroid scintigraphy after rhTSH administration is interpreted.

Outcome from status epilepticus after portosystemic shunt attenuation in 3 dogs treated with propofol and phenobarbital

Objective – To describe outcome of treatment with propofol and phenobarbital for status epilepticus (SE) after portosystemic shunt (PSS) attenuation. n nCase or Series Summary – Three dogs without preceding seizure activity, were diagnosed with a single extrahepatic PSS. Following standard preoperative medical therapy, an ameroid constrictor was placed surgically. Recovery was uneventful until spontaneous SE developed 46–96 hours after surgery. After unsuccessful seizure control with benzodiazepines, dogs were treated with a bolus of propofol followed by a propofol constant rate infusion. Phenobarbital was concurrently administered and supportive care was optimized. All dogs recovered uneventfully over the next 7–9 days. Over the following months phenobarbital was slowly tapered. All dogs have been free from antiepileptic drugs for several months, without recurrence of neurologic signs. n nNew or Unique Information Provided – In this case series, we describe the treatment of 3 dogs with propofol and phenobarbital for refractory SE following attenuation of a single congenital PSS. After weaning of the propofol constant rate infusion, and tapering and discontinuation of phenobarbital over the following months, all dogs experienced a complete recovery. This study provides evidence that use of propofol in combination with phenobarbital may be efficacious for management of SE in dogs after PSS surgery.OBJECTIVEnTo describe outcome of treatment with propofol and phenobarbital for status epilepticus (SE) after portosystemic shunt (PSS) attenuation.nnnCASE OR SERIES SUMMARYnThree dogs without preceding seizure activity, were diagnosed with a single extrahepatic PSS. Following standard preoperative medical therapy, an ameroid constrictor was placed surgically. Recovery was uneventful until spontaneous SE developed 46-96 hours after surgery. After unsuccessful seizure control with benzodiazepines, dogs were treated with a bolus of propofol followed by a propofol constant rate infusion. Phenobarbital was concurrently administered and supportive care was optimized. All dogs recovered uneventfully over the next 7-9 days. Over the following months phenobarbital was slowly tapered. All dogs have been free from antiepileptic drugs for several months, without recurrence of neurologic signs.nnnNEW OR UNIQUE INFORMATION PROVIDEDnIn this case series, we describe the treatment of 3 dogs with propofol and phenobarbital for refractory SE following attenuation of a single congenital PSS. After weaning of the propofol constant rate infusion, and tapering and discontinuation of phenobarbital over the following months, all dogs experienced a complete recovery. This study provides evidence that use of propofol in combination with phenobarbital may be efficacious for management of SE in dogs after PSS surgery.

Clinical evaluation of a novel liquid formulation of L-thyroxine for once daily treatment of dogs with hypothyroidism.

BACKGROUNDnA liquid solution of levothyroxine (L-T4) is available for treatment of canine hypothyroidism.nnnHYPOTHESISnOnce daily oral administration of a liquid L-T4 solution is effective and safe for controlling hypothyroidism in dogs.nnnANIMALSnThirty-five dogs with naturally occurring hypothyroidism.nnnMETHODSnDogs received L-T4 solution PO once daily at a starting dosage of 20 microg/kg body weight (BW). The dose was adjusted every 4 weeks, based on clinical signs and peak serum total T4 (tT4) concentrations. Target peak serum tT4 and thyroid stimulating hormone (TSH) concentrations, 4-6 hours posttreatment, were 35-95 nmol/L and < 0.68 ng/mL, respectively. Dogs were followed for up to 22 weeks after establishment of the maintenance dose.nnnRESULTSnClinical signs of hypothyroidism improved or resolved in 91% of dogs after 4 weeks of L-T4 treatment at 20 microg/kg once daily. The maintenance dose was established in 76, 94, and 100% of dogs after 4, 8, and 12 weeks of treatment, respectively. This was 20 microg L-T4/kg BW for 79% of the dogs, 30 microg/kg BW for 15%, and 10-15 microg/kg BW in the remaining 6%, once daily. Thereafter, median peak tT4 and TSH concentrations were 51 nmol/L and 0.18 ng/mL, respectively, and remained stable during the 22-week follow-up; clinical signs did not recur.nnnCONCLUSIONS AND CLINICAL IMPORTANCEnAll of the hypothyroid dogs had rapid clinical and hormonal responses to supplementation with the PO-administered L-T4 solution. The starting dosage of 20 microg L-T4/kg BW once daily was suitable for 79% of dogs.