Psyllium husk powder increases defecation frequency and faecal score, bulk and moisture in healthy cats.

OBJECTIVES: Constipation is the infrequent or difficult emission of hard, dry faeces and is a common digestive condition in cats. Psyllium is a low-fermentable fibre, with soluble and insoluble components and water-holding properties. It forms a mucilaginous gel with water and is used for the symptomatic treatment of constipation in various species. This study evaluated the effect of dietary psyllium on faecal characteristics in cats. METHODS: Healthy neutered adult cats (six female and three male, aged 3.3-4.4 years) were consecutively fed a dry extruded diet containing either 6% psyllium (test) or 6% cellulose (control) for 10 days each. During the last 3 days (the collection days) of both feeding periods, bowel movements and faecal scores were recorded, and faeces were collected to measure wet weight and moisture. The statistical analysis used linear mixed models with diet, day and their interaction as fixed effects and animal as a random term. RESULTS: The test diet was associated with significantly more bowel movements per day over 3 days (P = 0.0052) and on collection day 2 (P = 0.0229) than the control diet. The mean faecal score was higher (softer faeces) over all three collection days (P <0.0001) and on collection days 1, 2 and 3 (P = 0.0011, P = 0.0349, P = 0.0003, respectively) for the test diet vs the control diet; the total faecal wet weight (P = 0.0003) and faecal moisture (%) were also higher (P = 0.0426) for the test diet. Faeces associated with the test diet often had a dry shell and soft interior, which increased the faecal score. CONCLUSIONS AND RELEVANCE: Psyllium promoted more bowel movements and higher faecal moisture and faecal score in healthy cats, consistent with a previous uncontrolled clinical trial in constipated cats. Together, the studies support the use of dietary psyllium for managing cats with constipation.

Time-course and regional analyses of the physiopathological changes induced after cerebral injection of an amyloid ß fragment in rats.

Alzheimer's disease (AD) is a neurodegenerative pathology characterized by the presence of senile plaques and neurofibrillary tangles, accompanied by synaptic and neuronal loss. The major component of senile plaques is an amyloid ß protein (Aß) formed by pathological processing of the Aß precursor protein. We assessed the time-course and regional effects of a single intracerebroventricular injection of aggregated Aß fragment 25-35 (Aß(25-35)) in rats. Using a combined biochemical, behavioral, and morphological approach, we analyzed the peptide effects after 1, 2, and 3 weeks in the hippocampus, cortex, amygdala, and hypothalamus. The scrambled Aß(25-35) peptide was used as negative control. The aggregated forms of Aß peptides were first characterized using electron microscopy, infrared spectroscopy, and Congo Red staining. Intracerebroventricular injection of Aß(25-35) decreased body weight, induced short- and long-term memory impairments, increased endocrine stress, cerebral oxidative and cellular stress, neuroinflammation, and neuroprotective reactions, and modified endogenous amyloid processing, with specific time-course and regional responses. Moreover, Aß(25-35), the presence of which was shown in the different brain structures and over 3 weeks, provoked a rapid glial activation, acetylcholine homeostasis perturbation, and hippocampal morphological alterations. In conclusion, the acute intracerebroventricular Aß(25-35) injection induced substantial central modifications in rats, highly reminiscent of the human physiopathology, that could contribute to physiological and cognitive deficits observed in AD.

Use of reduced-energy content maintenance diets for modest weight reduction in overweight cats and dogs.

One option for controlled weight loss for dogs and cats in overweight condition could be to modestly restrict caloric intake using a reduced-energy ('light') maintenance diet, but there is no prior research on the safety and efficacy of such an approach. A prospective observational cohort study was performed in 67 overweight dogs and 17 overweight cats undergoing weight loss using reduced-energy maintenance diets from one manufacturer. Diets were fed at approximately 80% of maintenance energy requirements for ideal bodyweight for a period of 8 weeks. Essential nutrient intake was estimated for each dog and cat and compared with minimum requirement (MR) or adequate intake (AI, when no MR had been demonstrated) as set by the National Research Council in 2006. Weight loss was seen in 56/67 dogs (84%), losing a median of 4.7% (range 15.2% loss to 10.0% gain) of their starting body weight (SBW). Weight loss was also seen in all 17 cats, losing a median of 6.4% (range 2.0 loss to 15.2% loss) of SBW. Of the essential nutrients examined, only selenium, choline, potassium, and riboflavin were less than NRC recommendations in a minority of animals. However, no signs of any nutrient deficiency were observed in any of the dogs or cats during the study. In summary, modestly energy restricting overweight dogs and cats when feeding a low-energy maintenance diet can induce weight loss and might be a useful initial step for weight management. Although no adverse effects were seen, borderline intake of some micronutrients warrants further consideration.

In vivo and ex vivo analyses of amyloid toxicity in the Tc1 mouse model of Down syndrome.

RATIONALE: The prevalence of Alzheimer's disease is increased in people with Down syndrome. The pathology appears much earlier than in the general population, suggesting a predisposition to develop Alzheimer's disease. Down syndrome results from trisomy of human chromosome 21, leading to overexpression of possible Alzheimer's disease candidate genes, such as amyloid precursor protein gene. To better understand how the Down syndrome context results in increased vulnerability to Alzheimer's disease, we analysed amyloid-ß [25-35] peptide toxicity in the Tc1 mouse model of Down syndrome, in which ~75% of protein coding genes are functionally trisomic but, importantly, not amyloid precursor protein. RESULTS: Intracerebroventricular injection of oligomeric amyloid-ß [25-35] peptide in three-month-old wildtype mice induced learning deficits, oxidative stress, synaptic marker alterations, activation of glycogen synthase kinase-3ß, inhibition of protein kinase B (AKT), and apoptotic pathways as compared to scrambled peptide-treated wildtype mice. Scrambled peptide-treated Tc1 mice presented high levels of toxicity markers as compared to wildtype mice. Amyloid-ß [25-35] peptide injection in Tc1 mice induced significant learning deficits and enhanced glycogen synthase kinase-3ß activity in the cortex and expression of apoptotic markers in the hippocampus and cortex. Interestingly, several markers, including oxidative stress, synaptic markers, glycogen synthase kinase-3ß activity in the hippocampus and AKT activity in the hippocampus and cortex, were unaffected by amyloid-ß [25-35] peptide injection in Tc1 mice. CONCLUSIONS: Tc1 mice present several toxicity markers similar to those observed in amyloid-ß [25-35] peptide-treated wildtype mice, suggesting that developmental modifications in these mice modify their response to amyloid peptide. However, amyloid toxicity led to severe memory deficits in this Down syndrome mouse model.

In Vivo Characterization of ARN14140, a Memantine/Galantamine-Based Multi-Target Compound for Alzheimer's Disease.

Alzheimer's disease (AD) is a chronic pathological condition that leads to neurodegeneration, loss of intellectual abilities, including cognition and memory, and ultimately to death. It is widely recognized that AD is a multifactorial disease, where different pathological cascades (mainly amyloid and tau) contribute to neural death and to the clinical outcome related to the disease. The currently available drugs for AD were developed according to the one-target, one-drug paradigm. In recent times, multi-target strategies have begun to play an increasingly central role in the discovery of more efficacious candidates for complex neurological conditions, including AD. In this study, we report on the in vivo pharmacological characterization of ARN14140, a new chemical entity, which was obtained through a multi-target structure-activity relationship campaign, and which showed a balanced inhibiting profile against the acetylcholinesterase enzyme and the NMDA receptor. Based on the initial promising biochemical data, ARN14140 is here studied in mice treated with the amyloidogenic fragment 25-35 of the amyloid-ß peptide, a consolidated non-transgenic AD model. Sub-chronically treating animals with ARN14140 leads to a prevention of the cognitive impairment and of biomarker levels connected to neurodegeneration, demonstrating its neuroprotective potential as new AD agent.

Leucettine L41, a DYRK1A-preferential DYRKs/CLKs inhibitor, prevents memory impairments and neurotoxicity induced by oligomeric Aß25-35 peptide administration in mice.

Dual-specificity tyrosine phosphorylation-regulated kinases (DYRKs) and cdc2-like kinases (CLKs) are implicated in the onset and progression of Down syndrome (DS) and Alzheimer's disease (AD). DYRK1A has emerged as a possible link between amyloid-ß (Aß) and Tau, the major pathological proteins in AD. We here assessed the neuroprotective potential of a novel inhibitor of DYRKs/CLKs. The Leucettine L41, acting preferentially on DYRK1A, was tested in Aß25-35-treated mice, a nontransgenic model of AD-like toxicity. We co-injected intracerebroventricularly oligomeric Aß25-35 peptide and L41 in Swiss male mice. After 7 days, they were submitted to behavioral tests addressing spatial and non-spatial, short- and long-term memories. The oxidative stress, apoptotic markers, kinases involved in Tau phosphorylation, and synaptic integrity were analyzed by Western blot and ELISA in the hippocampus. L41, tested at 0.4, 1.2, 4 µg, prevented the Aß25-35-induced memory deficits in the Y-maze, passive avoidance and water-maze tests, with the most active dose being 4 µg. The inhibitor prevented the Aß25-35-induced oxidative stress, as revealed by measures of lipid peroxidation levels and reactive oxygen species accumulation, and abolished Aß25-35-induced expression of pro-apoptotic markers. L41 prevented the Aß25-35-induced decrease of AKT activation and increase of glycogen synthase kinase-3ß (GSK-3ß) activation, resulting in a decrease of Tau phosphorylation. Finally, L41 restored Aß25-35-reduced levels of synaptic markers. The novel DYRK1A-preferential inhibitor L41 therefore prevented Aß25-35-induced memory impairments and neurotoxicity in the mouse hippocampus. These in vivo data highlighted particularly DYRK1A as a major kinase involved in Aß pathology and suggested therapeutic developments for DYRK1A inhibitors in AD.

Alzheimer's disease related markers, cellular toxicity and behavioral deficits induced six weeks after oligomeric amyloid-ß peptide injection in rats.

Alzheimer's disease (AD) is a neurodegenerative pathology associated with aging characterized by the presence of senile plaques and neurofibrillary tangles that finally result in synaptic and neuronal loss. The major component of senile plaques is an amyloid-ß protein (Aß). Recently, we characterized the effects of a single intracerebroventricular (icv) injection of Aß fragment (25-35) oligomers (oAß(25-35)) for up to 3 weeks in rats and established a clear parallel with numerous relevant signs of AD. To clarify the long-term effects of oAß(25-35) and its potential role in the pathogenesis of AD, we determined its physiological, behavioral, biochemical and morphological impacts 6 weeks after injection in rats. oAß(25-35) was still present in the brain after 6 weeks. oAß(25-35) injection did not affect general activity and temperature rhythms after 6 weeks, but decreased body weight, induced short- and long-term memory impairments, increased corticosterone plasma levels, brain oxidative (lipid peroxidation), mitochondrial (caspase-9 levels) and reticulum stress (caspase-12 levels), astroglial and microglial activation. It provoked cholinergic neuron loss and decreased brain-derived neurotrophic factor levels. It induced cell loss in the hippocampic CA subdivisions and decreased hippocampic neurogenesis. Moreover, oAß(25-35) injection resulted in increased APP expression, Aß(1-42) generation, and increased Tau phosphorylation. In conclusion, this in vivo study evidenced that the soluble oligomeric forms of short fragments of Aß, endogenously identified in AD patient brains, not only provoked long-lasting pathological alterations comparable to the human disease, but may also directly contribute to the progressive increase in amyloid load and Tau pathology, involved in the AD physiopathology.

Intranasal formulation of erythropoietin (EPO) showed potent protective activity against amyloid toxicity in the Aß25₋35 non-transgenic mouse model of Alzheimer's disease.

Erythropoietin (EPO) promotes neurogenesis and neuroprotection. We here compared the protection induced by two EPO formulations in a rodent model of Alzheimer's disease (AD): rHu-EPO and a low sialic form, Neuro-EPO. We used the intracerebroventricular administration of aggregated Aß25₋35 peptide, a non-transgenic AD model. rHu-EPO was tested at 125-500 µg/kg intraperitoneally and Neuro-EPO at 62-250 µg/kg intranasally (IN). Behavioural procedures included spontaneous alternation, passive avoidance, water-maze and object recognition, to address spatial and non-spatial, short- and long-term memories. Biochemical markers of Aß25₋35 toxicity in the mouse hippocampus were examined and cell loss in the CA1 layer was determined. rHu-EPO and Neuro-EPO led to a significant prevention of Aß25₋35-induced learning deficits. Both EPO formulations prevented the induction of lipid peroxidation in the hippocampus, showing an antioxidant activity. rHu-EPO (250 µg/kg) or Neuro-EPO (125 µg/kg) prevented the Aß25₋35-induced increase in Bax level, TNFα and IL-1ß production and decrease in Akt activation. A significant prevention of the Aß25₋35-induced cell loss in CA1 was also observed. EPO is neuroprotective in the Aß25₋35 AD model, confirming its potential as an endogenous neuroprotection system that could be boosted for therapeutic efficacy. We here identified a new IN formulation of EPO showing high neuroprotective activity. Considering its efficacy, ease and safety, IN Neuro-EPO is a new promising therapeutic agent in AD.

Behavioural phenotyping of knockout mice for the sigma-1 (σ1) chaperone protein revealed gender-related anxiety, depressive-like and memory alterations.

The sigma-1 (σ1) protein regulates calcium homeostasis and acts as an endoplasmic reticulum chaperone. It can be activated by ligands which impact memory, depression, anxiety or addiction processes. We here characterized the behavioural phenotype of knockout (KO) mice for the σ1 protein. Two-month old male σ1⁻/⁻ mice showed signs of anxiety in the open-field, passive avoidance or elevated plus-maze test, but other activity or memory responses were unchanged. Female σ1⁻/⁻ mice showed deficits in spontaneous alternation or water-maze learning. Twelve-month old σ1⁺/⁻ female mice showed deficits in alternation and σ1⁻/⁻ mice in avoidance escape latency. Two- and 14-month old female σ1⁻/⁻ mice showed decreased plasma 17ß-estradiol levels. Treatment with 17ß-estradiol (0.1, 0.2 mg/kg i.p.) reversed the spatial memory deficits in young and aged mice. Male σ1 KO mice showed enhanced response in the forced swimming test. Igmesine, a σ1 agonist, failed to decrease immobility in σ1 KO mice. Fluoxetine and sertraline were more efficient in σ1 KO mice, an effect likely related to their σ1 antagonist activity. Imipramine, desipramine and amitriptyline were equally active. σ1 protein invalidation therefore affected stress or anxiety response but not memory in males. Changes in steroid tonus in female animals led, however, to memory impairments that increased with age.

Anti-amnesic and neuroprotective potentials of the mixed muscarinic receptor/sigma 1 (σ1) ligand ANAVEX2-73, a novel aminotetrahydrofuran derivative.

Tetrahydro-N, N-dimethyl-2, 2-diphenyl-3-furanmethanamine hydrochloride (ANAVEX2-73) binds to muscarinic acetylcholine and sigma(1) (σ(1)) receptors with affinities in the low micromolar range. We characterized its anti-amnesic and neuroprotective potentials in pharmacological and pathological amnesia models. Spatial working memory was evaluated using spontaneous alternation in the Y-maze and non-spatial memory using passive avoidance procedures. ANAVEX2-73 (0.01-3.0 mg/kg i.p.) alleviated the scopolamine- and dizocilpine-induced learning impairments. ANAVEX2-73 (300 µg/kg) also reversed the learning deficits in mice injected with Aß(25-35) peptide, a non-transgenic Alzheimer's disease model. When the drug was injected simultaneously with Aß(25-35), 7 days before the tests, it blocked the appearance of learning impairments. This protective activity was confirmed since ANAVEX2-73 blocked the Aß(25-35)-induced oxidative stress in the hippocampus. This effect was differentially sensitive to the muscarinic receptor antagonist scopolamine or the σ(1) protein antagonist BD1047, confirming the mixed muscarinic/σ(1) pharmacological action. Finally, its unique demethyl metabolite, ANAVEX19-144, was also effective and ANAVEX2-73 presented a longer duration of action, effective 12 h before Aß(25-35), than its related compound ANAVEX1-41. The neuroprotective activity of ANAVEX2-73, its mixed cholinergic/σ(1) activity, its low active dose range and its long duration of action together reinforce its therapeutic potential in Alzheimer's disease.

Antiamnesic and neuroprotective effects of the aminotetrahydrofuran derivative ANAVEX1-41 against amyloid beta(25-35)-induced toxicity in mice.

The antiamnesic and neuroprotective activities of the new aminotetrahydrofuran derivative tetrahydro-N,N-dimethyl-5,5-diphenyl-3-furanmethanamine hydrochloride (ANAVEX1-41), a nonselective muscarinic receptor ligand and sigma1 protein activator, were examined in mice injected intracerebroventricularly with amyloid beta(25-35) (Abeta(25-35)) peptide (9 nmol). Abeta(25-35) impaired significantly spontaneous alternation performance, a spatial working memory, and passive avoidance response. When ANAVEX1-41 (1-1000 microg/kg i.p.) was administered 7 days after Abeta(25-35), ie, 20 min before the behavioral tests, it significantly reversed the Abeta(25-35)-induced deficits, the most active doses being in the 3-100 microg/kg range. When the compound was preadministered 20 min before Abeta(25-35), ie, 7 days before the tests, it prevented the learning impairments at 30-100 microg/kg. Morphological analysis of corticolimbic structures showed that Abeta(25-35) induced a significant cell loss in the CA1 pyramidal cell layer of the hippocampus that was prevented by ANAVEX1-41 (100 microg/kg). Increased number of glial fibrillary acidic protein immunopositive cells in the retrosplenial cortex or throughout the hippocampus revealed an Abeta(25-35)-induced inflammation that was prevented by ANAVEX1-41. The drug also prevented the parameters of Abeta(25-35)-induced oxidative stress measured in hippocampus extracts, ie, the increases in lipid peroxidation and protein nitration. ANAVEX1-41, however, failed to prevent Abeta(25-35)-induced caspase-9 expression. The compound also blocked the Abeta(25-35)-induced caspase-3 expression, a marker of apoptosis. Both the muscarinic antagonist scopolamine and the sigma1 protein inactivator BD1047 prevented the beneficial effects of ANAVEX1-41 (30 or 100 microg/kg) against Abeta(25-35)-induced learning impairments, suggesting that muscarinic and sigma1 targets are involved in the drug effect. A synergic effect could indeed account for the very low active doses measured in vivo. These data outline the therapeutic potential of ANAVEX1-41 as a neuroprotective agent in Alzheimer's disease.