Oral administration of a recombinant cholera toxin B subunit promotes mucosal healing in the colon.

Cholera toxin B subunit (CTB) is a component of a licensed oral cholera vaccine. However, CTB has pleiotropic immunomodulatory effects whose impacts on the gut are not fully understood. Here, we found that oral administration in mice of a plant-made recombinant CTB (CTBp) significantly increased several immune cell populations in the colon lamina propria. Global gene expression analysis revealed that CTBp had more pronounced impacts on the colon than the small intestine, with significant activation of TGFß-mediated pathways in the colon epithelium. The clinical relevance of CTBp-induced impacts on colonic mucosa was examined. In a human colon epithelial model using Caco2 cells, CTBp, but not the non-GM1-binding mutant G33D-CTBp, induced TGFß-mediated wound healing. In a dextran sodium sulfate (DSS) acute colitis mouse model, oral administration of CTBp protected against colon mucosal damage as manifested by mitigated body weight loss, decreased histopathological scores, and blunted escalation of inflammatory cytokine levels while inducing wound healing-related genes. Furthermore, biweekly oral administration of CTBp significantly reduced disease severity and tumorigenesis in the azoxymethane/DSS model of ulcerative colitis and colon cancer. Altogether, these results demonstrate CTBp's ability to enhance mucosal healing in the colon, highlighting its potential application in ulcerative colitis therapy besides cholera vaccination.

Effects of methylphenidate on the behavior of male 5xFAD mice.

Alzheimer's disease is a neurodegenerative disorder characterized by a loss of memory and spatial orientation. It is also reported that the dopamine system is affected. Dopamine plays a prominent role in motor functions, motivation, emotion, arousal and reward, and it is important for learning and memory. One model that represents characteristic hallmarks of Alzheimer's disease is the 5xFAD mouse model, in which parenchymal plaque load starts at 2months of age. Transgenic 5xFAD mice show the first behavioral deficits at 6months, which are evident at 9months of age. In this study, we investigated the pharmacological influence of methylphenidate (MPH) on behavioral deficits of 5xFAD mice. Using a battery of behavioral tests, we observed no influence of MPH on anxiety in the elevated plus maze, whereas the locomotion and explorative activity in the open field was increased in transgenic and non-transgenic 5xFAD mice after the application of MPH. Further MPH inhibits habituation in the open field in healthy 5xFAD littermates after the application of 10mg/kg MPH. On the other hand, 10mg/kg MPH improved spatial memory in 6-month-old transgenic 5xFAD males, i.e., at a time point when deficits start to occur. However, in 9-month-old transgenic mice, MPH did not improve persisting learning and memory deficits. We concluded that MPH might improve the non-cognitive, apathy-like behavior (indicated by a reduced exploration), but it has no influence on sustained Alzheimer typical learning and memory deficits.

Behavioral and EEG changes in male 5xFAD mice.

Transgenic animal models of Alzheimer's disease (AD) are widely used to investigate mechanisms of pathophysiology and cognitive dysfunctions. A model with a very early development of parenchymal plaque load at the age of 2months is the 5xFAD mouse (Tg6799, Oakley et al. 2006). These 5xFAD mice over-express both human amyloid precursor protein (APP) and human presenilin 1 (PS1). Mice from this line have a high APP expression correlating with a high burden and an accelerated accumulation of the 42 amino acid species of amyloid-ß (Aß). The aim of this study was the behavioral and functional investigations of 5xFAD males because in most studies females of this strain were characterized. In comparison to literature of transgenic 5xFAD females, transgenic 5xFAD males showed decreased anxiety in the elevated plus maze, reduced locomotion and exploration in the open field and disturbances in learning performance in the Morris water maze starting at 9months of age. Electroencephalogram (EEG) recordings on 6month old transgenic mice revealed a decrease of delta, theta, alpha, beta and gamma frequency bands whereas the subdelta frequency was increased. EEG recordings during sleep showed a reduction of rapid eye movement sleep in relation to the amount of total sleep. Thus, 5xFAD males develop early functional disturbances and subsequently behavioral deficits and therefore they are a good mouse model for studying Alzheimer's disease.

Disrupted cross-laminar cortical processing in ß amyloid pathology precedes cell death.

Disruption of neuronal networks in the Alzheimer-afflicted brain is increasingly recognized as a key correlate of cognitive and memory decline in Alzheimer patients. We hypothesized that functional synaptic disconnections within cortical columnar microcircuits by pathological ß-amyloid accumulation, rather than cell death, initially causes the cognitive impairments. During development of cortical ß-amyloidosis with still few plaques in the transgenic 5xFAD mouse model single cell resolution mapping of neuronal thallium uptake revealed that electrical activity of pyramidal cells breaks down throughout infragranular cortical layer V long before cell death occurs. Treatment of 5xFAD mice with the glutaminyl cyclase inhibitor, PQ 529, partially prevented the decline of pyramidal cell activity, indicating pyroglutamate-modified forms, potentially mixed oligomers of Aß are contributing to neuronal impairment. Laminar investigation of cortical circuit dysfunction with current source density analysis identified an early loss of excitatory synaptic input in infragranular layers, linked to pathological recurrent activations in supragranular layers. This specific disruption of normal cross-laminar cortical processing coincided with a decline of contextual fear learning.

An immunohistochemical study of feline myocardial fibrosis.

The aim of the present study was to investigate the pathology of feline myocardial fibrosis. The hearts from 40 cats with myocardial fibrosis were compared with the hearts from 25 normal cats. Clinical data were available in 11 cases. Hearts with myocardial fibrosis were hypomotile and there were hyperechoic areas in the ventricular wall on echocardiography. The presence of myocardial fibrosis was correlated significantly with hypertrophy of the ventricles, atrial dilation and angiosclerosis. Immunohistochemical studies demonstrated that normal feline cardiomyocytes expressed matrix metalloproteinase (MMP)-2, MMP-9, MMP-14, tissue inhibitor of matrix metalloproteinase (TIMP)-2 and transforming growth factor (TGF)-ß2. Fibroblasts in normal hearts expressed only TIMP-2. In the hearts with myocardial fibrosis, expression of MMP-2, TIMP-3 and TGF-ß2 by cardiomyocytes was significantly increased, but TIMP-2 expression was diminished. Fibroblasts in the affected hearts showed expression of MMP-14 in several cases. These findings suggest that a complex fibrotic remodelling of the feline myocardium occurs in this disease and that cardiomyocytes are involved in this process.

Increase in proliferation and gliogenesis but decrease of early neurogenesis in the rat forebrain shortly after transient global ischemia.

Regarding regenerative strategies early post-ischemic therapeutic interventions might have a great impact on further pathophysiological cascades. To understand the early post-ischemic events we analyzed proliferation and neurogenesis as early as on day 3 after transient global ischemia in rats. Evaluations were performed not only in the dorsal hippocampus, where post-ischemic cell death develops selectively in the cornu ammonis, subfield 1 area, but also in distant areas like the ventricle wall and the striatum. Ischemia was induced by a transient two-vessel occlusion combined with hypotension. Animals received daily i.p. injections of 5-bromo-2-deoxyuridine until decapitation 1 or 3 days after ischemia. Immunohistochemistry was performed to detect 5-bromo-2-deoxyuridine and co-labeling with cell-specific markers. Three days after ischemia, proliferation significantly increased throughout the forebrain. Early neurogenesis, detected by doublecortin labeling, on the other hand, was restricted to the neurogenic zones of the dentate gyrus and the lateral ventricle. Global ischemia reduced the overall number of doublecortin-positive cells in the dentate gyrus, particularly in the upper blade of the dentate gyrus. However, the number of newly generated doublecortin- and 5-bromo-2-deoxyuridine double-labeled cells was unchanged. The vast majority of newly generated cells were microglia/macrophages, which invaded morphologically damaged as well as undamaged regions. Astroglial cells were activated all over the forebrain by the ischemic insult. They were co-localized almost completely with nestin in many areas, yet, sparsely proliferated after the insult. Interestingly, in locally defined zones we found nestin- and glial fibrillary acidic protein-signals clearly separated. In sham-operated animals, nestin could be detected in both neurogenic zones only without co-labeling with glial markers. In conclusion, during the first days after global ischemia, cell death of cornu ammonis, subfield 1-neurons was accompanied by a massive overall proliferation and activation of microglia/macrophages, a reduction of pre-ischemia existing doublecortin-positive precursors in the dentate gyrus and a re-expression of nestin in glial fibrillary acidic protein-positive astrocytes.

Opiate modulation of monoamines in the chick forebrain: possible role in emotional regulation?

Numerous studies have shown that the opiate system is crucially involved in emotionally guided behavior. In the present study, we focussed on the medio-rostral neostriatum/hyperstriatum ventrale (MNH) of the chick forebrain. This avian prefrontal cortex analogue is critically involved in auditory filial imprinting, a well-characterized juvenile emotional learning event. The high density of mu-opiate receptors expressed in the MNH led to the hypothesis that mu-opiate receptor-mediated processes may modulate the glutamatergic, dopaminergic, and/or serotonergic neurotransmission within the MNH and thereby have a critical impact on filial imprinting. Using microdialysis and pharmaco-behavioral approaches in young chicks, we demonstrated that: the systemic application of the mu-opiate receptor antagonist naloxone (5, 50 mg/kg) significantly increased extracellular levels of 5-HIAA and HVA; the systemic application of the specific mu-opiate receptor agonist DAGO (5 mg/kg) increased the levels of HVA and taurine, an effect that was antagonized by simultaneously applied naloxone (5 mg/kg); the local application of DAGO (1 mM) had no effects on 5-HIAA, HVA, glutamate, and taurine, however, the effects of systemically injected naloxone (5 mg/kg) were abolished by simultaneously applied DAGO (1 mM); the systemic application of naloxone (5 mg/kg) increased distress behavior (measured as the duration of distress vocalization during separation from the peer group). These results are in line with our hypothesis that the mu-opiate receptor-mediated modulation of serotonergic and dopaminergic neurotransmission alters the emotional and motivational status of the animal and thereby may play a modulatory role during filial imprinting in the newborn animal.

Clinical assessment of trunk flexor muscle strength in healthy girls 3 to 7 years of age.

We developed a clinical method for assessing trunk flexor muscle strength in healthy children that can be applied to assist physical therapists in determining strength accurately in pediatric patients. In this study, we assessed trunk flexor muscle strength in 75 healthy girls 3 to 7 years of age. Muscle strength was graded on a scale of 0 to 5 using modified, manual muscle testing methods. These methods attempted to minimize the amount of hip flexor muscle activity during trunk flexion and allow more isolated action of the abdominal trunk flexor muscles. The frequency of Normal (Grade 5) strength first appeared to predominate at age 5 years with the majority of children demonstrating Normal (Grade 5) strength by age 7 years. Regression analysis illustrated a positive linear relationship (beta = .37, p less than .001) between mean muscle grade and age group. We discuss muscle cross-sectional area, muscle-fiber diameter, muscle-cell number, maturation of the central nervous system, and changes in body proportions with age as possible contributing factors to the results of this study.