Liposomes coated with thiolated chitosan enhance oral peptide delivery to rats.

The aim of the present study was the in vivo evaluation of thiomer-coated liposomes for an oral application of peptides. For this purpose, salmon calcitonin was chosen as a model drug and encapsulated within liposomes. Subsequently, the drug loaded liposomes were coated with either chitosan-thioglycolic acid (CS-TGA) or an S-protected version of the same polymer (CS-TGA-MNA), leading to an increase in the particle size of about 500 nm and an increase in the zeta potential from approximately -40 mV to a maximum value of about +44 mV, depending on the polymer. Coated liposomes were demonstrated to effectively penetrate the intestinal mucus layer where they came in close contact with the underlying epithelium. To investigate the permeation enhancing properties of the coated liposomes ex vivo, we monitored the transport of fluoresceinisothiocyanate-labeled salmon calcitonin (FITC-sCT) through rat small intestine. Liposomes coated with CS-TGA-MNA showed the highest effect, leading to a 3.8-fold increase in the uptake of FITC-sCT versus the buffer control. In vivo evaluation of the different formulations was carried out by the oral application of 40 µg of sCT per rat, either encapsulated within uncoated liposomes, CS-TGA-coated liposomes or CS-TGA-MNA-coated liposomes, or given as a solution serving as negative control. The blood calcium level was monitored over a time period of 24h. The highest reduction in the blood calcium level, to a minimum of 65% of the initial value after 6h, was achieved for CS-TGA-MNA-coated liposomes. Comparing the areas above curves (AAC) of the blood calcium levels, CS-TGA-MNA-coated liposomes led to an 8.2-fold increase compared to the free sCT solution if applied orally in the same concentration. According to these results, liposomes coated with S-protected thiomers have demonstrated to be highly valuable carriers for enhancing the oral bioavailability of salmon calcitonin.

Antioxidant food supplements and obesity-related inflammation.

The obesity prevalence is growing worldwide and largely responsible for the increased incidence of cardiovascular disease, the most common cause of death in the western world. Excessive food intake along with insufficient physical exercise is the basic impetus for this development. The obese state is commonly associated with an increase in leptin levels and chronic immune-mediated inflammation. Despite high leptin levels, the leptin response, normally associated with satiety and satiation, seems to be impaired and individuals continue to consume calorie-rich food. Antioxidant food additives such as sodium sulphite, sodium benzoate and curcumin were shown to suppress the leptin release in lipopolysaccharide- treated murine adipocytes. Based on this, we hypothesize that the insufficient leptin release, caused by excessive consumption of food additives, may lead to a reduced exposure of the central nervous system to leptin and ultimately propagate obesity. On the other hand, leptin has been shown to favor Th1-type activity, which ultimately decreases tryptophan levels. Tryptophan derivatives, serotonin and melatonin, induce satiety/satiation through several mechanisms. In this context, the antioxidant suppression of leptin release and Th1-type activity is beneficial to increase serotonin and melatonin levels. The molecules in the mechanism described in this review are highly integrated in the reward system, and have been implicated in the addiction behavior of obesity. Based on these facts, the involvement of antioxidant food supplements in the mechanisms of the reward-deficiency syndrome which perpetuates obesity will be discussed.

Inflammation, adiponectin, obesity and cardiovascular risk.

The development of atherosclerotic lesions leading to myocardial infarction (MI) or stroke encompasses a cascade of cellular and molecular events that can well be characterized as a chronic immune-mediated inflammation occurring preferentially in the biologic surrounding of the so called metabolic syndrome. Adipokines, chemokines, cytokines, and their receptors are critically involved in the initiation and perpetuation of atherosclerosis, and they play important roles at all levels in the pathogenesis of this disease. Metabolic risk profiles associated with sedentary lifestyle, obesity, especially intra-abdominal fat accumulation, insulin resistance, and dyslipidemia pave the way for a chronic, immune-mediated vascular inflammation around vascular lipid deposits. In the present article, the impact of adiponectin, monocyte and T-cell associated cytokines (with emphasis on Neopterin), individual adipose tissue - distribution and pleiotropic drug effects on the individual course of atherosclerosis and associated cardiovascular disease are reviewed.

Asymmetric dimethylarginine (ADMA) is tightly correlated with growth in juveniles without correlations to obesity related disorders.

BACKGROUND: Asymmetrical dimethylarginine (ADMA) was found to be increased in conditions associated with atherosclerosis and metabolic disorders. We investigated ADMA in obese juveniles with pre-atherosclerotic symptoms and in normal weight juveniles. DESIGN: To elucidate correlations of ADMA in juveniles with obesity related disorders such as insulin resistance, low grade inflammation, hypertension and pre-atherosclerosis, we analysed ADMA by high performance liquid chromatography (HPLC) in 68 obese and 68 healthy, age and gender matched juveniles. RESULTS: ADMA levels are slightly, but significantly increased (p=0.04) in obese (0.78+/-0.01 micromol/l), compared to normal weight juveniles (0.74+/-0.01 micromol/l). There are no robust correlations of ADMA with obesity related disorders, like dyslipidemia, hypertension, low-grade inflammation and pre-atherosclerosis. Age, body length and alkaline phosphatase, as markers of growth are correlated with ADMA. Multiple testing revealed that, alkaline phosphatase turned out as highly significant positively correlated with ADMA in normal weight (r=0.45/p<0.0001) and obese (r=0.59/p<0.0001) children. CONCLUSIONS: We show here, that ADMA is slightly increased in obese juveniles without any robust correlations to obesity related disorders. ADMA is tightly correlated with alkaline phosphatase as a marker of growth in obese and normal weight, healthy juveniles.

Beta-CIT SPECT demonstrates reduced availability of serotonin transporters in patients with Fatal Familial Insomnia.

Fatal familial insomnia (FFI) is a rare hereditary human prion disease with unique clinical features including progressive sleep impairment and autonomic dysfunction. The serotonergic system is considered to be involved in the regulation of the sleep-wake cycle. In this study we demonstrate a reduced availability of serotonin transporters of 57% and 73% respectively in a thalamus-hypothalamus region of two FFI patients examined with beta-CIT SPECT as compared to age-expected control values.

Increased levels of the pro-inflammatory prostaglandin PGE2 in CSF from ALS patients.

Levels of the potent pro-inflammatory prostaglandin E(2) (PGE(2)) are elevated in postmortem spinal cords from patients with ALS, and inhibition of a key PGE(2)-synthesizing enzyme, cylcooxygenase-2, is neuroprotective in an in vitro model of ALS. The authors report that 82% of the patients with ALS studied had 2 to 10 times higher PGE(2) levels in CSF compared with normal control subjects. That affected areas of the CNS are inflamed in ALS supports this. CSF PGE(2) measurement may be useful in monitoring treatment for ALS.

Increased expression of the pro-inflammatory enzyme cyclooxygenase-2 in amyotrophic lateral sclerosis.

Mutations in the copper/zinc superoxide dismutase (mSOD1) gene are associated with a familial form of amyotrophic lateral sclerosis (ALS), and their expression in transgenic mice produces an ALS-like syndrome. Recent observations suggest a role for inflammatory-related events in the progression and propagation of the neurodegenerative process in ALS. Consistent with this view, the present study demonstrates that, during the course of the disease, the expression of cyclooxygenase type 2 (Cox-2), a key enzyme in the synthesis of prostanoids, which are potent mediators of inflammation, is dramatically increased. In both early symptomatic and end-stage transgenic mSOD1 mice, neurons and, to a lesser extent, glial cells in the anterior horn of the spinal cord exhibit robust Cox-2 immunoreactivity. Cox-2 mRNA and protein levels and catalytic activity are also significantly increased in the spinal cord of the transgenic mSOD1 mice. The time course of the spinal cord Cox-2 upregulation parallels that of motor neuronal loss in transgenic mSOD1 mice. We also show that Cox-2 activity is dramatically increased in postmortem spinal cord samples from sporadic ALS patients. We speculate that Cox-2 upregulation, through its pivotal role in inflammation, is instrumental in the ALS neurodegenerative process and that Cox-2 inhibition may be a valuable therapeutic avenue for the treatment of ALS.

Inducible nitric oxide synthase up-regulation in a transgenic mouse model of familial amyotrophic lateral sclerosis.

Mutations in copper/zinc superoxide dismutase (SOD1) are associated with a familial form of amyotrophic lateral sclerosis (ALS), and their expression in transgenic mice produces an ALS-like syndrome. Here we show that, during the course of the disease, the spinal cord of transgenic mice expressing mutant SOD1 (mSOD1) is the site not only of a progressive loss of motor neurons, but also of a dramatic gliosis characterized by reactive astrocytes and activated microglial cells. These changes are absent from the spinal cord of age-matched transgenic mice expressing normal SOD1 and of wild-type mice. We also demonstrate that, during the course of the disease, the expression of inducible nitric oxide synthase (iNOS) increases. In both early symptomatic and end-stage transgenic mSOD1 mice, numerous cells with the appearance of glial cells are strongly iNOS-immunoreactive. In addition, iNOS mRNA level and catalytic activity are increased significantly in the spinal cord of these transgenic mSOD1 mice. None of these alterations are seen in the cerebellum of these animals, a region unaffected by mSOD1. Similarly, no up-regulation of iNOS is detected in the spinal cord of age-matched transgenic mice expressing normal SOD1 or of wild-type mice. The time course of the spinal cord gliosis and iNOS up-regulation parallels that of motor neuronal loss in transgenic mSOD1 mice. Neuronal nitric oxide synthase expression is only seen in neurons in the spinal cord of transgenic mSOD1 mice, regardless of the stage of the disease, and of age-matched transgenic mice expressing normal SOD1 and wild-type mice. Collectively, these data suggest that the observed alterations do not initiate the death of motor neurons, but may contribute to the propagation of the neurodegenerative process. Furthermore, the up-regulation of iNOS, which in turn may stimulate the production of nitric oxide, provides further support to the presumed deleterious role of nitric oxide in the pathogenesis of ALS. This observation also suggests that iNOS may represent a valuable target for the development of new therapeutic avenues for ALS.

Fatal familial insomnia: a new Austrian family.

We present clinical, pathological and molecular features of the first Austrian family with fatal familial insomnia. Detailed clinical data are available in five patients and autopsy in four patients. Age at onset of disease ranged between 20 and 60 years, and disease duration between 8 and 20 months. Severe loss of weight was an early symptom in all five patients. Four patients developed insomnia and/or autonomic dysfunction, and all five patients developed motor abnormalities. Analysis of the prion protein (PrP) gene revealed the codon 178 point mutation and methionine homozygosity at position 129. In all brains, neuropathology showed widespread cortical astrogliosis, widespread brainstem nuclei and tract degeneration, and olivary 'pseudohypertrophy' with vacuolated neurons, in addition to neuropathological features described previously, such as thalamic and olivary degeneration. Western blotting of one brain and immunocytochemistry in four brains revealed quantitative and regional dissociation between PrP(res)(the protease resistant form of PrP) deposition and histopathology. In the cerebellar cortex of one patient, PrP(res) deposits were prominent in the molecular layer and displayed a peculiar patchy and strip-like pattern with perpendicular orientation to the surface. In another patient, a single vacuolated neuron in the inferior olivary nuclei contained prominent intravacuolar granular PrP(res) deposits, resembling changes of brainstem neurons in bovine spongiform encephalopathy.

The functional organization of the interictal spike complex in benign rolandic epilepsy.

PURPOSE: We studied the functional organization of the interictal epileptic spike complex in patients with benign rolandic epilepsy of childhood (BREC). METHODS: We recorded interictal epileptiform spikes and somatosensory evoked potentials after median nerve stimulation, providing a biologic marker for the location of the central sulcus in 12 patients with BREC. We used multiple dipole modeling to assess the number, the three-dimensional intracerebral location, and the time activity of the underlying neuronal sources. RESULTS: Although the interictal spike complex could be modeled by a single tangential dipolar source in seven patients (group 1), in the remaining five patients, two sources-a radial and a tangential dipole-were necessary adequately to explain the interictal spikes (group 2). The tangential source was located deeper than the radial source and was characterized by a frontal positivity and a centroparietal negativity with a phase reversal across the central sulcus, suggesting that the interictal spikes originated in the anterior wall of the central sulcus. The radial source showed a single electronegativity over the ipsilateral central region, which would be compatible with involvement of the top of either the pre- or postcentral gyrus. Both sources showed biphasic time patterns with an average latency difference of 30 ms. CONCLUSIONS: Our results indicate that in some patients with typical BREC, the interictal epileptiform spike complex is generated by multiple, simultaneously active neuronal populations within the central region and that epileptiform activity is propagated between these two adjacent cortical areas.

Epileptic negative myoclonus: An EEG-single-photon emission CT study indicating involvement of premotor cortex.

We report a combined EEG-single-photon emission CT (SPECT) study on a patient with epileptic negative myoclonus (ENM). Clinically, the ENM was characterized by brief repetitive lapses in postural tone of the right upper extremity when the arms were held outstretched, whereas no movement effect was observed during rest. Ictal EEG showed repetitive left frontal spikes with a maximum at electrodes EC1 and F1. EMG silent periods lasting from 100 to 200 ms followed the onset of the EEG transients by a latency of 20 to 40 ms. The N20 component of median nerve somatosensory evoked potentials-representing a biological marker of the location of central fissure-showed a phase reversal between electrodes P3 and C1 and thus was located considerably posterior to the spike maximum. We obtained accurate anatomic reference of cerebral blood flow changes visible on SPECT by a special coregistration technique of MRI and SPECT. SPECT performed during ENM showed a marked regional hyperperfusion in the left middle frontal gyrus and a less pronounced increase in tracer uptake in the left supramarginal gyrus. Our results suggest that ENM is generated by epileptic activity in the premotor area in the middle frontal gyrus corresponding to Brodmann's area 6.

Supplementary motor area seizures: propagation pathways as studied with invasive recordings.

We studied propagation of epileptic discharges in five patients with supplementary motor area (SMA) seizures with subdural grid electrodes implanted over the dorsolateral frontal neocortex and in the interhemispheric fissure. We found that both interictal and ictal epileptic discharges occurred synchronously in the SMA and the primary cortex. The actively involved electrodes were separated by silent electrodes. The time lag between the SMA and the primary motor cortex averaged 25 msec for interictal and 100 msec for ictal discharges. Cortical stimulations of the affected electrodes showed motor effects in corresponding body parts. All patients underwent resections of the EEG onset zone within the SMA while sparing the primary motor cortex and experienced a significant (>90%) reduction of seizure frequency. We conclude that epileptic activity is propagated between the SMA and the primary motor cortex by a somatotopically organized monosynaptic pathway.