Oligomeric amyloid ß induces IL-1ß processing via production of ROS: implication in Alzheimer's disease.

Alzheimer's disease (AD) is a chronic neurodegenerative disease characterized by progressive neuronal loss and cognitive decline. Oligomeric amyloid ß (oAß) is involved in the pathogenesis of AD by affecting synaptic plasticity and inhibiting long-term potentiation. Although several lines of evidence suggests that microglia, the resident immune cells in the central nervous system (CNS), are neurotoxic in the development of AD, the mechanism whether or how oAß induces microglial neurotoxicity remains unknown. Here, we show that oAß promotes the processing of pro-interleukin (IL)-1ß into mature IL-1ß in microglia, which then enhances microglial neurotoxicity. The processing is induced by an increase in activity of caspase-1 and NOD-like receptor family, pyrin domain containing 3 (NLRP3) via mitochondrial reactive oxygen species (ROS) and partially via NADPH oxidase-induced ROS. The caspase-1 inhibitor Z-YVAD-FMK inhibits the processing of IL-1ß, and attenuates microglial neurotoxicity. Our results indicate that microglia can be activated by oAß to induce neuroinflammation through processing of IL-1ß, a pro-inflammatory cytokine, in AD.

Minocycline selectively inhibits M1 polarization of microglia.

Minocycline is commonly used to inhibit microglial activation. It is widely accepted that activated microglia exert dual functions, that is, pro-inflammatory (M1) and anti-inflammatory (M2) functions. The in vivo status of activated microglia is probably on a continuum between these two extreme states. However, the mechanisms regulating microglial polarity remain elusive. Here, we addressed this question focusing on minocycline. We used SOD1(G93A) mice as a model, which exhibit the motor neuron-specific neurodegenerative disease, amyotrophic lateral sclerosis. Administration of minocycline attenuated the induction of the expression of M1 microglia markers during the progressive phase, whereas it did not affect the transient enhancement of expression of M2 microglia markers during the early pathogenesis phase. This selective inhibitory effect was confirmed using primary cultured microglia stimulated by lipopolysaccharide (LPS) or interleukin (IL)-4, which induced M1 or M2 polarization, respectively. Furthermore, minocycline inhibited the upregulation of NF-κB in the LPS-stimulated primary cultured microglia and in the spinal cord of SOD1(G93A) mice. On the other hand, IL-4 did not induce upregulation of NF-κB. This study indicates that minocycline selectively inhibits the microglia polarization to a proinflammatory state, and provides a basis for understanding pathogeneses of many diseases accompanied by microglial activation.

Production of interferon-gamma by microglia.

Neural cells do not usually interact with immune cells because of the lack of major histocompatibility complex (MHC) antigen expression. Interferon-gamma (IFN-gamma) enables this interaction via induction of MHC antigen expression in neural cells. Thus, IFN-gamma is a critical cytokine for the development of central nervous system (CNS) pathologies. IFN-gamma, however, is considered to be produced exclusively by lymphoid cells. Here, we show for the first time that murine microglia produce IFN-gamma in response to IL-12 and/or IL-18, using RT-PCR detection of IFN-gamma mRNA and Western blotting and immunohistochemical analysis for cytoplasmic expression of IFN-gamma. Stimulation of microglia with IL-12 and IL-18 resulted in MHC class II mRNA expression in microglia. Since IL-12 and IL-18 are produced in the CNS by glial cells, these cytokines may play a critical role in the initiation of neural-immune cell interaction and the induction of autoimmune processes in the CNS via induction of IFN-gamma and MHC antigens.

Static handgrip exercise modifies arterial baroreflex control of vascular sympathetic outflow in humans.

To examine effects of static exercise on the arterial baroreflex control of vascular sympathetic nerve activity, 22 healthy male volunteers performed 2 min of static handgrip exercise at 30% of maximal voluntary force, followed by postexercise circulatory arrest (PE-CA). Microneurographic recording of muscle sympathetic nerve activity (MSNA) was made with simultaneous recording of arterial pressure (Portapres). The relationship between MSNA and diastolic arterial pressure was calculated for each condition and was defined as the arterial baroreflex function. There was a close relationship between MSNA and diastolic arterial pressure in each subject at rest and during static exercise and PE-CA. The slope of the relationship significantly increased by >300% during static exercise (P < 0.001), and the x-axis intercept (diastolic arterial pressure level) increased by 13 mmHg during exercise (P < 0.001). These alterations in the baroreflex relationship were completely maintained during PE-CA. It is concluded that static handgrip exercise is associated with a resetting of the operating range and an increase in the reflex gain of the arterial barorelex control of MSNA.

Effects of lower body positive pressure on muscle sympathetic nerve activity response to head-up tilt.

The present study was performed to test the hypothesis that application of lower body positive pressure (LBPP) during orthostasis would reduce the baroreflex-mediated enhancement in sympathetic activity in humans. Eight healthy young men were exposed to a 70 degrees head-up tilt (HUT) on application of 30 mmHg LBPP. Muscle sympathetic nerve activity (MSNA) was microneurographically recorded from the tibial nerve, along with hemodynamic variables. We found that in the supine position with LBPP, MSNA remained unchanged (13.4 +/- 3.3 vs. 11.8 +/- 2.3 bursts/min, without vs. with LBPP; P > 0.05), mean arterial pressure was elevated, but arterial pulse pressure and heart rate did not alter. At 70 degrees HUT with LBPP, the enhanced MSNA response was reduced (33.8 +/- 5.0 vs. 22.5 +/- 2.2 bursts/min, without vs. with LBPP; P < 0.05), mean arterial pressure was higher, the decreased pulse pressure was restored, and the increased heart rate was attenuated. We conclude that the baroreflex-mediated enhancement in sympathetic activity during HUT was reduced by LBPP. Application of LBPP in HUT induced an obvious cephalad fluid shift as well as a restoration of arterial pulse pressure, which reduced the inhibition of the baroreceptors. However, the activation of the intramuscular mechanoreflexes produced by 30 mmHg LBPP might counteract the effects of baroreflexes.

Interrelations of vasoconstrictor sympathetic outflow to skin core temperature during unilateral sole heating in humans.

The purpose of the present study was to clarify how skin sympathetic nerve activity (SSNA) influences the core temperature during local heating of the unilateral sole of the foot for 60 min. We recorded SSNA microneurographically from the tibial or peroneal nerve simultaneously with skin blood flow, sweat rate at heated and non-heated sites, with tympanic temperature (Tty) as the core temperature. Sole heating began to suppress vasoconstrictive SSNA (vasoconstrictor) after 3.4 +/- 1.1 min, decrease Tty after 7.4 +/- 2.0 min, activate vasoconstrictor after 33.4 +/- 2.2 min, and increase Tty after 45.5 +/- 2.7 min. Regarding the interaction between vasoconstrictor and Tty during sole heating, we found the following: (1) the capability to suppress vasoconstrictors (decrease rate) showed positive correlations with the time delay from vasoconstrictor suppression to the Tty decrease (r = 0.752, p < 0.05), and with the Tty decrease rate (r = 0.795, p < 0.05), (2) the Tty decrease rate was inversely related to the capability to activate vasoconstrictors (increase rate) (r= -0.836, p < 0.05), and (3) the capability to activate vasoconstrictors was inversely related to the time delay from vasoconstrictor activation to the Tty increase (r = -0.856, p < 0.05) and showed a positive correlation with the Tty increase rate (r = 0.819, p < 0.05). These significant correlations indicate that the capability to control vasoconstrictors to the skin is one of the determinant factors maintaining core temperature in human thermoregulatory function. In conclusion, human thermoregulatory function is largely dependent on the suppression and activation capability of vasoconstrictors.

Influence of vestibulo-sympathetic reflex on muscle sympathetic outflow during head-down tilt.

To clarify the response of muscle sympathetic nerve activity (MSNA) to static stimulation of otolith organs in a craniocaudal direction (+Gz) in humans, we examined the effect of otolith stimulation on MSNA without changing the effect of cardiopulmonary baroreceptors using a 6-8.5 degrees head-down tilt (HDT) and lower body negative pressure (LBNP) device. Before the study, we established that 6-8.5 degrees HDT with 10 mmHg LBNP caused a fluid shift to the degree that the thoracic impedance was the same as the supine position without LBNP. Subjects were young male volunteers aged 22.1 +/- 3.8 years who gave informed consent. MSNA was recorded from the tibial nerve by microneurography simultaneously with heart rate (ECG), thoracic fluid volume (impedance method), and blood pressure (tonometric method). During 6-8.5 degrees HDT with 10 mmHg LBNP, MSNA was suppressed slightly without significantly changing heart rate, thoracic impedance, or mean arterial blood pressure. The results suggest that the sympathosuppression was related not to the result of cardiopulmonary [correction of cardioplumonary] loading but to the -Gz change (caudocranial direction [correction of dirction]) of 0.1 G. It is estimated that the vestibulo-sympathetic reflex may suppress sympathetic outflow to muscles in humans.

Effect of simulated microgravity exposure on thermoregulatory control of sweating.

The purpose of the present study was to investigate the alterations in thermoregulatory control following 14 days of head-down bed rest (HDBR). The threshold temperature for sweating onset and sweating sensitivity were determined from sweating rates on the chest and forearm, and tympanic temperature as an index of core temperature (Tc) in nine healthy males exposed to a 60-min heat stress with a water-perfused blanket before and after HDBR. The threshold temperature for sweating onset, that is, the Tc at which sweating began on the chest and forearm was 36.75 +/- 0.14 and 36.72 +/- 0.13 degrees C before HDBR, respectively. The value significantly increased to 37.05 +/- 0.09 (p<0.05) for the chest and 37.04 +/- 0.08 degrees C (p<0.05) for the forearm after HDBR. On the other hand, the sweating sensitivity which was indicated as a slope of the Tc-sweating rate relationship significantly decreased from 4.20 +/- 1.15 to 2.32 +/- 1.18 for the chest (p<0.05) and from 4.20 +/- 1.06 to 2.92 +/- 0.98 mg/min/cm2/degrees C for the forearm (p<0.05) after HDBR. These findings suggest that the heat-dissipatory function was attenuated after 14 days of HDBR.

Temporal expression of mRNAs for neuropoietic cytokines, interleukin-11 (IL-11), oncostatin M (OSM), cardiotrophin-1 (CT-1) and their receptors (IL-11Ralpha and OSMRbeta) in peripheral nerve injury.

The mRNA expression pattern of the neuropoietic cytokines, interleukin-11 (IL-11), oncostatin M (OSM) and cardiotrophin-1 (CT-1), and their receptor components (IL-11Ralpha and OSMRbeta) was examined in peripheral nerves on two different types of injury, crush and transection. The IL-11 mRNA increased after nerve damage and immediately returned to control levels. The OSM mRNA expression increased rapidly after nerve injury and relatively high expressions were maintained for at least 14 days. The CT-1 mRNA was not expressed in any time before and after the injury. Interestingly, IL-11Ralpha was expressed in the intact nerve and decreased after injury. The expression of OSMRbeta increased slightly after the injury. Moreover, temporal mRNA expression pattern of these neuropoietic cytokines and receptors was similar between the crushed and transected models. Each neuropoietic cytokine of IL-11, OSM and CT-1 has its own specific temporal mRNA expression pattern, which is also different from those of ciliary neuro-trophic factor (CNTF), leukemia inhibitory factor (LIF) and interleukin-6 (IL-6). These results suggest that all neuropoietic cytokines have distinctive functions in nerve degeneration and repair process in response to peripheral nerve injury.

[A patient of Charcot-Marie-tooth disease with rigid spine and respiratory failure].

This report describes a case of a 17-year-old girl with Charcot-Marie-Tooth disease (CMT) representing rigid spine and respiratory failure. At age 11, she tended to walk on her toes and had difficulty in getting up from the floor without support. She became aware of flexion limitation of the neck at the age of 12. At 15 years of age, She began to have dyspnea on effort. When she was 17 years old, neurological examination revealed mild weakness of the upper extremities and severe weakness of the distal lower extremities, generalized wasting and areflexia. Superficial sensation was mildly impaired distally, and vibration sensation was severely impaired in the lower extremities. Motor and sensory nerve conduction velocities were mildly reduced, and compound muscle action potential of the tibial and peroneal nerves and sensory nerve action potential on ulnar and sural nerves were absent. Electromyography showed neurogenic changes with denervation potentials. Sural nerve biopsy revealed severe loss of myelinated fibers without any onion-bulb formation. As for family history, her elder sister showed moderate loss of vibration sensation in the lower extremities. On the basis of these findings, she was diagnosed as having CMT type 2, though a mode of inheritance was uncertain. She also had peculiar findings of flexion limitation of the spine (rigid spine), contracture of the hip joint, and fatty degeneration of paraspinal muscles on CT. Percent vital capacity (VC) was 22.5%, and arterial blood gas analysis showed PaO2 of 60.5 mmHg and PaCO2 65.0 mmHg. To our knowledge, this is the first case of CMT accompanied by rigid spine and respiratory failure. Motor and sensory neuropathy combined with rigid spine also have not been reported previously. The relationship between rigid spine syndrome with neurogenic muscular atrophy and CMT type 2C with the clinical characteristics of diaphragm and vocal cord paresis is discussed.

Efficient selection for thermostable protease in Thermus thermophilus.

An efficient procedure was established to select for thermostable proteases in an extreme thermophile, Thermus thermophilus. A non-protease-secreting mutant derived from T. thermophilus TH125 was used as host and the expression plasmid for aqualysin I from T. aquaticus YT-1 was constructed as a source of thermostable protease. T. thermophilus cells harboring the recombinant plasmid produced active aqualysin I into the medium and were able to grow on a minimal medium containing milk casein as the sole source of carbon and nitrogen.

Increased soluble tumor necrosis factor receptor levels in the serum of elderly people.

BACKGROUND: Soluble (s) forms of tumor necrosis factor (TNF) receptors are the only natural molecules known to interfere with TNF activity by competing for TNF binding with receptors on target cells. In a variety of pathologic situations, the concentrations of sTNF receptors (R) increase. OBJECTIVE: To discuss possible causes of increased risks for infectious disease and cancer seen in the elderly. METHODS: The participants were healthy subjects (n = 48) of three age groups (young, middle-aged, and elderly). Patients with senile dementia of Alzheimer type (n = 25) were also studied. For detection of cytokines, interleukin (IL) 1alpha, IL-1beta, IL-6, macrophage colony-stimulating factor (M-CSF), granulocyte colony-stimulating factor, and TNF-alpha were measured in serum by enzyme-linked immunosorbent assays, as were soluble (s) IL-1 receptor antagonist (IL-1ra), sIL-6R, p55sTNF-R, and p75sTNF-R. RESULTS: IL-1alpha, IL-1beta, IL-6, and TNF-alpha were not detected, and sIL-6R and IL-1ra concentrations were not significantly different between the three age groups. However, sTNF-R and M-CSF were increased in sera from the elderly, both healthy and demented. A significant correlation was seen between sTNF-R and M-CSF concentrations. CONCLUSIONS: Increased sTNF-R levels may oppose the physiologic and protective effects of TNF by interference with its receptor binding. This interaction may contribute to the susceptibility of the elderly to infectious and neoplastic diseases.

[A case of Fisher syndrome showing pharyngeal-cervical-brachial weakness with an elevation of anti-GQ 1 b and anti-GT 1 a antibodies].

A 15-year-old boy developed ataxic gait, diplopia and hoarseness. Within 3 days after the onset, he had additional symptoms of dysphagia and dysarthria. He was admitted to our hospital 7 days after the onset of the disease. On admission, he had total ophthalmoplegia, ataxia, areflexia, facial diplegia, bulbar palsy and weakness of the neck and upper arms. Serum anti-GQ 1 b and anti-GT 1 a antibodies were significantly elevated. A diagnosis of Fisher syndrome associated with pharyngeal-cervical-brachial weakness was made. He was placed on a high dose of intravenous immunoglobins (12.5 g/day x 2 days) and had steroid pulse therapy (methylprednisolone 1 g x 3 days), which resulted in an almost complete recovery. There have been no reports of Fisher syndrome associated with brachio-pharyngeal-palsy. As in the case of the pharyngeal-cervical-brachial variant of Guillain Barré syndrome, anti-GT 1 a antibodies may be associated with Fisher syndrome with pharyngeal-cervical-brachial weakness.

Impaired cytokine production by peripheral blood mononuclear cells and monocytes/macrophages in Parkinson's disease.

OBJECTIVE: Although the pathogenesis of Parkinson's disease (PD) is still unknown, several reports suggest the presence of immunological abnormalities in the patients with PD such as impaired T cell responses or cytokine production by the peripheral immune system. MATERIAL AND METHOD: In this study, we examined cytokine production by peripheral blood mononuclear cells (PBMC) and monocyte/macrophages (PBM) in the patients with idiopathic PD, using age-related healthy donors as a normal control and cerebrovascular diseases (CVD) as a disease control. RESULTS: Production of TNF-alpha, IL-1alpha, IL-1beta and IL-6 by PBMC and TNF-alpha by PBM were significantly lower in the patients with PD as compared to the control groups. IFN-gamma production by LPS-stimulated PBMC in the patients with PD was also significantly lower than that in control groups. Cytokine production by PBMC from the patients with CVD who had a similar disability as the patient group was not significantly different from those in normal controls. Thus, impaired production of inflammatory cytokines may not be due to the mental and physical stress caused by their disability. CONCLUSION: In the patients with PD, a significant negative correlation was noted in 1alpha-1beta, IL-1beta and IL-6 levels produced by LPS-stimulated PBMC and Hoehn Yahr disability score of the patients, suggesting that the impaired cytokine production may progress with disease progression. These abnormalities in cytokine production may not be primary but may affect the prognosis of PD.

Drop in relapse rate of MS by combination therapy of three different phosphodiesterase inhibitors.

Phosphodiesterase inhibitors (PDEIs), when used in combination, synergistically suppress TNFalpha production by various cells and also suppress experimental demyelination at very low concentrations. We conducted a pilot study to determine whether the combination of three PDEIs suppresses the relapse of MS at the usual therapeutic doses. Of the 12 relapsing remitting MS, the mean relapse rate/year dropped remarkably (from 3.08+/-3.32 to 0.92+/-1.86) after PDEI treatment. Seven out of 12 (58.3%) were relapse-free in the follow up period (499+/-142 days). The combination of three PDEIs can be safe and useful strategy for the future treatment of MS. - 58

The effect of endothelin-1 on lipopolysaccharide-induced cyclooxygenase 2 expression in association with prostaglandin E(2).

We demonstrated previously that endothelin-1 (10(-14) to 10(-8) M) promotes lipopolysaccharide-induced cyclooxygenase 2 expression and prostaglandin E(2) production through endothelin ET(B) receptors effects which are up-regulated by lipopolysaccharide. In the present study, we confirmed these findings and showed that prostaglandin E(2) (10(-6) to 10(-5) M) inhibited the lipopolysaccharide plus endothelin-1-induced cyclooxygenase 2 expression more profoundly as compared to its inhibition of the lipopolysaccharide-induced cyclooxygenase 2 expression. The endothelin ET(B) receptor selective antagonist, N-cis-2, 6-dimethylpiperidino-carbonyl-L-gamma-methyl-leucyl-D-L-methoxy carbon yl-tryptophanyl-D-norleucine (BQ788), partly inhibited this suppression. Interestingly, the expression of endothelin ET(B) receptors in macrophages was increased by lipopolysaccharide plus prostaglandin E(2) (10(-8) to 10(-5) M) about 1.6-fold compared with that evoked by lipopolysaccharide stimulation alone. We also showed that treatment with endothelin-1 at 10(-14) M (15 min) elevated an intracellular cyclic AMP concentration in macrophages stimulated by lipopolysaccharide or lipopolysaccharide plus prostaglandin E(2) (10(-6) M) for 6 h, and the elevation in the latter cells was more pronounced. These results suggested that endothelin-1 shows an opposite modulation of lipopolysaccharide-induced cyclooxygenase 2 expression in macrophages through endothelin ET(B) receptors, depending on the level of extracellular prostaglandin E(2), and the changes of intracellular cyclic AMP by endothelin-1 may be involved in this mechanism.

[A case of metastatic extradural seminoma suspected intradural invasion by the measurements of HCG beta concentration in CSF].

A 34-year-old man underwent left orchidectomy for his left testicular seminoma. One month later, he developed paraplegia, hypesthesia under Th10 level and vesicorectal disturbance. He was diagnosed as having compressive myelopathy secondary to metastatic neoplasm at thoracic vertebra 10 and its extradural space which were revealed on magnetic resonance imaging. After administration of combination chemotherapy with cisplatin, etoposide and bleomycin, the extradural lesions diminished and the neurological symptoms gradually improved. In this case, intradural invasion of tumor cells was suspected because the level of human chorionic gonadotrophin beta subunit (HCG beta) concentration in cerebrospinal fluid (CSF) was higher than that in plasma, while radiographic scanning demonstrated regional tumor located at extradural space of Th10 level. It is important to evaluate the spread of tumor cells for the choice of therapy and the monitoring of HCG beta (plasma:CSF ratio) was considered to be one of the useful methods to detect the presence of central nerve system metastases from HCG-producing tumor.

[A case of antiphospholipid antibody syndrome with cerebral infarction showing slowly progressive pure motor monoparesis in unilateral upper extremity].

We reported a 68-year-old man with anti-phospholipid antibody syndrome who presented slowly progressive pure motor monoparesis(PMM) in left upper extremity as a sign of cerebral infarction. He had history of hypertension and hyperlipidemia. He first noticed clumsiness in left fingers, then weakness of left fingers with drop hand developing gradually in 2 to 6 weeks. He began to feel difficulty in raising left upper arm in 8 weeks and was admitted to our hospital. On admission, he exhibited severe weakness in distal portion and moderate weakness in proximal portion of left upper extremity. Deep tendon reflexes were slightly hyperactive in left side. Muscle strength of right upper extremity and bilateral lower extremities were normal. There was no sensory and autonomic abnormality. Laboratory examination revealed high titer of anti-cardiolipin IgM antibody. Brain MRI demonstrated a small cortical infarction in the right precentral gyrus. Cerebral angiography revealed severe stenosis in right common carotid artery. Other examinations including EMG were unremarkable. PMM in left upper extremity was considered to be caused by the ischemic lesion in the precentral motor cortex. Slowly progressive course might be explained by the hypovolemic factor due to the marked stenosis in right common carotid artery, poor collateral circulation, and abnormal coagulation caused by anti-phospholipid antibody syndrome.