Intranasal formulation of erythropoietin (EPO) showed potent protective activity against amyloid toxicity in the Aβ₂₅₋₃₅ 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 Aβ₂₅₋₃₅ 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 Aβ₂₅₋₃₅ 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 Aβ₂₅₋₃₅-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 Aβ₂₅₋₃₅-induced increase in Bax level, TNFα and IL-1β production and decrease in Akt activation. A significant prevention of the Aβ₂₅₋₃₅-induced cell loss in CA1 was also observed. EPO is neuroprotective in the Aβ₂₅₋₃₅ 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.

Pb5In3Bi5S17 [Pb(4.94(3))In(3.05(3))Bi(4.99(3))S17] and its structural relationship with Pb4In3Bi7S18

The title phase (pentalead triindium pentabismuth heptadecasulfide) has been synthesized and structurally characterized. Its structure contains mixed Bi/In, In/Bi and Pb/In positions; all atoms lie on crystallographic mirror planes. The structural relationship between Pb(5)In(3)Bi(5)S(17) and a phase known by the formula Pb(4)In(3)Bi(7)S(18) is discussed. A comparatively large and complex structural `seed' is defined which is common to both phases. The structural changes within this seed when moving from one phase to the other are described by graphical means.

Pb5.0(1)In8.4(1)Bi1.6(1)S20, a new quaternary lead indium bismuth sulfide

The title phase, first detected in the early 1980s but hitherto unpublished, has been resynthesized and structurally characterized. Unambiguous determination of the chemical composition was not possible by structure analysis alone, but required additional analytical methods. The complex structure shows a close similarity to the structures of two related compounds, one known by the formula Pb(1.6)In(8)Bi(4)S(19) and the other being the ternary compound Pb(6)In(10)S(21). This is despite the fact that the three phases correspond to very different Pb:Bi ratios. A geometric mechanism is described by which the three structures can be transformed into each other, provided that the heavy atoms Pb and Bi are treated as equivalent.

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 Aβ(25-35) peptide, a non-transgenic Alzheimer's disease model. When the drug was injected simultaneously with Aβ(25-35), 7 days before the tests, it blocked the appearance of learning impairments. This protective activity was confirmed since ANAVEX2-73 blocked the Aβ(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 Aβ(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.

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 17β-estradiol levels. Treatment with 17β-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.

Levetiracetam compared to valproic acid: plasma concentration levels, adverse effects and interactions in aneurysmal subarachnoid hemorrhage

OBJECTIVE

Both valproic acid and levetiracetam are anti-epileptic drugs, often used either alone or in combination. The present study compares valproate (VPA) with levetiracetam (LEV) as an intravenous (i.v.) anticonvulsant treatment in intensive care patients suffering from aneurysmal subarachnoid hemorrhage (aSAH) with a high risk of seizures.

PATIENTS AND METHODS

A prospective, single-center patient registry of 35 intensive care unit (ICU) patients with onset seizure and/or high risk of seizures underwent an anticonvulsive, first-line single treatment regimen either with VPA or LEV. Plasma concentrations (pc), interactions between drugs in the ICU context, adverse effects and seizure occurrences were observed and recorded.

RESULTS

A significant decrease in the pc in patients treated with LEV was observed after changing from intravenous (160±51μmol/l) to enteral liquid application (113±58μmol/l), corresponding to a 70.3% bioavailability for enteral liquid applications. The pc in VPA patients decreased significantly, from (491±138μmol/l) to (141±50μmol/l), after adding meropenem to the therapy (p<0.05). Three epileptic seizures occurred during anticonvulsive therapy in the LEV group, and two in the VPA group, including one non-convulsive status epilepticus (NCSE).

CONCLUSION

Though this finding needs further verification, the enteral liquid application of levetiracetam seems to be associated with lower bioavailability than the common oral application of levetiracetam. The use of the antibiotic drug meropenem together with valproic acid leads to lower pc levels in patients treated with of valproic acid. For clinical practice, this indicates the need to monitor the levels of valproic acid in combination with meropenem.

Time-course and regional analyses of the physiopathological changes induced after cerebral injection of an amyloid β 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 β protein (Aβ) formed by pathological processing of the Aβ precursor protein. We assessed the time-course and regional effects of a single intracerebroventricular injection of aggregated Aβ fragment 25-35 (Aβ(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 Aβ(25-35) peptide was used as negative control. The aggregated forms of Aβ peptides were first characterized using electron microscopy, infrared spectroscopy, and Congo Red staining. Intracerebroventricular injection of Aβ(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, Aβ(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 Aβ(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.

Monitoring of the inflammatory response after aneurysmal subarachnoid haemorrhage in the clinical setting: review of literature and report of preliminary clinical experience

BACKGROUND

Clinical and experimental studies showed a marked inflammatory response in aneurysmal subarachnoid haemorrhage (SAH), and it has been proposed to play a key role in the development of cerebral vasospasm (CVS). Inflammatory response and occurrence of CVS may represent a common pathogenic pathway allowing point of care diagnostics of CVS. Therefore, monitoring of the inflammatory response might be useful in the daily clinical setting of an ICU. The aim of the current report is to give a summary about factors contributing to the complex pathophysiology of inflammatory response in SAH and to discuss possible monitoring modalities.

METHODS

Review and analysis of the existing literature and definition of own study protocols.

RESULTS

In cerebrospinal fluid, interleukin (IL)-6 has been found to be significantly higher in patients with CVS during the peri-vasospasm period. While systemic inflammatory response syndrome, high C-reactive protein levels and leukocyte counts has been linked with the occurrence of CVS, less has been reported about cytokines levels in the jugular bulb of the internal jugular vein and in the peripheral blood. Preliminary evaluation of own data suggests, that IL-6 values in the peripheral blood and the arterio-jugular differences of IL-6 are increased with the inflammatory response after SAH.

CONCLUSION

Monitoring of the inflammatory response, in particular IL-6, might be a useful tool for the daily clinical management of patients with SAH and CVS.

Central venous catheter-induced delayed hydrothorax via progressive erosion of central venous wall

Central venous catheter (CVC)-induced hydrothorax is a delayed complication after the placement of an indwelling subclavian or internal jugular central venous catheter. The catheter tips may cause long-lasting mechanical damages that lead to a slow erosion of the wall of the superior vena cava (SVC), thereby resulting in hydrothorax. The damage may stem from the catheter tips being positioned inappropriately or from the relocation of the catheter tip that was initially ideally positioned. We describe an 80-year-old woman with CVC-induced hydrothorax. She presented with spinal subdural hematoma and preoperatively underwent a multiple-lumen CVC insertion through her left subclavian vein. Her recovery course was uneventful after surgical hematoma removal and spinal cord decompression. However, thirty hours after the CVC placement, the patient began to suffer from an increasing dyspnea. The chest X-ray showed right-sided, massive pleural effusion and a widened mediastinum, requiring the removal of the CVC and the drainage of the pleural fluid. After these procedures, the respiratory status improved rapidly. The present case report suggests that the complication of a hydrothorax may occur after a patient's position changes, and it usually occurs in cases where the catheter tip was initially placed in the ideal position. Operators responsible for CVC placement have to be aware of this delayed complication and have the catheter tips remain in a consistently appropriate position.

The kisspeptin system of the human hypothalamus: sexual dimorphism and relationship with gonadotropin-releasing hormone and neurokinin B neurons

Kisspeptin signaling via the kisspeptin receptor G-protein-coupled receptor-54 plays a fundamental role in the onset of puberty and the regulation of mammalian reproduction. In this immunocytochemical study we addressed the (i) topography, (ii) sexual dimorphism, (iii) relationship to gonadotropin-releasing hormone (GnRH) neurons and (iv) neurokinin B content of kisspeptin-immunoreactive hypothalamic neurons in human autopsy samples. In females, kisspeptin-immunoreactive axons formed a dense periventricular plexus and profusely innervated capillary vessels in the infundibular stalk. Most immunolabeled somata occurred in the infundibular nucleus. Many cells were also embedded in the periventricular fiber plexus. Rostrally, they formed a prominent periventricular cell mass (magnocellular paraventricular nucleus). Robust sex differences were noticed in that fibers and somata were significantly less numerous in male individuals. In dual-immunolabeled specimens, fine kisspeptin-immunoreactive axon varicosities formed axo-somatic, axo-dendritic and axo-axonal contacts with GnRH neurons. Dual-immunofluorescent studies established that 77% of kisspeptin-immunoreactive cells in the infundibular nucleus synthesize the tachykinin peptide neurokinin B, which is known to play crucial role in human fertility; 56 and 17% of kisspeptin fibers in the infundibular and periventricular nuclei, respectively, contained neurokinin B immunoreactivity. Site-specific co-localization patterns implied that kisspeptin neurons in the infundibular nucleus and elsewhere contributed differentially to these plexuses. This study describes the distribution and robust sexual dimorphism of kisspeptin-immunoreactive elements in human hypothalami, reveals neuronal contacts between kisspeptin-immunoreactive fibers and GnRH cells, and demonstrates co-synthesis of kisspeptins and neurokinin B in the infundibular nucleus. The neuroanatomical information will contribute to our understanding of central mechanisms whereby kisspeptins regulate human fertility.