[Show abstract][Hide abstract] ABSTRACT: Treatment of neuromuscular diseases is still an unsolved problem. Evidence over the last years strongly indicates the involvement of malformation and dysfunction of neuromuscular junctions in the development of such medical conditions. Stabilization of NMJs thus seems to be a promising approach to attenuate the disease progression of muscle wasting diseases. An important pathway for the formation and maintenance of NMJs is the agrin/Lrp4/MuSK pathway. Here we demonstrate that the agrin biologic NT-1654 is capable of activating the agrin/Lrp4/MuSK system in vivo, leading to an almost full reversal of the sarcopenia-like phenotype in neurotrypsin-overexpressing (SARCO) mice. We also show that injection of NT-1654 accelerates muscle re-innervation after nerve crush. This report demonstrates that a systemically administered agrin fragment has the potential to counteract the symptoms of neuromuscular disorders.
[Show abstract][Hide abstract] ABSTRACT: Dimiracetam, a bicyclic 2-pyrrolidinone derivative originally developed as cognition enhancer, is a member of the nootropic family for which anedoctal efficacy in models of neuropathic pain has been reported. Its antineuropathic activity was evaluated in established models of neuropathic pain induced by nerve injury, chemotherapy or MIA-induced osteoarthritis. Acutely, dimiracetam was very effective in models of antiretroviral drug induced painful neuropathy, oxaliplatin-induced hyperalgesia and in the MIA-osteoarthritis. Chronic dimiracetam dosing in the MIA and ART- induced models completely reverted hyperalgesia back to the level of healthy controls. Once reached, the maximal effect was maintained despite dose diminution and increased inter-dose interval. The effect of the last dose outlasted dimiracetam half-life longer than 12 times. In synaptosomal preparations, dimiracetam counteracted the NMDA-induced release of glutamate with highest potency in the spinal cord, possibly via NMDA receptor isoforms containing pH-sensitive GluN1 and GluN2A subunits. Dimiracetam appears to be a promising and safe treatment for neuropathic pain conditions for which there are very limited therapeutic options.
Full-text · Article · Jan 2014 · Neuropharmacology
[Show abstract][Hide abstract] ABSTRACT: An international task force of academic and industry leaders in sarcopenia research met on December 5, 2012 in Orlando, Florida to develop guidelines for designing and executing randomized clinical trials of sarcopenia treatments. The Task Force reviewed results from previous trials in related disease areas to extract lessons relevant to future sarcopenia trials, including practical issues regarding the design and conduct of trials in elderly populations, the definition of appropriate target populations, and the selection of screening tools, outcome measures, and biomarkers. They discussed regulatory issues, the challenges posed by trials of different types of interventions, and the need for standardization and harmonization. The Task Force concluded with recommendations for advancing the field toward better clinical trials.
No preview · Article · Aug 2013 · The Journal of Nutrition Health and Aging
[Show abstract][Hide abstract] ABSTRACT: Introduction:
Sarcopenia is considered to be an enormous burden for both the individuals affected and for society at large. A multifactorial aetiology of this geriatric syndrome has been discussed. Amongst other pathomechanisms, the degeneration of the neuromuscular junction (NMJ) may be of major relevance. The intact balance between the pro-synaptic agent agrin and the anti-synaptic agent neurotrypsin ensures a structurally and functionally intact NMJ. Excessive cleavage of the native motoneuron-derived agrin by neurotrypsin into a C-terminal Agrin Fragment (CAF) leads to functional disintegration at the NMJ and may consecutively cause sarcopenia. The present study evaluates the hypothesis that CAF serum concentration is a potential marker for the loss of appendicular lean mass in older adults. It also explores how CAF concentration is influenced by vitamin D supplementation and physical exercise.
Serum was taken from 69 (47 female) prefrail community-dwelling older adults participating in a training intervention study to measure the CAF concentration using the Western blot technique. All participants were supplemented orally with vitamin D3 before the training intervention period commenced. Appendicular lean mass (aLM) was evaluated by dual energy X-ray absorptiometry. Multiple linear regression models were used to identify factors significantly associated with CAF concentration.
Appendicular lean mass, age and sex were identified as significant explanatory factors for CAF concentration. Gait speed and hand grip strength were not associated with CAF concentration. Male participants showed a strong correlation (r=-0.524) between CAF serum concentration and aLM, whereas this was not the case (r=-0.219) in females. Vitamin D supplementation and physical exercise were significantly associated with a reduction in CAF concentration, especially in participants with initially high CAF concentrations.
C-terminal Agrin Fragment could be a potential marker for identifying sarcopenia in a subgroup of affected individuals in the future. The decline of muscle mass seems to be a CAF-associated process in males, whereas the situation in females may be more complex and multifactorial. CAF concentration is reduced by vitamin D supplementation and physical exercise and therefore suggests a potentially positive effect on NMJs. Further prospective studies of sarcopenic patients in addition to muscle biopsy and electromyographical investigations are planned to verify the external validity of the CAF concept.
No preview · Article · Jun 2012 · Experimental gerontology
[Show abstract][Hide abstract] ABSTRACT: Sarcopenia is a recently defined medical condition described as age-associated loss of skeletal muscle mass and function. Recently, a transgenic mouse model was described linking dispersal of the neuromuscular junction caused by elevated agrin degradation to the rapid onset of sarcopenia. These mice show a significant elevation of serum levels of a C-terminal agrin fragment (CAF) compared to wild-type littermates. A series of experiments was designed to ascertain the significance of elevated agrin degradation in the development of human sarcopenia. A quantitative Western blot method was devised to detect CAF in sera of humans. A first trial on consenting blood donors (n=169; age 19-74years) detected CAF in the limited range of 2.76±0.95ng/ml. In sarcopenia patients (diagnosed according to clinical and instrumental standards) mean CAF levels were significantly elevated (p=9.8E10-9; n=73; age 65-87years) compared to aged matched controls. Of all sarcopenia patients, 40% had elevated, non-overlapping CAF levels compared to controls. Evidence is presented for a pathogenic role of the agrin/neurotrypsin system in a substantial subset of sarcopenia patients. These patients are characterized by elevated CAF blood levels compared to aged-matched healthy volunteers suggesting the identification of an agrin-dependent form of sarcopenia. Elevated CAF levels in a large subpopulation of sarcopenic patients suggest the existence of a specific form of sarcopenia for which CAF could become a biomarker and a new target for therapeutic interventions. The feasibility of this approach was demonstrated by the development of a small molecule capable of inhibiting neurotrypsin in vitro and in vivo.
Full-text · Article · Mar 2012 · Experimental gerontology
[Show abstract][Hide abstract] ABSTRACT: A first Task Force on Sarcopenia was organized in Castres, near Toulouse, in 2008, with a series of papers on Sarcopenia published in the JNHAin 2009. Folowing this work a second international task force on Sarcopenia was organized in Rome in 2009 and the consensus paper was published in the JAMDA. Our third international Task Force was hosted in Albuquerque on Designing sarcopenia trials. We are happy to present now the abstract presented at our 4° International Task Force on Sarcopenia biomarkers just before the International Conference on Sacopenia research in 2011. Recommendations for imaging biomarkers in sarcopenia therapeutic trials; Defining Sarcopenia; Use of MRI and CT in Clinical Trials of Sarcopenia; Muscle quality and function: Implications for sarcopenia definitions and therapeutic targets; Modifiable risk factors for sarcopenia and mobility disability, which could be targeted in multicomponent interventions trials; Electrical Impedance Myography:A New Tool for the Assessment of Sarcopenia; Challenges in assessment of muscle strength and function - Lessons from als clinical trials; Novel Imaging Methods for Early Drug Development;Qualification of novel methodologies at the European Medicines Agency; Agrin-dependent sarcopenia. The consensus paper from this symposium will be submitted for publication shortly.
No preview · Article · Dec 2011 · The Journal of Nutrition Health and Aging
[Show abstract][Hide abstract] ABSTRACT: A decrease of Brain Derived Neurotrophic factor (BDNF) in the hippocampus and other limbic structures is a putative causal factor of depressive disorders. Racetam derivatives have been reported to act on BDNF. In fact, levetiracetam stimulates BDNF expression in rat cortical astrocyte cultures (Cardile et al., 2003) and piracetam increases the number of BDNF immunopositive hippocampal cells (Park et al., 2010).
Based on these premises, the present study was aimed at evaluating the potential ability of some “racetam” compounds (pramiracetam, dimiracetam, oxiracetam and levetiracetam) to increase mobility time in the rat forced swimming test (Porsolt Test) after single and repeated treatment. The majority of anti-depressants increase swimming time and their effectiveness shows significant correlation with their clinical efficacy [Petit-Demouliere et al. 2005, Psychopharmacol, 177, 245-255]. In the rat forced swimming test, dimiracetam (100 mg/kg p.o.), 30 min post dosing, produced a statistically significant increase of mobility time indicating the induction of an antidepressant-like effect comparable to that shown by amitryptiline (15 mg/kg s.c., acute administration). By contrast, dimiracetam at the dose of 50 or 200 mg/kg p.o. did not exhibit efficacy. After single administration, at all tested doses (50-200 mg/kg p.o.) pramiracetam, oxiracetam and levetiracetam were devoid of antidepressant-like activity. In the rat forced swimming test after repeated b.i.d. administration for 10 days, dimiracetam (100 mg/kg p.o.) and amitryptiline (15 mg/kg s.c.), but not pramiracetam, oxiracetam and levetiracetam (100 mg/kg p.o.), prolonged the swimming time. Animals were tested on day 11, 60 min after the last compound administration. Dimiracetam at the active doses did not change rat motor coordination, spontaneous motility or exploratory activity evaluated by rotarod or hole board tests, respectively. Due to these results and to the excellent safety profile shown so far, dimiracetam seems to represent a promising alternative to traditional antidepressants.
[Show abstract][Hide abstract] ABSTRACT: The use of antitumoral chemotherapy in cancer patients is often strongly limited by the development of a painful peripheral neuropathy (Kennedy, J. Med. Chem. 50: 2547-2556, 2007). Many “classical” analgesic drugs are only poorly effective in relieving neuropathic pain which therefore remains an unmet medical need. In this study, an animal model mimicking the hand and foot syndrome observed in sorafenib-treated patients was established. Sorafenib is a novel kinase inhibitor that prevents tumor proliferation and angiogenesis and that is widely used in treating liver and renal carcinomas.
Sorafenib (10-30 mg/kg) administered i.p. once daily induced an allodynic response to thermal stimuli (4°C cold plate). The peak of allodynic severity appears at day 14 after treatment and remains unaltered until day 21. A similar allodynic response was observed after oral administration of 80 or 160 mg/kg, but not after intravenous administration of 10 mg/kg for 2 weeks. At the allodynic oral doses, sorafenib induced a reduction of spontaneous motility and reactivity.
No mechanical allodynia or hyperalgesia were observed when pain threshold was assessed in the paw-pressure or in the von Frey tests.
The ability of a few antineuropathic compounds to prevent the sorafenib-induced cold allodynia was tested after acute or chronic administration. Acutely, both dimiracetam (300 mg/kg p.o.) and pregabalin (30 mg/kg p.o.) but not gabapentin (100 mg/kg p.o.) or duloxetine (30 mg/kg p.o.) were effective at 15 min after administration.
After chronic, 14-day b.i.d. administration, both dimiracetam (150 mg/kg p.o.) and pregabalin (15 mg/kg p.o.) effectively prevented the cold allodynia induced by sorafenib, with the effect persisting 48 h (dimiracetam) or 24 h (pregabalin) after the last administration.
[Show abstract][Hide abstract] ABSTRACT: BND-11624, a pyrrolidinone derivative, has a broad spectrum of antiallodynic and antihyperalgesic activity in several animal models of neuropathic pain after acute administration. A series of experiments were designed to test BND-11624 capability of maintaining efficacy after chronic administration. Allodynia was tested in rats after induction of neuropathy with antiretroviral agents and hyperalgesia assessed in a model of osteoarthritic pain caused by the injection into the rat knee joint of monosodium acetate. After 2 week dosing, oral BND-11624 fully reverted the abnormal pain responses, more so than the tested competitors. After the last dosing BND-11624 effect lasted up to 24 h, much longer than what seen at earlier times. Having discovered that BND-11624 modulates the activity of specific subtypes of NMDA receptors (Bonanno et al, accompanying poster) and knowing that NMDA is involved with long term plasticity of neuronal circuits, we hypothesized that such a mechanism might result in a dose sparing schedule upon chronic treatment. Thus, we designed experiments to evaluate the effects of steady and decremental doses of BND-11624 compared to a steady dose of pregabalin used as positive control.
Chronic BND-11624 administration (4 weeks) produced a strong antiallodynic effect in the antiviral agent (2',3'-di-deoxycytidine, 25 mg/kg i.v.) induced neuropathy. The magnitude of the effect was retained in spite of downtitration schedule model. Fiftysix hours after the last dosing a significant effect was still present. On the contrary, pregabalin’s effect, albeit superior at the onset, was equalled after 10 days and waned afterwards. In the range of effective doses, BND-11624 did not produce any inhibition of motor coordination, as evaluated by the rat rotarod.
BND-11624 appears to be a promising drug candidate with a unique profile as to the therapeutic administration schedule.
[Show abstract][Hide abstract] ABSTRACT: To investigate the mechanism of action of BND-11624, a pyrrolidinone derivative active in neuropathic pain
models (Ghelardini et al., accompanying poster), its possible interaction with glutamate (GLU) transmission was investigated in vitro. At this purpose, the ability of BND-11624 to modulate the release of GLU, or noradrenaline
(NE), or dopamine (DA) mediated by activation of NMDA receptors, which have been previously shown to
represent pharmacologically distinguishable NMDA receptor subtypes, was studied in rat brain synaptosomes
purified from hippocampus (NE and GLU release studies), corpus striatum (DA release) and spinal cord (GLU
release). Additionally, the modulation by BND-11624 of the mGluR1 and mGluR5 metabotropic GLU
receptor-mediated effects on the NE release was examined in hippocampal synaptosomes .
Studying transmitter release from synaptosomes offers the advantage of assessing a pure presynaptic effect.
Moreover, the superfusion of a synaptosomal thin layer, as in our release experiments, minimizes indirect effects.
As a result, if an exogenously added drug modifies the release of a given neurotransmitter, it will be assumed
that this is due to a direct action of the tested compound on the nerve terminals releasing the transmitter in point.
BND-11624 did not possess by itself agonist properties at the NMDA receptors regulating the release of
[3H]DA, [3H]NE or [3H]D-Aspartate ([3H]D-Asp is a non-metabolizable analog used to label the GLU
intraterminal pools), in as much as it did not modify the release of the three transmitters studied both in the
absence or in the presence of the NMDA receptor co-agonist glycine. When tested as an antagonist, BND-11624 differently affected the NMDA receptors modulating the release of the above mentioned transmitters: it
preferentially antagonized the potentiation driven by NMDA of [3H]D-Asp release in spinal cord (IC50: 18 nM)
and hippocampus (IC50: 2.6 uM). The compound affected also the NMDA-induced potentiation of DA release in
the corpus striatum, but with a lower potency (IC50: 37.4 uM); while no antagonism was seen in the case of the
NE release in hippocampus. BND-11624 did not display either agonist or antagonist activity at mGluR1 and
mGluR5 inhibiting the stimulus-induced release of [3H]NE.
In conclusion, the marked ability of BND-11624 to reduce the NMDA-mediated potentiation of the excitatory
aminoacid release in the hippocampus and, especially, in spinal cord may be important for analgesia, considering the key role of glutamate release and NMDA receptors in neuropathic pain.