The time to develop treatments for diabetic neuropathy.

BACKGROUND: Diabetic neuropathy is a multifaceted condition affecting up to 50% of individuals with long standing diabetes. The most common presentation is peripheral diabetic sensory neuropathy (DPN). METHODS: We carried out a systematic review of papers dealing with diabetic neuropathy on Pubmed in addition to a targeted Google search.Search terms included small fiber neuropathy,diffuse peripheral neuropathy, quantitative sensory testing, nerve conduction testing, intra-epidermal nerve fiber density, corneal confocal reflectance microscopy, aldose reductase inhbitors, nerve growth factor, alpha-lipoic acid, ruboxistaurin, nerve growth factor antibody, and cibinetide. RESULTS: Over the past half century, there have been a number of agents undergoing unsuccessful trials for treatment of DPN.There are several approved agents for relief of pain caused by diabetic neuropathy, but these do not affect the pathologic process. EXPERT OPINION: The failure to find treatments for diabetic neuropathy can be ascribed to (1) the complexity of design of studies and (2) the slow progression of the condition, necessitating long duration trials to prove efficacy.We propose a modification of the regulatory process to permit early introduction of agents with demonstrated safety and suggestion of benefit as well as prolongation of marketing exclusivity while long term trials are in progress to prove efficacy.

Botulinum Toxin and Neuronal Regeneration after Traumatic Injury of Central and Peripheral Nervous System.

Botulinum neurotoxins (BoNTs) are toxins produced by the bacteria Clostridiumbotulinum, the causing agent for botulism, in different serotypes, seven of which (A-G) are well characterized, while others, such as H or FA, are still debated. BoNTs exert their action by blocking SNARE (soluble N-ethylmale-imide-sensitive factor-attachment protein receptors) complex formation and vesicle release from the neuronal terminal through the specific cleavage of SNARE proteins. The action of BoNTs at the neuromuscular junction has been extensively investigated and knowledge gained in this field has set the foundation for the use of these toxins in a variety of human pathologies characterized by excessive muscle contractions. In parallel, BoNTs became a cosmetic drug due to its power to ward off facial wrinkles following the activity of the mimic muscles. Successively, BoNTs became therapeutic agents that have proven to be successful in the treatment of different neurological disorders, with new indications emerging or being approved each year. In particular, BoNT/A became the treatment of excellence not only for muscle hyperactivity conditions, such as dystonia and spasticity, but also to reduce pain in a series of painful states, such as neuropathic pain, lumbar and myofascial pain, and to treat various dysfunctions of the urinary bladder. This review summarizes recent experimental findings on the potential efficacy of BoNTs in favoring nerve regeneration after traumatic injury in the peripheral nervous system, such as the injury of peripheral nerves, like sciatic nerve, and in the central nervous system, such as spinal cord injury.

Modeling drug exposure in rodents using e-cigarettes and other electronic nicotine delivery systems.

Smoking tobacco products is the leading cause of preventable death worldwide. Coordinated efforts have successfully reduced tobacco cigarette smoking in the United States; however, electronic cigarettes (e-cigarette) and other electronic nicotine delivery systems (ENDS) recently have replaced traditional cigarettes for many users. While the clinical risks associated with long-term ENDS use remain unclear, advancements in preclinical rodent models will enhance our understanding of their overall health effects. This review examines the peripheral and central effects of ENDS-mediated exposure to nicotine and other drugs of abuse in rodents and evaluates current techniques for implementing ENDS in preclinical research.

Using a new high-throughput video-tracking platform to assess behavioural changes in Daphnia magna exposed to neuro-active drugs.

Recent advances in imaging allow to monitor in real time the behaviour of individuals under a given stress. Light is a common stressor that alters the behaviour of fish larvae and many aquatic invertebrate species. The water flea Daphnia magna exhibits a vertical negative phototaxis, swimming against light trying to avoid fish predation. The aim of this study was to develop a high-throughput image analysis system to study changes in the vertical negative phototaxis of D. magna first reproductive adult females exposed to 0.1 and 1 µg/L of four neuro-active drugs: diazepam, fluoxetine, propranolol and carbamazepine. Experiments were conducted using a custom designed experimental chamber containing four independent arenas and infrared illumination. The apical-located visible light and the GigE camera located in front of the arenas were controlled by the Ethovision XT 11.5 sofware (Noldus Information Technology, Leesburg, VA). Total distance moved, time spent per zone (bottom vs upper zones) and distance among individuals were analyzed in dark and light conditions, and the effect of different intensities of the apical-located visible light was also investigated. Results indicated that light intensity increased the locomotor activity and low light intensities allowed to better discriminate individual responses to the studied drugs. The four tested drugs decreased the response of exposed organisms to light: individuals moved less, were closer to the bottom and at low light intensities were closer each other. At high light intensities, however, exposed individuals were less aggregated. Propranolol, carbamazepine and fluoxetine induced the most severe behavioural effects. The tested drugs at environmental relevant concentrations altered locomotor activity, geotaxis, phototaxis and aggregation in D. magna individuals in the lab. Therefore the new image analysis system presented here was proven to be sensitive and versatile enough to detect changes in diel vertical migration across light intensities and low concentration levels of neuro-active drugs.

Amyotrophic Lateral Sclerosis Incidence and Previous Prescriptions of Drugs for the Nervous System.

BACKGROUND: An increased frequency of psychotic disorders in amyotrophic lateral sclerosis (ALS) families compared to controls has been reported. Aim of our study was to assess the relationship between nervous system drugs prescriptions and subsequent onset of ALS in a large Italian population. METHODS: The study population consisted of all subjects over 15 years at the 2001 Italian census, resident in Turin since 1996 (n = 687,324), followed up for ALS occurrence from 2002 to 2014. Exposure to nervous system drugs was measured until 2012, or until 1 year before ALS onset. The association was estimated for ever and cumulative exposure, through Cox proportional Hazards models adjusted for sex, age, education, marital status and drug co-exposure. RESULTS: In the analysis for ever exposure, opioids were significantly inversely associated with ALS risk (hazard ratio (HR) 0.59; 95% CI 0.35-0.97), while antiepileptics (HR 1.35; 95% CI 0.92-2.00) showed a marginally significantly positive association. Examining cumulative exposure, the protective role of opioids associated with more than 4 prescriptions and the risk effect of antiepileptics for over 6 prescriptions was confirmed. CONCLUSIONS: The present study revealed associations of ALS onset with previous exposure to opioids, maybe through the activation of δ receptor and σ receptors and antiepileptics, which are novel findings to our knowledge.

The use of botulinum toxin in the treatment of sialorrhea in parkinsonian disorders.

Drooling is a common symptom in parkinsonian disorders. Our aim was to assess the safety and effect of botulinum toxin when applied to parotid glands without ultrasound guidance for sialorrhea in parkinsonian disorders in a retrospective study with a long-term follow-up. We evaluated 53 patients (64.2% male and 35.8% female) with a mean age of 70.18 ± 9.25 years who were treated in our centre between 2007 and 2013. We analysed the mean dose, latency, effect duration, response and adverse effects of treating sialorrhea by injecting botulinum toxin type A (Botox) into the parotid glands without ultrasound guidance. A total of 41 patients with Parkinson's disease, 6 with progressive supranuclear palsy, 4 with multiple system atrophy and 2 with corticobasal degeneration were included. The mean duration of the disease at onset was 10.51 ± 6.81 years and the mean sialorrhea duration was 1.99 ± 1.55 years. The initial dose used for each parotid gland was 14.53 ± 3.95 units of Botox, with a mean dose of 22.17 ± 8.76 units. There was an improvement after treatment in 65.22% of patients with an average score of 6.85 ± 1.58 points on a scale from 0 to 10. The duration of the treatment effect was 4.38 ± 2.11 months, with a latency period of 10.06 ± 9.63 days. Adverse effects were mild and infrequent. Botulinum toxin is a safe and effective therapy for the treatment of sialorrhea in parkinsonian disorders and there is no requirement for ultrasound guidance. It has a rapid onset and lasting effect without requiring a high dosage.

Outcomes of greater occipital nerve injections in pediatric patients with chronic primary headache disorders.

BACKGROUND: Chronic migraine is common in pediatrics and generally disabling. In adults, infiltration of the area around the greater occipital nerve can provide short- to medium-term benefit in some patients. This study reports the efficacy of greater occipital nerve infiltrations in pediatric patients with chronic primary headache disorders. METHODS: Retrospective chart review of patients <18 years with a chronic primary headache disorder undergoing a first-time injection. Infiltrations were unilateral and consisted of a mixture of methylprednisolone acetate, adjusted for weight, and lidocaine 2%. RESULTS: Forty-six patients were treated. Thirty-five (76%) had chronic migraine, 9 (20%) new daily persistent headache (NDPH), and 2 (4%) a chronic trigeminal autonomic cephalalgia. Medication overuse was present in 26%. Ages ranged from 7 to 17 years. Follow-up data were available for 40 (87%). Overall, 53% (21/40) benefitted, and 52% (11/21) benefitted significantly. Benefit onset ranged from 0 to 14 days, mean 4.7 (SD 4.3), with mean benefit duration of 5.4 (SD 4.9) weeks. In chronic migraine, 62% (18/29) benefitted, and 56% (10/18) significantly benefitted. In NDPH, 33% (3/9) benefitted; 33% (n = 1) significantly. Neither child with a chronic trigeminal autonomic cephalalgia benefitted. In logistic regression modeling, medication overuse, age, sex, and sensory change in the distribution of the infiltrated nerve did not predict outcome. There were no serious side effects. CONCLUSIONS: Greater occipital nerve injections benefitted 53% of pediatric patients with chronic primary headache disorders. Efficacy appeared greater in chronic migraine than NDPH. Given the benign side effect profile, a greater occipital nerve infiltration seems appropriate before more aggressive approaches.

Thickened saliva after effective management of drooling with botulinum toxin A.

AIM: The aim of this study was to evaluate the rheological properties of saliva after submandibular botulinum toxin type A (BoNT-A) injections. METHOD: We enrolled 15 children (11 males and six females; age range 3-17 y, mean age 9 y 10 mo) diagnosed with spastic (n=9) or dyskinetic (n=6) quadriplegic cerebral palsy (CP); Gross Motor Function Classification System level IV or V; and two children with intellectual disability (IQ<70) who experienced moderate to severe drooling. Salivary flow rate and drooling quotient were measured at baseline and at different times after BoNT-A injections up to 24 weeks. The mucin concentration of saliva was analysed before and after BoNT-A treatment. RESULTS: Both submandibular salivary flow rate (baseline 0.38 mL/min; 24 wks after injection 0.26 mL/min) and drooling quotient (baseline 42.5%; 24 wks 28.80%) were substantially reduced, with a concomitant increase in mucin concentration within 8 weeks after BoNT-A injection (from 0.612 to 1.830 U/mL). The parents of nine children observed thickened saliva. Swallowing and chewing were problematic in seven children. Two of these children needed treatment with mucolytics because of pooling of thickened saliva in the throat. INTERPRETATION: When making decisions about the use of BoNT-A, the risk of problems with masticatory and swallowing functions as a result of thickening of saliva after BoNT-A treatment should be taken into account.

[Pharmacological treatment of diabetic neuropathy in the elderly]. / Tratamiento farmacológico de la neuropatía diabética dolorosa en el anciano.

Diabetic neuropathy is the third most common complication of diabetes mellitus. When this neuropathy is accompanied by pain, it requires a specific treatment. In the elderly patient, the pain has an enormous impact on quality of life, as it is associated with anxiety, depression and sleep disorders, leading to a direct impact on the functionality of the patient. Likewise, there are a number of changes at the central and peripheral nervous system, which contribute to the chronicity of painful processes, and eventually also affect and impact on the quality of life of elderly patients. It is fundamental before initiating treatment, to know of all aspects related to drug pharmacokinetics and pharmacodynamics, especially those related to aging, because this will allow you to select the best drug for each patient. This article aims to review the pathophysiological concepts related to diabetic neuropathy in the elderly and the best treatment options.

[Therapy of polyneuropathies. Causal and symptomatic]. / Therapie von Polyneuropathien. Kausal und symptomatisch.

In the first instance, polyneuropathies are treated causally. The most common underlying cause is diabetes mellitus or alcohol abuse. In a large number of patients with polyneuropathy, however, the underlying cause cannot be definitively identified. For these--but equally for patients with etiologically clear polyneuropathy--a stock-taking of clinical symptoms should be carried out and, where indicated, symptomatic treatment initiated. In addition to medication aimed at combating pain, muscular spasm, autonomic functional disorders, and for the prevention of thrombosis, physical measures (physiotherapy, foot care, orthopedic shoes) are of primary importance.