Detrimental effects of soluble α-synuclein oligomers at excitatory glutamatergic synapses.

Introduction: Oligomeric and fibrillar species of the synaptic protein α-synuclein are established key players in the pathophysiology of Parkinson's disease and other synucleinopathies. Increasing evidence in the literature points to prefibrillar oligomers as the main cytotoxic species driving dysfunction in diverse neurotransmitter systems even at early disease stages. Of note, soluble oligomers have recently been shown to alter synaptic plasticity mechanisms at the glutamatergic cortico-striatal synapse. However, the molecular and morphological detrimental events triggered by soluble α-synuclein aggregates that ultimately lead to excitatory synaptic failure remain mostly elusive. Methods: In the present study, we aimed to clarify the effects of soluble α-synuclein oligomers (sOligo) in the pathophysiology of synucleinopathies at cortico-striatal and hippocampal excitatory synapses. To investigate early defects of the striatal synapse in vivo, sOligo were inoculated in the dorsolateral striatum of 2-month-old wild-type C57BL/6J mice, and molecular and morphological analyses were conducted 42 and 84 days post-injection. In parallel, primary cultures of rat hippocampal neurons were exposed to sOligo, and molecular and morphological analyses were performed after 7 days of treatment. Results: In vivo sOligo injection impaired the post-synaptic retention of striatal ionotropic glutamate receptors and decreased the levels of phosphorylated ERK at 84 days post-injection. These events were not correlated with morphological alterations at dendritic spines. Conversely, chronic in vitro administration of sOligo caused a significant decrease in ERK phosphorylation but did not significantly alter post-synaptic levels of ionotropic glutamate receptors or spine density in primary hippocampal neurons. Conclusion: Overall, our data indicate that sOligo are involved in pathogenic molecular changes at the striatal glutamatergic synapse, confirming the detrimental effect of these species in an in vivo synucleinopathy model. Moreover, sOligo affects the ERK signaling pathway similarly in hippocampal and striatal neurons, possibly representing an early mechanism that anticipates synaptic loss.

Rabphilin-3A as a novel target to reverse α-synuclein-induced synaptic loss in Parkinson's disease.

Toxic aggregates of α-synuclein (αsyn) are considered key drivers of Parkinson's disease (PD) pathology. In early PD, αsyn induces synaptic dysfunction also modulating the glutamatergic neurotransmission. However, a more detailed understanding of the molecular mechanisms underlying αsyn-triggered synaptic failure is required to design novel therapeutic interventions. Here, we described the role of Rabphilin-3A (Rph3A) as novel target to counteract αsyn-induced synaptic loss in PD. Rph3A is a synaptic protein interacting with αsyn and involved in stabilizing dendritic spines and in promoting the synaptic retention of NMDA-type glutamate receptors. We found that in vivo intrastriatal injection of αsyn-preformed fibrils in mice induces the early loss of striatal synapses associated with decreased synaptic levels of Rph3A and impaired Rph3A/NMDA receptors interaction. Modulating Rph3A striatal expression or interfering with the Rph3A/αsyn complex with a small molecule prevented dendritic spine loss and rescued associated early motor defects in αsyn-injected mice. Notably, the same experimental approaches prevented αsyn-induced synaptic loss in vitro in primary hippocampal neurons. Overall, these findings indicate that approaches aimed at restoring Rph3A synaptic functions can slow down the early synaptic detrimental effects of αsyn aggregates in PD.

Efficacy of lidocaine 7 %, tetracaine 7 % self-occlusive cream in reducing MAL-cPDT-associated pain in subjects with actinic keratosis: A randomized, single-blind, vehicle-controlled trial (The "3P-Trial").

INTRODUCTION: Conventional photodynamic therapy (cPDT) is considered a very effective treatment of actinic keratosis (AK) lesions. However, its use is limited by the fact that this procedure could be very painful. The use of topical anesthetics such as tetracaine or lignocaine/prilocaine has shown disappointing results in term of pain reduction. A self-occlusive topical 7% lidocaine/7% tetracaine anesthetic cream (LT-C) approved by the FDA to provide local topical anesthesia in adults undergoing superficial dermatological procedures is available. There are no data regarding its pain reducing effect during cPDT. We perform a prospective, randomized, single-blind, two-center trial (The 3P-Trial) to assess the pain reduction effect of LT-C versus vehicle in subjects with AK undergoing cPDT. MATERIAL AND METHODS: Fifty AK subjects (74 ± 10 years, 32 men, 18 women) with on average 17 lesions were enrolled after their written informed consent. Eight subjects presented also a total of 16 basal cell carcinoma lesions. Twenty-five were randomized to LT-cream, applied 1 h before the Methyl amino levulinate (MAL)-cPDT session and 25 to cream vehicle. The main outcome was the patient-assessed evaluation of pain score during and just after the conclusion of cPDT session (mean of the two values) using a 10-point visual analog scale (VAS). The cPDT session (LED Red light 630 nm) was performed with a duration of 6 ± 2 min with a standard fluence of 37 J/cm2. All treated lesions were prepared by gentle superficial curettage. RESULTS: All the randomized subjects concluded the trial. The mean ± SD of VAS score in vehicle group was 6.2 ± 2.7 (95 % CI of the mean: 5.0-7.5). In the group treated with LT-cream the VAS score was 3.3 ± 1.9 (95 % CI of the mean: 2.5-4.1). The active cream reduced the VAS score by 47 %. Median values of pain VAS score in the active group was reduced by 60 % in comparison with vehicle group (3.0 vs 7.5). The difference between the two groups was statistically significant (p = 0.0009; Mann-Whitney test). DISCUSSION: The 3P-trial has demonstrated that the preventive application of the self-occlusive lidocaine 7%-tetracaine 7% cream is very effective in reducing the procedure-associated pain during MAL-cPDT for the treatment of AK lesions.

Peristomal allergic contact dermatitis caused by ostoma pastes and role of Gantrez ES-425.

BACKGROUND: Peristomal allergic contact dermatitis is an emerging problem and contact sensitization is probably more common than previously thought. Our objective was to identify sensitization to the most common topical equipment for ostomy in patients with history of peristomal dermatitis. METHODS: Twenty-six patients with suspected peristomal contact dermatitis were patch tested with our standard series and with products for stoma care (adhesive pastes, powders, adhesive skin barriers). Thirteen patients and 20 volunteers were also patch tested with Gantrez ES-425, which is a common component of adhesive pastes. RESULTS: Eighteen patients showed one or more positive reactions, 12 to one or more of the most commonly used adhesive pastes. Ten out of 13 patients tested to Gantrez ES-425 had a positive reaction. CONCLUSIONS: Allergic contact dermatitis of the peristomal area is probably more common than previously reported. Patch testing is the method of choice to determine sensitization to products for stoma care, and Gantrez ES-425 should be considered for patch testing.

Radiodermatitis after spinal arteriovenous fistula embolisation.

We report acute radiation dermatitis on a patient's back and left arm, which developed 4 weeks after endovascular embolisation of a spinal arteriovenous malformation. Vesciculation and erosions were followed by a gradual re-epithelisation of the skin resulting in rectangular hyperpigmented patches that resolved almost completely within 1 month. Fluoroscopic radiodermatitis has been reported with more frequency over the past decades because of the rise in duration and number of procedures performed under fluoroscopic guidance. Articles concerning this issue are mostly limited to case reports after coronary interventions, renal artery catheterisations, transjugular intrahepatic portosystemic shunt procedures and embolisations of intracranial arteriovenous malformation. To the best of our knowledge, only two cases of radiation dermatitis after spinal arteriovenous malformation embolisation have been reported to date.

Daylight photodynamic therapy with methyl-aminolevulinate for the treatment of actinic cheilitis.

Actinic cheilitis (AC) is a common premalignant condition that requires an effective treatment to reduce the risk of malignant transformation. Photodynamic therapy (PDT) has been recently added to the armamentarium available for AC treatment. Daylight PDT (D-PDT) is a novel PDT modality in which the activation of the topical photosensitizer is induced by the exposure to natural daylight instead of artificial light sources without preliminary occlusion. This simplified procedure was found to be more tolerated as compared to conventional PDT. We report our preliminary experience on the use of D-PDT using methyl-aminolevulinate cream in 10 patients with refractory AC of the lower lip. Patients received two consecutive D-PDT sessions with an interval of 7-14 days. At 3 months after therapy, a complete response was observed in seven patients, with sustained results in five patients over an observational period of 6-12 months. Treatment was well tolerated.