A Brief Review of In Vitro Models for Injury and Regeneration in the Peripheral Nervous System

Nerve axonal injury and associated cellular mechanisms leading to peripheral nerve damage are important topics of research necessary for reducing disability and enhancing quality of life. Model systems that mimic the biological changes that occur during human nerve injury are crucial for the identification of cellular responses, screening of novel therapeutic molecules, and design of neural regeneration strategies. In addition to in vivo and mathematical models, in vitro axonal injury models provide a simple, robust, and reductionist platform to partially understand nerve injury pathogenesis and regeneration. In recent years, there have been several advances related to in vitro techniques that focus on the utilization of custom-fabricated cell culture chambers, microfluidic chamber systems, and injury techniques such as laser ablation and axonal stretching. These developments seem to reflect a gradual and natural progression towards understanding molecular and signaling events at an individual axon and neuronal-soma level. In this review, we attempt to categorize and discuss various in vitro models of injury relevant to the peripheral nervous system and highlight their strengths, weaknesses, and opportunities. Such models will help to recreate the post-injury microenvironment and aid in the development of therapeutic strategies that can accelerate nerve repair.

A Broad Overview on Pituitary Adenylate Cyclase-Activating Polypeptide Role in the Eye: Focus on Its Repairing Effect in Cornea

Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) is a neuropeptide with widespread distribution throughout the central and peripheral nervous system as well as in many other peripheral organs. It plays cytoprotective effects mediated mainly through the activation of specific receptors. PACAP is known to play pleiotropic effects on the eye, including the cornea, protecting it against different types of insult. This review firstly provides an overview of the anatomy of the cornea and summarizes data present in literature about PACAP’s role in the eye and, in particular, in the cornea, either in physiological or pathological conditions.

CHARACTERISTICS OF PERIPHERAL NERVOUS SYSTEM IN PATIENTS WITH PSORIASIS

Psoriasis is a chronic non-infectious inflammatory dermatosis characterized by excessive proliferation of epithelial cells, impaired differentiation, often involving the musculoskeletal system. Materials and Methods. The authors examined 60 patients with psoriasis, 39 men and 21 women, aged from 21 to 69 (the average subject age was 46.3±13.94). All patients underwent a standard dermatological and neurological examination. Motor function was assessed according to knee jerk, elbow jerk and Achilles jerk. Pain sensitivity was established after pricking the thumb dorsum with a special blunt-end needle. Nonparametric methods were used for statistical analysis. The Mann-Whitney U-test was used to check the differences between independent groups of patients. The distribution of characteristic was assessed using a probability calculator. Differences were statistically significant at 95 % probability (p<0.05). Results. Mild psoriasis was found in 8 patients (13.3 %), moderate-to-severe psoriasis – in 14 patients (23 %) (PASI=11–30), severe psoriasis – in 38 patients (63.7 %) (PASI>30). Type I psoriasis was detected in 32 patients (53.2 %), type II – in 28 patients (46.8 %). Dysfunctions of the peripheral nervous system were found in 30 patients (50 %). In 12 subjects (20 %) symmetrical sensory and motor disturbances were observed in the distal parts of all four limbs. In 9 patients (15 %) symmetrical decrease in knee and Achilles jerks was observed. Symmetrical decrease in tactile and temperature sensitivity in the distal parts of the lower extremities was noted in 9 patients with psoriasis (15 %). Conclusion. Distal symmetric sensorimotor polyneuropathy is common in patients with psoriasis. Severe psoriasis is accompanied by distal symmetric sensorimotor polyneuropathy. Key words: psoriasis, comorbidity, demyelination, polyneuropathy. Псориаз – это хронический неинфекционный воспалительный дерматоз, характеризующийся избыточной пролиферацией эпителиоцитов, нарушением их дифференциации, нередко вовлекающий в процесс опорно-двигательный аппарат. Материалы и методы. Обследовано 60 больных псориазом, из них 39 мужчин и 21 женщина в возрасте от 21 до 69 лет (средний возраст обследуемых 46,3±13,94 года). Всем больным проводился стандартный дерматологический и неврологический осмотр. Двигательная функция исследовалась с помощью оценки коленного, локтевого и ахиллова рефлексов. Болевая чувствительность устанавливалась после укола тыльной поверхности большого пальца специальной иглой с притупленным концом. Для статистического анализа использовались непараметрические методы. Для проверки отличий между независимыми группами больных применялся Mann – Whitney U-test. Распределение признака оценивалось с помощью вероятностного калькулятора. Статистические значимыми считались отличия при уровне вероятности более 95 % (p<0,05). Результаты. Легкая степень псориаза установлена у 8 (13,3 %) больных, умеренно тяжелый псориаз – у 14 (23 %) пациентов (индекс PASI 11–30 баллов), тяжелая форма псориаза – у 38 (63,7 %) больных (индекс PASI более 30 баллов). Псориаз I типа определялся у 32 (53,2 %) больных, II типа – у 28 (46,8 %). У 30 (50 %) больных обнаружены нарушения функции периферической нервной системы. У 12 (20 %) чел. наблюдались симметричные сенсорные и двигательные нарушения в дистальных отделах всех четырех конечностей. У 9 (15 %) чел. отмечалось симметричное снижение коленного и ахиллова рефлексов. Девять (15 %) больных псориазом имели симметричное снижение тактильной и температурной чувствительности в дистальных отделах нижних конечностей. Выводы. У больных псориазом часто встречается дистальная симметричная сенсорно-моторная полинейропатия. Тяжелое течение псориаза сопровождается дистальной симметричной сенсорно-моторной полинейропатией. Ключевые слова: псориаз, коморбидность, демиелинизация, полинейропатия.