Opracowanie modelu protezy nerwu obwodowego z polimeru naturalnego

Presented are the results of investigations into the preparation of a peripheral nerve prosthesis. The prosthesis is built up of a multichannel core having a diameter of 2 to 5 mm. The core prepared by freeze drying is housed in a polymeric sleeve. The prosthesis core is made of microcrystalline chitosan (MCCh) while the sleeve is prepared from poly(DL-lactide-coglycolide) copolymer. The usefulness of the prepared biomaterial was assessed by in vivo testing on animals.W pracy przedstawiono badania prowadzące do opracowania modelu protezy nerwu obwodowego. Proteza zbudowana jest z wielokanałowego rdzenia o średnicy od 2 do 5 mm wytworzonego metodą liofilizacji i osadzonego w tulei polimerowej. Rdzeń protezy wytworzono z mikrokrystalicznego chitozanu (MKCh), natomiast tuleję stanowi błona uzyskana z resorbowalnego kopolimeru poli(DL-laktyd-ko-glikolid). Opracowany biomateriał poddano ocenie przydatności w warunkach in vivo z wykorzystaniem zwierząt

Polymer hollow fiber-encapsulated peripheral nerve extracts change their activity towards injured hippocampal neurites in rats

The regeneration of the adult mammalian central nervous system (CNS) requires changes of the nonpromising environment. Applying peripheral nerve grafts and their extracts are both the useful method to induce regeneration of injured CNS neurites. Our previous reports showed that degeneration of peripheral nerves enhanced their neurotrophic activity in a time-dependent manner. Electrophoretical analysis of proteins obtained from degenerating sciatic nerves revealed significant changes in fractions of low molecular mass.The aim of the present work was to examine the influence of fractionated extracts from 7-day-predegenerated and non-predegenerated peripheral nerves upon injured hippocampal neurites in adult rats. The extracts were closed in fibrin-filled connective tissue chambers (CTC) or within CTC-wrapped polymer hollow fibers (PHF) of 30 kDa cut-off. The cell bodies of regrowing fibers were labeled with FITC-HRP.The CTCs appeared to be useful tool for implantation of artificial grafts into mammalian CNS. Full-spectrum nerve extracts induced strong regeneration of injured hippocampal neurites. The number of labeled cells within hippocampus was significantly lower in PHF groups than in CTC ones, indicating that low-mass proteins present in peripheral nerve extracts are not sufficient to induce successful regeneration

Deficiency of the RNA-binding protein ELAVL1/HuR leads to the failure of endogenous and exogenous neuroprotection of retinal ganglion cells

Introduction: ELAVL1/HuR is a keystone regulator of gene expression at the posttranscriptional level, including stress response and homeostasis maintenance. The aim of this study was to evaluate the impact of hur silencing on the age-related degeneration of retinal ganglion cells (RGC), which potentially describes the efficiency of endogenous neuroprotection mechanisms, as well as to assess the exogenous neuroprotection capacity of hur-silenced RGC in the rat glaucoma model. Methods: The study consisted of in vitro and in vivo approaches. In vitro, we used rat B-35 cells to investigate, whether AAV-shRNA-HuR delivery affects survival and oxidative stress markers under temperature and excitotoxic insults. In vivo approach consisted of two different settings. In first one, 35 eight-week-old rats received intravitreal injection of AAV-shRNA-HuR or AAV-shRNA scramble control. Animals underwent electroretinography tests and were sacrificed 2, 4 or 6 months after injection. Retinas and optic nerves were collected and processed for immunostainings, electron microscopy and stereology. For the second approach, animals received similar gene constructs. To induce chronic glaucoma, 8 weeks after AAV injection, unilateral episcleral vein cauterization was performed. Animals from each group received intravitreal injection of metallothionein II. Animals underwent electroretinography tests and were sacrificed 8 weeks later. Retinas and optic nerves were collected and processed for immunostainings, electron microscopy and stereology. Results: Silencing of hur induced apoptosis and increased oxidative stress markers in B-35 cells. Additionally, shRNA treatment impaired the cellular stress response to temperature and excitotoxic insults. In vivo, RGC count was decreased by 39% in shRNA-HuR group 6 months after injection, when compared to shRNA scramble control group. In neuroprotection study, the average loss of RGCs was 35% in animals with glaucoma treated with metallothionein and shRNA-HuR and 11.4% in animals with glaucoma treated with metallothionein and the scramble control shRNA. An alteration in HuR cellular content resulted in diminished photopic negative responses in the electroretinogram. Conclusions: Based on our findings, we conclude that HuR is essential for the survival and efficient neuroprotection of RGC and that the induced alteration in HuR content accelerates both the age-related and glaucoma-induced decline in RGC number and function, further confirming HuR’s key role in maintaining cell homeostasis and its possible involvement in the pathogenesis of glaucoma

Vestibular Schwannoma tumor withdrawal – case report

Vestibular Schwannomas (VS), benign intracranial tumors originating from the vestibulocochlear nerve, whose symptoms usually are hearing loss, tinnitus, and balance dysfunction. Rarely, however, if untreated, these neoplasms can cause significant patient compromise – resulting in facial paralysis, brainstem compression, and even death. Neurosurgical problems are the neuro-vascular structures often surrounding the tumors. The annual incidence of cystic vestibu-lar schwannomas in literature is 19.4%. A 66-year-old woman came to our clinic with serious hearing loss, balance dysfunction and tinnitus in the left ear. Full imaging diagnostic of the head was performed (TK, MRI and angio-MRI) which showed a cystic vestibular Schwannoma n. VIII (CVS). After 12 years of observation we noticed full neurological symptoms withdrawal and significant reduction of the tumor volume.Osłoniaki nerwu przedsionkowo-ślimakowego (n. VIII) to grupa łagodnych nowotworów, zwykle wyrastających z przewodu słuchowego wewnętrznego (PSW) i penetrujących wtórnie do okolicy kąta mostowo-móżdżkowego (KMM). Guzy rosną zazwyczaj powoli, jednak ze względu na otaczające je struktury nerwowo-naczyniowe stanowią duży problem operacyjny w neurochirurgii. W piśmiennictwie częstość występowania osłoniaka z torbielą wynosiła 19,4%. Najczęstszymi objawami są: utrata słuchu, szumy w uszach i zawroty głowy. Kobieta 66-letnia kobieta zgłosiła się z objawami znacznego niedosłuchu ucha lewego, odczuwaniem pisków i trzasków w uchu lewym, zaburzeniami równo-wagi. U chorej wykonano pełną diagnostykę obrazową w postaci tomografii komputerowej (TK) głowy i rezonansu magnetycznego (RM) głowy. Początko-wo wysunięto podejrzenie zmiany w okolicy lewego KMM o charakterze he-mangioblastomy. Angio-MR głowy nie potwierdziło rozpoznania. Wysunięto podejrzenie osłoniaka n. VIII z torbielą. Pacjentka była poddana 12-letniej obserwacji. W tym czasie doszło do całkowitego wycofania się objawów neurologicznych i znacznej regresji guza

Dead-ended autologous connective tissue chambers in peripheral nerve repair - early observations

The effects of the repair of nerve gap injuries are still unsatisfactory, despite the great progress in microsurgery. Until now, there is no effective method to induce the regeneration of the transected peripheral nerve when its distal stump is missing. The aim of this work was to examine whether the implantation of dead-ended connective tissue chambers can promote the outgrowth of injured peripheral neurites. This method differs from all previous nerve guides because it totally eliminates the distal part of the nerve and restricts the influence of surrounding tissues. We have also tried to establish whether some neurotrophic factors can be applied by means of these chambers. The results of this work show that dead-ended autologous connective tissue chambers can be a useful tool in peripheral nerve injuries treatment, even when the distal part of the nerve is missing

Neurofibromatosis type II – case report

We present a case report of a 49-year-old female patient with type II neurofi-bromatosis (NF-2), recognized at the age of 34. NF-2 is one of the phakomatoses in which multiple neoplasms of the central nervous system (CNS) occur: neuromas (Schwannomas), meningiomas, ependymomas, pilocytic astrocytomas and other benign neoplasms. NF-2 is an incurable genetic disorder and the only way to treat patients is detailed diagnostic imaging, early recognition and removal CNS tumors. The most important aspect is to recognize and cure Schwannomas of the acoustic nerve in their early stages because it is the only way to prevent hearing loss and to help NF-2 patients to maintain a good quality of life. The main way to treat Schwannomas of the acoustic nerves is their surgical removal.W niniejszej pracy przedstawiono przypadek 49-letniej chorej z nerwiakowłók-niakowatością typu 2 (neurofibromatosis type II – NF-2), rozpoznaną w wieku 34 lat. Omówiono NF-2 jako jedną z fakomatoz, w której występują m.in. mno-gie zmiany nowotworowe ośrodkowego układu nerwowego (OUN), przede wszystkim osłoniaki, jak nerwiaki i schwannoma, ale również oponiaki, wyściół-czaki, glejaki włosowatokomórkowe i inne łagodne nowotwory OUN [1]. Jest to choroba genetycznie uwarunkowana, tym samym nieuleczalna [2], a jedynym sposobem postępowania z chorymi na NF-2 jest dokładna diagnostyka obrazowa, wczesne rozpoznawanie zmian guzowatych OUN i ich usuwanie [3]. Szczególnie ważne jest wczesne rozpoznawanie i leczenie osłoniaków nerwu słuchowego (n. VIII), gdyż tylko wówczas istnieje możliwość zachowania słuchu i w związku z tym zapewnienie komfortu życia chorym z NF-2. Operacyjne usuwanie osłoniaków n. VIII jest zasadniczym sposobem ich leczenia [1]