Natural killer (NK) cells provide the first line of defence against pathogens and tumors. Their activation status is regulated by pro-inflammatory cytokines and by ligands that either target inhibitory or activating cell surface receptors belonging to the immunoglobulin-like, C-type lectin or natural cytotoxicity receptor families. Apart from non-classical HLA-E, membrane-bound heat shock protein 70 (Hsp70) has been identified as a tumor-specific recognition structure for NK cells expressing high amounts of the C-type lectin receptor CD94, acting as one component of an activating heterodimeric receptor complex. Full-length Hsp70 protein (Hsp70) or the 14-mer Hsp70 peptide T-K-D-N-N-L-L-G-R-F-E-L-S-G (TKD) in combination with pro-inflammatory cytokines enhances the cytolytic activity of NK cells towards Hsp70 membrane-positive tumors. Based on these findings cytokine/TKD-activated NK cells were adoptively transferred in tumor patients. These findings were compared to results of clinical trials using cytokine-activated NK cells.
Although approved for the treatment of pancreatic cancer, the chemotherapeutic agent ifosfamide is not an effective therapy for this type of tumour. Ifosfamide must be activated by cytochrome P450 (P450) enzymes in the liver, initially to a short lived intermediate and then to toxic metabolites that are subsequently distributed by the circulatory system. Particularly for pancreatic cancer, this liver-mediated conversion results in relatively high systemic toxicities and poor therapeutic concentrations at the liver-distant site of the tumour. Activation of ifosfamide at the site of the tumour may allow lower doses to be used, while increasing the therapeutic index due to the resultant active concentrations generated locally. A cell-based therapy has been conceived where encapsulated, 293-derived cells genetically modified to overexpress a cytochrome P450 enzyme, are implanted near solid tumours. The cells are encapsulated in polymers of cellulose sulphate in order to provide a means of immunoprotection in vivo as well as to physically constrain them to the vicinity of the tumour. A major advantage of this strategy is that it allows one standard cell line to be applied to all patients and this approach can be extended to the treatment of other tumour types. After proof of principle studies in animal models, a phase I/II clinical trial was initiated in patients with stage III/IV nonresectable pancreatic cancer. Encapsulated cells were angiographically placed into the tumour vasculature of 14 patients and followed by systemic low dose ifosfamide treatment. Angiographic delivery of encapsulated cells proved feasible in all but one patient, and was well tolerated with no capsule or ifosfamide treatment-related adverse events. Four of the treated patients showed tumour regressions after capsule delivery and ifosfamide treatment in computer-tomography scans. The other 10 patients showed no further tumour growth (i.e. stable disease) during 20 weeks observation period. The median life expectancy of the patient collective was extended two fold as compared to age and status matched historical controls, with a 3-fold improvement in one year survival being attained. Evidence for a clinical benefit of the treatment was also obtained on the basis of standard parameters for quality of life. This approach has been evaluated by the European Medicines Evaluation Agency (EMEA) and orphan drug status has been granted. A pivotal clinical trial is now being planned with the help of the EMEA. Taken together, the data from this clinical trial suggest that encapsulated cytochrome P450-expressing cells combined with chemotherapy may be useful for the local treatment of a number of solid tumours and support the performance of further clinical studies of this new treatment.
The interest in facial transplantation led to development of many experimental models and novel immunosuppressive protocols. These studies allowed testing the immunological response to immunosuppressive protocols, and tolerance induction studies with supportive cell based therapies in composite tissues allograft transplants.In this article we present our experience with face transplantation models developed in our laboratory. We also summarize immunological responses and different immunosuppressive protocols used for tolerance induction through donor chimerism.
Medical problems associated with the increasing number of patients suffering from brain diseases have resulted in a constant search for effective therapeutics. Considering the complicated pathological processes occurring in diseases of the central nervous system and the limited capability of the neural tissue to regenerate, therapy of neurological diseases is extremely difficult. The lack of efficient medical treatment results in complex problems associated with rehabilitation and thus in functional disturbances, which prevent patients from restoring their independence and returning to complete, also professional, activity, Cell therapy has recently been considered as a possible approach in the treatment of brain diseases. Its aim is to supply pathologically changed brain tissue with factors promoting regeneration and with cells that may replace the damaged ones. Bone marrow cells have become a potential source of cells in this type of therapy. Bone marrow contains at least two major kinds of stem cells: haematopoietic stem cells, which give rise to the blood cells and mesenchymal stem cells, which can differentiate into cells of mesenchymal lineage and produce an array of growth factors essential for repair. The review presents the achievements of studies on use of bone marrow cells in the therapy of various brain diseases of traumatic or neurodegenerative aetiology.
The face allotransplantation is a unique procedure, requiring a lifetime immunosuppressive therapy, and as such brings an ethical debate among medical societies and general public. The indications for this procedure have to be considered when the classic reconstructive procedures failed, and the patients are left with debilitating defects precluding them from normal social life.The transplantation protocol must be approved and registered by the institutional review board and health agencies. It is crucial that a thorough assessment of the patient for each indication will be performed by a multidisciplinary team and panel of experts in the field of plastic and reconstructive surgery, maxillo facial surgery, immunology of transplantations and psychiatry. The thorough psychiatric and psychological evaluation of potential candidates is mandatory, as well as evaluation by ethic experts.Numerous experimental models and extensive anatomical studies in cadaver model lead to the clinical success of face transplantation, raising a complex ethical question despite the fact that it is an important progress in plastic and reconstructive surgery.Three face transplantations have been performed since 2005. The transplants differed and were tailored, to match the extend of each patient facial defect.In this article we present the clinical cases of face transplantation based on our experience and dissections studies and a literature review.
Human brain is a very complex biological system considering its cytoarchitecture, neuronal network, localisation of functional regions and integration. Until second half of the XX century it was believed that CNS is deprived of regenerative processes. At present there are many studies that confirm constant formation of new neurones in the human brain. However, this process of cell exchange is far less effective in comparison with the regeneration and functional renewal of other tissues of our organism. In the following article we present current data on local neurogenesis in the adult brain. There are at least 3 regions of CNS where cell proliferembrioation takes place: subventricular zone – SVZ, subgranular zone – SGZ and posterior periventricular area – PPv. It has been estimated that single radial glial cell, which is the progenitor of cells residing in the aforementioned regions of the brain, would be enough to form 4×107 of new brains. Other tissues of our organism could become another source of stem cells for brain regeneration. This solution is tempting when we consider a theory of peripheral blood stem cells that reside in different organ niches. Injured tissue produces higher amounts of chemokines such as SDF-1 or LIF that causes increased migration of stem cells towards the “calling- for-help” organ. The last part of the article presents the progress that has been made in regeneration therapies of certain neurological disorders: cerebral stroke, Parkinson’s disease, multiple sclerosis, spinal cord injuries, amyotrophic lateral sclerosis, Huntigton’s disease and Alzheimer’s disease.
PL
Mózg człowieka jest bardzo skomplikowanym biologicznym systemem pod względem cytoarchitektury, sieci neuronalnej, lokalizacji ośrodków funkcjonalnych oraz integracji. Do drugiej połowy XX wieku panował pogląd, że po okresie rozwoju OUN jest pozbawiony jakiejkolwiek zdolności regeneracyjnej. Istnieje obecnie wiele badań potwierdzających fakt, iż w dorosłym mózgu ludzi ma miejsce ciągły proces tworzenia się nowych neuronów, chociaż oczywiście proces wymiany komórek ośrodkowego układu nerwowego prezentuje się nie najlepiej w porównaniu z regeneracją i funkcjonalną odnową, które mają miejsce w innych organach naszego organizmu. W poniższym artykule przedstawione zostały aktualne dane dotyczące miejscowej neurogenezy w dojrzałym mózgu. W mózgu człowieka znajdują się przynajmniej 3 obszary, gdzie mają miejsce procesy proliferacji komórkowej: strefa przykomorowa (subventricularzone, SVZ), strefa przyziarnista (subgranularzone, SGZ), oraz tylna strefa okołokomorowa (posterior periventricular area, PPv). Wyliczono, że pojedyncza komórka gleju radialnego, której mitotyczni potomkowie rezydują w wymienionych strefach rozrodczych, wystarczyłaby do utworzenia 4x107 mózgów. Innym źródłem odnowy dla mózgu mogłyby stać się komórki macierzyste pozyskiwane z innych tkanek naszego organizmu. Takie rozwiązanie znajduje swoje uzasadnienie w ramach teorii o krążących w krwi obwodowej komórkach macierzystych zasiedlających poszczególne nisze narządowe. Znacznie upraszczając, uszkodzony narząd wydziela zwiększoną ilość chemoatraktantów, takich jak SDF-1 czy LIF, i tym przyciąga do siebie zwiększoną ilość komórek macierzystych. W dalszej części artykułu przedstawiono postęp, jaki dokonał się w terapiach regeneracyjnych w przypadku niektórych schorzeń neurologicznych: udaru mózgu, choroby Parkinsona, stwardnienia rozsianego, urazów rdzenia, stwardnienia zanikowego bocznego, choroby Huntingtona oraz choroby Alzheimera.
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