What is the potential use of platelet-rich-plasma (PRP) in cancer treatment? A mini review.

Platelet-rich-plasma (PRP) is an autologous human platelet concentrate extracted from plasma. PRP has been investigated in order to be used in many fields, with emphasis on the musculoskeletal field applied to sports injuries, as well as on other medical fields such as cardiac surgery, gynecology, pediatric surgery, urology, ophthalmology and plastic surgery. Cancer treatment is another important field where PRP should be investigated; thus, it is important validating PRP preparation protocols to be used in clinical research. Many protocols should be revised since, overall, most studies do not provide necessary information to allow them to be multiplied or replicated. The current review focuses on several topics about cancer, mainly on innovative studies about PRP use as a feasible therapeutic alternative to treat bladder cancer - a field where it could play a key role. Relevant aspects such as platelets' contribution to immune regulation and the supportive role they play in innate and adaptive immune functions are also addressed. Another important topic reviewed in the current study refers to inflammatory process regulation associated with cancer and thrombosis sites, which indicated that tumor-induced platelet activation could be used as an important therapeutic target in the future. New aspects concerning nitric oxide's ability to restrain platelet adhesion and aggregation in order to slow metastasis progress in cancer patients provide an important advantage in cancer treatment. Finally, the current review has pointed out perspectives and the main concerns about, and possibilities of, PRP use in cancer treatment.

Nanostructured platelet-rich plasma: state of art in dental treatments / Plasma-rico em plaquetas nanoestruturado: estado da arte nos tratamentos dentais

Objectives: Reviewing information available about platelet-rich plasma (PRP) applied to dental treatments, introducing the general concept of PRP, as well as analyzing actual data about, and challenges faced by, the dental field. Data & sources: The current study analyzed the most informative publications about PRP application available in this field and gathered the maximum information about it as possible. Conclusions: PRP use, either alone or in association with other biomaterials, can significantly favor different fields such as tissue engineering, since it is an innovative technique that attracts the interest of clinicians and basic scientists. However, it is necessary conducting better designed and controlled experiments to enable successful tissue healing based on PRP use. Clinical significance: The current review can be used by clinicians as source of information about the actual rules and protocols adopted in the herein addressed field, besides providing specific examples of such applications. (AU)

Objetivos: Revisar as informações disponíveis sobre o plasma-rico em plaquetas (PRP) aplicado a tratamentos odontológicos, introduzir o conceito geral de PRP e analisar dados reais sobre os desafios enfrentados pelo campo odontológico. Dados e fontes: O presente estudo analisou as publicações mais informativas sobre a aplicação do PRP disponíveis neste campo e reuniu o máximo de informações possível. Conclusões: O uso do PRP, isoladamente ou em associação com outros biomateriais, pode favorecer significativamente diferentes campos, como a engenharia de tecidos, uma vez que é uma técnica inovadora que atrai o interesse de clínicos e cientistas básicos. No entanto, é necessário realizar experimentos mais bem projetados e controlados para permitir a cura bem-sucedida dos tecidos com base no uso do PRP. Significado clínico: A revisão atual pode ser usada pelos médicos como fonte de informações sobre as regras e protocolos atuais adotados no campo aqui tratado, além de fornecer exemplos específicos de tais aplicações.(AU)

Effect of Human Adipose Tissue Mesenchymal Stem Cells on the Regeneration of Ovine Articular Cartilage.

Cell therapy is a promising approach to improve cartilage healing. Adipose tissue is an abundant and readily accessible cell source. Previous studies have demonstrated good cartilage repair results with adipose tissue mesenchymal stem cells in small animal experiments. This study aimed to examine these cells in a large animal model. Thirty knees of adult sheep were randomly allocated to three treatment groups: CELLS (scaffold seeded with human adipose tissue mesenchymal stem cells), SCAFFOLD (scaffold without cells), or EMPTY (untreated lesions). A partial thickness defect was created in the medial femoral condyle. After six months, the knees were examined according to an adaptation of the International Cartilage Repair Society (ICRS 1) score, in addition to a new Partial Thickness Model scale and the ICRS macroscopic score. All of the animals completed the follow-up period. The CELLS group presented with the highest ICRS 1 score (8.3 ± 3.1), followed by the SCAFFOLD group (5.6 ± 2.2) and the EMPTY group (5.2 ± 2.4) (p = 0.033). Other scores were not significantly different. These results suggest that human adipose tissue mesenchymal stem cells promoted satisfactory cartilage repair in the ovine model.

Neuroprotection and immunomodulation by xenografted human mesenchymal stem cells following spinal cord ventral root avulsion.

The present study investigates the effects of xenotransplantation of Adipose Tissue Mesenchymal Stem Cells (AT-MSCs) in animals after ventral root avulsion. AT-MSC has similar characteristics to bone marrow mesenchymal stem cells (BM-MSCs), such as immunomodulatory properties and expression of neurotrophic factors. In this study, Lewis rats were submitted to surgery for unilateral avulsion of the lumbar ventral roots and received 5 × 10(5) AT-MSCs via the lateral funiculus. Two weeks after cell administration, the animals were sacrificed and the moto neurons, T lymphocytes and cell defense nervous system were analyzed. An increased neuronal survival and partial preservation of synaptophysin-positive nerve terminals, related to GDNF and BDNF expression of AT-MSCs, and reduction of pro-inflammatory reaction were observed. In conclusion, AT-MSCs prevent second phase neuronal injury, since they suppressed lymphocyte, astroglia and microglia effects, which finally contributed to rat motor-neuron survival and synaptic stability of the lesioned motor-neuron. Moreover, the survival of the injected AT- MSCs lasted for at least 14 days. These results indicate that neuronal survival after lesion, followed by mesenchymal stem cell (MSC) administration, might occur through cytokine release and immunomodulation, thus suggesting that AT-MSCs are promising cells for the therapy of neuronal lesions.

Fibrin network architectures in pure platelet-rich plasma as characterized by fiber radius and correlated with clotting time.

Fibrin networks are obtained through activation of platelet-rich plasma (PRP) for use in tissue regeneration. The importance of fibrin networks relies on mediation of release of growth factors, proliferation of tissue cells and rheological properties of the fibrin gels. Activation of PRP usually involves the decomposition of fibrinogen by agonists, in a wide range of concentrations. Therefore fibrin networks with a large structural diversity are formed, making comparative evaluations difficult. In order to standardize the fibrin networks, we used the statistical techniques central composite rotatable design and response-surface analysis, to correlate the radius of the fibers with the ratios between the agonists (autologous serum/calcium chloride) and agonist/PRP. From an individual and interactive analysis of the variables, architectures characterized by thick, medium and thin fibers were delineated on the response-surface. Furthermore, the architectures were correlated with coagulation time. This approach is valuable for standardizing the PRP preparation for clinical applications.

Viability of umbilical cord blood mononuclear cell subsets until 96 hours after collection.

BACKGROUND: Umbilical cord blood (UCB) is a good source of hematopoietic stem cells for transplantation and cell therapy. In 2006, the Brazilian Public Network of Cord Blood Banks was founded; however, because our country is large, logistic problems could hamper the collection of numerous samples. Our aim was to evaluate the viability of several UCB cell subsets until 96 hours after collection, to examine whether this delay would be acceptable for processing and freezing the samples. STUDY DESIGN AND METHODS: Two experiments were performed: in the first one, volume reduction of the UCB units was carried out before analysis. In the second one, analysis was carried out with no previous manipulation. Samples were stored at room temperature and one aliquot was taken daily for analysis. We examined CD34+ cell, B-cell precursor, mature B and T lymphocyte, monocyte, granulocyte, and mesenchymal stem cell (MSCs) concentrations. RESULTS: Thirty-six UCB units were analyzed. CD34+ cells and mature T lymphocytes increased (viability 99%). Mature B lymphocytes and MSCs decreased, maintaining viability. Granulocytes decreased with loss of viability. Monocytes and immature B lymphocytes remained stable. Clonogenic assays showed a decrease in colony-forming unit (CFU) number in UCB units stored for 96 hours. CONCLUSION: UCB manipulation did not influence cell viability. All cell subsets remained viable until 96 hours after collection. CD34+ cells and T lymphocytes increased, probably due to the loss of other subsets. CFU growth during the period analyzed and confirmed stem cell functionality, despite the decrease at 96 hours. Results demonstrated that UCB units could probably be processed up to 96 hours after collection.

Liver transplantation in a patient with S(beta)o-thalassemia.

BACKGROUND: Patients presenting sickle cell disease may develop different types of hepatic complications. Intrahepatic cholestasis is a potentially fatal complication of the disease, and sometimes the only possible solution is transplantation. Postoperative transfusion management has not yet been well established. In this report, we describe the transfusional program of a patient presenting sickle cell disease and intrahepatic cholestasis who underwent liver transplantation 2 years ago. METHODS: Data were obtained from the chart and the blood bank records. RESULTS: The liver transplantation was performed successfully. Despite mild allograft dysfunction 3 months after surgery, secondary to intrahepatic sickling, the patient has been doing well with the transfusional management adopted (sickle-cell hemoglobin <20%). CONCLUSION: Sickle cell disease should not be a criterion for exclusion from liver transplantation. Regular transfusion with monitoring of sickle-cell hemoglobin is a very important measure to minimize the risk of intrahepatic sickling and possible rejection.

Célula precursora de sangue de cordäo umbilical humano: viabilidade para transplantes e terapia gênica / Umbilical cord blood: a new source of hematopoietic cells for transplantation and gene therapy

O transplante de células precursoras de linhagem hematopoiética é utilizado como importante arma terapêutica nas neoplasias hematológicas e doenças genéticas. A principal fonte destas células tem sido, há alguns anos, a medula óssea de doadores voluntários. Entretanto, dada à dificuldade em se encontrar doador HLA compatível, houve necessidade de se procurar outros tipos de fonte. Nos últimos 14 anos, o sangue de cordäo umbilical vem sendo analisado como possível fonte alternativa. Apresenta como vantagem, em relaçäo à medula óssea, ser material facilmente obtido e manipulado com facilidade. O sangue de cordäo é extremamente rico em células precursoras, fornecendo em cultura, número de colônias de CFU-GM suficientes para recuperaçäo da linhagem hematopoiética. Outra vantagem é a baixa incidência de doença enxerto versus hospedeiro (GVHD) quando utilizado em transplante. Tanto a criopreservaçäo quanto o tempo de congelamento näo alteraram o número dos vários tipos de linfócitos do sangue de cordäo. Quanto à sua aplicaçäo na prática médica, recentemente dois autores demonstraram a sua viabilidade em transplantes em situaçöes clínicas de grande risco. Kurtzberg et al (1996) e Wagner et al (1996) transplantaram pacientes utilizando sangue de cordäo de indivíduos näo relacionados, alguns incompatíveis até a três antígenos HLA, obtendo bons resultados. O sangue de cordäo pode também ser utilizado em terapia gênica. De acordo com dados de literatura, suas células apresentam maior capacidade de proliferaçäo que as da medula, podendo ser eficientemente infectadas com retrovírus, apresentando alto nível de expressäo da seqüência introduzida. Resultados recentemente obtidos em nosso laboratório demonstraram que houve melhor crescimento celular quando se utilizou a metilcelulose como meio, possibilitando a repicagem das colônicas para replaqueamentos e utilizaçäo em cultura de longa duraçäo. De acordo com os dados da literatura publicados ao longo destes anos, o sangue de cordäo será, no futuro, a fonte de células precrursoras de linhagem hematopoiética mais utilizada em terapia gênica e transplantes.