ABSTRACT
Mesenchymal stromal/stem cells stem (MSC) have been widely studied due to their great potential for application in tissue engineering and regenerative and translational medicine. In MSC-based therapy for human diseases, cell proliferation is required to obtain a large and adequate number of cells to ensure therapeutic efficacy. During in vitro culture, cells are under an artificial environment and manipulative stress that can affect genetic stability. Several regulatory agencies have established guidelines to ensure greater safety in cell-based regenerative and translational medicine, but there is no specific definition about the maximum number of passages that ensure the lowest possible risk in MSC-based regenerative medicine. In this context, the aim of this study was to analyze DNA damage and chromosome alterations in adipose-derived mesenchymal stromal cells (ADMSC) until the eleventh passage and to provide additional subsidies to regulatory agencies related to number of passages in these cells. Thus, two methods in genetic toxicology were adopted: comet assay and micronucleus test. The comet assay results showed an increase in DNA damage from the fifth passage onwards. The micronucleus test showed a statistically significant increase of micronucleus from the seventh passage onwards, indicating a possible mutagenic effect associated with the increase in the number of passages. Based on these results, it is important to emphasize the need to assess genetic toxicology and inclusion of new guidelines by regulatory agencies to guarantee the safety of MSC-based therapies for human diseases.
ABSTRACT
The damaging effects of neuwiedase, a non-hemorrhagic snake venom metalloproteinase from P-I class, on gastrocnemius muscle are studied herein. Following neuwiedase injection, ultrastructural alterations were detected early showing disarrangement of skeletal muscle fibers (characterized by discontinuity of Z lines), mitochondrial swelling, and disruption of plasma membrane and basal lamina. Degradation of skeletal muscle and the appearance of an amorphous substance, primarily composed of cellular debris, were noted after 24 hours. The presence of neuwiedase at the injection site (detected by immunocytochemistry) revealed highly specific labeling of myofibril components of damaged myocytes. In addition, proteolysis of muscle proteins assayed through myofibrils extracted from gastrocnemius muscle indicated that neuwiedase provoked degradation of myofibrils, especially myosin. These results suggest that skeletal muscle damage, induced by neuwiedase, is probably due to its proteolytic action on myofibrils, which are responsible for the maintenance of the cellular architecture.
Subject(s)
Animals , Rabbits , Bothrops , Metalloproteases/isolation & purification , Muscle, Skeletal/ultrastructure , Viper Venoms , RabbitsABSTRACT
O Trypanosoma evansi é um tripanosoma da secçäo salivaria pertencente ao subgênero Trypanozoon. Ele causa a "surra" no velho mundo e o "mal de caderas" na área subtropical da Argentina e no Pantanal, Brasil. Há similaridades entre as lesöes e patogenia causadas por T. brucei, T. evansi e T. equiperdum, inclusive no consumo de plaquetas na coagulaçäo intravascular disseminada (DIC). O presente estudo mostra os valores de APTT, PT e contagem de plaquetas evidenciando a DIC no primeiro relato de infecçäo natural pelo T. evansi em cäo no Pantanal, Brasil
Subject(s)
Animals , Dogs/parasitology , Disseminated Intravascular Coagulation/veterinary , TrypanosomaABSTRACT
Paciente de 52 anos submetida a transplante cardíaco ortotópico em maio de 1991, tendo apresentado como complicaçäo tardia o surgimento de carcinoma epidermóide de amígdala. O diagnóstico inicial foi de neoplasia metastática de sítio primário desconhecido porque o tumor primário somente manifestou-se após 6 meses do surgimento da metástase à distância. A incidência de neoplasia no primeiro ano pós-transplante cardíaco é pouco freqüente, assim como o carcinoma epidermóide de amígdala na populaçäo normal. Näo encontramos relato de caso na literatura entre pacientes submetidos a transplante cardíaco e apresentando carcinoma epidermóide de amígdala.