Células madre hematopoyéticas

Las células madre hematopoyéticas (CMH) son, con diferencia, las mejor conocidas de las células madre adultas. Se definen como aquéllas capaces de repoblar a largo plazo todos los linajes hematopoyéticos cuando son trasplantadas a receptores sometidos a un tratamiento mie- loablativo que permita su injerto. En humanos adultos, las CMH se encuentran fundamentalmente en la médula ósea (MO), con una fre- cuencia relativa de 1 entre 104 a 1 entre 105 células nucleadas. Aunque quedan muchas lagunas por conocer, y de hecho aún no es posible su identificación ni su aislamiento de forma prospectiva con una certeza o pureza absoluta, los últimos años han sido pródigos en avances relativos a su caracterización y aplicaciones clínicas. En cuanto a sus aplicaciones, las CMH fueron las primeras en ser trasplantadas con éxito hace más de medio siglo. Inicialmente sólo podían obtenerse a partir de la MO, pero actualmente se obtienen me- diante un proceso mucho menos traumático llamado aféresis, tras ser movilizadas a la sangre periférica o, más recientemente, a partir de la sangre del cordón umbilical. Los trasplantes hematopoyéticos han salva- do miles de vidas de pacientes con hemopatías malignas y enfermedades hereditarias. Otra potencial aplicación de las CMH es la inducción de tolerancia inmunológica. Finalmente, las CMH constituyen una diana excepcional para la terapia génica (TG), y no es casualidad que los dos primeros éxitos de esta joven disciplina estén basados en CMH

La Biomedicina del segle XXI

En els darrers trenta anys, la nostra societat ha assistit perplexa al desenvolupament d'una revolució que, sens dubte, la història jutjarà com la de més transcendència des que els humans habiten el planeta Terra. Ens referim a l'immens progrés en el coneixement de la ciència i la tècnica i al desenvolupament de les seves aplicacions. La biologia i, en particular, el desenvolupament de la biologia molecular, ocupa un espai majoritari en aquest procés. També la informàtica, l'electrònica, la robòtica o, de manera més general, la física i la química, estan en la primera línia de la seva evolució. Aquest capítol pretén posar totes aquestes troballes juntes en benefici de la nova medicina que ha sorgit d'aquesta barreja. Sense cap pretensió de voler resumir tots els avenços que componen aquesta nova medicina, hem volgut discutir breument el que signifiquen ara mateix i en un futur molt proper aquests canvis que comporten, entre molts altres, el diagnòstic i tractament millors del càncer, la teràpia gènica per a malalties genètiques fins ara incurables, els diferents tipus de diagnòstic per imatge amb un sofisticat suport informàtic, el coneixement del nostre genoma, la producció de proteïnes de propietats terapèutiques per biotecnologia, així com la connexió dels malalts a una xarxa de metges i d'hospitals que els permeti estar adequadament atesos. Nogensmenys, aquestes millores espectaculars d'un món altament tecnificat no ens han de fer ignorar els desafiaments ètics que tot això pot comportar, així com quelcom més elemental i bàsic, que és la solidaritat i caritat envers els febles, oblidats o mancats de recursos.In the last 30 years, we have assisted astonished to the development of a revolution that, with no doubt, history will judge as the most important since humans live in this planet. We refer to the progress in the knowledge of science and technology, and to the development of their applications. Biology, and, in particular, the development of molecular biology, is fundamental in this process. Also computer science, electronics, robotics, or, in a more general way, physics and chemistry are also in the frontline of their growth. This chapter only pretends to put together all these findings in favor of a new medicine. This is not an exhaustive review of these major advances, but just a brief summary of few breakthroughs like the improved diagnosis and treatment of cancer, gene therapy as a solution for genetic diseases, improved image based diagnosis methods, unravelling of the human genome, production of therapeutic recombinant proteins by biotechnology, as well as the new medical care system by having patients connected to physician and hospital networks. Nevertheless, those spectacular improvements in a highly technified world cannot avoid the new ethic challenges emerging in this process. At the same time, solidarity towards weak, poor and discriminated people does not have to be forgotten

Variable readthrough responsiveness of nonsense mutations in hemophilia A

Readthrough therapy relies on the use of small molecules that enable premature termination codons in mRNA open reading frames to be misinterpreted by the translation machinery, thus allowing the generation of full-length, potentially functional proteins from mRNA carrying nonsense mutations. In patients with hemophilia A, nonsense mutations potentially sensitive to readthrough agents represent approximately 16% of the point mutations. The aim of this study was to measure the readthrough effect of different compounds and to analyze the influence of premature termination codon context in selected nonsense mutations causing hemophilia A. To this end, primary fibroblasts from three patients with hemophilia A caused by nonsense mutations (p.W1586X, p.Q1636X and p.R1960X) and Chinese hamster ovary (CHO) cells transfected with 12 different plasmids encoding mutated F8 (p.Q462X, p.Q1705X, p.Q1764X, p.W274X, p.W1726X, p.W2015X, p.W2131X, p.R1715X, p.R1822X, p.R1960X, p.R2071X and p.R2228X) were treated with gentamicin, geneticin, PTC124, RTC13 or RTC14. Responses were assessed by analyzing not only F8 mRNA expression and FVIII biosynthesis (FVIII antigen by ELISA, western blot and immunofluorescence) but also the FVIII activity (by chromogenic assay). In the patients' fibroblasts, readthrough agents neither stabilized F8 mRNA nor increased FVIII protein or activity to detectable levels. In CHO cells, only in five of the 12 F8 variants, readthrough treatment increased both FVIII antigen and activity levels, which was associated with a reduction in intracellular accumulation of truncated forms and an increase in full-length proteins. These results provide experimental evidence of genetic context dependence of nonsense suppression by readthrough agents and of factors predicting responsiveness

Response of the human myocardium to ischemic injury and preconditioning: The role of cardiac and comorbid conditions, medical treatment, and basal redox status

Vàlvula aòrtica; Isquèmia; MiocardiVálvula aórtica; Isquemia; MiocardioAortic valve; Ischemia; MyocardiumBackground The diseased human myocardium is highly susceptible to ischemia/reoxygenation (I/R)-induced injury but its response to protective interventions such as ischemic preconditioning (IPreC) is unclear. Cardiac and other pre-existing clinical conditions as well as previous or ongoing medical treatment may influence the myocardial response to I/R injury and protection. This study investigated the effect of both on myocardial susceptibility to I/R-induced injury and the protective effects of IPreC. Methods and results Atrial myocardium from cardiac surgery patients (n = 300) was assigned to one of three groups: aerobic control, I/R alone, and IPreC. Lactate dehydrogenase leakage, as a marker of cell injury, and cell viability were measured. The basal redox status was determined in samples from 90 patients. The response to I/R varied widely. Myocardium from patients with aortic valve disease was the most susceptible to injury whereas myocardium from dyslipidemia patients was the least susceptible. Tissue from females was better protected than tissue from males. Myocardium from patients with mitral valve disease was the least responsive to IPreC. The basal redox status was altered in the myocardium from patients with mitral and aortic valve disease. Conclusions The response of the myocardium to I/R and IPreC is highly variable and influenced by the underlying cardiac pathology, dyslipidemia, sex, and the basal redox status. These results should be taken into account in the design of future clinical studies on the prevention of I/R injury and protection.This study was supported by the Instituto de Salud Carlos III (FIS) [grant number 12/00119]

Oxidative Stress in Structural Valve Deterioration : A Longitudinal Clinical Study

The cause of structural valve deterioration (SVD) is unclear. Therefore, we investigated oxidative stress markers in sera from patients with bioprosthetic heart valves (BHVs) and their association with SVD. Blood samples were taken from SVD (Phase A) and BHV patients during the first 24 (Phase B1) and >48 months (Phase B2) after BHV implantation to assess total antioxidant capacity (TAC), malondialdehyde (MDA), and nitrotyrosine (NT). The results show that MDA levels increased significantly 1 month after surgery in all groups but were higher at 6 months only in incipient SVD patients. NT levels increased gradually for the first 24 months after implantation in the BHV group. Patients with transcatheter aortic valve implantation (TAVI) showed even higher levels of stress markers. After >48 months, MDA and NT continued to increase in BHV patients with a further elevation after 60-72 months; however, these levels were significantly lower in the incipient and established SVD groups. In conclusion, oxidative stress may play a significant role in SVD, increasing early after BHV implantation, especially in TAVI cases, and also after 48 months' follow-up, but decreasing when SVD develops. Oxidative stress potentially represents a target of therapeutic intervention and a biomarker of BHV dysfunctio