Molecular screening for 22Q11.2 deletion syndrome in patients with congenital heart disease.

Few studies have investigated the prevalence of 22q11.2 deletion syndrome (22q11.2DS) among patients with isolated heart defects or nonconotruncal heart defects. Polymerase chain reaction (PCR) followed by length polymorphism restriction fragment analysis (RFLP) is useful for low-cost molecular diagnosis and screening. This cross-sectional study included 392 patients with congenital heart disease, described clinical features, and performed PCR-RFLP for analysis of polymorphism in three loci with a high heterozygosity rate located in the typically deleted region of 1.5 megabases. Heterozygosity excluded 22q11.2DS. Patients with homozygosity for the three markers underwent multiplex ligation-dependent probe amplification (MLPA) and fluorescence in situ hybridization (FISH) for the final diagnosis, estimating the prevalence of 22q11.2DS. The use of PCR-RFLP excluded 22q11.2DS in 81.6 % (n = 320) of 392 patients. Of the remaining 72 patients, 65 underwent MLPA, showing 22q11.2DS in five cases (prevalence, 1.27 %). Four of these five patients underwent FISH, confirming the MLPA results. All five patients with the deletion had heart diseases commonly found with 22q11.2DS (interrupted aortic arch, persistent truncus arteriosus, tetralogy of Fallot, and ventricular septal defect plus atrial septal defect). Two patients had congenital extracardiac anomaly (one with arched palate and micrognathia and one with hypertelorism). Three patients reported recurrent respiratory infections, and one patient reported hypocalcemia. All were underweight or short in stature for their age. This study contributed to showing the prevalence of 22q11.2DS in patients with any congenital heart disease, with or without other features of the syndrome. Patients with 22q11.2DS may not have all the major features of the syndrome, and those that are found may be due to the heart defect.

Mesenchymal stem cells as a platform for gene therapy protocols.

Mesenchymal stem cells (MSCs) are considered as the adult stem cells with the greatest therapeutic potential, due to characteristics such as plasticity, intrinsic tropism towards lesions, paracrine activity, and immunosuppressive activity. This potential may be optimised by transforming them with genes which will improve their therapeutic ability or are therapeutic by themselves. This review presents a summary of the main types of viral or plasmid vectors used to transform therapeutic MSCs and their use in different pathologies. Although this strategy holds great promise, results are still heterogeneous, showing that more studies are needed to optimise gene transfer methods and models.

The isolation of stem cells from human deciduous teeth pulp is related to the physiological process of resorption.

INTRODUCTION: The aim of this study was to isolate and grow cells from sound human deciduous teeth pulp with different levels of resorption and evaluate stem cell parameters. METHODS: Pulp tissue was removed from 30 different patients, aged from 6 to 12 years. From all the teeth, 21 were in advanced levels of resorption (group 1), and the remaining nine teeth did not show any visible resorption (group 2). Pulp tissue was removed and dissociated, and the suspension was seeded onto 12-well plates. The phenotype of the cells (n = 5) was analyzed on fifth and tenth passages by flow cytometry for clusters of differentiation (CD)29/PE, CD34/PE, CD44/FITC, CD45/FITC, CD90/FITC, CD117/PE, CD133/PE, CD146/FITC, CD184/PE, Stromal Cell Surface Marker 1 (STRO-1)/FITC and human leukocyte antigen major histocompatibility complex class II surface receptor (HLA-DR)/FITC, and by reverse transcription-polymerase chain reaction (RT-PCR) for octamer-binding transcription factor 4 (OCT-4). On the same passages, cells were differentiated into adipocytes, osteoblasts, and chondrocytes. RESULTS: Cell isolation was successful in 25 samples, but only 17 of these reached 90% confluence. It was not possible to establish cell culture from group 2. Cells on both fifth and tenth passages were positive for CD29, CD44, and CD90 and also for the expression of OCT-4. Moderate labeling was observed for CD117 and CD133, whereas a low expression was detected for CD34, CD45, HLA-DR, CD184, CD146, and STRO-1. All cultures differentiated into three cell types. CONCLUSIONS: The isolated pulp cells can be considered stem cells. The facility for obtaining cells seems to be related to the root resorption process, so, therefore, the cells from group 1 were able to proliferate in vitro, whereas group 2 cells were not.

Beyond retrovirus infection: HIV meets gene therapy

The human immunodeficiency virus (HIV) is classified as a retrovirus because of its RNA genome and the fact that it requires reverse transcriptase to convert it into DNA. This virus belongs to the lentivirinae subfamily and is able to infect quiescent cells but is better known for its association with acquired immunodeficiency syndrome (AIDS) and can be described as one of the most effective vectors for gene transfer. Biosafety concerns are present whenever viral vectors are employed but are particularly pertinent to the development of HIV-based vectors. Insertional mutagenesis and the production of new replication-competent viruses (RCV) have been pointed to as major problems, but experimental data have shown that safe protocols can be developed for their production and application. Virological, evolutionary, immunological and cell biology studies must be conducted jointly to allow the clinical use of HIV vectors. This review will focus on the general properties, production and applications of retrovectors in gene therapy, with particular emphasis on those based on HIV systems.