Terapia de rehabilitación cognitiva para trastornos depresivos: estudio piloto sobre la mejora y mantenimiento del funcionamiento cognitivo y psicosocial / Cognitive remediation therapy for depressive disorders: Pilot study on the improvement and maintenance of cognitive and psychosocial functioning

Los trastornos depresivos son una de las principales causas de discapacidad global y la presencia de déficits cognitivos se relacionan con un peor pronóstico. Dado que la rehabilitación cognitiva en este trastorno está poco estudiada, y menos sus efectos a largo plazo, nuestro objetivo fue investigar sus beneficios en la mejora cognitiva y funcional de estos pacientes. Veintidós participantes fueron asignados aleatoriamente a: a) terapia cognitivo conductual grupal; y b) terapia cognitivo conductual grupal+terapia de rehabilitación cognitiva. Se realizó una evaluación al inicio del tratamiento, a los 3 y 6 meses de la finalización del mismo. Los participantes asignados al grupo con terapia de rehabilitación cognitiva mejoraron más su funcionamiento ejecutivo y estos efectos se mantenían en el tiempo. Sin embargo, no se encontraron diferencias entre ambos grupos en funcionamiento psicosocial. Estos resultados apoyan la importancia de seguir investigando la utilidad de la rehabilitación cognitiva en la recuperación de pacientes con trastornos depresivos

Depressive disorders are one of the main causes of global burden disease and cognitive impairment is associated with worse prognosis. Cognitive Remediation Therapy (CRT) and its long-term effects are understudied; our aim is to investigate the benefits of CRT in the cognitive and functional improvement and maintenance of theses patients. Twenty-two participants were randomly assigned to: a) Group Cognitive Behavioral Therapy (CBT-G) and b) CBT-G plus CRT. Patients were evaluated before treatment, at 3 and 6 months after the end of the treatment. Participants assigned to the TRC group improved more in executive function and its effects remain over time. However, no differences were found between groups in psychosocial functioning improving. These results support the relevance of continue investigating the usefulness of CRT in depression patients recovery

Characterization, Recombinant Production and Structure-Function Analysis of NvCI, A Picomolar Metallocarboxypeptidase Inhibitor from the Marine Snail Nerita versicolor.

A very powerful proteinaceous inhibitor of metallocarboxypeptidases has been isolated from the marine snail Nerita versicolor and characterized in depth. The most abundant of four, very similar isoforms, NvCla, was taken as reference and N-terminally sequenced to obtain a 372-nucleotide band coding for the protein cDNA. The mature protein contains 53 residues and three disulphide bonds. NvCIa and the other isoforms show an exceptionally high inhibitory capacity of around 1.8 pM for human Carboxypeptidase A1 (hCPA1) and for other A-like members of the M14 CPA subfamily, whereas a twofold decrease in inhibitory potency is observed for carboxypeptidase B-like members as hCPB and hTAFIa. A recombinant form, rNvCI, was produced in high yield and HPLC, mass spectrometry and spectroscopic analyses by CD and NMR indicated its homogeneous, compact and thermally resistant nature. Using antibodies raised with rNvCI and histochemical analyses, a preferential distribution of the inhibitor in the surface regions of the animal body was observed, particularly nearby the open entrance of the shell and gut, suggesting its involvement in biological defense mechanisms. The properties of this strong, small and stable inhibitor of metallocarboxypeptidases envisage potentialities for its direct applicability, as well as leading or minimized forms, in biotechnological/biomedical uses.

Synthesis and Structural/Functional Characterization of Selective M14 Metallocarboxypeptidase Inhibitors Based on Phosphinic Pseudopeptide Scaffold: Implications on the Design of Specific Optical Probes.

Metallocarboxypeptidases (MCPs) of the M14 family are Zn2+-dependent exoproteases present in almost every tissue or fluid in mammals. These enzymes perform a large variety of physiological functions and are involved in several pathologies, such as pancreatic diseases, inflammation, fibrinolysis, and cancer. Here, we describe the synthesis and functional/structural characterization of a series of reversible tight-binding phosphinic pseudopeptide inhibitors that show high specificity and potency toward these proteases. Characterization of their inhibitory potential against a large variety of MCPs, combined with high-resolution crystal structures of three selected candidates in complex with human carboxypeptidase A (CPA)1, allowed to decipher the structural determinants governing selectivity for type-A of the M14A MCP family. Further, the phosphinic pseudopeptide framework was exploited to generate an optical probe selectively targeting human CPAs. The phosphinic pseudopeptides presented here constitute the first example of chemical probes useful to selectively report on type-A MCPs activity in complex media.

Discovery of Mechanism-Based Inactivators for Human Pancreatic Carboxypeptidase A from a Focused Synthetic Library.

Metallocarboxypeptidases (MCPs) are involved in many biological processes such as fibrinolysis or inflammation, development, Alzheimer's disease, and various types of cancer. We describe the synthesis and kinetic characterization of a focused library of 22 thiirane- and oxirane-based potential mechanism-based inhibitors, which led to discovery of an inhibitor for the human pro-carboxypeptidase A1. Our structural analyses show that the thiirane-based small-molecule inhibitor penetrates the barrier of the pro-domain to bind within the active site. This binding leads to a chemical reaction that covalently modifies the catalytic Glu270. These results highlight the importance of combined structural, biophysical, and biochemical evaluation of inhibitors in design strategies for the development of spectroscopically nonsilent probes as effective beacons for in vitro, in cellulo, and/or in vivo localization in clinical and industrial applications.

Computer-assisted cognitive remediation therapy in schizophrenia: Durability of the effects and cost-utility analysis.

The durability of computer-assisted cognitive remediation (CACR) therapy over time and the cost-effectiveness of treatment remains unclear. The aim of the current study is to investigate the effectiveness of CACR and to examine the use and cost of acute psychiatric admissions before and after of CACR. Sixty-seven participants were initially recruited. For the follow-up study a total of 33 participants were enrolled, 20 to the CACR condition group and 13 to the active control condition group. All participants were assessed at baseline, post-therapy and 12 months post-therapy on neuropsychology, QoL and self-esteem measurements. The use and cost of acute psychiatric admissions were collected retrospectively at four assessment points: baseline, 12 months post-therapy, 24 months post-therapy, and 36 months post-therapy. The results indicated that treatment effectiveness persisted in the CACR group one year post-therapy on neuropsychological and well-being outcomes. The CACR group showed a clear decrease in the use of acute psychiatric admissions at 12, 24 and 36 months post-therapy, which lowered the global costs the acute psychiatric admissions at 12, 24 and 36 months post-therapy. The CACR is durable over at least a 12-month period, and CACR may be helping to reduce health care costs for schizophrenia patients.

Transexualidad y reproducción: situación actual desde el punto de vista clínico y legal / Transsexualism and reproduction: Clinical and legal situation

Se diagnostican como transexuales las personas que se identifican con el sexo opuesto y rechazan el género propio. Existen distintas hipótesis que intentan explicar el origen de la transexualidad, siendo las más aceptadas las teorías con bases biológicas. La prevalencia estimada es variable en función de la zona geográfica, siendo más frecuentes los transexuales femeninos que los masculinos. Las técnicas de reproducción asistida facilitan las opciones reproductivas de este colectivo que acude, cada vez más, a los centros clínicos especializados para tratar de formar una familia defendiendo el derecho a la reproducción de todo ser humano. Los transexuales pueden verse favorecidos especialmente por las técnicas de preservación de la fertilidad, pudiendo criopreservar sus gametos antes de la reasignación de sexo como estrategia preventiva en vistas a un posible deseo de reproducción futura. La falta de recomendaciones o guías consensuadas sobre la aplicabilidad de las técnicas de reproducción asistida en individuos transexuales y el vacío normativo existente dificultan su acceso a estas técnicas. Esta revisión recoge las posibles opciones reproductivas de los transexuales desde un punto de vista clínico y analiza la situación actual en el marco de la legislación española vigente (AU)

People who identify themselves with the opposite sex and reject their own gender are diagnosed as transsexuals. Different hypotheses have tried to explain the origin of transsexualism, biological theories being the most accepted. The estimated prevalence is variable, this depending on the geographic area. Female are more frequent than male transsexuals. Assisted reproduction techniques facilitate the reproductive options of this group who increasingly come to specialized clinical centers to try to form a family, defending the reproductive rights of every human being. Transsexuals could be especially favored by fertility preservation techniques, being able to cryopreserve their gametes before sex reassignment as a preventive strategy in view of a possible desire for future reproduction. Lack of recommendations or agreed on guidelines and absence of regulations about the applicability of assisted reproduction in transsexuals hinders their access to these techniques. This review summarizes the possible reproductive options of transsexuals from a clinical point of view and analyzes the current situation in the framework of Spanish law (AU)

A functional and structural study of the major metalloprotease secreted by the pathogenic fungus Aspergillus fumigatus.

Fungalysins are secreted fungal peptidases with the ability to degrade the extracellular matrix proteins elastin and collagen and are thought to act as virulence factors in diseases caused by fungi. Fungalysins constitute a unique family among zinc-dependent peptidases that bears low sequence similarity to known bacterial peptidases of the thermolysin family. The crystal structure of the archetype of the fungalysin family, Aspergillus fumigatus metalloprotease (AfuMep), has been obtained for the first time. The 1.8 Šresolution structure of AfuMep corresponds to that of an autoproteolyzed proenzyme with separate polypeptide chains corresponding to the N-terminal prodomain in a binary complex with the C-terminal zinc-bound catalytic domain. The prodomain consists of a tandem of cystatin-like folds whose C-terminal end is buried into the active-site cleft of the catalytic domain. The catalytic domain harbouring the key catalytic zinc ion and its ligands, two histidines and one glutamic acid, undergoes a conspicuous rearrangement of its N-terminal end during maturation. One key positively charged amino-acid residue and the C-terminal disulfide bridge appear to contribute to its structural-functional properties. Thus, structural, biophysical and biochemical analysis were combined to provide a deeper comprehension of the underlying properties of A. fumigatus fungalysin, serving as a framework for the as yet poorly known metallopeptidases from pathogenic fungi.

Computer-assisted cognitive remediation therapy: cognition, self-esteem and quality of life in schizophrenia.

BACKGROUND: Quality of life (QoL) is an important outcome in the treatment of schizophrenia. Cognitive deficits have an impact on functional outcomes. Cognitive remediation therapy is emerging as a psychological intervention that targets cognitive impairment, but the effect of computer-assisted cognitive remediation on neuropsychology and social functioning and wellbeing remains unclear. The aim of the current study is to investigate the neurocognitive outcomes of computer-assisted cognitive remediation (CACR) therapy in a sample of schizophrenia patients, and to measure the quality of life and self-esteem as secondary outcomes. METHODS: Sixty-seven people with schizophrenia were randomly assigned to computer-assisted cognitive remediation or an active control condition. The main outcomes were neuropsychological measures and secondary outcomes (self-esteem and quality of life). Measurements were recorded at baseline and post-treatment. RESULTS: The CACR therapy group improved in speed of processing, working memory and reasoning and problem-solving cognitive domains. QoL and self-esteem measures also showed significant improvements over time in this group. CONCLUSIONS: Computer-assisted cognitive remediation therapy for people with schizophrenia achieved improvements in neuropsychological performance and in QoL and self-esteem measurements.

Structural and Functional Analysis of the Complex between Citrate and the Zinc Peptidase Carboxypeptidase A.

A high-resolution carboxypeptidase-Zn(2+)-citrate complex was studied by X-ray diffraction and enzyme kinetics for the first time. The citrate molecule acts as a competitive inhibitor of this benchmark zinc-dependent peptidase, chelating the catalytic zinc ion in the active site of the enzyme and inducing a conformational change such that carboxypeptidase adopts the conformation expected to occur by substrate binding. Citrate adopts an extended conformation with half of the molecule facing the zinc ion, while the other half is docked in the S1' hydrophobic specificity pocket of the enzyme, in contrast with the binding mode expected for a substrate like phenylalanine or a peptidomimetic inhibitor like benzylsuccinic acid. Combined structural and enzymatic analysis describes the characteristics of the binding of this ligand that, acting against physiologically relevant zinc-dependent proteases, may serve as a general model in the design of new drug-protecting molecules for the oral delivery of drugs of peptide origin.

Linking amyloid protein aggregation and yeast survival.

Protein aggregation and amyloid formation lie behind an increasing number of human diseases. Here we describe the application of an "aggregation reporter", in which the test protein is fused to dihydrofolate reductase, as a general method to assess the intracellular solubility of amyloid proteins in eukaryotic background. Because the aggregation state of the target protein is linked directly to yeast cells survival in the presence of methotrexate, protein solubility can be monitored in vivo without the requirement of a functional assay for the protein of interest. In addition, the approach allows the in vivo visualization of the cellular location and aggregated state of the target protein. To demonstrate the applicability of the assay in the screening of genes or compounds that modulate amyloid protein aggregation in living cells, we have used as models the Alzheimer's amyloid ß peptide, polyglutamine expansions of huntingtin, α-synuclein and non-aggregating variants thereof. Moreover, the anti-aggregational properties of small molecules and the effects of the yeast protein quality control machinery have also been evaluated using this method.

Deciphering the role of the thermodynamic and kinetic stabilities of SH3 domains on their aggregation inside bacteria.

The formation of insoluble deposits by globular proteins underlies the onset of many human diseases. Recent studies suggest a relationship between the thermodynamic stability of proteins and their in vivo aggregation. However, it has been argued that, in the cell, the occurrence of irreversible aggregation might shift the system from equilibrium, in such a way that it could be the rate of unfolding and associated kinetic stability instead of the conformational stability that controls protein deposition. This is an important but difficult to decipher question, because kinetic and thermodynamic stabilities appear usually correlated. Here we address this issue by comparing the in vitro folding kinetics and stability features of a set of non-natural SH3 domains with their aggregation properties when expressed in bacteria. In addition, we compare the in vitro stability of the isolated domains with their effective stability in conditions that mimic the cytosolic environment. Overall, the data argue in favor of a thermodynamic rather than a kinetic control of the intracellular aggregation propensities of small globular proteins in which folding and unfolding velocities largely exceed aggregation rates. These results have implications regarding the evolution of proteins.

Progress in metallocarboxypeptidases and their small molecular weight inhibitors.

In what corresponds to a life span, metallocarboxypeptidases (MCPs) have jumped from being mere contaminants in animal pancreas powders (in depression year 1929) to be key players in cellular and molecular processes (in yet-another-depression years 2009-2010). MCPs are unique zinc-dependent enzymes that catalyze the breakdown of the amide bond at the C-terminus of peptide and protein substrates and participate in the recovery of dietary amino acids, tissue organogenesis, neurohormone and cytokine maturation and other important physiological processes. More than 26 genes code for MCPs in the human genome, many of them still waiting to be fully understood in terms of physiological function. A variety of MCPs have been linked to diseases in man: acute pancreatitis and pancreas cancer, type 2 diabetes, Alzheimer's Disease, various types of cancer, and fibrinolysis and inflammation. Many of these discoveries have been made possible thanks to recent advances, as exemplified by plasma carboxypeptidases N and B, known for fifty and twenty years, respectively, which have had their structures released only very recently. Plasma carboxypeptidase B is a biological target for therapy because of its involvement in the coagulation/fibrinolysis processes. Besides, the widespread use of carboxypeptidase A as a benchmark metalloprotease since the early days of Biochemistry has allowed the identification and design of an increasingly vast repertory of small molecular weight inhibitors. With these two examples we wish to emphasize that MCPs have become part of the drug discovery portfolio of pharmaceutical companies and academic research laboratories. This paper will review key developments in the discovery and design of MCP small molecular weight inhibitors, with an emphasis on the discovery of chemically diverse entities. Although encouraging advances have been achieved in the last few years, the specificity and oral bioavailability of the new chemotherapeutic agents seem to pose a challenge to medicinal chemists.

The X-ray structure of carboxypeptidase A inhibited by a thiirane mechanism-based inhibitor.

The three-dimensional X-ray crystal structure of carboxypeptidase A, a zinc-dependent hydrolase, covalently modified by a mechanism-based thiirane inactivator, 2-benzyl-3,4-epithiobutanoic acid, has been solved to 1.38 A resolution. The interaction of the thiirane moiety of the inhibitor with the active site zinc ion promotes its covalent modification of Glu-270 with the attendant opening of the thiirane ring. The crystal structure determination at high resolution allowed for the clear visualization of the covalent ester bond to the glutamate side chain. The newly generated thiol from the inhibitor binds to the catalytic zinc ion in a monodentate manner, inducing a change in the zinc ion geometry and coordination, while its benzyl group fits into the S1' specificity pocket of the enzyme. The inhibitor molecule is distorted at the position of the carbon atom that is involved in the ester bond linkage on one side and the zinc coordination on the other. This particular type of thiirane-based metalloprotease inhibitor is for the first time analyzed in complex to the target protease at high resolution and may be used as a general model for zinc-dependent proteases.

Analysis of a new crystal form of procarboxypeptidase B: further insights into the catalytic mechanism.

A new triclinic crystal structure form of porcine pancreatic procarboxypeptidase B (PCPB) was obtained at higher resolution than the previously known tetragonal crystal structure. This new crystal polymorph has allowed for a corrected, accurate assignment of residues along the polypeptide chain based on the currently available gene sequence information and crystallographic data. The present structure shows unbound PCPB in a distinct molecular packing as compared to the previous benzamidine complexed form. Its catalytically important Tyr248 residue is oriented and hydrogen-bonded to solvent water molecules, and locates the furthest away from the catalytic zinc ion as compared to previous structures. A relatively long stretch of residues flanking Tyr248 and guarding the access to the catalytic zinc ion was found to be sequentially unique to the M14 family of peptidases. Predictions from a normal mode analysis indicated that this stretch of residues belongs to a rigid subdomain in the protein structure. The specific presence of a tyrosyl residue at the most exposed position in this region would allow for a delicate balance between extreme hydrophobicity and hydrophilicity, and affect substrate binding and the kinetic efficiency of the enzyme.

Cyclobutane-containing peptides: evaluation as novel metallocarboxypeptidase inhibitors and modelling of their mode of action.

Different types of cyclobutane-containing peptides (CBPs) were screened for the first time as ligands of metallocarboxypeptidases (MCPs). CBPs are conformationally constrained, low molecular-weight compounds which showed moderate yet selective inhibitory activity against mammalian MCPs. The most potent compound was a carboxypeptidase B inhibitor. Docked protein-ligand complexes indicated that CBPs may bind to the target proteases via electrostatic interactions and aromatic stacking to catalytically crucial residues and that the placement of functional groups seems to be assisted by the rigid CBP backbone. The easily obtainable CBPs may offer a valuable alternative in the design of novel inhibitors to disease-linked metallocarboxypeptidases like human plasma carboxypeptidase B.

A new type of five-membered heterocyclic inhibitors of basic metallocarboxypeptidases.

A structure-based virtual screening survey was used to identify potential inhibitors of the human M14 family of metallocarboxypeptidases. A good correlation between docking energy scores and measured K(i) values was observed, indicating an efficient performance of the screening procedure. Among various compounds displaying K(i) values in the low micromolar range, N-(3-chlorophenyl)-4-((5-(3-methoxybenzylthio)-1,3,4-oxadiazol-2-yl)methyl)thiazol-2-amine emerged as the most powerful inhibitor for human carboxypeptidase B (CPB). According to molecular docking, this compound fits into CPB active site cleft through coordination of the catalytic zinc ion with the 1,3,4-oxadiazole moiety. This represents a novel five-membered heterocyclic type of inhibitor for disease-linked metallocarboxypeptidases and an interesting lead for further development.

Aromatic organic compounds as scaffolds for metallocarboxypeptidase inhibitor design.

We have identified and characterized a set of quinoline, naphthalene and quinazoline derivatives as inhibitors of metallocarboxypeptidases, a class of metal-dependent proteolytic enzymes. The aromatic organic compounds were selected from a high-throughput screening survey and, with some exceptions, showed a good correlation between inhibitory potency and docking energy value. The in vitro inhibition tests gave K(i) values in the lower micromolar range for metallocarboxypeptidases with different specificities, and a tendency to behave as more powerful inhibitors of CPB was observed for most of the compounds tested. The kinetic results were further analyzed by structural analysis via molecular docking. The most potent aromatic organic inhibitor docks to human CPB mostly through burial of its hydrophobic moiety deep into the enzyme's active site cleft and by interacting with the catalytic zinc ion. The significance of our results in designing inhibitors against disease-related CPs from the identified ligands is examined herein.

Design, selection, and characterization of thioflavin-based intercalation compounds with metal chelating properties for application in Alzheimer's disease.

Metal chelation is considered a rational therapeutic approach for interdicting Alzheimer's amyloid pathogenesis. At present, enhancing the targeting and efficacy of metal-ion chelating agents through ligand design is a main strategy in the development of the next generation of metal chelators. Inspired by the traditional dye Thioflavin-T, we have designed new multifunctional molecules that contain both amyloid binding and metal chelating properties. In silico techniques have enabled us to identify commercial compounds that enclose the designed molecular framework (M1), include potential antioxidant properties, facilitate the formation of iodine-labeled derivatives, and can be permeable through the blood-brain barrier. Iodination reactions of the selected compounds, 2-(2-hydroxyphenyl)benzoxazole (HBX), 2-(2-hydroxyphenyl)benzothiazole (HBT), and 2-(2-aminophenyl)-1H-benzimidazole (BM), have led to the corresponding iodinated derivatives HBXI, HBTI, and BMI, which have been characterized by X-ray diffraction. The chelating properties of the latter compounds toward Cu(II) and Zn(II) have been examined in the solid phase and in solution. The acidity constants of HBXI, HBTI, and BMI and the formation constants of the corresponding ML and ML2 complexes [M = Cu(II), Zn(II)] have been determined by UV-vis pH titrations. The calculated values for the overall formation constants for the ML2 complexes indicate the suitability of the HBXI, HBTI, and BMI ligands for sequestering Cu(II) and Zn(II) metal ions present in freshly prepared solutions of beta-amyloid (Abeta) peptide. This was confirmed by Abeta aggregation studies showing that these compounds are able to arrest the metal-promoted increase in amyloid fibril buildup. The fluorescence features of HBX, HBT, BM, and the corresponding iodinated derivatives, together with fluorescence microscopy studies on two types of pregrown fibrils, have shown that HBX and HBT compounds could behave as potential markers for the presence of amyloid fibrils, whereas HBXI and HBTI may be especially suitable for radioisotopic detection of Abeta deposits. Taken together, the results reported in this work show the potential of new multifunctional thioflavin-based chelating agents as Alzheimer's disease therapeutics.

The crystal structure of thrombin-activable fibrinolysis inhibitor (TAFI) provides the structural basis for its intrinsic activity and the short half-life of TAFIa.

Mature thrombin-activable fibrinolysis inhibitor (TAFIa) is a highly unstable metallocarboxypeptidase that stabilizes blood clots by clipping C-terminal lysine residues from partially degraded fibrin. In accordance with its in vitro antifibrinolytic activity, animal studies have reported that inhibition of mature TAFI aids in the prevention of thrombosis. The level of TAFI activity is stringently regulated through (i) controlled proteolytic truncation of the zymogen (TAFI), generating the mature enzyme, TAFIa, and (ii) the short half-life of TAFIa. TAFI itself exhibits an intrinsic enzymatic activity, which is likely required to provide a baseline level of antifibrinolytic activity. The novel crystal structure presented here reveals that the active site of TAFI is accessible, providing the structural explanation for the its intrinsic activity. It also supports the notion that an "instability region" exists, in agreement with site-directed mutagenesis studies. Sulfate ions, bound to this region, point toward a potential heparin-binding site and could explain how heparin stabilizes TAFIa.

Direct interaction between a human digestive protease and the mucoadhesive poly(acrylic acid).

Carboxypeptidase A1 has been the subject of extensive research in the last 30 y and is one of the most widely studied zinc metalloenzymes. However, the three-dimensional structure of the human form of the enzyme is not yet available. This report describes the three-dimensional structure of human carboxypeptidase A1 (hCPA1) derived from crystals that belong to the tetragonal space group P4(3)2(1)2 and diffract to 1.6 angstroms resolution. A description of the ternary complex hCPA1-Zn2+-poly(acrylic acid) is included as a model of the interaction of mucoadhesive polymers with proteases in the gastrointestinal tract. The direct mode of interaction between poly(acrylic acid) and the active site of the target protease was confirmed by in vitro inhibition assays. The structure was further analyzed in silico through the optimal docking-area method. The characterization of binding sites on the surface of hCPA1 and a comparison with other available carboxypeptidase structures provided further insights into the formation of multiprotein complexes and the activation mechanisms of carboxypeptidase zymogens. The high-resolution structure of hCPA1 provides an excellent template for the modelling of physiologically relevant carboxypeptidases and could also contribute to the design of specific agents for biomedical purposes.