Argentina-Alzheimer's Disease Neuroimaging Initiative: pioneering Alzheimer's Research in Latin America and its Implications for Regional Advancement.

The Alzheimer's Disease Neuroimaging Initiative (ADNI) has fostered collaboration among researchers around the world, catalyzing innovation and accelerating progress in the field. In Latin America, this initiative advanced the validation and development of Alzheimer's disease biomarkers for the first time in our region. In 2011, as part of the international ADNI, Argentina-ADNI (Arg-ADNI) was founded. The following years were characterized by strong support from entities such as the Alzheimer's Association, transforming into the emergence of several multinational studies focusing on prevention and diagnosis, and treatment of dementias. These studies are heirs to the tradition of Arg-ADNI: the Dominantly Inherited Alzheimer Network, Latin American Initiative for Lifestyle Intervention to Prevent Cognitive Decline, Longitudinal Early-Onset Alzheimer's Disease Study, and Initiative for the Study of Down Syndrome and Alzheimer's Disease. These initiatives have contributed significantly to the development of regional research and serve as essential tools for health policy planning in Latin America. HIGHLIGHTS: In Latin America, the Alzheimer's Disease Neuroimaging Initiative (ADNI) advanced the validation and development of Alzheimer's disease biomarkers for the first time in our region. ADNI has been the basis that boosted several multinational studies focusing on both prevention and diagnosis, and treatment of dementias (Dominantly Inherited Alzheimer Network, LatAm-FINGER, LEADS). These initiatives with the support from the Alzheimer's Association have contributed significantly to the development of regional research This is an example of collaboration between high-income countries with low- and middle-income countries aimed at global scientific development and inclusion.

[Frequency of cutaneous drug reactions in the outpatient dermatology clinic at the National Institute of Cardiology Ignacio Chávez over a ten-year period]. / Frecuencia de reacciones adversas cutáneas a medicamentos en la consulta externa de dermatología del Instituto Nacional de Cardiología Ignacio Chávez, en un periodo de diez años.

Cutaneous adverse drug reactions, or pharmacodermias, are the most common form of adverse drug reactions (ADR). It was our interest to know their epidemiological behavior in a tertiary hospital level in Mexico. We stablished the frequency of ADR in 61 infants and adults hospitalized patients and those seen in the outpatient Dermatology Clinic at the National Institute of Cardiology Ignacio Chávez in Mexico City (INCICh) over a period of 10 years. The most frequently diagnosed pharmacodermias were acneiform dermatitis, cutaneous hyperpigmentation and maculopapular exanthema mainly associated to prednisone, hydroxychloroquine, cephalothin, amiodarone and vitamin B-complex, although we registered less frequently more severe and hazardous reactions. These results were consistent with other reports in our country. Multiple drugs administered at a time was an important causative factor for the ADR. It is necessary for every practitioner to develop skills that permit the identification of these dermatoses in order to correctly manage each case and diminish the morbimortality associated.

Las reacciones adversas cutáneas a medicamentos o farmacodermias constituyen la forma más común de las reacciones adversas a medicamentos (RAM), por lo que fue nuestro interés conocer su comportamiento epidemiológico en un hospital de tercer nivel en México. Establecimos su frecuencia en 61 pacientes, infantes y adultos, hospitalizados y de la Consulta externa de Dermatología en el Instituto Nacional de Cardiología Ignacio Chávez (INCICh) en la Ciudad de México, en 10 años, y encontramos que la reacciones más frecuentes fueron la dermatitis acneiforme, la hiperpigmentación cutánea y el exantema maculopapular principalmente asociados a prednisona, hidroxicloroquina, cefalotina, amiodarona y complejo B, aunque con menos frecuencia registramos reacciones más graves, lo cual es consistente con otros reportes similares en nuestro país. La polifarmacia de la mayoría de los pacientes que presentaron estas RAM fue un factor determinante en su presentación. Es fundamental desarrollar habilidades para reconocer el cuadro clínico de estas dermatosis, con el fin de abordar correctamente cada caso y disminuir la morbimortalidad de las RAM.

[Economic burden assessment for the management of asthma patients at Mexico's National Institute for Respiratory Diseases]. / Evaluación de la carga económica para el tratamiento de pacientes con asma en el Instituto Nacional de Enfermedades Respiratorias de México.

OBJETIVO: Determinar la carga económica anual del asma, desde una perspectiva institucional y con base en la clasificación recomendada por GINA, en una cohorte retrospectiva de adultos atendidos en el Instituto Nacional de Enfermedades Respiratorias (INER) de México. MÉTODOS: Estudio observacional, longitudinal y retrospectivo, llevado a cabo a partir de la información recabada de 247 pacientes femeninas con asma. Se estimaron los costos directos anuales: visitas, pruebas de laboratorio, tratamiento farmacológico y de las crisis o exacerbaciones, para determinar la carga anual de la enfermedad desde una perspectiva institucional, y según la clasificación de la Iniciativa Global para el Asma. RESULTADOS: El costo promedio anual fue de $43,813,92, que aumentó en relación con la necesidad de aumento de dosis de corticoides inhalados y beta-agonistas de acción prolongada. El costo promedio de la consulta médica fue de $2004.57, $982.82 por gestión de crisis y $2645.95 por pruebas de laboratorio. El tratamiento farmacológico representó la principal carga económica, con un costo promedio anual de $38,180.58. CONCLUSIONES: Los resultados resaltan una carga económica del asma estimada en un costo anual por paciente de $43,813.92 MXN (DE=93,348.85), en el contexto del tercer nivel de atención en el sistema de salud público mexicano. La gravedad del asma, los tratamientos y los biológicos fueron los principales factores que aumentaron los costos directos de la atención.

OBJECTIVE: Determine the annual economic burden of the disease from an institutional perspective and based on GINA's recommended classification in a retrospective cohort of adults treated at Instituto Nacional de Enfermedades Respiratorias (INER) of Mexico City. METHODS: A retrospective, longitudinal observational study comprised by data from 247 female asthma patients, annual direct costs were estimated including: visits, laboratory tests, pharmacological treatment and management of crisis or exacerbations, to determine the annual burden of the disease from an institutional perspective and according to Global Initiative for Asthma classification. RESULTS: The average annual cost was $43,813.92, which increased in relation to the need of inhaled corticosteroids and long-acting beta agonists dosage increase. The average doctor's appointment cost was $2,004.57, $982.82 for crisis management and $2,645.95 for laboratory testing. Pharmacological treatment represented the main economic burden with an annual average cost of $38,180.58. CONCLUSIONS: The results highlight an economic burden of asthma estimated at an annual cost per patient of $43,813.92 MXN (SD=93,348.85) in the context of the third level of care in the Mexican public health system. The asthma severity and treatments such as biologics were the main factors that increased direct costs of care.

Hereditary angioedema: Patient journey approach in Mexico.

Objective: To understand the patient's journey with HAE from symptom initiation to diagnosis, treatment allocation, follow-up, and the impact of the disease on their quality of life in Mexico. Methods: A survey was administered to the patients with HAE. Participants completed a questionnaire covering five domains: patient journey; effects on productivity, school performance and daily activities; quality of life; anxiety and depression. Responses were analyzed using descriptive statistics. Results: A total of 17 surveys were analyzed (15 women and 2 men, age range: 23-67 years). Type I HAE was most common (71%), normal C1 inhibitor HAE was 12% and 18% did not know their HAE type. The average disease evolution was 13.7 years and the time from symptom initiation to diagnosis was 20 years. 59% of patients knew of one or two treatments available, 12% knew 3 treatments and 18% were aware of 4 or more, 12% were not aware of any treatments. 53% had a job, 18% referred a severely anxious state, 41% were depressed and all patients referred some social impact due to HAE. Conclusions: There is a need to reinforce the knowledge of general practitioners on HAE to promote an earlier diagnosis and awareness of rare diseases and their impact on quality of life among the general population and promote the removal of barriers to treatment.

Objetivo: Conocer el seguimiento pacientes mexicanos con angioedema hereditario, desde el inicio de los síntomas hasta el diagnóstico, prescripción del tratamiento y seguimiento, y repercusión en la calidad de vida. Métodos: Estudio transversal, llevado a cabo a partir de la aplicación de una encuesta a pacientes con angioedema hereditario, que abarcó cinco ámbitos: seguimiento del paciente; afectación en la productividad, el rendimiento escolar y las actividades cotidianas; calidad de vida; ansiedad y depresión. Las respuestas se analizaron mediante estadística descriptiva. Resultados: Se analizaron 17 encuestas (15 mujeres y 2 hombres, rango de edad: 23-67 años). El angioedema hereditario tipo I fue el más frecuente (71%), el angioedema hereditario clásico con inhibidor de C1 fue del 12%; y el 18% no conocía su tipo de angioedema hereditario. La evolución media de la enfermedad fue del 13.7 años y el tiempo transcurrido desde el inicio de los síntomas hasta el diagnóstico fue de 20 años. El 59% de los pacientes conocía uno o dos tratamientos disponibles y el 12% no conocía ninguno. El 53% tenía trabajo, el 18% refería un estado de ansiedad grave, el 41% tenía depresión y todos referían algún efecto social debido al angioedema hereditario. Conclusiones: Es necesario reforzar los conocimientos de los médicos acerca del angioedema hereditario para establecer el diagnóstico temprano, el conocimiento de las enfermedades raras, su repercusión en la calidad de vida entre la población y eliminar los factores que entorpecen el tratamiento.

Neuropsychological profile of Alzheimer's disease based on amyloid biomarker findings results from a South American cohort.

OBJECTIVE: Increased life expectancy and exponential growth of adults suffering from Alzheimer's disease (AD) worldwide, has led to biomarkers incorporation for diagnosis in early stages. Use of neuropsychological testing remains limited. This study aimed to identify which neuropsychological tests best indicated underlying AD pathophysiology. METHODS: One hundred and forty-one patients with MCI (Mild Cognitive Impairment) were studied. A neuropsychological test battery based on the Uniform Data Set (UDS) from the Alzheimer's Disease Centers program of the National Institute on Aging (NIA) was performed and amyloid markers recorded; according to presence or absence of amyloid identified by positive PIB-PET findings, or low CSF Aß42 levels, patients were separated into MCI amyloid-(n:58) and MCI amyloid + (n = 83) cases. RESULTS: Statistical differences were found in all memory tests between groups. Delayed recall score at thirty minutes on the Rey Auditory Verbal Learning Test (AVLT) was the best predictor of amyloid pathology presence (AUC 0.68), followed by AVLT total learning (AUC 0.66) and AVLT Recognition (AUC 0.59) scores, providing useful cut off values in the clinical setting. CONCLUSIONS: Use of neuropsychological testing, specifically AVLT scores with cutoff values, contributed to the correct diagnosis of MCI due to AD in this SouthAmerican cohort.

Healthcare resource utilization and costs in pediatric pulmonary arterial hypertension in a third-level hospital in Mexico.

Aim: The objective of this study was to evaluate the healthcare costs and resource utilization of pediatric pulmonary arterial hypertension management at a third-level hospital in Mexico. Methods: A retrospective cohort study was conducted in a pediatric population with pulmonary arterial hypertension. Only direct medical costs, derived from pharmacological treatment, laboratory tests, physician visits and hospitalizations, were considered. From an institutional perspective, all costs were accounted for in 2019 US dollars. Results: A total of 82 patients were included. Of these, 55% were female and the mean age was 6.9 (standard deviation ± 4) years. The mean annual cost was $17,452.14 (standard deviation ± $38,944.10), with a median cost of $8832.75. Conclusion: Pulmonary arterial hypertension is a costly disease, with hospitalization and pharmacological treatment being areas with a higher economic burden. Functional class IV has greater resource utilization and costs.

Correlation between 99mTc-TRODAT-1 SPECT and 18F-FDOPA PET in patients with Parkinson's disease: a pilot study.

OBJECTIVE: To determine whether technetium-99m-labeled tropane derivative single-photon emission computed tomography (99mTc-TRODAT-1 SPECT) provides results comparable to those of the less widely available, less accessible tool fluorine-18-labeled fluorodopa positron-emission tomography (18F-FDOPA PET) in the setting of a movement disorders clinic. MATERIALS AND METHODS: In this prospective pilot study, eight subjects with a clinical diagnosis of Parkinson's disease were randomly selected from among patients under treatment at a movement disorders clinic and submitted to 99mTc-TRODAT-1 SPECT and 18F-FDOPA PET. The results were read by two experienced observers, and a semiquantitative analysis was performed. RESULTS: The visual and semiquantitative analyses were concordant for all studies, showing that radiotracer uptake in the contralateral striatum on the most affected side was lower when 99mTc-TRODAT-1 SPECT was employed. The semiquantitative analysis demonstrated a significant correlation between 18F-FDOPA PET and 99mTc-TRODAT-1 SPECT (r = 0.73; p < 0.01). CONCLUSION: It appears that 99mTc-TRODAT-1 SPECT is a valid option for the study of dopaminergic function in a clinical setting.

OBJETIVO: Determinar se a 99mTc-TRODAT-1 SPECT fornece resultados comparáveis aos da 18F-FDOPA PET, ferramenta menos acessível e menos amplamente disponível, no contexto de uma clínica de distúrbios do movimento. MATERIAIS E MÉTODOS: Neste estudo prospectivo, oito indivíduos com diagnóstico clínico de doença de Parkinson foram selecionados aleatoriamente entre pacientes em tratamento em uma clínica de distúrbios do movimento e submetidos a 99mTc-TRODAT-1 SPECT e 18F-FDOPA PET. Os resultados foram lidos por dois observadores experientes e uma análise semiquantitativa foi realizada. RESULTADOS: As análises visual e semiquantitativa foram concordantes para todos os estudos, mostrando que a captação do radiotraçador no estriado contralateral do lado mais afetado foi menor quando a 99mTc-TRODAT-1 SPECT foi empregada. A análise semiquantitativa demonstrou uma correlação significativa entre 18F-FDOPA PET e 99mTc-TRODAT-1 SPECT (r = 0,73; p < 0,01). CONCLUSÃO: A 99mTc-TRODAT-1 SPECT parece ser uma opção válida para o estudo da função dopaminérgica em um ambiente clínico.

Amyloid and anatomical correlates of executive functioning in middle-aged offspring of patients with late-onset Alzheimer's disease.

A traditional hallmark of cognitive impairment associated with late-onset Alzheimer´s disease (LOAD) is episodic memory impairment. However, early alterations have been identified in brain regions associated with executive function in asymptomatic, middle-age offspring of patients with LOAD (O-LOAD) compared to those with no family history. We hypothesized that executive function among O-LOAD would correlate with structural and amyloid brain imaging differently from those without a family history of LOAD (control subjects, CS). Executive function, cortical thickness, and in-vivo Aß deposits were quantified in 30 O-LOAD and 25 CS. Associations were observed among O-LOAD only. Cortical thickness in the left lateral orbitofrontal cortex was positively associated with Design Fluency. The Stroop Color and Word Test, correlated positively with right rostral mid-frontal cortex thickness. Trails Making Test-B was inversely related to left medial orbitofrontal thickness. Tower of London total time was positively associated with ß-amyloid deposition in the right precuneus. These results support previous evidence that early executive dysfunction might reflect subtle, early changes in persons at risk of LOAD and suggests that executive function alterations deserve further exploration in the LOAD literature.

Correlation between 99mTc-TRODAT-1 SPECT and 18F-FDOPA PET in patients with Parkinson's disease: a pilot study / Correlação entre 99mTc-TRODAT-1 SPECT e 18F-FDOPA PET em pacientes com doença de Parkinson: um estudo piloto

Abstract Objective: To determine whether technetium-99m-labeled tropane derivative single-photon emission computed tomography (99mTc-TRODAT-1 SPECT) provides results comparable to those of the less widely available, less accessible tool fluorine-18-labeled fluorodopa positron-emission tomography (18F-FDOPA PET) in the setting of a movement disorders clinic. Materials and Methods: In this prospective pilot study, eight subjects with a clinical diagnosis of Parkinson's disease were randomly selected from among patients under treatment at a movement disorders clinic and submitted to 99mTc-TRODAT-1 SPECT and 18F-FDOPA PET. The results were read by two experienced observers, and a semiquantitative analysis was performed. Results: The visual and semiquantitative analyses were concordant for all studies, showing that radiotracer uptake in the contralateral striatum on the most affected side was lower when 99mTc-TRODAT-1 SPECT was employed. The semiquantitative analysis demonstrated a significant correlation between 18F-FDOPA PET and 99mTc-TRODAT-1 SPECT (r = 0.73; p < 0.01). Conclusion: It appears that 99mTc-TRODAT-1 SPECT is a valid option for the study of dopaminergic function in a clinical setting.

Resumo Objetivo: Determinar se a 99mTc-TRODAT-1 SPECT fornece resultados comparáveis aos da 18F-FDOPA PET, ferramenta menos acessível e menos amplamente disponível, no contexto de uma clínica de distúrbios do movimento. Materiais e Métodos: Neste estudo prospectivo, oito indivíduos com diagnóstico clínico de doença de Parkinson foram selecionados aleatoriamente entre pacientes em tratamento em uma clínica de distúrbios do movimento e submetidos a 99mTc-TRODAT-1 SPECT e 18F-FDOPA PET. Os resultados foram lidos por dois observadores experientes e uma análise semiquantitativa foi realizada. Resultados: As análises visual e semiquantitativa foram concordantes para todos os estudos, mostrando que a captação do radiotraçador no estriado contralateral do lado mais afetado foi menor quando a 99mTc-TRODAT-1 SPECT foi empregada. A análise semiquantitativa demonstrou uma correlação significativa entre 18F-FDOPA PET e 99mTc-TRODAT-1 SPECT (r = 0,73; p < 0,01). Conclusão: A 99mTc-TRODAT-1 SPECT parece ser uma opção válida para o estudo da função dopaminérgica em um ambiente clínico.

Neurobiological substrates underlying corpus callosum hypoconnectivity and brain metabolic patterns in the valproic acid rat model of autism spectrum disorder.

Atypical connectivity between brain regions and altered structure of the corpus callosum (CC) in imaging studies supports the long-distance hypoconnectivity hypothesis proposed for autism spectrum disorder (ASD). The aim of this study was to unveil the CC ultrastructural and cellular changes employing the valproic acid (VPA) rat model of ASD. Male Wistar rats were exposed to VPA (450 mg/kg i.p.) or saline (control) during gestation (embryonic day 10.5), and maturation, exploration, and social behavior were subsequently tested. Myelin content, ultrastructure, and oligodendroglial lineage were studied in the CC at post-natal days 15 (infant) and 36 (juvenile). As a functional outcome, brain metabolic activity was determined by positron emission tomography. Concomitantly with behavioral deficits in juvenile VPA rats, the CC showed reduced myelin basic protein, conserved total number of axons, reduced percentage of myelinated axons, and aberrant and less compact arrangements of myelin sheath ultrastructure. Mature oligodendrocytes decreased and oligodendrocyte precursors increased in the absence of astrogliosis or microgliosis. In medial prefrontal and somatosensory cortices of juvenile VPA rats, myelin ultrastructure and oligodendroglial lineage were preserved. VPA animals exhibited global brain hypometabolism and local hypermetabolism in brain regions relevant for ASD. In turn, the CC of infant VPA rats showed reduced myelin content but preserved oligodendroglial lineage. Our findings indicate that CC hypomyelination is established during infancy and prior to oligodendroglial pattern alterations, which suggests that axon-oligodendroglia communication could be compromised in VPA animals. Thus, CC hypomyelination may underlie white matter alterations and contribute to atypical patterns of connectivity and metabolism found in ASD.

Efficacy, Safety, and Cost-Minimization Analysis of Continuous Infusion of Low-Dose Gemcitabine Plus Cisplatin in Patients With Unresectable Malignant Pleural Mesothelioma.

BACKGROUND: Malignant pleural mesothelioma (MPM) is rare and aggressive neoplasia, with a poor prognosis; furthermore, the monetary cost of its treatment represents a major challenge for many patients. The economic burden this malignancy imposes is underscored by the fact that asbestos exposure, which is the most frequent risk factor, is much more prevalent in the lower socioeconomic population of developing countries. The aims of the present study were to evaluate the efficacy, safety, and cost of continuous infusion of low-dose Gemcitabine plus Cisplatin (CIGC) as a treatment strategy for patients with unresectable MPM. METHODS: We performed a prospective cohort study to determine efficacy and safety of continuous infusion gemcitabine at a dose of 250 mg/m2 in a 6-h continuous infusion plus cisplatin 35 mg/m2 on days 1 and 8 of a 21-day cycle in patients with unresectable MPM. We also performed a cost-minimization analysis to determine if this chemotherapy regimen is less expensive than other currently used regimens. RESULTS: The median number of chemotherapy cycles was six (range 1-11 cycles); objective response rate was documented in 46.2%, and disease control rate was seen in 81.2%. Median PFS was 8.05 months (CI 95% 6.97-9.13); median OS was 16.16 months (CI 95% 12.5-19.9). The cost minimization analysis revealed savings of 66.4, 61.9, and 97.7% comparing CIGC with short-infusion gemcitabine plus cisplatin (SIGC), cisplatin plus pemetrexed (CP), and cisplatin plus pemetrexed and bevacizumab (CPB), respectively. Furthermore, this chemotherapy regimen proved to be safe at the administered dosage. CONCLUSION: CIGC is an effective and safe treatment option for patients with unresectable MPM; besides, this combination is a cost-saving option when compared with other frequently used chemotherapy schemes. Therefore, this treatment scheme should be strongly considered for patients with unresectable MPM and limited economic resources.

Cost-effectiveness analysis of first and second-generation EGFR tyrosine kinase inhibitors as first line of treatment for patients with NSCLC harboring EGFR mutations.

BACKGROUND: Tyrosine-kinase inhibitors (TKIs) have become the cornerstone treatment of patients with non-small cell lung cancer that harbor oncogenic EGFR mutations. The counterpart of these drugs is the financial burden that they impose, which often creates a barrier for accessing treatment in developing countries. The aim if the present study was to compare the cost-effectiveness of three different first and second generation TKIs. METHODS: We designed a retrospective cost-effectiveness analysis of three different TKIs (afatinib, erlotinib, and gefitinib) administered as first-line therapy for patients with NSCLC that harbor EGFR mutations. RESULTS: We included 99 patients with the following TKI treatment; 40 treated with afatinib, 33 with gefitinib, and 26 with erlotinib. Median PFS was not significantly different between treatment groups; 15.4 months (95% CI 9.3-19.5) for afatinib; 9.0 months (95% CI 6.3- NA) for erlotinib; and 10.0 months (95% CI 7.46-14.6) for gefitinib. Overall survival was also similar between groups: 29.1 months (95% CI 25.4-NA) for afatinib; 27.1 months (95% CI 17.1- NA) for erlotinib; and 23.7 months (95% CI 18.6-NA) for gefitinib. There was a statistically significant difference between the mean TKIs costs; being afatinib the most expensive treatment. This difference was observed in the daily cost of treatment (p < 0.01), as well as the total cost of treatment (p = 0.00095). Cost-effectiveness analysis determined that afatinib was a better cost-effective option when compared with first-generation TKIs (erlotinib and gefitinib). CONCLUSION: In our population, erlotinib, afatinib, and gefitinib were statistically equally effective in terms of OS and PFS for the treatment of patients with advanced EGFR-mutated NSCLC population. Owing to its marginally increased PFS and OS, the cost-effectiveness analysis determined that afatinib was a slightly better cost-effective option when compared with first-generation TKIs (erlotinib and gefitinib).

Prognostic value of ATN Alzheimer biomarkers: 60-month follow-up results from the Argentine Alzheimer's Disease Neuroimaging Initiative.

PURPOSE: To describe results of the Amyloid, Tau, Neurodegeneration (ATN) research framework classification in the Argentine-Alzheimer's Disease Neuroimaging Initiative (arg-ADNI) cohort. METHODS: Twenty-three patients with mild cognitive impairment (MCI), 12 dementia of Alzheimer's type (DAT), and 14 normal controls were studied following the ADNI2 protocol. Patients were categorized according to presence or absence of the biomarkers for amyloid beta (Aß; A: amyloid positron emission tomography [PET] scan or cerebrospinal fluid [CSF] Aß42), tau (T: CSF phosphorylated-tau), and neurodegeneration (N: CSF total-tau, fluorodeoxyglucose [FDG]-PET scan, or structural magnetic resonance imaging [MRI] scan). RESULTS: A+T+N+ biomarker profile was identified at baseline in 91% of mild dementia patients, 20% of early MCI patients, 46% of late MCI patients, and 14% of control subjects. Suspected non-AD pathophysiology (SNAP, A-T-N+) was found in 8% of mild dementia, 20% of early MCI, 15% of late MCI, and 7% of control subjects. Conversion rates to dementia after 5-year follow-up were 85% in A+T+N+ MCI patients and 50% in A-T-N+ patients. CONCLUSIONS: We present initial 5-year follow-up results of a regional ADNI based on AD biomarkers and the ATN classification.

A novel mutation in PSEN1 (p.T119I) in an Argentine family with early- and late-onset Alzheimer's disease.

Mutations in PSEN1 are the most common cause of early-onset Alzheimer's disease (AD). In this article, we present an Argentine family with autosomal dominant early- and late-onset AD. The proband and 6 family members were available for genetic testing and clinical and neuropsychological assessments. Cerebrospinal fluid biomarkers were analyzed in the proband and a cousin (mutation carrier), who also underwent positron emission tomography using F-18-2-fluoro-2-deoxy-D-glucose and Pittsburgh compound B. Exon sequencing of PSEN1, PSEN2, and APP revealed a novel heterozygous variant in PSEN1 (c.356C>T; p.T119I). Median age of onset in the family was 56 years. However, the proband's uncle showed initial symptoms at age 71. Although no DNA was available, he was an obligate carrier because his daughter (proband's cousin) carried the mutation. Both the proband and his cousin exhibited biomarker evidence (cerebrospinal fluid or imaging) of underlying Alzheimer's pathology. Overall, our results support that the PSEN1 p.T119I variant is likely pathogenic.

Biomarkers for Alzheimer's disease. Where we stand and where we are headed.

Alzheimer disease (AD) is one of the major unresolved health burdens accompanying the increase in life expectancy. The great paradigm shift for this disease has resulted from finding amyloid deposition and neurobrillary degeneration 20 years and 10 years, respectively, prior to onset of the typical clinical memory loss symptoms. The advent of AD biomarkers has enabled a molecular definition of AD, making the clinical definition almost dispensable. Various types of AD biomarkers are available in our country. Each biomarker reflects a particular process and stage of the disease. Although costs restrict their use, the biomarker analysis may be justified in certain clinical scenarios, such as an early onset or an atypical presentation of the disease. Today, the usefulness of biomarkers in AD clinical research is beyond question. Furthermore, the introduction of biomarkers into medical practice has led to significant changes in therapeutic interventions, even in the absence of disease-modifying drugs.

La enfermedad de Alzheimer (EA) es uno de los mayores flagelos aún no resueltos que acompañan al aumento de la expectativa de vida. El gran cambio de paradigma en los últimos años fue consecuencia de descubrir que el depósito amiloideo se presenta hasta 20 años antes, y la degeneración neurofibrilar hasta 10 años antes, de que aparezca la sintomatología clínica típica de pérdida de memoria. La aparición de los biomarcadores permitió reestructurar el concepto de la EA, intentándose llegar a una definición molecular de la misma casi prescindiendo de la emblemática clínica. Existen distintos tipos de biomarcadores de EA disponibles en nuestro país. Cada uno nos habla de un proceso y un momento distinto de la enfermedad. Aunque su uso clínico aún se encuentra restringido por cuestiones de costos, existen escenarios particulares en donde sí se justifica, casi siempre en relación a presentaciones clínicas atípicas o de comienzo muy temprano. Sin embargo, hoy en día ya nadie discute que son imprescindibles en investigaciones clínicas sobre EA. La incorporación de biomarcadores en la práctica médica ha generado cambios significativos en la intervención terapéutica de los pacientes, incluso en un contexto en el que todavía no hay medicamentos modificadores de la enfermedad.

The lateral neocortex is critical for contextual fear memory reconsolidation.

Memories are a product of the concerted activity of many brain areas. Deregulation of consolidation and reprocessing of mnemonic traces that encode fearful experiences might result in fear-related psychopathologies. Here, we assessed how pre-established memories change with experience, particularly the labilization/reconsolidation of memory, using the whole-brain analysis technique of positron emission tomography in male mice. We found differences in glucose consumption in the lateral neocortex, hippocampus and amygdala in mice that underwent labilization/reconsolidation processes compared to animals that did not reactivate a fear memory. We used chemogenetics to obtain insight into the role of cortical areas in these phases of memory and found that the lateral neocortex is necessary for fear memory reconsolidation. Inhibition of lateral neocortex during reconsolidation altered glucose consumption levels in the amygdala. Using an optogenetic/neuronal recording-based strategy we observed that the lateral neocortex is functionally connected with the amygdala, which, along with retrograde labeling using fluorophore-conjugated cholera toxin subunit B, support a monosynaptic connection between these areas and poses this connection as a hot-spot in the circuits involved in reactivation of fear memories.

Quantification methods comparison in brain 18F-FDOPA PET.

18F-FDOPA PET is one of the most widely used molecular imaging techniques to assess presynaptic dopaminergic activity. A variety of analytical methods have been developed to quantify 18F-FDOPA PET images and in most, the striatal-to-occipital ratio (SOR) is used as a quantitative parameter. A manual strategy is typically used for quantification purposes, which can have some caveats, being time-consuming and having some inter-rater variability. In the present study we aimed to test whether automated quantification methods can provide an efficient alternative to manual quantification to overcome its limitations and compare each method's capacity to discriminate between normal and abnormal subjects. 18F-FDOPA PET images of 60 subjects were analyzed and quantified with one manual and two automated methods. SUVRs were obtained for caudate and putamen nucleus in both cases. We were able to reach the same level of discrimination with manual and automated strategies, and a threshold for normal/abnormal discrimination could be obtained. We believe automated strategies for VOI quantification can help molecular imaging physicians in the process of interpretation of studies, making the process faster, yet reliable and objective.

Cortical thickness, brain metabolic activity, and in vivo amyloid deposition in asymptomatic, middle-aged offspring of patients with late-onset Alzheimer's disease.

The natural history of preclinical late-onset Alzheimer's disease (LOAD) remains obscure and has received less attention than that of early-onset AD (EOAD), in spite of accounting for more than 99% of cases of AD. With the purpose of detecting early structural and functional traits associated with the disorder, we sought to characterize cortical thickness and subcortical grey matter volume, cerebral metabolism, and amyloid deposition in persons at risk for LOAD in comparison with a similar group without family history of AD. We obtained 3T T1 images for gray matter volume, FDG-PET to evaluate regional cerebral metabolism, and PET-PiB to detect fibrillar amyloid deposition in 30 middle-aged, asymptomatic, cognitively normal individuals with one parent diagnosed with LOAD (O-LOAD), and 25 comparable controls (CS) without family history of neurodegenerative disorders (CS). We observed isocortical thinning in AD-relevant areas including posterior cingulate, precuneus, and areas of the prefrontal and temporoparietal cortex in O-LOAD. Unexpectedly, this group displayed increased cerebral metabolism, in some cases overlapping with the areas of cortical thinning, and no differences in bilateral hippocampal volume and hippocampal metabolism. Given the importance of age in this sample of individuals potentially developing early AD-related changes, we controlled results for age and observed that most differences in cortical thickness and metabolism became nonsignificant; however, greater deposition of ß-amyloid was observed in the right hemisphere including temporoparietal cortex, postcentral gyrus, fusiform inferior and middle temporal and lingual gyri. If replicated, the present observations of morphological, metabolic, and amyloid changes in cognitively normal persons with family history of LOAD may bear important implications for the definition of very early phenotypes of this disorder.

Argentina-Alzheimer's disease neuroimaging initiative (Arg-ADNI): neuropsychological evolution profile after one-year follow up.

The Argentina-Alzheimer's disease neuroimaging initiative (Arg-ADNI) study is a longitudinal prospective cohort of 50 participants at a single institution in Buenos Aires, Argentina. Longitudinal assessments on a neuropsychological test battery were performed on 15 controls, 24 mild cognitive impairment (MCI) patients and 12 Alzheimer's disease (AD) dementia patients. In our study population, there was a high prevalence of positive AD biomarkers in the AD group, 92.3% (12/13); and a low prevalence in the normal controls, 20%; almost half (48%) of the patients diagnosed with MCI had positive amyloid detection. After a one year, the significant differences found at baseline on neuropsychological testing were similar at the follow-up assessment even though the AD group had significantly altered its functional performance (FAQ and CDR). The exception was semantic fluency, which showed greater impairment between the AD group and MCI and normal controls respectively. For these tests, the addition of AD biomarkers as a variable did not significantly alter the variations previously found for the established clinical group's model. Finally, the one-year conversion rate to dementia was 20% in the MCI cohort.