Articulación agroecológica: estrategias para la reconversión a escala territorial

Entre los principales argumentos que pretenden descalificar una agricultura sustentable están sus bajos rendimientos y elevados costos. Además, se argumenta una limitada aplicabilidad (solo a escala de pequeñas fincas). Esta polémica se halla presente en la Cuba actual, urgida de soluciones a corto plazo para la alimentación de toda su población. Por ello, se necesita disponer de estrategias y modelos de desarrollo que respondan a los requerimientos actuales, asumiendo el reto de diseñar una agricultura sostenible sobre bases agroecológicas, productiva y eficiente, aplicable a diferentes condiciones y escalas productivas. Este fue reto del proyecto “Articulación agroecológica; diseño de alternativas sostenibles para la seguridad alimentaria local” promovido por la Asociación Cubana de Técnicos Agrícolas y Forestales (ACTAF) y la ONG Holandesa HIVOS. Esta acción se viene ejecutando desde hace 4 años (2011-2015) en 5 municipios cubanos, con apoyo financiero de la Unión Europea, de la Colaboración Suiza para el Desarrollo (COSUDE) y del Ministerio de la Agricultura de Cuba (MINAG). Se partió de la hipótesis de que el desarrollo agrario sostenible sobre bases agroecológicas tiene que diseñarse y conducirse localmente (escala municipal). Para ello, se planteó como objetivo, “contribuir al incremento y la sostenibilidad de la seguridad alimentaria cubana, facilitando la adopción de alternativas de articulación agroecológica en las estrategias de desarrollo agrario municipal”. Para el logro de este objetivo se planteó la necesidad de crear y fortalecer capacidades locales de desarrollo agrario, a partir de instituciones existentes y en coherencia con los programas oficiales de la agricultura local y los intereses y necesidades sentidas de los agricultores. Se trabajó desde un Equipo de Proyecto apoyado por un Equipo Técnico conformado por especialistas de diferentes entidades científicas y docentes nacionales. A nivel local se conformaron Equipos de Articulación Local (EAL) con integrantes designados por cada municipio. Estos EAL constituyeron el principal ente implementador del proyecto y se concibieron como el germen inicial de lo que debía ser el Equipo Municipal de Desarrollo Agrario de cada territorio. Alrededor de estos EAL se articularon las principales instituciones locales vinculadas a la agricultura y se seleccionó una cooperativa para demostrar la pertinencia de la reconversión agroecológica a escala superior a la pequeña finca. Se pudo comprobar que lograr el involucramiento de decisores importantes de la localidad es del todo imprescindible para un proceso de reconversión agroecológica a escala territorial, pues este debe ser visto como contribuyente al logro de los objetivos de las instituciones locales para la seguridad alimentaria de la población y minimizar la dependencia externa al territorio para el desarrollo de toda la cadena productiva. Disponer de servicios técnicos locales que puedan contribuir con insumos alternativos, asesoría y capacitación, aporta a la reconversión capacidad de contextualización de conocimientos y tradiciones campesinas y establece puentes con instituciones científicas especializadas para su complementación con los avances de la ciencia y la técnica.Eje: B2 Paisajes, territorios y agroecología (Relatos de experiencias)Facultad de Ciencias Agrarias y Forestale

Phase I clinical trial in healthy adults of a nasal vaccine candidate containing recombinant hepatitis B surface and core antigens

SummaryBackgroundThe nasal vaccine candidate (NASVAC), comprising hepatitis B virus (HBV) surface (HBsAg) and core antigens (HBcAg), has been shown to be highly immunogenic in animal models.MethodsA phase I double-blinded, placebo-controlled randomized clinical trial was carried out in 19 healthy male adults with no serologic markers of immunity/infection to HBV. This study was aimed at exploring the safety and immunogenic profile of nasal co-administration of both HBV recombinant antigens. The trial was performed according to Good Clinical Practice guidelines. Participants ranged in age from 18 to 45 years and were randomly allocated to receive a mixture of 50μg HBsAg and 50μg HBcAg or 0.9% physiologic saline solution, as a placebo, via nasal spray in a five-dose schedule at 0, 7, 15, 30, and 60 days. A total volume of 0.5ml was administered in two dosages of 125μl per nostril. Adverse events were actively recorded 1h, 6h, 12h, 24h, 48h, 72h, 7 days and 30 days after each dose. Anti-HBs and anti-HBc titers were evaluated using corresponding ELISA kits at days 30 and 90.ResultsThe vaccine candidate was safe and well tolerated. Adverse reactions included sneezing (34.1%), rhinorrhea (12.2%), nasal stuffiness (9.8%), palate itching (9.8%), headache (9.8%), and general malaise (7.3%). These reactions were all self-limiting and mild in intensity. No severe or unexpected events were recorded during the trial. The vaccine elicited anti-HBc seroconversion in 100% of subjects as early as day 30 of the immunization schedule, while a seroprotective anti-HBs titer (≥10IU/l) was at a maximum at day 90 (75%). All subjects in the placebo group remained seronegative during the trial.ConclusionThe HBsAg–HBcAg vaccine candidate was safe, well tolerated and immunogenic in this phase I study in healthy adults. To our knowledge, this is the first demonstration of safety and immunogenicity for a nasal vaccine candidate comprising HBV antigens

Pre-Clinical Evaluation of a Novel Nanoemulsion-Based Hepatitis B Mucosal Vaccine

Hepatitis B virus infection remains an important global health concern despite the availability of safe and effective prophylactic vaccines. Limitations to these vaccines include requirement for refrigeration and three immunizations thereby restricting use in the developing world. A new nasal hepatitis B vaccine composed of recombinant hepatitis B surface antigen (HBsAg) in a novel nanoemulsion (NE) adjuvant (HBsAg-NE) could be effective with fewer administrations.Physical characterization indicated that HBsAg-NE consists of uniform lipid droplets (349+/-17 nm) associated with HBsAg through electrostatic and hydrophobic interactions. Immunogenicity of HBsAg-NE vaccine was evaluated in mice, rats and guinea pigs. Animals immunized intranasally developed robust and sustained systemic IgG, mucosal IgA and strong antigen-specific cellular immune responses. Serum IgG reached > or = 10(6) titers and was comparable to intramuscular vaccination with alum-adjuvanted vaccine (HBsAg-Alu). Normalization showed that HBsAg-NE vaccination correlates with a protective immunity equivalent or greater than 1000 IU/ml. Th1 polarized immune response was indicated by IFN-gamma and TNF-alpha cytokine production and elevated levels of IgG(2) subclass of HBsAg-specific antibodies. The vaccine retains full immunogenicity for a year at 4 degrees C, 6 months at 25 degrees C and 6 weeks at 40 degrees C. Comprehensive pre-clinical toxicology evaluation demonstrated that HBsAg-NE vaccine is safe and well tolerated in multiple animal models.Our results suggest that needle-free nasal immunization with HBsAg-NE could be a safe and effective hepatitis B vaccine, or provide an alternative booster administration for the parenteral hepatitis B vaccines. This vaccine induces a Th1 associated cellular immunity and also may provide therapeutic benefit to patients with chronic hepatitis B infection who lack cellular immune responses to adequately control viral replication. Long-term stability of this vaccine formulation at elevated temperatures suggests a direct advantage in the field, since potential excursions from cold chain maintenance could be tolerated without a loss in therapeutic efficacy

ABX203, инновационная терапевтическая вакцина для больных хроническим гепатитом В

Despite the existence of effective prophylactic vaccines, chronic hepatitis B remains a major public health problem, with more than 350 million people infected   worldwide.  Chronic  infection   increases the  risk of serious  liver diseases  such  as cirrhosis and  hepatocellular carcinoma.  Available therapies for chronic  hepatitis  B  have  limited  efficacy and require  long-term   continuous  treatments;  that  is why the  development of therapeutic vaccines has been  investigated as  promising  approach.  In this sense, a novel  vaccine  formulation  called ABX203 (HeberNasvac), based  on  the  combination of the hepatitis B virus nucleocapsid and surface antigens, was developed. ABX203 has been studied in phase I, phase II and phase III clinical trial in treatment-naïve chronically infected  patients  in Bangladesh  and  in healthy  volunteers  in Cuba with promising  results. In the present work we reviewed the main preclinical and   clinical  results  of  ABX203 development. Altogether, the data demonstrates safety and immunogenicity of ABX203 vaccine and support  its use as a novel and competitive treatment alternative for chronic hepatitis B. The vaccine has been granted marketing authorization in Cuba.Несмотря на существование эффективной вакцинопрофилактики, хронический гепатит В, которым  во  всем  мире  инфицировано  более 350 млн человек, остается одной из основных проблем здравоохранения. Хроническая инфекция увеличивает  риск серьезной печеночной  патологии  – цирроза  и гепатоцеллюлярного рака. Существующие методы лечения хронического  гепатита В недостаточно  эффективны и требуют длительной непрерывной терапии. Вот почему в качестве перспективного подхода изучается возможность разработки терапевтических  вакцин. В этих целях был создан инновационный вакцинальный препарат ABX203 (Назвак),  в состав которого входят сердцевинный (HBcAg) и поверхностный (HBsAg) антигены вируса  гепатита В.  Терапевтическая двухкомпонентная вакцина ABX203, зарегистрированная на  Кубе,  изучалась  в  клинических исследованиях  I,  II  и III  фазы у ранее  не леченных хронически  инфицированных  пациентов в Бангладеш и у здоровых добровольцев на Кубе и показала многообещающие результаты. Эта статья представляет собой обзор основных результатов доклинических и клинических исследований  вакцины ABX203. На основании анализа  представленных  данных можно говорить о безопасности  и иммуногенности вакцины ABX203, что позволяет применять ее как инновационный и конкурентоспособный вариант лечения хронического гепатита В

ABX203, a novel therapeutic vaccine for chronic hepatitis B patients

Despite the existence of effective prophylactic vaccines, chronic hepatitis B remains a major public health problem, with more than 350 million people infected   worldwide.  Chronic  infection   increases the  risk of serious  liver diseases  such  as cirrhosis and  hepatocellular carcinoma.  Available therapies for chronic  hepatitis  B  have  limited  efficacy and require  long-term   continuous  treatments;  that  is why the  development of therapeutic vaccines has been  investigated as  promising  approach.  In this sense, a novel  vaccine  formulation  called ABX203 (HeberNasvac), based  on  the  combination of the hepatitis B virus nucleocapsid and surface antigens, was developed. ABX203 has been studied in phase I, phase II and phase III clinical trial in treatment-naïve chronically infected  patients  in Bangladesh  and  in healthy  volunteers  in Cuba with promising  results. In the present work we reviewed the main preclinical and   clinical  results  of  ABX203 development. Altogether, the data demonstrates safety and immunogenicity of ABX203 vaccine and support  its use as a novel and competitive treatment alternative for chronic hepatitis B. The vaccine has been granted marketing authorization in Cuba

Development of a nasal vaccine for chronic hepatitis B infection that uses the ability of hepatitis B core antigen to stimulate a strong Th1 response against hepatitis B surface antigen

There are estimated to be 350 million chronic carriers of hepatitis B infection worldwide. Patients with chronic hepatitis B are at risk of liver cirrhosis with associated mortality because of hepatocellular carcinoma and other complications. An important goal, therefore, is the development of an effective therapeutic vaccine against chronic hepatitis B virus (HBV). A major barrier to the development of such a vaccine is the impaired immune response to HBV antigens observed in the T cells of affected patients. One strategy to overcome these barriers is to activate mucosal T cells through the use of nasal vaccination because this may overcome the systemic immune downregulation that results from HBV infection. In addition, it may be beneficial to present additional HBV epitopes beyond those contained in the traditional hepatitis B surface antigen (HbsAg) vaccine, for example, by using the hepatitis B core antigen (HBcAg). This is advantageous because HBcAg has a unique ability to act as a potent Th1 adjuvant to HbsAg, while also serving as an immunogenic target. In this study we describe the effect of coadministration of HBsAg and HBcAg as part of a strategy to develop a more potent and effective HBV therapeutic vaccine