Antero Abrunhosa

Nanoradioliposomes molecularly modulated to study the lung deep lymphatic drainage

Abstract Lung deep lymphatic drainage (LDLD) plays an important role in the removal of foreign materials from lungs being alveolar macrophages the first line of phagocytic defence with high affinity for pathogenic microorganisms. Bacillus subtilis is a well-known genome- decoded saprophyte of the human respiratory tract used in research and in the biotechnology industry. Lung deep lymphatic chains (LDLC) constitute one of the first sites of lung tumours’ dissemination. In this work we intended to develop and validate a non-invasive method for assessing LDLC by nanoradioliposomes aerosolised modulated on the Bacillus subtilis spore wall. The final goal was to produce a nanoradioliposome formulation that can mimics the dynamics of preferential removal of spores by LDLD and present the ideal properties as a tracer for molecular imaging studies. Seven different liposomal formulations were tested, and the formulation-F demonstrated physicochemical and radiopharmaceutical properties that make it an ideal candidate as an in vivo probe for molecular imaging studies of the LDLC. Nanoradioliposomes of the formulation-F after labelling with 99mTc-HMPAO were administered as aerosols to 20 Sus scrofa. Hilar and interpulmonary communications were visualized in first 5 minutes post-inhalation, infradiaphragmatic chains between 10 and 20 minutes, the ganglia of the aortic chain at 20 minutes and those of the renal hilar region at 30 minutes. Conclusion the proposed method enables visualization of deep lymphatic lung network and lymph nodes. Besides, this technique involving the modulation of nanoradioliposomes targeting specific organs or tissues may be an important tool for diagnostic or even for therapeutic purposes.

Testing the excitation/inhibition imbalance hypothesis in a mouse model of the autism spectrum disorder: in vivo neurospectroscopy and molecular evidence for regional phenotypes

BackgroundExcitation/inhibition (E/I) imbalance remains a widely discussed hypothesis in autism spectrum disorders (ASD). The presence of such an imbalance may potentially define a therapeutic target for the treatment of cognitive disabilities related to this pathology. Consequently, the study of monogenic disorders related to autism, such as neurofibromatosis type 1 (NF1), represents a promising approach to isolate mechanisms underlying ASD-related cognitive disabilities. However, the NF1 mouse model showed increased γ-aminobutyric acid (GABA) neurotransmission, whereas the human disease showed reduced cortical GABA levels. It is therefore important to clarify whether the E/I imbalance hypothesis holds true. We hypothesize that E/I may depend on distinct pre- and postsynaptic push-pull mechanisms that might be are region-dependent.MethodsIn current study, we assessed two critical components of E/I regulation: the concentration of neurotransmitters and levels of GABA(A) receptors. Measurements were performed across the hippocampi, striatum, and prefrontal cortices by combined in vivo magnetic resonance spectroscopy (MRS) and molecular approaches in this ASD-related animal model, the Nf1+/− mouse.ResultsCortical and striatal GABA/glutamate ratios were increased. At the postsynaptic level, very high receptor GABA(A) receptor expression was found in hippocampus, disproportionately to the small reduction in GABA levels. Gabaergic tone (either by receptor levels change or GABA/glutamate ratios) seemed therefore to be enhanced in all regions, although by a different mechanism.ConclusionsOur data provides support for the hypothesis of E/I imbalance in NF1 while showing that pre- and postsynaptic changes are region-specific. All these findings are consistent with our previous physiological evidence of increased inhibitory tone. Such heterogeneity suggests that therapeutic approaches to address neurochemical imbalance in ASD may need to focus on targets where convergent physiological mechanisms can be found.

Nanorradiolipossomas modulados molecularmente para estudar a drenagem linfática pulmonar profunda

Resumo A drenagem linfatica pulmonar profunda (DLPP) desempenha um papel importante na remocao de materiais estranhos, constituindo os macrofagos alveolares a primeira linha de defesa fagocitaria, dada a grande afinidade para microrganismos patogenicos. Os Bacillus subtilis sao saprofitas do tracto respiratorio humano com ampla utilizacao em investigacao e em biotecnologia. As cadeias linfaticas pulmonares profundas (CLPP) constituem um dos primeiros locais de disseminacao de tumores pulmonares. Neste trabalho pretendeu-se desenvolver e validar um metodo nao invasivo para avaliar as CLPP atraves de nanorradiolipossomas aerosolisados e modulados pela parede do esporo do Bacillus subtilis . O objectivo final foi produzir uma formulacao de nanorradiolipossomas capaz de imitar a dinâmica da remocao de esporos pelas CLPP e simultaneamente ter propriedades ideais como tracador para imagiologia molecular. Testamos sete diferentes formulacoes lipossomicas, tendo a formulacao F demonstrado possuir propriedades fisicoquimicas e radiofarmaceuticas que a tornam o tracador ideal para imagiologia molecular in vivo das CLPP. Os nanorradiolipossomas da formulacao F apos marcacao com 99m Tc-HMPAO foram administrados sob a forma de aerossois a 20 Sus scrofa . Visualizaram-se comunicacoes hilares e interpulmonares nos primeiros 5 minutos apos a inalacao, as cadeias infradiafragmaticas entre os 10 e os 20 minutos, os gânglios da cadeia aortica aos 20 minutos e os da regiao hilar renal aos 30 minutos. Em conclusao, o metodo proposto visualiza os gânglios linfaticos e a rede linfatica pulmonar profunda. A modulacao dos nanorradiolipossomas permite que eles atinjam orgaos ou tecidos especificos, conferindo-lhes importantes potencialidades no âmbito do diagnostico e/ou da terapeutica. Rev Port Pneumol 2009; XV (2): 261-293

Data driven diagnostic classification in Alzheimer's disease based on different reference regions for normalization of PiB-PET images and correlation with CSF concentrations of Aβ species

Positron emission tomography (PET) neuroimaging with the Pittsburgh Compound_B (PiB) is widely used to assess amyloid plaque burden. Standard quantification approaches normalize PiB-PET by mean cerebellar gray matter uptake. Previous studies suggested similar pons and white-matter uptake in Alzheimers disease (AD) and healthy controls (HC), but lack exhaustive comparison of normalization across the three regions, with data-driven diagnostic classification. We aimed to compare the impact of distinct reference regions in normalization, measured by data-driven statistical analysis, and correlation with cerebrospinal fluid (CSF) amyloid β (Aβ) species concentrations. 243 individuals with clinical diagnosis of AD, HC, mild cognitive impairment (MCI) and other dementias, from the Biomarkers for Alzheimers/Parkinsons Disease (BIOMARKAPD) initiative were included. PiB-PET images and CSF concentrations of Aβ38, Aβ40 and Aβ42 were submitted to classification using support vector machines. Voxel-wise group differences and correlations between normalized PiB-PET images and CSF Aβ concentrations were calculated. Normalization by cerebellar gray matter and pons yielded identical classification accuracy of AD (accuracy-96%, sensitivity-96%, specificity-95%), and significantly higher than Aβ concentrations (best accuracy 91%). Normalization by the white-matter showed decreased extent of statistically significant multivoxel patterns and was the only method not outperforming CSF biomarkers, suggesting statistical inferiority. Aβ38 and Aβ40 correlated negatively with PiB-PET images normalized by the white-matter, corroborating previous observations of correlations with non-AD-specific subcortical changes in white-matter. In general, when using the pons as reference region, higher voxel-wise group differences and stronger correlation with Aβ42, the Aβ42/Aβ40 or Aβ42/Aβ38 ratios were found compared to normalization based on cerebellar gray matter.