In Vivo Detection of Amyloid-β Deposits Using Heavy Chain Antibody Fragments in a Transgenic Mouse Model for Alzheimer's Disease

This study investigated the in vivo properties of two heavy chain antibody fragments (VHH), ni3A and pa2H, to differentially detect vascular or parenchymal amyloid-β deposits characteristic for Alzheimer's disease and cerebral amyloid angiopathy. Blood clearance and biodistribution including brain uptake were assessed by bolus injection of radiolabeled VHH in APP/PS1 mice or wildtype littermates. In addition, in vivo specificity for Aβ was examined in more detail with fluorescently labeled VHH by circumventing the blood-brain barrier via direct application or intracarotid co-injection with mannitol. All VHH showed rapid renal clearance (10–20 min). Twenty-four hours post-injection 99mTc-pa2H resulted in a small yet significant higher cerebral uptake in the APP/PS1 animals. No difference in brain uptake were observed for 99mTc-ni3A or DTPA(111In)-pa2H, which lacked additional peptide tags to investigate further clinical applicability. In vivo specificity for Aβ was confirmed for both fluorescently labeled VHH, where pa2H remained readily detectable for 24 hours or more after injection. Furthermore, both VHH showed affinity for parenchymal and vascular deposits, this in contrast to human tissue, where ni3A specifically targeted only vascular Aβ. Despite a brain uptake that is as yet too low for in vivo imaging, this study provides evidence that VHH detect Aβ deposits in vivo, with high selectivity and favorable in vivo characteristics, making them promising tools for further development as diagnostic agents for the distinctive detection of different Aβ deposits

Lipocalin 2 modulates the cellular response to amyloid beta

The production, accumulation and aggregation of amyloid beta (Aß) peptides in Alzheimer's disease (AD) are influenced by different modulators. Among these are iron and iron-related proteins, given their ability to modulate the expression of the amyloid precursor protein and to drive Aß aggregation. Herein, we describe that lipocalin 2 (LCN2), a mammalian acute-phase protein involved in iron homeostasis, is highly produced in response to Aß1-42 by choroid plexus epithelial cells and astrocytes, but not by microglia or neurons. Although Aß1-42 stimulation decreases the dehydrogenase activity and survival of wild-type astrocytes, astrocytes lacking the expression of Lcn2 are not affected. This protection results from a lower expression of the proapoptotic gene Bim and a decreased inflammatory response. Altogether, these findings show that Aß toxicity to astrocytes requires LCN2, which represents a novel mechanism to target when addressing AD.Cell Death and Differentiation advance online publication, 23 May 2014; doi:10.1038/cdd.2014.68.We thank Dr. Ioannis Sotiropoulos for reagents and comments. Sandro Da Mesquita and Ana Catarina Ferreira are recipients of PhD fellowships and Fernanda Marques is recipient of a postdoctoral fellowship by the Fundacao para a Ciencia e Tecnologia (FCT, Portugal)/FEDER. This work was supported by a grant from FCT/FEDER (EXPL/NEUOSD/2196/2013)

Relapsing-Remitting Multiple Sclerosis diagnosis from cerebrospinal fluids via Fourier transform infrared spectroscopy coupled with multivariate analysis

Abstract Multiple sclerosis (MS) is a chronic, progressive, inflammatory and degenerative disease of central nervous system. Here, we aimed to develop a method for differential diagnosis of Relapsing-Remitting MS (RRMS) and clinically isolated syndrome (CIS) patients, as well as to identify CIS patients who will progress to RRMS, from cerebrospinal fluid (CSF) by infrared (IR) spectroscopy and multivariate analysis. Spectral analyses demonstrated significant differences in the molecular contents, especially in the lipids and Z conformation of DNA of CSF from CIS, CIS to RRMS transformed (TCIS) and RRMS groups. These changes enables the discrimination of diseased groups and controls (individuals with no neurological disease) from each other using hierarchical cluster and principal component analysis. Some CIS samples were consistently clustered in RRMS class, which may indicate that these CIS patients potentially will transform to RRMS over time. Z-DNA band at 795 cm−1 that is existent only in diseased groups and significant increase in carbonyl amount, decrease in amideI/amide II and lipid/protein ratios observed only for RRMS groups can be used as diagnostic biomarkers. The results of the present study shed light on the early diagnosis of RRMS by IR spectroscopy complemented with multivariate analysis tools

Structural investigation of donor age effect on human bone marrow mesenchymal stem cells: FTIR spectroscopy and imaging

Stem cell studies hold enormous potential for development of new therapies for tissue regeneration and repair. Bone marrow mesenchymal stem cells (BM-MSCs) can differentiate into a variety of non-hematopoietic tissues and contribute maintenance of healthy hematopoiesis by providing supportive cellular microenvironment into BM. Here, we investigated age-related differences in BM-MSCs by using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and FTIR imaging together with hierarchical clustering as a novel methods to clarify global alterations in the structure and function of macromolecules in characterized BM-MSCs of different aged donors. The results may contribute to identification of age-related new molecular marker(s) to determine the effects of donor age on MSCs. The spectral results reflected that there were significant increases in the concentration of saturated lipids, proteins, glycogen, and nucleic acids in children and adolescent group BM-MSCs when compared to the infants and early and mid adults. The concentration of mentioned macromolecules in adult (early and mid) BM-MSCs were significantly lower than the concentrations in the children and adolescents. These results were attributed to the increase in the proliferation activity in younger BM-MSCs. The distribution of macromolecules into the cells was shown as in the form of chemical maps by FTIR imaging, and the results are in agreement with the ATR-FTIR spectroscopy results. The cellular activity degree was determined by the thiazolyl blue tetrazolium bromide (MTT) proliferation assay to support ATR-FTIR spectroscopy results. BM-MSCs of five different age groups were discriminated by making the hierarchical cluster analysis where the spectral data according to alterations in structure and composition of macromolecules were considered