Memory support training and lifestyle modifications to promote healthy aging in persons at risk for Alzheimer's disease: a digital application supported intervention (Brain Boosters)

BACKGROUND

Evidence-based interventions to protect against cognitive decline among older adults at risk for Alzheimer's disease and related dementias (ADRD) are urgently needed. Rehabilitation approaches to support memory and behavioral/lifestyle interventions are recognized as promising strategies for preserving or improving cognitive health, although few previous interventions have combined both approaches. This paper describes the protocol of the Brain Boosters intervention, which synergistically combines training in compensatory and healthy lifestyle behaviors and supports implementation and tracking of new behaviors with a digital application.

METHODS

The study utilizes a single-site, single-blinded, randomized controlled design to compare a structured lifestyle and compensatory aid intervention to an education-only self-guided intervention. We plan to enroll 225 community-dwelling adults (25% from underrepresented groups) aged 65 + who endorse subjective cognitive decline (SCD) and low baseline levels of healthy lifestyle behaviors. Both interventions will be administered in group format, consisting of 15 two-hour classes that occur weekly for ten weeks and taper to bi-monthly and monthly, for an intervention duration of 6 months. Participants in both interventions will receive education about a variety of memory support strategies and healthy lifestyle behaviors, focusing on physical and cognitive activity and stress management. The structured intervention will also receive support in adopting new behaviors and tracking set goals aided by the Electronic Memory and Management Aid (EMMA) digital application. Primary outcomes include global cognition (composite of memory, attention, and executive function tests) and everyday function (Everyday Cognition Questionnaire). Data will be collected at baseline and outcome visits, at approximately 6, 12, and 18 months. Qualitative interviews, self-report surveys (e.g., indicators of self-determination, health literacy) and EMMA data metrics will also be used to identify what components of the intervention are most effective and for whom they work.

DISCUSSION

Successful project completion will provide valuable information about how individuals with SCD respond to a compensation and preventative lifestyle intervention assisted by a digital application, including an understanding of factors that may impact outcomes, treatment uptake, and adherence. The work will also inform development, scaling, and personalization of future interventions that can delay disability in individuals at risk for ADRD.

TRIAL REGISTRATION

ClinicalTrials.gov. (NCT05027789, posted 8/30/2021).

The impact of COVID-19 on organ donation and transplantation in the UK: lessons learned from the first year of the pandemic

The COVID-19 pandemic had a major impact on UK deceased organ donation and transplantation activity. We used national audit data from NHS Blood and Transplant to explore in detail the effects of the pandemic in comparison with 12 months pre-pandemic, and to consider the impact of the mitigating strategies and challenges placed on ICU by 'waves' of patients with COVID-19. Between 11 March 2020 and 10 March 2021, referrals to NHS Blood and Transplant of potential organ donors were initially inversely related to the number of people with COVID-19 undergoing mechanical ventilation in intensive care (incident rate ratio (95%CI) per 1000 patients 0.93 (0.88-0.99), p = 0.018), although this pattern reversed during the second wave (additional incident rate ratio (95%CI) 1.12 (1.05-1.19), p < 0.001). Adjusted numbers of donors (incident rate ratio (95%CI) 0.71 (0.61-0.81), p < 0.001) and organs retrieved (incident rate ratio (95%CI) 0.89 (0.82-0.97), p = 0.007) were inversely dependent on COVID-19 workload, though weekly numbers of transplants were unrelated (incident rate ratio (95%CI) 0.95 (0.86-1.04), p = 0.235). Non-COVID-19 mortality fell from 15,007 to 14,087 during the first wave (rate ratio (95%CI) 0.94 (0.92-0.96), p < 0.001) but climbed from 18,907 to 19,372 during the second wave (rate ratio (95%CI) 1.02 (1.00-1.05), p = 0.018). There were fewer in-hospital deaths from cardiac arrest and intracranial catastrophes throughout (rate ratio (95%CI) 0.83 (0.81-0.86), p < 0.001 and rate ratio (95%CI) 0.88 (0.85-0.91), p < 0.001, respectively). There were overall fewer eligible donors (n = 4282) when compared with pre-pandemic levels (n = 6038); OR (95%CI) 0.58 (0.51-0.66), p < 0.001. The total number of donations during the year fell from 1620 to 1140 (rate ratio (95%CI) 0.70 (0.65-0.76), p < 0.001), but the proportion of eligible donors who proceeded to donation (27%) was unchanged (OR (95%CI) 0.99 (0.91-1.08), p = 0.821). The reduction in donations and transplantation during the pandemic was multifactorial, but these data highlight the impact in the UK of a fall in eligible donors and an inverse relationship of referrals to COVID-19 workload. Despite the challenges faced, the foundations underpinning the UK deceased organ donation programme remained strong.

Collision cross sections of high-mannose N-glycans in commonly observed adduct states--identification of gas-phase conformers unique to [M-H](-) ions

We report collision cross sections (CCS) of high-mannose N-glycans as [M + Na](+), [M + K](+), [M + H](+), [M + Cl](-), [M + H2PO4](-) and [M - H](-) ions, measured by drift tube (DT) ion mobility-mass spectrometry (IM-MS) in helium and nitrogen gases. Further analysis using traveling wave (TW) IM-MS reveal the existence of distinct conformers exclusive to [M - H](-) ions.

Strain-specific antiviral activity of iminosugars against human influenza A viruses

Objectives

Drugs that target host cell processes can be employed to complement drugs that specifically target viruses, and iminosugar compounds that inhibit host α-glucosidases have been reported to show antiviral activity against multiple viruses. Here the effect and mechanism of two iminosugar α-glucosidase inhibitors, N-butyl-deoxynojirimycin (NB-DNJ) and N-nonyl-deoxynojirimycin (NN-DNJ), on human influenza A viruses was examined.

Methods

The viruses examined were a recently circulating seasonal influenza A(H3N2) virus strain A/Brisbane/10/2007, an older H3N2 strain A/Udorn/307/72, and A/Lviv/N6/2009, a strain representative of the currently circulating pandemic influenza A(H1N1)pdm09 virus.

Results

The inhibitors had the strongest effect on Brisbane/10 and NN-DNJ was more potent than NB-DNJ. Both compounds showed antiviral activity in cell culture against three human influenza A viruses in a strain-specific manner. Consistent with its action as an α-glucosidase inhibitor, NN-DNJ treatment resulted in an altered glycan processing of influenza haemagglutinin (HA) and neuraminidase (NA), confirmed by MS. NN-DNJ treatment was found to reduce the cell surface expression of the H3 subtype HA. The level of sialidase activity of NA was reduced in infected cells, but the addition of exogenous sialidase to the cells did not complement the NN-DNJ-mediated inhibition of virus replication. Using reassortant viruses, the drug susceptibility profile was determined to correlate with the origin of the HA.

Conclusions

NN-DNJ inhibits influenza A virus replication in a strain-specific manner that is dependent on the HA.

Alzheimer's Disease Neuroimaging Initiative (ADNI): clinical characterization

BACKGROUND

Neuroimaging measures and chemical biomarkers may be important indices of clinical progression in normal aging and mild cognitive impairment (MCI) and need to be evaluated longitudinally.

OBJECTIVE

To characterize cross-sectionally and longitudinally clinical measures in normal controls, subjects with MCI, and subjects with mild Alzheimer disease (AD) to enable the assessment of the utility of neuroimaging and chemical biomarker measures.

METHODS

A total of 819 subjects (229 cognitively normal, 398 with MCI, and 192 with AD) were enrolled at baseline and followed for 12 months using standard cognitive and functional measures typical of clinical trials.

RESULTS

The subjects with MCI were more memory impaired than the cognitively normal subjects but not as impaired as the subjects with AD. Nonmemory cognitive measures were only minimally impaired in the subjects with MCI. The subjects with MCI progressed to dementia in 12 months at a rate of 16.5% per year. Approximately 50% of the subjects with MCI were on antidementia therapies. There was minimal movement on the Alzheimer's Disease Assessment Scale-Cognitive Subscale for the normal control subjects, slight movement for the subjects with MCI of 1.1, and a modest change for the subjects with AD of 4.3. Baseline CSF measures of Abeta-42 separated the 3 groups as expected and successfully predicted the 12-month change in cognitive measures.

CONCLUSION

The Alzheimer's Disease Neuroimaging Initiative has successfully recruited cohorts of cognitively normal subjects, subjects with mild cognitive impairment (MCI), and subjects with Alzheimer disease with anticipated baseline characteristics. The 12-month progression rate of MCI was as predicted, and the CSF measures heralded progression of clinical measures over 12 months.

Plasma fatty acid profiles in autism: a case-control study

Increasing evidence is mounting in support of fatty acid metabolism playing a role in neurodevelopmental disorders such as autism. In order to definitely determine whether fatty acid concentrations were associated with autism, we quantitatively measured 30 fatty acids from seven lipid classes in plasma from a large subset of subjects enrolled in the Childhood Autism Risk from Genetics and the Environment (CHARGE) study. The CHARGE study is a large, population-based case-control study on children aged 2-5 born in California. Our subset consisted of 153 children with autism and 97 developmentally normal controls. Results showed that docosahexaenoic acid (DHA, 22:6n-3) was significantly decreased in phosphatidylethanolamine. Dimethyl acetals were significantly decreased in phosphatidylethanolamine and phosphatidylcholine as well. These results are consistent with the only other study to measure dimethyl acetals in children with autism, and suggest that the function of peroxisomes and the enzymes of the peroxisome involved with fatty acid metabolism may be affected in autism.

Altered glycosylation of proteins in cancer: what is the potential for new anti-tumour strategies

It is becoming increasingly apparent that cell surface oligosaccharides play pivotal roles as recognition molecules in a range of cell communication and adhesion processes. Alterations in cellular glycosylation are also associated with diseases, including cancer, and may have functional significance. This paper gives an overview of the complex topic of cellular glycosylation mechanisms and reviews the well-documented alterations in cellular glycosylation of proteins in malignancy. One particular type of cancer-associated glycosylation change, the incomplete synthesis of O-linked glycans, is highlighted, and its possible functional significance in cancer cell metastatic mechanisms is discussed. The significance that cancer-associated changes in glycoprotein glycosylation may have in new approaches to anti-tumour therapies is explored.

The goat mammary glandular epithelial (GMGE) cell line promotes polyfucosylation and N,N′-diacetyllactosediaminylation of N-glycans linked to recombinant human erythropoietin

We have established a continuous, non-transformed cell line from primary cultures from Capra hircus mammary gland. Low-density cultures showed a homogeneous epithelial morphology without detectable fibroblastic or myoepithelial cells. The culture was responsive to contact inhibition of proliferation and its doubling time was dependent on the presence of insulin and epidermal growth factor (EGF). GMGE cells secrete caseins regardless of the presence or absence of lactogenic hormones in the culture media. Investigation of the total N-glycan pool of human erythropoietin (rhEPO) expressed in GMGE cells by monosaccharide analysis, HPLC profiling, and mass spectrometry, indicated significant differences with respect to the same protein expressed in Chinese hamster ovary (CHO) cells. N-Glycans of rhEPO-GMGE are core-fucosylated, but fucosylation of outer arms was also found. Our results also revealed the presence of low levels of sialylation (>95% Neu5Ac), N,N'-diacetyllactosediamine units, and possibly Gal-Gal non-reducing terminal elements.

Epitope recognition of antibodies that define the sialomucin, endolyn (CD164), a negative regulator of haematopoiesis

Endolyn (CD164) is a sialomucin that functions as an adhesion molecule and a negative regulator of CD34+ CD38- human haematopoietic precursor cell proliferation. The 105A5 and 103B2/9E10 CD164 monoclonal antibodies (mAbs), which act as surrogate ligands, recognize distinct glycosylation-dependent classes I and II epitopes located on domain I of the native and recombinant CD164 proteins. Here, we document five new CD164 mAbs, the 96 series, that rely on conformational integrity, but not glycosylation, of exons 2- and 3-encoded CD164 domains, thereby resembling the class III mAbs, N6B6 and 67D2. Although all the 96 series class III mAbs labelled both the 105A5+ and 103B2/9E10+ cells, cross-competition and immunoblotting studies allow them to be categorized into two distinct class III subgroups, i.e. the N6B6-like subgroup that only recognizes 80-100 kDa proteins and the 67D2-like subgroup that also recognizes a higher molecular weight (>220 kDa) form. To more closely define the reactivity patterns of mAbs to the classes I and II epitopes, the global glycosylation patterns of the soluble human (h) CD164 proteins were determined using lectin binding, high-performance liquid chromatography (HPLC) and mass spectrometry. hCD164 recombinant proteins bound to the lectins, Galanthus nivalis agglutinin, Datura stramonium agglutinin, Sambucus nigra agglutinin, Maackia amurensis agglutinin and peanut agglutinin, indicating the presence of high mannose and complex N-glycans, in addition to core 1 O-glycans (the Tn antigen) and alpha2-3 and alpha2-6 sialic acid moieties. Our HPLC and mass spectrometry results revealed both high mannose and complex N-glycosylation with various numbers of branches increasing the complexity of the glycosylation pattern. Most O-glycans were small, core 1 or 2 based. High levels of sialylation in alpha2-3 and alpha2-6 linkages, without sialyl-Lewis X, indicate that the majority of these hCD164 recombinant proteins are unable to bind to selectins in our assay system, but may interact with Siglec molecules.

White matter lesions impair frontal lobe function regardless of their location

OBJECTIVE

To analyze the effect of white matter lesions in different brain regions on regional cortical glucose metabolism, regional cortical atrophy, and cognitive function in a sample with a broad range of cerebrovascular disease and cognitive function.

METHODS

Subjects (n = 78) were recruited for a study of subcortical ischemic vascular disease (SIVD) and Alzheimer disease (AD) contributions to dementia. A new method was developed to define volumes of interest from high-resolution three-dimensional T1-weighted MR images. Volumetric measures of MRI segmented white matter signal hyperintensities (WMH) in five different brain regions were related to regional PET glucose metabolism (rCMRglc) in cerebral cortex, MRI measures of regional cortical atrophy, and neuropsychological assessment of executive and memory function.

RESULTS

WMH was significantly higher in the prefrontal region compared to the other brain regions. In all subjects, higher frontal and parietal WMH were associated with reduced frontal rCMRglc, whereas occipitotemporal WMH was only marginally associated with frontal rCMRglc. These associations were stronger and more widely distributed in nondemented subjects where reduced frontal rCMRglc was correlated with WMH for all regions measured. In contrast, there was no relationship between WMH in any brain region and rCMRglc in either parietal or occipitotemporal regions. WMHs in all brain regions were associated with low executive scores in nondemented subjects.

CONCLUSIONS

The frontal lobes are most severely affected by SIVD. WMHs are more abundant in the frontal region. Regardless of where in the brain these WMHs are located, they are associated with frontal hypometabolism and executive dysfunction.

Complement regulation at the molecular level: the structure of decay-accelerating factor

The human complement regulator CD55 is a key molecule protecting self-cells from complement-mediated lysis. X-ray diffraction and analytical ultracentrifugation data reveal a rod-like arrangement of four short consensus repeat (SCR) domains in both the crystal and solution. The stalk linking the four SCR domains to the glycosylphosphatidylinositol anchor is extended by the addition of 11 highly charged O-glycans and positions the domains an estimated 177 A above the membrane. Mutation mapping and hydrophobic potential analysis suggest that the interaction with the convertase, and thus complement regulation, depends on the burial of a hydrophobic patch centered on the linker between SCR domains 2 and 3.

High-performance liquid chromatography analysis of ganglioside carbohydrates at the picomole level after ceramide glycanase digestion and fluorescent labeling with 2-aminobenzamide

The functional importance of glycolipids has emphasized the need for more sensitive methods of detection, characterization, and quantification than has often been possible using traditional thin-layer chromatographic techniques. We describe the use of ceramide glycanase and HPLC to identify and quantify gangliosides in which the carbohydrate is in Glcbeta1--> linkage with ceramide. Detection of released carbohydrate was by fluorescent labeling with 2-aminobenzamide at the reducing terminal prior to HPLC analysis. Under the conditions described, ceramide glycanase hydrolyzed all of the common gangliosides studied, offering a broad spectrum of specificity. Release and detection of carbohydrate were linear over a wide range (over two orders of magnitude) of micromolar glycolipid substrate concentrations. Use of an N-linked glycan as an internal standard allowed accurate quantification and a recovery of 93% was achieved. The method additionally maintained the sensitivity (chromatographic peaks containing 1 pmol were readily detected from tissue samples) and comparable resolution to related assays. This was shown by the separation, not only of isomeric carbohydrates from the "a" and "b" series, but also of ganglioside carbohydrate differing only by the presence of either N-acetyl- or N-glycolylneuraminic acid. Application of the method to neutral glycosphingolipids and to tissue samples, including 10-microl quantities of plasma, is illustrated. Glycan structures were confirmed by exoglycosidase digestion and/or matrix-assisted laser desorption/ionization mass spectrometry.

Ionization and fragmentation of neutral and acidic glycosphingolipids with a Q-TOF mass spectrometer fitted with a MALDI ion source

This paper reports the use of a quadrupole time-of-flight (Q-TOF) mass spectrometer fitted with a matrix-assisted laser desorption/ionization (MALDI) ion source for the analysis of neutral and acidic glycosphingolipids. All compounds gave strong [M + Na]+ ions with 2,5-dihydroxybenzoic acid as the matrix, with no loss of sensitivity with increasing mass as was observed from the corresponding ions produced by electrospray. Neutral glycosphingolipids showed negligible in-source fragmentation but sialylated compounds fragmented by loss of sialic acid. However, these losses were not accompanied by unfocused post-source-decay ions as observed with MALDI-reflectron-TOF instruments. The MS/MS spectra were almost identical to those obtained by electrospray. Fragmentation of all compounds was mainly by glycosidic cleavage to give ions, both with and without the ceramide moiety, which defined the carbohydrate chain sequence. Weak ions which defined the sphingosine chain length and abundant ions, produced by loss of the acyl chain, were present when this chain contained a 2-hydroxy group. The technique was applied to the identification of ceramide-trihexosides present in tissues from mice genetically modified to model one of the glycolipid storage diseases (Fabry disease).

Characterization of human apolipoprotein B100 oligosaccharides in LDL subfractions derived from normal and hyperlipidemic plasma: deficiency of alpha-N-acetylneuraminyllactosyl-ceramide in light and small dense LDL particles

The carbohydrate composition of apolipoprotein (apo) B100, particularly its degree of sialylation, may contribute to the atherogenic properties of low-density lipoprotein (LDL). We analyzed LDL apoB100 glycans derived from normolipidemic, hypercholesterolemic, and hypertriglyceridemic diabetic subjects. Using exoglycosidase carbohydrate sequencing and matrix-assisted laser desorption/ionization mass spectrometry to analyze fluorescently labeled oligosaccharides, we report evidence for several carbohydrates not previously identified on apoB100, including truncated complex biantennary N-glycans and hybrid N-glycans. The distribution and diversity of the apoB100 glycans isolated from all individuals was highly conserved. The N-glycan composition of apoB100 derived from five LDL subpopulations (LDL1, d = 1.018-1.023; LDL2, d = 1.023-1.030; LDL3, d = 1.030-1.040; LDL4, d = 1.040-1.051; LDL5, d = 1.051-1.065 g/ml) did not vary in normolipidemic or hypercholesterolemic subjects. Furthermore, we found no evidence for "desialylated" apoB100 glycans in any of the samples analyzed. Analysis of the most abundant LDL ganglioside, alpha-N-acetylneuraminyllactosyl-ceramide, revealed a deficiency in small dense LDL and in the most buoyant subpopulation. These data provide a novel explanation for the apparent deficiency of sialic acid in small dense LDL and indicate that the global apoB100 N-glycan composition is invariable in the patient groups studied.

Extension of the in-gel release method for structural analysis of neutral and sialylated N-linked glycans to the analysis of sulfated glycans: application to the glycans from bovine thyroid-stimulating hormone

This paper reports an extension of the in-gel technique for releasing N-linked glycans from glycoproteins for analysis by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry reported by B. Küster, S. F. Wheeler, A. P. Hunter, R. A. Dwek, and D. J. Harvey (1997, Anal. Biochem. 250, 82-101) to allow it to be used for sulfated glycans. The method was used to identify N-linked glycans from bovine thyroid-stimulating hormone. Following glycan release, either in gel or in solution, the glycans were fractionated directly with a porous graphatized carbon column. The sulfated glycans were examined by MALDI mass spectrometry in negative ion mode with d-arabinosazone as the matrix and both neutral and acidic glycans were examined in positive ion mode from 2,5-dihydroxybenzoic acid. Negative ion post-source decay spectra were also obtained. Twenty-two neutral and fifteen sulfated N-linked glycans were identified and it was shown that negligible loss of sulfate groups occurred even though these groups are often readily lost during MALDI analysis. The glycans were mainly sulfated hybrid and biantennary complex structures. Negative ion post-source decay and positive ion collision-induced fragmentation spectra were obtained.

Ionization and collision-induced fragmentation of N-linked and related carbohydrates using divalent cations

Maltoheptaose and several N-linked glycans were ionized by electrospray as adducts with the divalent cations Mg2+, Ca2+, Mn2+, Co2+ and Cu2+. [M + metal]2+ ions were the major species in all cases with calcium giving the highest sensitivity. In addition, copper gave [M + Cu]+ ions. Other cations gave singly charged ions only by elimination of a protonated monosaccharide. Fragmentation of the [M + metal]2+ ions produced both singly and doubly charged ions with the relative abundance of doubly charged ions decreasing in the order Ca > Mg > Mn > Co > Cu. Singly charged ions were formed by elimination of a protonated monosaccharide residue followed, either by successive monosaccharide residue losses, or by a 2,4A cross-ring cleavage of the reducing-terminal monosaccharide. Formation of doubly charged fragments from [M + metal]2+ ions involved successive monosaccharide-residue losses either with or without O,2A or 2,4A cross-ring cleavages of the reducing-terminal monosaccharide. Abundant diagnostic doubly charged ions formed by loss of the 3-antenna from the O,2A cross-ring product were specific to [M + Ca]2+ ions. Fragmentation of [M + Cu]+ ions was similar to that of the corresponding [M + H]+ ions in that most cross-ring fragments were absent.

A family of novel, acidic N-glycans in Bowes melanoma tissue plasminogen activator have L2/HNK-1-bearing antennae, many with sulfation of the fucosylated chitobiose core

A family of about 20 novel acidic bi- and tri-antennary N-glycans, amounting to almost half those expressed on Bowes melanoma tissue-plasminogen activator (t-PA) were found to possess Galbeta1-->4GlcNAcbeta1-->, sulfated and sialylated GalNAcbeta1-->4GlcNAcbeta1--> or sulfated GlcAbeta1--> 3Galbeta1-->4GlcNAcbeta1--> antennae, of which those containing sulfated GlcA, depicting the L2/HNK-1 carbohydrate epitope, were preferentially located on the 6 arm. A proportion of the glycans were highly charged, because of multiple and variously distributed sulfation, some of which was located on the fucosylated chitobiose core. Multiple expression of the L2/HNK-1 epitope on a single glycan was observed. The most abundant compound was a biantennary glycan carrying sulfated GlcA on the 6-branched antenna and an alpha2-->6 sialylated GalNAc on the other. The N-glycosylation sequon containing Asn448, which is known to express all of the sulfate-carrying N-glycans contains, unusually, an arginine residue. An electrostatic interaction between this cationic amino acid and the core-sulfate group of the N-glycan is proposed to reduce mobility of the carbohydrate in the region of the t-PA active site. Because of the 'brain-type' nature of the N-glycans described in this neuro-ectodermal cell line, the possibility of neural t-PA interacting with the L2/HNK-1-recognizing molecule, laminin, of the central nervous system extracellular matrix is discussed.