Recognition of cognitive dysfunction in hospitalised older patients: a flash mob study.

BACKGROUND: It is important that healthcare professionals recognise cognitive dysfunction in hospitalised older patients in order to address associated care needs, such as enhanced involvement of relatives and extra cognitive and functional support. However, studies analysing medical records suggest that healthcare professionals have low awareness of cognitive dysfunction in hospitalised older patients. In this study, we investigated the prevalence of cognitive dysfunction in hospitalised older patients, the percentage of patients in which cognitive dysfunction was recognised by healthcare professionals, and which variables were associated with recognition. METHODS: A multicentre, nationwide, cross-sectional observational study was conducted on a single day using a flash mob study design in thirteen university and general hospitals in the Netherlands. Cognitive function was assessed in hospitalised patients aged ≥ 65 years old, who were admitted to medical and surgical wards. A Mini-Cog score of < 3 out of 5 indicated cognitive dysfunction. The attending nurses and physicians were asked whether they suspected cognitive dysfunction in their patient. Variables associated with recognition of cognitive dysfunction were assessed using multilevel and multivariable logistic regression analyses. RESULTS: 347 of 757 enrolled patients (46%) showed cognitive dysfunction. Cognitive dysfunction was recognised by attending nurses in 137 of 323 patients (42%) and by physicians in 156 patients (48%). In 135 patients (42%), cognitive dysfunction was not recognised by either the attending nurse or physician. Recognition of cognitive dysfunction was better at a lower Mini-Cog score, with the best recognition in patients with the lowest scores. Patients with a Mini-Cog score < 3 were best recognised in the geriatric department (69% by nurses and 72% by physicians). CONCLUSION: Cognitive dysfunction is common in hospitalised older patients and is poorly recognised by healthcare professionals. This study highlights the need to improve recognition of cognitive dysfunction in hospitalised older patients, particularly in individuals with less apparent cognitive dysfunction. The high proportion of older patients with cognitive dysfunction suggests that it may be beneficial to provide care tailored to cognitive dysfunction for all hospitalised older patients.

Aging Effect, Reproducibility, and Test-Retest Reliability of a New Cerebral Amyloid Angiopathy MRI Severity Marker-Cerebrovascular Reactivity to Visual Stimulation.

BACKGROUND: Decreased cerebrovascular reactivity, measured as changes in blood-oxygen-level-dependent (BOLD) signal, is a potential new cerebral amyloid angiopathy (CAA) severity marker. Before clinical application, the effect of aging on BOLD parameters, and reproducibility and test-retest reliability of these parameters should be assessed. PURPOSE: Assess the effect of healthy aging on cerebrovascular reactivity (BOLD amplitude, time to peak, and time to baseline). And determine reproducibility and test-retest reliability of these parameters. STUDY TYPE: Prospective-observational. POPULATION: Eighty-six healthy adults (mean age 56 years, 55% female), 10 presymptomatic D-CAA mutation carriers (mean age 34 years, 70% female), and 10 symptomatic D-CAA mutation carriers (mean age 54 years, 70% female). FIELD STRENGTH/SEQUENCE: 3-T, three-dimensional (3D) T1-weighted MRI and gradient echo BOLD fMRI. ASSESSMENT: To assess test-retest reliability of BOLD parameters, i.e. BOLD amplitude, time to peak, and time to baseline, BOLD fMRI scans were repeated three times immediately after each other, in both controls and mutation carriers. To assess reproducibility, BOLD fMRI scans were repeated with a 3-week interval for each subject. STATISTICAL TESTS: Linear regression analyses and two-way mixed absolute agreement intra-class correlation approach. RESULTS: Healthy aging was associated with decreased BOLD amplitude (ß = -0.711) and prolonged time to baseline (ß = 0.236) in the visual cortex after visual stimulation Reproducibility of BOLD amplitude was excellent (ICC 0.940) in the subgroup of healthy adults. Test-retest reliability for BOLD amplitude was excellent in healthy adults (ICC 0.856-0.910) and presymptomatic D-CAA mutation carriers (ICC 0.959-0.981). In symptomatic D-CAA mutation carriers, test-retest reliability was poor for all parameters (ICCs < 0.5). DATA CONCLUSION: Healthy aging is associated with decreased cerebrovascular reactivity, measured by changes in BOLD response to visual stimulation. The BOLD amplitude appears to be a robust measurement in healthy adults and presymptomatic D-CAA mutation carriers, but not in symptomatic D-CAA mutation carriers.

Longitudinal Progression of Magnetic Resonance Imaging Markers and Cognition in Dutch-Type Hereditary Cerebral Amyloid Angiopathy.

BACKGROUND: Hemorrhagic and ischemic magnetic resonance imaging lesions as well as the more recently described decrease in vasomotor reactivity have been suggested as possible biomarkers for cerebral amyloid angiopathy (CAA). Analyses of these markers have been primarily cross-sectional during the symptomatic phase of the disease, with little data on their longitudinal progression, particularly in the presymptomatic phase of the disease when it may be most responsive to treatment. We used the unique opportunity provided by studying Dutch-type hereditary cerebral amyloid angiopathy (D-CAA) to determine longitudinal progression of CAA biomarkers during the presymptomatic as well as the symptomatic phase of the disease. METHODS: In this longitudinal case-control study, magnetic resonance imaging markers and cognitive performance were assessed at baseline and after ≈4 years in 10 presymptomatic and 6 symptomatic D-CAA mutation carriers and 20 control subjects. These magnetic resonance imaging markers included hemorrhagic and ischemic manifestations, measurements of cerebral blood flow, and vasomotor reactivity to visual stimulation. RESULTS: In presymptomatic D-CAA mutations carriers, vasomotor reactivity showed a decline over time for blood-oxygen-level-dependent amplitude (P=0.011) and prolongation of time to peak (P<0.001). In contrast, no significant changes in hemorrhagic markers, ischemic markers, cerebral blood flow, and cognition were found. In symptomatic D-CAA mutation carriers, the number of intracerebral hemorrhages increased over the 4-year period (P=0.007). CONCLUSIONS: Our findings indicate that in the presymptomatic phase of D-CAA, cerebrovascular reactivity measured by the blood-oxygen-level-dependent amplitude and time to peak to visual stimulation progressively worsens and can thus be regarded as a disease progression marker. In the symptomatic phase, the most salient marker of progression appears to be recurrent intracerebral hemorrhage.

The association between hyperkyphosis and fall incidence among community-dwelling older adults.

Hyperkyphosis, an increased kyphosis angle of the thoracic spine, was associated with a higher fall incidence in the oldest quartile of a large prospective cohort of community-dwelling older adults. Hyperkyphosis could serve as an indicator of an increased fall risk as well as a treatable condition. INTRODUCTION: Hyperkyphosis is frequently found in adults aged 65 years and older and may be associated with falls. We aimed to investigate prospectively in community-dwelling older adults whether hyperkyphosis or change in the kyphosis angle is associated with fall incidence. METHODS: Community-dwelling older adults (n = 1220, mean age 72.9 ± 5.7 years) reported falls weekly over 2 years. We measured thoracic kyphosis through the Cobb angle between the fourth and 12th thoracic vertebra on DXA-based vertebral fracture assessments and defined hyperkyphosis as a Cobb angle ≥ 50°. The change in the Cobb angle during follow-up was dichotomized (< 5 or ≥ 5°). Through multifactorial regression analysis, we investigated the association between the kyphosis angle and falls. RESULTS: Hyperkyphosis was present in 15% of the participants. During follow-up, 48% of the participants fell at least once. In the total study population, hyperkyphosis was not associated with the number of falls (adjusted IRR 1.12, 95% CI 0.91-1.39). We observed effect modification by age (p = 0.002). In the oldest quartile, aged 77 years and older, hyperkyphosis was prospectively associated with a higher number of falls (adjusted IRR 1.67, 95% CI 1.14-2.45). Change in the kyphosis angle was not associated with fall incidence. CONCLUSIONS: Hyperkyphosis was associated with a higher fall incidence in the oldest quartile of a large prospective cohort of community-dwelling older adults. Because hyperkyphosis is a partially reversible condition, we recommend investigating whether hyperkyphosis is one of the causes of falls and whether a decrease in the kyphosis angle may contribute to fall prevention.

Frailty is associated with in-hospital mortality in older hospitalised COVID-19 patients in the Netherlands: the COVID-OLD study.

BACKGROUND: During the first wave of the coronavirus disease 2019 (COVID-19) pandemic, older patients had an increased risk of hospitalisation and death. Reports on the association of frailty with poor outcome have been conflicting. OBJECTIVE: The aim of the present study was to investigate the independent association between frailty and in-hospital mortality in older hospitalised COVID-19 patients in the Netherlands. METHODS: This was a multicentre retrospective cohort study in 15 hospitals in the Netherlands, including all patients aged ≥70 years, who were hospitalised with clinically confirmed COVID-19 between February and May 2020. Data were collected on demographics, co-morbidity, disease severity and Clinical Frailty Scale (CFS). Primary outcome was in-hospital mortality. RESULTS: A total of 1,376 patients were included (median age 78 years (interquartile range 74-84), 60% male). In total, 499 (38%) patients died during hospital admission. Parameters indicating presence of frailty (CFS 6-9) were associated with more co-morbidities, shorter symptom duration upon presentation (median 4 versus 7 days), lower oxygen demand and lower levels of C-reactive protein. In multivariable analyses, the CFS was independently associated with in-hospital mortality: compared with patients with CFS 1-3, patients with CFS 4-5 had a two times higher risk (odds ratio (OR) 2.0 (95% confidence interval (CI) 1.3-3.0)) and patients with CFS 6-9 had a three times higher risk of in-hospital mortality (OR 2.8 (95% CI 1.8-4.3)). CONCLUSIONS: The in-hospital mortality of older hospitalised COVID-19 patients in the Netherlands was 38%. Frailty was independently associated with higher in-hospital mortality, even though COVID-19 patients with frailty presented earlier to the hospital with less severe symptoms.

B-vitamins and body composition: integrating observational and experimental evidence from the B-PROOF study.

PURPOSE: Higher folate and vitamin-B12 have been linked to lower risk of overweight. However, whether this is a causal effect of these B-vitamins on obesity risk remains unclear and evidence in older individuals is scarce. This study aimed to assess the role of B-vitamin supplementation and levels on body composition in older individuals. METHODS: A double-blind, randomized controlled trial in 2919 participants aged ≥ 65 years with elevated homocysteine levels. The intervention comprised a 2-year supplementation with a combination of folic acid (400 µg) and vitamin B12 (500 µg), or with placebo. Serum folate, vitamin-B12, active vitamin-B12 (HoloTC), methylmalonic acid (MMA), and anthropometrics were measured at baseline and after 2 years of follow-up. Dietary intake of folate and vitamin-B12 was measured at baseline in a subsample (n = 603) using a validated food-frequency questionnaire. Fat mass index (FMI) and fat-free mass index (FFMI) were assessed with Dual Energy X-ray absorptiometry (DXA). RESULTS: Cross-sectional analyses showed that a 1 nmol/L higher serum folate was associated with a 0.021 kg/m2 lower BMI (95% CI - 0.039; - 0.004). Higher HoloTC (per pmol/L log-transformed) was associated with a 0.955 kg/m2 higher FMI (95% CI 0.262; 1.647), and higher MMA (per µgmol/L) was associated with a 1.108 kg/m2 lower FMI (95% CI - 1.899; - 0.316). However, random allocation of B-vitamins did not have a significant effect on changes in BMI, FMI or FFMI during 2 years of intervention. CONCLUSIONS: Although observational data suggested that folate and vitamin B12 status are associated with body composition, random allocation of a supplement with both B-vitamins combined versus placebo did not confirm an effect on BMI or body composition.

The association between apathy, decline in physical performance, and falls in older persons.

BACKGROUND: Symptoms of apathy are common in older persons. Negative effects on physical performance and fall risk are plausible, considering the pathophysiology of apathy. However, literature is scarce. AIM: To longitudinally assess the association between apathy and (1) decline of physical performance and (2) the number of falls in older community-dwelling persons. METHODS: The 'B vitamins for the PRevention Of Osteoporotic Fractures' study provided data on 2919 older persons over a period of 2 years. Apathy was assessed using the Geriatric Depression Scale 3. A physical performance score (PPS) was calculated using three performance tests. Falls were registered prospectively. We calculated adjusted odds ratios (ORs), Incidence Rate Ratios (IRRs), and their 95% confidence intervals. Effect modification by age and gender was investigated. We also investigated mediation by baseline PPS for the association between apathy and the number of falls. RESULTS: Apathy and decline of PPS were independently associated. After stratification, the effect only remained in men. Age was an effect modifier; higher ORs for decreasing age. Apathy was also independently associated with the number of falls. After stratification, women had higher IRRs than men. Age modified the association in the opposite direction: higher IRRs for increasing age. Baseline PPS was a mediator in the association. CONCLUSION: The impact of apathy on physical performance and fall incidents varied with age and gender. Potentially, in older individuals with apathy, fall risk is preceded by a decline in physical performance. In clinical practice, identifying apathy in older persons might be useful to target mobility preserving interventions.

Beta-blocker use and fall risk in older individuals: Original results from two studies with meta-analysis.

AIMS: To investigate the association between use of ß-blockers and ß-blocker characteristics - selectivity, lipid solubility, intrinsic sympathetic activity (ISA) and CYP2D6 enzyme metabolism - and fall risk. METHODS: Data from two prospective studies were used, including community-dwelling individuals, n = 7662 (the Rotterdam Study) and 2407 (B-PROOF), all aged ≥55 years. Fall incidents were recorded prospectively. Time-varying ß-blocker use was determined using pharmacy dispensing records. Cox proportional hazard models adjusted for age and sex were applied to determine the association between ß-blocker use, their characteristics - selectivity, lipid solubility, ISA and CYP2D6 enzyme metabolism - and fall risk. The results of the studies were combined using meta-analyses. RESULTS: In total 2917 participants encountered a fall during a total follow-up time of 89 529 years. Meta-analysis indicated no association between use of any ß-blocker, compared to nonuse, and fall risk, hazard ratio (HR) = 0.97 [95% confidence interval (CI) 0.88-1.06]. Use of a selective ß-blocker was also not associated with fall risk, HR = 0.92 (95%CI 0.83-1.01). Use of a nonselective ß-blocker was associated with an increased fall risk, HR = 1.22 (95%CI 1.01-1.48). Other ß-blocker characteristics including lipid solubility and CYP2D6 enzyme metabolism were not associated with fall risk. CONCLUSION: Our study suggests that use of a nonselective ß-blocker, contrary to selective ß-blockers, is associated with an increased fall risk in an older population. In clinical practice, ß-blockers have been shown effective for a variety of cardiovascular indications. However, fall risk should be considered when prescribing a ß-blocker in this age group, and the pros and cons for ß-blocker classes should be taken into consideration.

A Randomized Controlled Trial to Examine the Effect of 2-Year Vitamin B12 and Folic Acid Supplementation on Physical Performance, Strength, and Falling: Additional Findings from the B-PROOF Study.

Elevated homocysteine concentrations are associated with a decline in physical function in elderly persons. Homocysteine-lowering therapy may slow down this decline. This study aimed to examine the effect of a 2-year intervention of vitamin B12 and folic acid supplementation on physical performance, handgrip strength, and risk of falling in elderly subjects in a double-blind, randomized placebo-controlled trial. Participants aged ≥65 years with elevated plasma homocysteine concentrations [12-50 µmol/L (n = 2919)] were randomly assigned to daily supplementation of 500 µg vitamin B12, 400 µg folic acid, and 600 IU vitamin D3, or to placebo with 600 IU vitamin D3. Physical performance (range 0-12) and handgrip strength (kg) were measured at baseline and after 2 years. Falls were reported prospectively on a research calendar. Intention-to-treat (primary) and per-protocol (secondary) analyses were performed. Physical performance level and handgrip strength significantly decreased during the follow-up period, but this decline did not differ between groups. Moreover, time to first fall was not significantly different (HR: 1.0, 95% CI 0.9-1.2). Secondary analyses on a per-protocol base identified an interaction effect with age on physical performance. In addition, the treatment was associated with higher follow-up scores on the walking test (cumulative OR: 1.3, 95% CI 1.1-1.5). Two-year supplementation of vitamin B12 and folic acid was neither effective in reducing the age-related decline in physical performance and handgrip strength, nor in the prevention of falling in elderly persons. Despite the overall null-effect, the results provide indications for a positive effect of the intervention on gait, as well as on physical performance among compliant persons >80 years. These effects should be further tested in future studies.

Effect of vitamin B12 and folic acid supplementation on biomarkers of endothelial function and inflammation among elderly individuals with hyperhomocysteinemia.

B-vitamin trials failed to demonstrate beneficial effects on cardiovascular outcomes, but hyperhomocysteinemia still stands out as an independent cardiovascular risk factor, particularly in elderly individuals. B-vitamins may influence early vascular dysfunction, such as endothelial dysfunction, or may have adverse effects, for example on inflammation. We investigated the effect of B-vitamins on endothelial function and inflammation within an interventional study. This study was conducted within the framework of the B-PROOF trial, which included 2919 hyperhomocysteinemic elderly individuals, who received daily vitamin B12 (500 µg) and folic acid (400 µg) or placebo for 2 years. Using an electrochemiluminescence platform, we measured intercellular adhesion molecule 1 (ICAM-1), vascular adhesion molecule 1 (VCAM-1), serum amyloid A (SAA), vascular endothelial growth factor (VEGF) and C-reactive protein (CRP) at baseline and follow-up in a subsample of 522 participants (271 intervention group; 251 placebo). Treatment effects were analyzed with ANCOVA. The participants had a mean age of 72 years, and 55% of them were male. At the 2-year follow-up, B-vitamins did not change the ICAM-1 (+36% change in the intervention group versus +32% change in the placebo group; p = 0.72), VCAM-1 (+27% vs +25%; p = 0.39), VEGF (-1% vs +4%; p = 0.40), SAA (+34% vs +38%; p = 0.85) or CRP levels (+26% vs +36%; p = 0.70) as compared to placebo. In conclusion, in elderly patients with hyperhomocysteinemia, vitamin B12 and folic acid are unlikely to influence either endothelial function or low-grade systemic inflammation. ClinicalTrials.gov Identifier: NCT00696514.

Effect of Vitamin B12 and Folic Acid Supplementation on Bone Mineral Density and Quantitative Ultrasound Parameters in Older People with an Elevated Plasma Homocysteine Level: B-PROOF, a Randomized Controlled Trial.

High plasma homocysteine (Hcy) levels are associated with increased osteoporotic fracture incidence. However, the mechanism remains unclear. We investigated the effect of Hcy-lowering vitamin B12 and folic acid treatment on bone mineral density (BMD) and calcaneal quantitative ultrasound (QUS) parameters. This randomized, double-blind, placebo-controlled trial included participants aged ≥65 years with plasma Hcy levels between 12 and 50 µmol/L. The intervention comprised 2-year supplementation with either a combination of 500 µg B12, 400 µg folic acid, and 600 IU vitamin D or placebo with 600 IU vitamin D only. In total, 1111 participants underwent repeated dual-energy X-ray assessment and 1165 participants underwent QUS. Femoral neck (FN) BMD, lumbar spine (LS) BMD, calcaneal broadband ultrasound attenuation (BUA), and calcaneal speed of sound (SOS) were assessed. After 2 years, FN-BMD and BUA had significantly decreased, while LS-BMD significantly increased (all p < 0.01) and SOS did not change in either treatment arm. No statistically significant differences between the intervention and placebo group were present for FN-BMD (p = 0.24), LS-BMD (p = 0.16), SOS (p = 0.67), and BUA (p = 0.96). However, exploratory subgroup analyses revealed a small positive effect of the intervention on BUA at follow-up among compliant persons >80 years (estimated marginal mean 64.4 dB/MHz for the intervention group and 61.0 dB/MHz for the placebo group, p = 0.04 for difference). In conclusion, this study showed no overall effect of treatment with vitamin B12 and folic acid on BMD or QUS parameters in elderly, mildly hyperhomocysteinemic persons, but suggests a small beneficial effect on BUA in persons >80 years who were compliant in taking the supplement.

Non-linear associations between serum 25-OH vitamin D and indices of arterial stiffness and arteriosclerosis in an older population.

BACKGROUND: several studies have been pointing towards a non-linear relationship between serum 25(OH)D and cardiovascular disease. Next to vitamin D deficiency, also higher levels of 25(OH)D have been reported to be associated with increased cardiovascular risk. We aimed to investigate the nature of the relationship between serum 25(OH)D and measures of arterial stiffness and arteriosclerosis in an elderly population. DESIGN: cross-sectional. SETTING/SUBJECTS: a subgroup of the B-PROOF study was included to determine associations between serum 25(OH)D and arterial stiffness and atherosclerosis (n = 567, 57% male, age 72.6 ± 5.6 years, mean serum 25(OH)D 54.6 ± 24.1 nmol/l). METHODS: carotid intima media thickness (IMT) was assessed using ultrasonography and pulse wave velocity (PWV) was determined with applanation tonometry. Associations were tested using multivariable restricted cubic spline functions and stratified linear regression analysis. RESULTS: the associations between serum 25(OH)D and carotid IMT or PWV were non-linear. Spline functions demonstrated a difference between 25(OH)D deficient and sufficient individuals. In serum 25(OH)D sufficient participants (≥50 nmol/l; n = 287), a positive association with IMT and serum 25(OH)D was present (ß 1.24; 95%CI [0.002; 2.473]). PWV levels were slightly lower in vitamin D deficient individuals, but the association with 25(OH)D was not significant. CONCLUSION: our study demonstrates that associations of serum 25(OH)D and PWV and IMT in an elderly population are not linear. In particular from serum 25(OH)D levels of 50 nmol/l and up, there is a slight increase of IMT with increasing 25(OH)D levels.

Is the QCI framework suited for monitoring outcomes and costs in a teaching hospital using value-based healthcare principles? A retrospective cohort study.

OBJECTIVES: The objective is to develop a pragmatic framework, based on value-based healthcare principles, to monitor health outcomes per unit costs on an institutional level. Subsequently, we investigated the association between health outcomes and healthcare utilisation costs. DESIGN: This is a retrospective cohort study. SETTING: A teaching hospital in Rotterdam, The Netherlands. PARTICIPANTS: The study was performed in two use cases. The bariatric population contained 856 patients of which 639 were diagnosed with morbid obesity body mass index (BMI) <45 and 217 were diagnosed with morbid obesity BMI ≥45. The breast cancer population contained 663 patients of which 455 received a lumpectomy and 208 a mastectomy. PRIMARY AND SECONDARY OUTCOME MEASURES: The quality cost indicator (QCI) was the primary measures and was defined asQCI = (resulting outcome * 100)/average total costs (per thousand Euros)where average total costs entail all healthcare utilisation costs with regard to the treatment of the primary diagnosis and follow-up care. Resulting outcome is the number of patients achieving textbook outcome (passing all health outcome indicators) divided by the total number of patients included in the care path. RESULTS: The breast cancer and bariatric population had the highest resulting outcome values in 2020 Q4, 0.93 and 0.73, respectively. The average total costs of the bariatric population remained stable (avg, €8833.55, min €8494.32, max €9164.26). The breast cancer population showed higher variance in costs (avg, €12 735.31 min €12 188.83, max €13 695.58). QCI values of both populations showed similar variance (0.3 and 0.8). Failing health outcome indicators was significantly related to higher hospital-based costs of care in both populations (p <0.01). CONCLUSIONS: The QCI framework is effective for monitoring changes in average total costs and relevant health outcomes on an institutional level. Health outcomes are associated with hospital-based costs of care.

Distinct functional subnetworks of cognitive domains in older adults with minor cognitive deficits.

Although past research has established a relationship between functional connectivity and cognitive function, less is known about which cognitive domains are associated with which specific functional networks. This study investigated associations between functional connectivity and global cognitive function and performance in the domains of memory, executive function and psychomotor speed in 166 older adults aged 75-91 years (mean = 80.3 ± 3.8) with minor cognitive deficits (Mini-Mental State Examination scores between 21 and 27). Functional connectivity was assessed within 10 standard large-scale resting-state networks and on a finer spatial resolution between 300 nodes in a functional connectivity matrix. No domain-specific associations with mean functional connectivity within large-scale resting-state networks were found. Node-level analysis revealed that associations between functional connectivity and cognitive performance differed across cognitive functions in strength, location and direction. Specific subnetworks of functional connections were found for each cognitive domain in which higher connectivity between some nodes but lower connectivity between other nodes were related to better cognitive performance. Our findings add to a growing body of literature showing differential sensitivity of functional connections to specific cognitive functions and may be a valuable resource for hypothesis generation of future studies aiming to investigate specific cognitive dysfunction with resting-state functional connectivity in people with beginning cognitive deficits.

Uniting education, research, healthcare, and society to advance women's heart health.

Complex health challenges require professionals to operate across disciplines and to better connect with society. Here, we showcase a community-engaged and challenge-based educational model in which undergraduate students conduct transdisciplinary research on authentic complex biomedical problems. This concept reinforces translational medicine, human capital, and exemplifies synergy between education, research, healthcare, and society.

Ultrastructural Localization of Endogenous LC3 by On-Section Correlative Light-Electron Microscopy.

The visualization of autophagic organelles at the ultrastructural level by electron microscopy (EM) is essential to establish their identity and reveal details that are important for understanding the autophagic process. However, EM methods often lack molecular information, obstructing the correlation of ultrastructural information obtained by EM to fluorescence microscopy-based localization of specific autophagy proteins. Furthermore, the rarity of autophagosomes in unaltered cellular conditions hampers investigation by EM, which requires high magnification, and hence provides a limited field of view. In answer to both challenges, an on-section correlative light-electron microscopy (CLEM) method based on fluorescent labeling was applied to correlate a common autophagosomal marker, LC3, to EM ultrastructure. The method was used to rapidly screen cells in fluorescence microscopy for LC3 labeling in combination with other relevant markers. Subsequently, the underlying ultrastructural features of selected LC3-labeled spots were identified by CLEM. The method was applied to starved cells without adding inhibitors of lysosomal acidification. In these conditions, LC3 was found predominantly on autophagosomes and rarely in autolysosomes, in which LC3 is rapidly degraded. These data show both the feasibility and sensitivity of this approach, demonstrating that CLEM can be used to provide ultrastructural insights on LC3-mediated autophagy in native conditions-without drug treatments or genetic alterations. Overall, this method presents a valuable tool for ultrastructural localization studies of autophagy proteins and other scarce antigens by bridging light microscopy to EM data.

Nicotinic acetylcholine receptor signaling maintains epithelial barrier integrity.

Disruption of epithelial barriers is a common disease manifestation in chronic degenerative diseases of the airways, lung, and intestine. Extensive human genetic studies have identified risk loci in such diseases, including in chronic obstructive pulmonary disease (COPD) and inflammatory bowel diseases. The genes associated with these loci have not fully been determined, and functional characterization of such genes requires extensive studies in model organisms. Here, we report the results of a screen in Drosophila melanogaster that allowed for rapid identification, validation, and prioritization of COPD risk genes that were selected based on risk loci identified in human genome-wide association studies (GWAS). Using intestinal barrier dysfunction in flies as a readout, our results validate the impact of candidate gene perturbations on epithelial barrier function in 56% of the cases, resulting in a prioritized target gene list. We further report the functional characterization in flies of one family of these genes, encoding for nicotinic acetylcholine receptor (nAchR) subunits. We find that nAchR signaling in enterocytes of the fly gut promotes epithelial barrier function and epithelial homeostasis by regulating the production of the peritrophic matrix. Our findings identify COPD-associated genes critical for epithelial barrier maintenance, and provide insight into the role of epithelial nAchR signaling for homeostasis.

Neurovascular coupling in early stage dementia - A case-control study.

Cerebral amyloid angiopathy (CAA) is frequently found post mortem in Alzheimer's dementia, but often undetected during life especially since in vivo hallmarks of CAA and its vascular damage become overt relatively late in the disease process. Decreased neurovascular coupling to visual stimulation has been put forward as an early MRI marker for CAA disease severity. The current study investigates the role of neurovascular coupling in AD related dementia and its early stages. We included 25 subjective cognitive impairment, 33 mild cognitive impairment and 17 dementia patients and 44 controls. All participants underwent magnetic resonance imaging of the brain and neuropsychological assessment. Univariate general linear modeling analyses were used to assess neurovascular coupling between patient groups and controls. Moreover, linear regression analyses was used to assess the associations between neurovascular coupling and cognition. Our data show that BOLD amplitude is lower in dementia (mean 0.8 ± 0.2, p = 0.001) and MCI patients (mean 0.9 ± 0.3, p = 0.004) compared with controls (mean 1.1 ± 0.2). A low BOLD amplitude was associated with low scores in multiple cognitive domains. We conclude that cerebrovascular dysfunction, most likely due CAA, is an important comorbidity in early stages of dementia and has an independent effect on cognition.

The platelet interior revisited: electron tomography reveals tubular alpha-granule subtypes.

We have used (cryo) electron tomography to provide a 3-dimensional (3D) map of the intracellular membrane organization of human platelets at high spatial resolution. Our study shows that the open canalicular system and dense tubular system are highly intertwined and form close associations in specialized membrane regions. 3D reconstructions of individual alpha-granules revealed large heterogeneity in their membrane organization. On the basis of their divergent morphology, we categorized alpha-granules into the following subtypes: spherical granules with electron-dense and electron-lucent zone containing 12-nm von Willebrand factor tubules, subtypes containing a multitude of luminal vesicles, 50-nm-wide tubular organelles, and a population with 18.4-nm crystalline cross-striations. Low-dose (cryo) electron tomography and 3D reconstruction of whole vitrified platelets confirmed the existence of long tubular granules with a remarkably curved architecture. Immunoelectron microscopy confirmed that these extended structures represent alpha-granule subtypes. Tubular alpha-granules represent approximately 16% of the total alpha-granule population and are detected in approximately half of the platelet population. They express membrane-bound proteins GLUT3 and alphaIIb-beta3 integrin and contain abundant fibrinogen and albumin but low levels of beta-thromboglobulin and no von Willebrand factor. Our 3D study demonstrates that, besides the existence of morphologically different alpha-granule subtypes, high spatial segregation of cargo exists within individual alpha-granules.

Pre- and post-Golgi translocation of glucosylceramide in glycosphingolipid synthesis.

Glycosphingolipids are controlled by the spatial organization of their metabolism and by transport specificity. Using immunoelectron microscopy, we localize to the Golgi stack the glycosyltransferases that produce glucosylceramide (GlcCer), lactosylceramide (LacCer), and GM3. GlcCer is synthesized on the cytosolic side and must translocate across to the Golgi lumen for LacCer synthesis. However, only very little natural GlcCer translocates across the Golgi in vitro. As GlcCer reaches the cell surface when Golgi vesicular trafficking is inhibited, it must translocate across a post-Golgi membrane. Concanamycin, a vacuolar proton pump inhibitor, blocks translocation independently of multidrug transporters that are known to translocate short-chain GlcCer. Concanamycin did not reduce LacCer and GM3 synthesis. Thus, GlcCer destined for glycolipid synthesis follows a different pathway and transports back into the endoplasmic reticulum (ER) via the late Golgi protein FAPP2. FAPP2 knockdown strongly reduces GM3 synthesis. Overall, we show that newly synthesized GlcCer enters two pathways: one toward the noncytosolic surface of a post-Golgi membrane and one via the ER toward the Golgi lumen LacCer synthase.