Medicine (Austin & Northern Health) - Research Publications
Permanent URI for this collection
Search Results
1 - 10 of 27
-
ItemNo Preview AvailableINCREASED PLASMA NEUROFILAMENT LIGHT AND CEREBRAL ATROPHY IN PATIENTS WITH TYPE 2 DIABETES AND LEFT VENTRICULAR HYPERTROPHY(LIPPINCOTT WILLIAMS & WILKINS, 2023-01)
-
ItemNo Preview AvailableComparison of white matter hyperintensity abnormalities and cognitive performance in individuals with low and high cardiovascular risk: Data from the Diabetes and Dementia (D2) study(Wiley, 2021-12)Abstract Background Type 2 diabetes Mellitus (T2DM) is recognised as a major contributor to cognitive decline. People with T2DM demonstrate increased white matter hyperintensity (WMH) abnormalities on MRI compared to control individuals. We investigated associations between a validated vascular risk score: The Framingham Risk Score (FRS), WMH volumes and cognitive function in the Diabetes‐and‐Dementia (D2) study, a longitudinal cohort study of community dwelling people with T2DM. Method One hundred and twenty‐three non‐demented participants with T2DM (age 66.7±6.8 years, range 50‐80, 68M/55F) completed neuropsychological assessments, health questionnaires to allow FRS calculation, 24‐hour ambulatory blood pressure monitoring, and a 3T‐MRI scan. WMH were calculated using the functionality "run‐samseg" in FreeSurfer 7. Quality control on the traced lesions was performed using an in‐house semi‐automated MATLAB tool. Periventricular and deep WMH volumes were estimated based on the edited lesion traces. We divided participants into low (n=61) and high (n=62) FRS groups based on the median score (x=48.7). Differences in WMH volumes were compared between the FRS groups after correcting for sex and age. We compared cognitive performance between low/high FRS individuals across five composite cognitive domains: memory, language, visuospatial skills, executive function, and attention‐and‐processing‐speed. The composite score for each domain was the normalised z‐scores average for the respective tests. Result Participants with high FRS (implicating greater vascular risk) were significantly older (age F(1, 122)=14.97; p<0.001), were less likely to be female (sex χ2=16.73, p<0.001), and tend to have less than 12 years of education (χ2= 3.69, p = 0.041). Relative to individuals with low FRS, those with high FRS showed significantly higher WMH volumes (F(1, 121)=6.11; p=0.015). Significant differences were also identified for periventricular (F(1, 121)=6.16; p=0.014) and deep (F(1, 121)=4.25; p=0.042) WMH volumes. When the cognitive data were analysed, the low FRS group performed signifcantly better than the high FRS group only on the attention‐and‐processing‐speed factor (F(1,115)=5.17; p=0.025). Conclusion High cardiovascular risk, defined as a high FRS, in participants with T2DM was associated with greater WMH volume, a marker of white matter dysfunction, and with deficits in processing speed and attention. Subclinical cognitive deficits were common in our community dwelling cohort without known or preceding cognitive dysfunction.
-
ItemNo Preview AvailableReduced urinary levels of angiotensin-converting enzyme 2 activity predict acute kidney injury in critically ill patients(AUSTRALASIAN MED PUBL CO LTD, 2020-12)Objective: Angiotensin-converting enzyme 2 activity reflects non-classical renin-angiotensin system upregulation. We assessed the association of urinary angiotensin-converting enzyme 2 (uACE2) activity with acute kidney injury (AKI). Design, setting and participants: A prospective observational study in which we measured uACE2 activity in 105 critically ill patients at risk of AKI. We report AKI stage 2 or 3 at 12 hours of urine collection (AKI12h) and AKI stage 2 or 3 at any time during intensive care unit stay in patients free from any stage of AKI at inclusion (AKIICU). AKI prediction was assessed using area under the receiver-operating characteristics curve (AUROC) and net reclassification indices (NRIs). Main outcome measure: AKI stage 2 or 3 at 12 hours of urine collection. Results: Within 12 hours of inclusion, 32 of 105 patients (30%) had developed AKI12h. Corrected uACE2 activity was significantly higher in patients without AKI12h compared with those with AKI12h (median [interquartile range], 13 [6-24] v 7 [4-10] pmol/min/mL per mmol/L of urine creatinine; P < 0.01). A 10-unit increase in uACE2 was associated with a 28% decrease in AKI12h risk (odds ratio [95% CI], 0.72 [0.46-0.97]). During intensive care unit admission, 39 of 76 patients (51%) developed AKIICU. uACE2 had an AUROC for the prediction of AKI12h of 0.68 (95% CI, 0.57-0.79), and correctly reclassified 28% of patients (positive NRI) to AKI12h. Patients with uACE2 > 8.7 pmol/min/mL per mmol/L of urine creatinine had a significantly lower risk of AKIICU on log-rank analysis (52% v 84%; P < 0.01). Conclusions: Higher uACE2 activity was associated with a decreased risk of AKI stage 2 or 3. Our findings support future evaluations of the role of the non-classical renin-angiotensin system during AKI.
-
ItemNo Preview AvailableImmunological dysfunction persists for 8 months following initial mild-to-moderate SARS-CoV-2 infection(NATURE PORTFOLIO, 2022-02)A proportion of patients surviving acute coronavirus disease 2019 (COVID-19) infection develop post-acute COVID syndrome (long COVID (LC)) lasting longer than 12 weeks. Here, we studied individuals with LC compared to age- and gender-matched recovered individuals without LC, unexposed donors and individuals infected with other coronaviruses. Patients with LC had highly activated innate immune cells, lacked naive T and B cells and showed elevated expression of type I IFN (IFN-β) and type III IFN (IFN-λ1) that remained persistently high at 8 months after infection. Using a log-linear classification model, we defined an optimal set of analytes that had the strongest association with LC among the 28 analytes measured. Combinations of the inflammatory mediators IFN-β, PTX3, IFN-γ, IFN-λ2/3 and IL-6 associated with LC with 78.5-81.6% accuracy. This work defines immunological parameters associated with LC and suggests future opportunities for prevention and treatment.
-
ItemFc engineered ACE2-Fc is a potent multifunctional agent targeting SARS-CoV2 (vol 13, 889372, 2022)(FRONTIERS MEDIA SA, 2023-01-10)[This corrects the article .].
-
ItemPlasma Neurofilament Light Chain and Clinical Diagnosis in Frontotemporal Dementia Syndromes(IOS PRESS, 2022)BACKGROUND: Frontotemporal dementia (FTD) syndromes, mimics, phenocopy (phFTD), and slowly progressive behavioral variant FTD (bvFTD) can be difficult to distinguish clinically. Biomarkers such as neurofilament light chain (NfL) may be helpful. OBJECTIVE: To study plasma NfL levels in people with FTD syndromes and determine if plasma NfL can distinguish between FTD syndromes and phFTD. METHODS: Plasma NfL levels were estimated using both Simoa® Quanterix HD-X™ and SR-X™ machines grouped via final diagnosis after investigation and review. RESULTS: Fifty participants were studied: bvFTD = 20, semantic variant FTD (svFTD) = 11, non-fluent variant FTD (nfvFTD) = 9, FTD with motor neuron disease (MND) = 4, phFTD = 2, slow progressors = 3, FTD mimic = 1, mean age 67.2 (SD 8.4) years. NfL levels were significantly higher in the FTD group compared to phenocopy group (p = 0.003). Median NfL (IQR) pg/mL was comparable in the FTD syndromes: bvFTD 41.10 (50.72), svFTD 44.38 (16.61), and nfvFTD 42.61 (22.93), highest in FTD with MND 79.67 (45.32) and lowest in both phFTD 13.99 (0.79) and slow progressors 17.97 (3.62). CONCLUSION: Plasma NfL appears to differentiate FTD syndromes and mimics. However, a lower NfL may predict a slower, but not necessarily absence of neurodegeneration, and therefore appears limited in distinguishing slow progressors from FTD phenocopies. Larger numbers of patients from all clinical groups are required to strengthen diagnostic utility.
-
ItemPlasma Angiotensin Converting Enzyme 2 (ACE2) Activity in Healthy Controls and Patients with Cardiovascular Risk Factors and/or Disease(MDPI, 2022-09)Angiotensin converting enzyme 2 (ACE2) is an endogenous negative regulator of the renin-angiotensin system, a key factor in the development of cardiovascular disease (CVD). ACE2 is also used by SARS-CoV-2 for host cell entry. Given that COVID-19 is associated with hypercoagulability, it is timely to explore the potential relationship between plasma ACE2 activity and the coagulation profile. In this cross-sectional study, ACE2 activity and global coagulation assays (GCA) including thromboelastography, thrombin, and fibrin generation were measured in adult healthy controls (n = 123; mean age 41 ± 17 years; 35% male) and in patients with cardiovascular risk factors and/or disease (n = 258; mean age 65 ± 14 years; 55% male). ACE2 activity was significantly lower in controls compared to patients with cardiovascular risk factors and/or disease (median 0.10 (0.02, 3.33) vs. 5.99 (1.95, 10.37) pmol/mL/min, p < 0.001). Of the healthy controls, 48% had undetectable ACE2 activity. Controls with detectable ACE2 had lower maximum amplitude (p < 0.001). In patients with cardiovascular risk factors and/or disease, those in the 3rd tertile were older and male (p = 0.002), with a higher Framingham grade and increased number of cardiovascular risk factors (p < 0.001). In conclusion, plasma ACE2 activity is undetectable to very low in young healthy controls with minimal clinically relevant associations to GCA. Patients with cardiovascular risk factors and/or disease have increased plasma ACE2 activity, suggesting that it may be an important biomarker of endothelial dysfunction and atherosclerosis.
-
ItemFc engineered ACE2-Fc is a potent multifunctional agent targeting SARS-CoV2(FRONTIERS MEDIA SA, 2022-07-28)Joining a function-enhanced Fc-portion of human IgG to the SARS-CoV-2 entry receptor ACE2 produces an antiviral decoy with strain transcending virus neutralizing activity. SARS-CoV-2 neutralization and Fc-effector functions of ACE2-Fc decoy proteins, formatted with or without the ACE2 collectrin domain, were optimized by Fc-modification. The different Fc-modifications resulted in distinct effects on neutralization and effector functions. H429Y, a point mutation outside the binding sites for FcγRs or complement caused non-covalent oligomerization of the ACE2-Fc decoy proteins, abrogated FcγR interaction and enhanced SARS-CoV-2 neutralization. Another Fc mutation, H429F did not improve virus neutralization but resulted in increased C5b-C9 fixation and transformed ACE2-Fc to a potent mediator of complement-dependent cytotoxicity (CDC) against SARS-CoV-2 spike (S) expressing cells. Furthermore, modification of the Fc-glycan enhanced cell activation via FcγRIIIa. These different immune profiles demonstrate the capacity of Fc-based agents to be engineered to optimize different mechanisms of protection for SARS-CoV-2 and potentially other viral pathogens.
-
ItemNo Preview AvailableImproved tissue preparation for multimodal vibrational imaging of biological tissues(Elsevier BV, 2022-12)
-
ItemObesity and carotid artery remodeling.(Springer Science and Business Media LLC, 2015-08-24)BACKGROUND/OBJECTIVE: The present study tested the hypothesis that obesity-related changes in carotid intima-media thickness (IMT) might represent not only preclinical atherosclerosis but an adaptive remodeling meant to preserve circumferential wall stress (CWS) in altered hemodynamic conditions characterized by body size-dependent increase in stroke volume (SV) and blood pressure (BP). SUBJECTS/METHODS: Common carotid artery (CCA) luminal diameter (LD), IMT and CWS were measured in three different populations in order to study: (A) cross-sectional associations between SV, BP, anthropometric parameters and CCA LD (266 healthy subjects with wide range of body weight (24-159 kg)); (B) longitudinal associations between CCA LD and 3-year IMT progression rate (ΔIMT; 571 healthy non-obese subjects without increased cardiovascular (CV) risk); (C) the impact of obesity on CCA geometry and CWS (88 obese subjects without CV complications and 88 non-obese subjects matched for gender and age). RESULTS: CCA LD was independently associated with SV that was determined by body size. In the longitudinal study, baseline LD was an independent determinant of ΔIMT, and ΔIMT of subjects in the highest LD quartile was significantly higher (28±3 μm) as compared with those in the lower quartiles (8±3, 16±4 and 16±3 μm, P=0.001, P<0.05 and P=0.01, respectively). In addition, CCA CWS decreased during the observational period in the highest LD quartile (from 54.2±8.6 to 51.6±7.4 kPa, P<0.0001). As compared with gender- and age-matched lean individuals, obese subjects had highly increased CCA LD and BP (P<0.0001 for both), but only slightly higher CWS (P=0.05) due to a significant increase in IMT (P=0.005 after adjustment for confounders). CONCLUSIONS: Our findings suggest that in obese subjects, the CCA wall thickens to compensate the luminal enlargement caused by body size-induced increase in SV, and therefore, to normalize the wall stress. CCA diameter in obesity could represent an additional biomarker, depicting the impact of altered hemodynamics on arterial wall.