Semi-automated protocol to quantify and characterize fluorescent three-dimensional vascular images

The microvasculature facilitates gas exchange, provides nutrients to cells, and regulates blood flow in response to stimuli. Vascular abnormalities are an indicator of pathology for various conditions, such as compromised vessel integrity in small vessel disease and angiogenesis in tumors. Traditional immunohistochemistry enables the visualization of tissue cross-sections containing exogenously labeled vasculature. Although this approach can be utilized to quantify vascular changes within small fields of view, it is not a practical way to study the vasculature on the scale of whole organs. Three-dimensional (3D) imaging presents a more appropriate method to visualize the vascular architecture in tissue. Here we describe the complete protocol that we use to characterize the vasculature of different organs in mice encompassing the methods to fluorescently label vessels, optically clear tissue, collect 3D vascular images, and quantify these vascular images with a semi-automated approach. To validate the automated segmentation of vascular images, one user manually segmented one hundred random regions of interest across different vascular images. The automated segmentation results had an average sensitivity of 83±11% and an average specificity of 91±6% when compared to manual segmentation. Applying this procedure of image analysis presents a method to reliably quantify and characterize vascular networks in a timely fashion. This procedure is also applicable to other methods of tissue clearing and vascular labels that generate 3D images of microvasculature.

In vitro activity of omadacycline against clinical isolates of Nocardia

Nocardiosis typically requires a prolonged treatment duration of ≥6 months and initial combination therapy with 2-3 antibiotics. First-line regimens for nocardiosis are associated with considerable toxicity; therefore, alternative therapies are needed. Omadacycline is an aminomethylcycline with broad antimicrobial activity whose in vitro activity against Nocardia species has not been formally assessed. The in vitro potency of omadacycline was evaluated against 300 Nocardia clinical isolates by broth microdilution. The most common Nocardia species tested were N. cyriacigeorgica (21%), N. nova (20%), and N. farcinica (12%). The most common specimens were respiratory (178 isolates, 59%) and wound (57 isolates, 19%). Omadacycline minimum inhibitory concentrations (MICs) across all Nocardia species ranged from 0.06 µg/mL to 8 µg/mL, with an MIC50 of 2 µg/mL and MIC90 of 4 µg/mL. The lowest MICs were found among N. paucivorans (MIC50 = 0.25 µg/mL, MIC90 = 0.25 µg/mL), N. asiatica (MIC50 = 0.25 µg/mL, MIC90 = 1 µg/mL), N. abscessus complex (MIC50 = 0.5 µg/mL, MIC90 = 1 µg/mL), N. beijingensis (MIC50 = 0.5 µg/mL, MIC90 = 2 µg/mL), and N. otitidiscaviarum (MIC50 = 1 µg/mL, MIC90 = 2 µg/mL). The highest MICs were found among N. farcinica (MIC50 = 4 µg/mL, MIC90 = 8 µg/mL). In vitro potency differed by species among Nocardia clinical isolates. Further studies are warranted to evaluate the potential clinical utility of omadacycline for nocardiosis.

Sequence- and Structure-Dependent Cytotoxicity of Phosphorothioate and 2'-O-Methyl Modified Single-Stranded Oligonucleotides

Single-stranded oligonucleotides (SSOs) are a rapidly expanding class of therapeutics that comprises antisense oligonucleotides, microRNAs, and aptamers, with ten clinically approved molecules. Chemical modifications such as the phosphorothioate backbone and the 2'-O-methyl ribose can improve the stability and pharmacokinetic properties of therapeutic SSOs, but they can also lead to toxicity in vitro and in vivo through nonspecific interactions with cellular proteins, gene expression changes, disturbed RNA processing, and changes in nuclear structures and protein distribution. In this study, we screened a mini library of 277 phosphorothioate and 2'-O-methyl-modified SSOs, with or without mRNA complementarity, for cytotoxic properties in two cancer cell lines. Using circular dichroism, nucleic magnetic resonance, and molecular dynamics simulations, we show that phosphorothioate- and 2'-O-methyl-modified SSOs that form stable hairpin structures through Watson-Crick base pairing are more likely to be cytotoxic than those that exist in an extended conformation. In addition, moderate and highly cytotoxic SSOs in our dataset have a higher mean purine composition than pyrimidine. Overall, our study demonstrates a structure-cytotoxicity relationship and indicates that the formation of stable hairpins should be a consideration when designing SSOs toward optimal therapeutic profiles.

Systematic review of non-invasive ventilation and craniofacial fractures: a multidisciplinary perspective and recommendations for management

The anatomically complex craniofacial skeleton demands special consideration when caring for cases of polytrauma or medically compromised patients with craniofacial fractures. This paper utilises a systematic review and multidisciplinary opinions to create an algorithm for the hospital-based care of patients with craniofacial fractures (base of skull, orbit, paranasal sinus, and mandible) who require non-invasive ventilation (NIV). Each fracture location has a unique predisposition to a different type of emphysema and associated morbidity. The risk of developing emphysema, combined with its potential severity, is stratified against the harm of not providing NIV for the holistic care of the patient. The aim of this paper is to synthesise evidence from a systematic review of existing literature with multidisciplinary opinions to develop a concise algorithm that outlines the optimal treatment of patients with craniofacial fractures who require NIV.

Dynamics and recognition of homeodomain containing protein-DNA complex of IRX4

Iroquois Homeobox 4 (IRX4) belongs to a family of homeobox TFs having roles in embryogenesis, cell specification, and organ development. Recently, large scale genome-wide association studies and epigenetic studies have highlighted the role of IRX4 and its associated variants in prostate cancer. No studies have investigated and characterized the structural aspect of the IRX4 homeodomain and its potential to bind to DNA. The current study uses sequence analysis, homology modeling, and molecular dynamics simulations to explore IRX4 homeodomain-DNA recognition mechanisms and the role of somatic mutations affecting these interactions. Using publicly available databases, gene expression of IRX4 was found in different tissues, including prostate, heart, skin, vagina, and the protein expression was found in cancer cell lines (HCT166, HEK293), B cells, ascitic fluid, and brain. Sequence conservation of the homeodomain shed light on the importance of N- and C-terminal residues involved in DNA binding. The specificity of IRX4 homodimer bound to consensus human DNA sequence was confirmed by molecular dynamics simulations, representing the role of conserved amino acids including R145, A194, N195, S190, R198, and R199 in binding to DNA. Additional N-terminal residues like T144 and G143 were also found to have specific interactions highlighting the importance of N-terminus of the homeodomain in DNA recognition. Additionally, the effects of somatic mutations, including the conserved Arginine (R145, R198, and R199) residues on DNA binding elucidated the importance of these residues in stabilizing the protein-DNA complex. Secondary structure and hydrogen bonding analysis showed the roles of specific residues (R145, T191, A194, N195, R198, and R199) in maintaining the homogeneity of the structure and its interaction with DNA. The differences in relative binding free energies of all the mutants shed light on the structural modularity of this protein and the dynamics behind protein-DNA interaction. We also have predicted that the C-terminal sequence of the IRX4 homeodomain could act as a potential cell-penetrating peptide, emphasizing the role these small peptides could play in targeting homeobox TFs.

Evaluating the sensitivity and specificity of dried blood spots for serological testing of HIV, syphilis, hepatitis B and C Elecsys assays on the Roche Cobas system

This study was performed to validate a dried blood spot (DBS) method for the serological screening of HIV, syphilis, hepatitis B and C. It included 250 paired DBS and serum samples and 116 unpaired DBS samples from 366 unique patients from two laboratories between 8 October and 2 November 2021. As determined by original test request, these were tested using a DBS method for HIV Ag/Ab (n=216), anti-treponemal Ab (n=166), hepatitis B sAg (n=100), and hepatitis C Ab (n=100) Elecsys assays on the Roche Cobas automated platform. Using the manufacturer's (serum) cut-off for reactivity ('positivity'), the sensitivity and specificity of DBS testing compared with serum were: for HIV Ag/Ab 100% and 100%, for anti-treponemal Ab 68.3% and 100%, for hepatitis B sAg 95.9% and 100%, and for hepatitis C Ab 84.0% and 100%, respectively. Adjusting the assay cut-off using receiver operator curve analysis increased sensitivity of DBS testing for anti-treponemal Ab to 90.0%, hepatitis B sAg to 97.9% and hepatitis C Ab to 94.0% whilst maintaining specificity of 98.8%, 100% and 100%, respectively. With optimisation of assay cut-off, DBS can perform comparably with serum for serological testing for HIV, syphilis, hepatitis B and C and may be a valuable tool in increasing access to testing in New Zealand.

Targeting the COMMD4-H2B protein complex in lung cancer

BACKGROUND

Lung cancer is the biggest cause of cancer-related deaths worldwide. Non-small cell lung cancer (NSCLC) accounts for 85-90% of all lung cancers. Identification of novel therapeutic targets are required as drug resistance impairs chemotherapy effectiveness. COMMD4 is a potential NSCLC therapeutic target. The aims of this study were to investigate the COMMD4-H2B binding pose and develop a short H2B peptide that disrupts the COMMD4-H2B interaction and mimics COMMD4 siRNA depletion.

METHODS

Molecular modelling, in vitro binding and site-directed mutagenesis were used to identify the COMMD4-H2B binding pose and develop a H2B peptide to inhibit the COMMD4-H2B interaction. Cell viability, DNA repair and mitotic catastrophe assays were performed to determine whether this peptide can specially kill NSCLC cells.

RESULTS

Based on the COMMD4-H2B binding pose, we have identified a H2B peptide that inhibits COMMD4-H2B by directly binding to COMMD4 on its H2B binding binding site, both in vitro and in vivo. Treatment of NSCLC cell lines with this peptide resulted in increased sensitivity to ionising radiation, increased DNA double-strand breaks and induction of mitotic catastrophe in NSCLC cell lines.

CONCLUSIONS

Our data shows that COMMD4-H2B represents a novel potential NSCLC therapeutic target.

The potential impact of periodontitis on cerebral small vessel disease

Cerebral small vessel disease (CSVD) is a term used to describe abnormalities in the intracranial microvasculature affecting small arteries, arterioles, capillaries, and venules. The etiology of these conditions is not fully understood but inflammation appears to play a significant role. Periodontal diseases have been associated with conditions such as stroke and dementia, which are clinical consequences of CSVD. Periodontitis is a highly prevalent chronic multifactorial inflammatory disease regulated by the host immune response against pathogenic bacterial colonization around the teeth. The inflammatory response and the microbial dysbiosis produce pro-inflammatory cytokines that can reach the brain and promote local changes. This review will explore the potential association between periodontitis and CSVD by assessing the impact of periodontitis-induced inflammation and periodontopathogenic bacteria on the underlying mechanisms leading to CSVD. Given the association of periodontitis with stroke and dementia, which are clinical features of CSVD, it may be possible to suggest a link with CSVD. Current evidence linking periodontitis with neuroimaging findings of CSVD enforces the possible link between these conditions.

Determinants of lipid clinic referral and attendance in a multi-ethnic adult population in south London: a cross-sectional study

BACKGROUND

Primary dyslipidaemias, including familial hypercholesterolaemia, are underdiagnosed genetic disorders that substantially increase risk for premature coronary artery disease in adults. Early identification of primary dyslipidaemias via lipid clinic referral optimises patient management and enables cascade screening of relatives. Improving the identification of primary dyslipidaemias, and understanding disparities in ascertainment and management, is an NHS priority. We aimed to assess determinants of lipid clinic referral or attendance (LCR) in ethnically diverse adults.

METHODS

We did a retrospective cross-sectional study using the Lambeth DataNet containing anonymised data from 41 general practitioner (GP) practices in south London. We looked at referral data for adult patients aged 18 years and older from Jan 1, 1995, until May 14, 2018. LCR was the main outcome. We used sequential multilevel logistic regression models adjusted for practice effects to estimate the odds of LCR assessed across six ethnic groups (reference group White) and patient-level factors (demographic, socioeconomic, lifestyle, comorbidities, total cholesterol [TC] >7·5mmol/L, statin prescription, and practice factors). The study was approved by NHS South East London Clinical Commissioning Group (CCG) and NHS Lambeth CCG.

FINDINGS

780 (0·23%) of 332 357 adult patients were coded as referred (n=538) or seen (n=252) in a lipid clinic. 164 487 (46·49%) were women (appendix). The fully adjusted model for odds of LCR showed the following significant associations for age (odds ratio [OR] 0·96, 95% CI 0·96-0·97, p<0·001); Black, African, Caribbean, or Black-British ethnicity (0·67, 0·53-0·84, p=0·001); ex-smoker status (1·29, 1·05-1·57, p=0·014); TC higher than 7·5 mmol/L (12·18, 9·60-15·45, p<0·001); statin prescription (14·01, 10·85-18·10, p<0·001); diabetes (0·72, 0·58-0·91, p=0·005); high-frequency GP attendance at seven or more GP consultations in the past year (1·49, 1·21-1·84, p<0·001); high GP-density (0·5-0·99 full-time equivalent GPs per 1000 patients; 2·70, 1·23-5·92, p=0·013). Sensitivity analyses for LCR restricted to familial hypercholesterolaemia-coded patients (n=581) found associations with TC higher than 7·5 mmol/L (4·26, 1·89-9·62, p<0·001), statin prescription (16·96, 2·19-131·36, p=0·007), and high GP-density (5·73, 1·27-25·93, p=0·023), with no significant associations with ethnicity. The relative contribution of GP practices to LCR was 6·32% of the total variance. There were no significant interactions between ethnicity and deprivation, age, or obesity.

INTERPRETATION

While interpretation is limited by the accuracy and completeness of coded records, the study showed factors associated with a higher likelihood of LCR included individuals recorded as having TC higher than 7·5 mmol/L, statin prescription, ex-smoker status, high-frequency GP attendance, and registration at a GP practice with 0·5-0·99 GP density. Patients with increasing age; Black, African, Caribbean, or Black-British ethnicity patients; and patients with diabetes had lower odds of LCR. Finally, the difference in odds of LCR between Black and White patients highlights potential health inequalities.

FUNDING

NHS Race & Health Observatory.

Quality of life in people living with HIV in Aotearoa New Zealand: an exploratory cross-sectional study

Quality of life (QoL) in people living with HIV (PLHIV) is reportedly worse than in people without HIV, with many factors impacting on this. We aimed to investigate QoL in PLHIV in New Zealand (NZ). In-person interviews were conducted including socio-demographic, health, social connectedness, and stigma-related questions. QoL was measured using the 13-question PozQoL Scale - summed to give a score between 13 and 65. Univariate linear regression was used to investigate factors associated with differences in PozQoL scores. PLHIV (n = 188) of different ethnicities from throughout NZ participated. The mean age was 47 years; 65% were men; 61% were men who have sex with men; 61% had been living with HIV for ≥10 years. The mean summary PozQoL score was 47.16. Factors associated with a lower mean PozQol included no sex in the last 12 months (-9.03), inability to meet basic needs (-7.47), ever (-6.49) or recently (-5.03), experiencing stigma or discrimination, mental health condition (-5.74), HIV diagnosis <5 years (-5.48), poor health (-5.43), being unemployed (-5.02), not having support (-4.71), and greater internalised stigma (-2.81). Improving QoL will require investment in peer support and community welfare programmes to better support PLHIV, and stigma reduction campaigns targeting the broader community.

A descriptive analysis of first trimester urinary concentrations of 14 bisphenol analogues in the MIREC Canadian pregnancy cohort

BACKGROUND

Concern over the health effects of BPA, particularly for the developing fetus, has led to an increasing use of bisphenol analogues in industrial and consumer products, which may be as hormonally active as BPA. Biomonitoring data for many bisphenol analogues, especially in pregnant populations, are limited.

METHODS

We measured concentrations of 14 bisphenol analogues in 1st trimester urine samples (n = 1851) from the Maternal-Infant Research on Environmental Chemicals (MIREC) Canadian pregnancy cohort (2008-2011). We examined patterns of exposure according to sociodemographic and sampling characteristics as well as occupation and frequency of consumption of canned fish within the previous 3 months.

RESULTS

BPA was detected in 89% of participants with a specific gravity standardized geometric mean concentration of 0.990 μg/L. Biphenol 4,4' (BP 4,4'), 4,4'-dihydroxydiphenyl ether (DHDPE), and bisphenol E (BPE) were detected in >97% of participants. Bisphenol F (BPF) and bisphenol S (BPS) were detected in >60% of participants. Specific gravity standardized geometric mean concentrations of these 5 compounds ranged from 0.024 to 0.564 μg/L. Nine bisphenol analogues were detected in <9% of participants. Concentrations of BP 4,4', DHDPE, and BPE were higher in younger women and those with higher pre-pregnancy BMI, lower household income, lower education, and among smokers. We found a similar pattern of differences in BPF for age, education, and smoking status while BPS similarly differed across categories of pre-pregnancy BMI. Participants who were unemployed or working in the service industry had higher molar sum of 7 bisphenol analogues than those working in healthcare, education, or an office setting. Canned fish consumption was not related to bisphenol analogue concentrations.

CONCLUSION

BP 4,4', DHDPE, BPE, BPF, and BPS were highly detected in 1st trimester urine samples in this large pan-Canadian pregnancy cohort. This suggests widespread exposure to these analogues around 2008-2011 and warrants further investigation into associations with health outcomes.

Determinants of lipid-lowering medication prescribing in a multi-ethnic adult population diagnosed with familial hypercholesterolaemia in South London

BACKGROUND

Familial hypercholesterolaemia (FH) (prevalence 1 in 250) is an inherited condition that significantly increases risk of premature cardiovascular disease. Early diagnosis can potentially normalise cardiovascular risk with lipid-lowering medicines (statins and fibrates). Only 7% of patients with FH are identified in the UK. Improving identification, and understanding disparities in ascertainment and management, is an NHS priority.

AIM

To assess determinants of lipid-lowering prescribing in ethnically diverse adults with an FH code. METHOD: Retrospective cross-sectional analysis of Lambeth DataNet, containing anonymised adult patient data from 41 practices in South London. Stata 17 was used to run sequential multilevel logistic regression models, adjusted for practice effects, to estimate the odds of no lipid-lowering prescription in FH-coded adults; this was assessed across 10 ethnic groups and other patient-level factors: demographic, socioeconomic, lifestyle, comorbidities, and practice factors (consultation frequency and practice list size).

RESULTS

One hundred and sixty-one of 801 (20%) of adults with an FH code received no lipid-lowering medication. The fully adjusted model for no lipid-lowering prescriptions showed the following associations: age (years) odds ratio (OR) 0.93 (P<0.001, 95% confidence interval [CI] = 0.91 to 0.95), male sex OR 0.47 (P = 0.002, 95% CI = 0.29 to 0.76), diabetes OR 0.26 (P = 0.04, 95% CI = 0.70 to 0.96), hypertension OR 0.30 (P<0.01, 95% CI = 0.12 to 0.72), and frequency of GP attendance OR 0.48 (P = 0.03, 95% CI = 0.24 to 0.94). Sensitivity analyses examining determinants of high-intensity statin prescribing found similar results.

CONCLUSION

The study suggests important determinants of lipid-lowering prescribing in an ethnically diverse adult population included older age, male sex, hypertension, and diabetes. Ethnicity showed no significant associations with lipid-lowering prescribing after adjusting for other determinants including deprivation measures.

Saddle Thigh Block Design Can Influence Rider and Horse Biomechanics

The association between rider-saddle interaction and horse kinematics has been little studied. It was hypothesized that differences in a thigh block design would influence (a) rider-saddle interface pressures, (b) rider kinematics, and (c) equine limb/spinal kinematics. Eighteen elite sport horses/riders were trotted using correctly fitted dressage saddles with thigh blocks S (vertical face) and F (deformable face). Contact area, mean, and peak pressure between rider and saddle were determined using an on-saddle pressure mat. Spherical markers allowed for the measurement of horse/rider kinematics using two-dimensional video analysis. The kinematics of the equine thoracolumbosacral spine were obtained using skin-mounted inertial measuring units. Results were compared between thigh blocks (paired t-test p ≤ 0.05). With F, the contact area, mean, and peak pressure between rider and saddle were significantly higher (p = 0.0001), and the rider trunk anterior tilt was reduced, indicating altered rider-saddle interaction. The horse thoracic axial rotation and flexion/extension were reduced (p = 0.01-0.03), caudal thoracic and lumbar lateral bend was increased (p = 0.02-0.04), and carpal flexion increased (p = 0.01-0.05) with F compared to S. During straight-line locomotion when in sitting trot, thigh block F was associated with altered rider-saddle interaction and rider and equine kinematics, leading to a more consistent rider-saddle interface, a more upright rider trunk during stance, an increased horse thoracic stability and lumbar lateral bend, and forelimb flexion, supporting the importance of optimising rider-saddle-horse interaction.

New insights into cognitive decline in chronic kidney disease

Chronic kidney disease (CKD) is known to be associated with cognitive impairment, but the mechanisms that underlie this kidney–brain connection are unclear. A recent study provides evidence that CKD is an independent risk factor for cognitive decline due to cerebral small vessel disease.

Neuropathology of microbleeds in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)

Cerebral microbleeds (CMBs) detected on magnetic resonance imaging are common in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). The neuropathologic correlates of CMBs are unclear. In this study, we characterized findings relevant to CMBs in autopsy brain tissue of 8 patients with genetically confirmed CADASIL and 10 controls within the age range of the CADASIL patients by assessing the distribution and extent of hemosiderin/iron deposits including perivascular hemosiderin leakage (PVH), capillary hemosiderin deposits, and parenchymal iron deposits (PID) in the frontal cortex and white matter, basal ganglia and cerebellum. We also characterized infarcts, vessel wall thickening, and severity of vascular smooth muscle cell degeneration. CADASIL subjects had a significant increase in hemosiderin/iron deposits compared with controls. This increase was principally seen with PID. Hemosiderin/iron deposits were seen in the majority of CADASIL subjects in all brain areas. PVH was most pronounced in the frontal white matter and basal ganglia around small to medium sized arterioles, with no predilection for the vicinity of vessels with severe vascular changes or infarcts. CADASIL subjects have increased brain hemosiderin/iron deposits but these do not occur in a periarteriolar distribution. Pathogenesis of these lesions remains uncertain.

Structural investigation of CDCA3-Cdh1 protein-protein interactions using in vitro studies and molecular dynamics simulation

The anaphase-promoting complex/cyclosome (APC/C) ubiquitin ligase and its cofactor, Cdh1, regulate the expression of several cell-cycle proteins and their functions during mitosis. Levels of the protein cell division cycle-associated protein 3 (CDCA3), which is functionally required for mitotic entry, are regulated by APC/C^Cdh1 . CDCA3 is an intrinsically disordered protein and contains both C-terminal KEN box and D-box recognition motifs, enabling binding to Cdh1. Our previous findings demonstrate that CDCA3 has a phosphorylation-dependent non-canonical ABBA-like motif within the linker region bridging these two recognition motifs and is required for efficient binding to Cdh1. Here, we sought to identify and further characterize additional residues that participate within this ABBA-like motif using detailed in vitro experiments and in silico modeling studies. We identified the role of H-bonds, hydrophobic and ionic interactions across the CDCA3 ABBA-like motif in the linker region between KEN and D-box motifs. This linker region adopts a well-defined structure when bound to Cdh1 in the presence of phosphorylation. Upon alanine mutation, the structure of this region is lost, leading to higher flexibility, and alteration in affinities due to binding to alternate sites on Cdh1. Our findings identify roles for the anchoring residues in the non-canonical ABBA-like motif to promote binding to the APC/C^Cdh1 and regulation of CDCA3 protein levels.

Chronic kidney disease promotes cerebral microhemorrhage formation

BACKGROUND

Chronic kidney disease (CKD) is increasingly recognized as a stroke risk factor, but its exact relationship with cerebrovascular disease is not well-understood. We investigated the development of cerebral small vessel disease using in vivo and in vitro models of CKD.

METHODS

CKD was produced in aged C57BL/6J mice using an adenine-induced tubulointerstitial nephritis model. We analyzed brain histology using Prussian blue staining to examine formation of cerebral microhemorrhage (CMH), the hemorrhagic component of small vessel disease and the neuropathological substrate of MRI-demonstrable cerebral microbleeds. In cell culture studies, we examined effects of serum from healthy or CKD patients and gut-derived uremic toxins on brain microvascular endothelial barrier.

RESULTS

CKD was induced in aged C57BL/6J mice with significant increases in both serum creatinine and cystatin C levels (p < 0.0001) without elevation of systolic or diastolic blood pressure. CMH was significantly increased and positively correlated with serum creatinine level (Spearman r = 0.37, p < 0.01). Moreover, CKD significantly increased Iba-1-positive immunoreactivity by 51% (p < 0.001), induced a phenotypic switch from resting to activated microglia, and enhanced fibrinogen extravasation across the blood-brain barrier (BBB) by 34% (p < 0.05). On analysis stratified by sex, the increase in CMH number was more pronounced in male mice and this correlated with greater creatinine elevation in male compared with female mice. Microglial depletion with PLX3397 diet significantly decreased CMH formation in CKD mice without affecting serum creatinine levels. Incubation of CKD serum significantly reduced transendothelial electrical resistance (TEER) (p < 0.01) and increased sodium fluorescein permeability (p < 0.05) across the endothelial monolayer. Uremic toxins (i.e., indoxyl sulfate, p-cresyl sulfate, and trimethylamine-N-oxide) in combination with urea and lipopolysaccharide induced a marked drop in TEER compared with the control group (p < 0.0001).

CONCLUSIONS

CKD promotes the development of CMH in aged mice independent of blood pressure but directly proportional to the degree of renal impairment. These effects of CKD are likely mediated in part by microglia and are associated with BBB impairment. The latter is likely related to gut-derived bacteria-dependent toxins classically associated with CKD. Overall, these findings demonstrate an important role of CKD in the development of cerebral small vessel disease.

Abstract TP223: Cerebral Microbleeds In Sickle Cell Disease

Introduction: Stroke due to sickle cell disease is often attributed to large vessel involvement in the disorder. The role of cerebral microvascular disease in sickle cell disease has received little attention. In this study, we examined development of cerebral microvascular lesions in a mouse model of sickle cell disease. We focused on cerebral microhemorrhages, the neuropathologic substrate of cerebral microbleeds.

Methods: We studied microvascular disease in a well-characterized mouse model of humanized transgenic sickle (HbSS-BERK) and control (HbAA-BERK) mice expressing >99% human sickle hemoglobin (Hb) and normal human HbA, respectively. HbSS-BERK express human α and βS globins on a mixed genetic background. HbAA-BERK mice express normal human α and βA globin thus producing only normal human hemoglobin A, on the same mixed genetic background as HbSS-BERK. Seven- to nine-month-old mice (N=18 HbSS, N=12 HbAA) were examined. We collected mouse brains and performed standard histology using Prussian blue staining to detect CMH formation at 20x magnification. The average number, total area, and size of Prussian blue-positive deposits were quantified. In separate studies, Toluidine Blue staining was used to identify mast cells.

Results: HbSS mice showed approximately 70% more cerebral microhemorrhages than controls (mean±SE of 1.17± 0.22 vs 0.69±0.13 number/cm 2, p=0.04). Lesion size did not differ between HbSS and control mice. Activated mast cells were identified in HbSS mouse brain but not in control mice.

Conclusions: In this mouse model of sickle cell disease, HbSS mice demonstrated significantly increased development of cerebral microhemorrhages. These findings emphasize the potential importance of cerebral microvascular disease in sickle cell disease. Cerebral mast cell activation in sickle cell disease may be a novel target for investigation.

Arteriolar neuropathology in cerebral microvascular disease

Cerebral microvascular disease (MVD) is an important cause of vascular cognitive impairment. MVD is heterogeneous in aetiology, ranging from universal ageing to the sporadic (hypertension, sporadic cerebral amyloid angiopathy [CAA] and chronic kidney disease) and the genetic (e.g., familial CAA, cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy [CADASIL] and cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy [CARASIL]). The brain parenchymal consequences of MVD predominantly consist of lacunar infarcts (lacunes), microinfarcts, white matter disease of ageing and microhaemorrhages. MVD is characterised by substantial arteriolar neuropathology involving ubiquitous vascular smooth muscle cell (SMC) abnormalities. Cerebral MVD is characterised by a wide variety of arteriolar injuries but only a limited number of parenchymal manifestations. We reason that the cerebral arteriole plays a dominant role in the pathogenesis of each type of MVD. Perturbations in signalling and function (i.e., changes in proliferation, apoptosis, phenotypic switch and migration of SMC) are prominent in the pathogenesis of cerebral MVD, making 'cerebral angiomyopathy' an appropriate term to describe the spectrum of pathologic abnormalities. The evidence suggests that the cerebral arteriole acts as both source and mediator of parenchymal injury in MVD.

Abstract TP198: Periodontitis Enhances Cerebral Microhemorrhage Development In A Mouse Model Of Hypertension

Introduction: Periodontitis is a highly prevalent disorder that is increasingly recognized as a risk factor for cerebrovascular disease. In this study we examined the role of periodontitis in the development of cerebral microvascular disease.

Methods: Hypertension was induced in aged (17 months old) male C57BL/6J mice via infusion of angiotensin II (ATII) at 1000 ng/kg/min via Alzet pump over 4 weeks. Periodontitis was induced by giving P. gingivalis -LPS (20 μg in 2 μL) injections between the first and second maxillary molars on both the right and left sides twice a week for six weeks. At end of six weeks, we collected mouse brains (N=5 each for Hypertension, Periodontitis, Hypertension + Periodontitis, and Control) and performed standard histology using Prussian blue staining to detect cerebral microhemorrhages (CMH) formation at 20x magnification. The average number, total area, and size of Prussian blue-positive deposits were quantified.

Results: ATII-induced hypertension in animals (Systolic blood pressure: 113±2 mmHg to 156±3 mmHg, mean+SE, p<0.0001; Diastolic blood pressure: 82±2 mmHg to 119±3 mmHg, p<0.0001). Presence of hypertension produced significant increase in number of CMH compared to controls (1.97±0.29 per cm 2 vs. 1.24±0.20 per cm 2 , p<0.05). Presence of periodontitis did not alter the number of microhemorrhages (1.68±0.13 per cm 2 vs.1.97±0.29 per cm 2 ). However, size of microhemorrhages doubled in the presence of periodontitis with hypertension (10.58±2.55 μm 2 per cm 2 vs. 5.05±1.15 μm 2 per cm 2 , p<0.05).

Conclusions: In this mouse model of ATII-induced hypertension, periodontitis appears to increase size of CMH rather than induce development of new lesions. These findings suggest a role for periodontitis in cerebrovascular disease by modifying and exacerbating pre-existing stroke risk factors rather than acting as an independent risk factor.

Paediatric Society and Hyperinsulinism Charity National Surveys on CGM Access for Patients With Recurrent Hypoglycaemia

Context

Recurrent hypoglycemia can result in significant neurological impairments in children and continuous glucose monitoring (CGM) technology has been shown to reduce recurrent hypoglycemia in conditions such as type 1 diabetes. In the United Kingdom, CGM devices are currently only recommended by the National Institute of Clinical Excellence (NICE) for patients with diabetes and not for other diagnoses.

Objective

To examine access to CGM technology for children and young people with recurrent hypoglycemia in the United Kingdom.

Methods

In 2021, the British Society of Paediatric Endocrinology and Diabetes (BSPED) conducted a national health professional survey in England, Wales, Scotland, and Northern Ireland looking at CGM access to funding for children and young people with recurrent hypoglycemia, without the diagnosis of diabetes. The UK Children's Hyperinsulinism Charity (UK CHC) also conducted a national patient survey.

Results

Responses from BSPED were received from 55 units while the UK CHC received 69 responses from individual families, the largest response to a survey carried out by the charity. The results of the BSPED and UK CHC surveys found that funding streams for CGM were highly variable. Only 29% were able to access CGM for recurrent hypoglycemia and from these, 65% were self-funding CGM. Quality of life benefits were evident from the UK CHC survey on the utility of CGM in reducing worry, improving sleep, lessening the burden of frequently finger-pricking and reducing out-of-hours appointments as a result of hypoglycemia. Patient-reported utilization rates of blood glucose test strips per week were significantly reduced.

Conclusion

BSPED and UK CHC national surveys support a call and a consideration for CGM access to be widened to patients who suffer from recurrent hypoglycemia such as those with hyperinsulinism or metabolic conditions. The prevention of recurrent hypoglycemia and improving quality of life for patients and carers remain a cornerstone management for people who suffer from frequent hypoglycemia. CGM education is critical to support its use and understand its limitations. Further research is warranted to determine the safety and efficacy of CGM in detection and reduction of hypoglycemic events, impact of hospital stay, and long-term neurological outcomes in those who suffer from recurrent hypoglceamia.

Local zinc treatment enhances fracture callus properties in diabetic rats

The effects of locally applied zinc chloride (ZnCl₂ ) on early and late-stage parameters of fracture healing were evaluated in a diabetic rat model. Type 1 Diabetes has been shown to negatively impact mechanical parameters of bone as well as biologic markers associated with bone healing. Zinc treatments have been shown to reverse those outcomes in tests of nondiabetic and diabetic animals. This study is the first to assess the efficacy of a noncarrier mediated ZnCl₂ on bony healing in diabetic animals. This is a promising basic science approach which may lead to benefits for diabetic patients in the future. Treatment and healing were assessed through quantification of callus zinc, radiographic scoring, microcomputed tomography (µCT), histomorphometry, and mechanical testing. Local ZnCl₂ treatment increased callus zinc levels at 1 and 3 days after fracture (p ≤ 0.025). Femur fractures treated with ZnCl₂ showed increased mechanical properties after 4 and 6 weeks of healing. Histomorphometry of the ZnCl₂ -treated fractures found increased callus cartilage area at Day 7 (p = 0.033) and increased callus bone area at Day 10 (p = 0.038). In contrast, callus cartilage area was decreased (p < 0.01) after 14 days in the ZnCl₂ -treated rats. µCT analysis showed increased bone volume in the fracture callus of ZnCl₂ -treated rats at 6 weeks (p = 0.0012) with an associated increase in the proportion of µCT voxel axial projections (Z-rays) spanning the fracture site. The results suggest that local ZnCl₂ administration improves callus chondrogenesis leading to greater callus bone formation and improved fracture healing in diabetic rats.

Prywatyzacja stresu

W artykule Mark Fisher rozwija przedstawioną w Realizmie kapitalistycznym z 2008 roku intuicję dotyczącą związku, jaki zachodzi między neoliberalizmem (niszczeniem związków zawodowych, prywatyzacją usług publicznych, „uelastycznieniem” rynku pracy), jego ideologicznym usprawiedliwieniem (Thatcherowskie „nie ma alternatywy”) a zdrowiem psychicznym, zwłaszcza jego medykalizacją i prywatyzacją. Zdaniem Fishera lewicowym remedium na opisywane w zasadniczej części artykułu problemy nie jest kopiowanie przeszłych form organizacji politycznej, lecz powrót do projektu „lewicowego modernizmu”, który tak naprawdę nigdy nie został zrealizowany.