Pain in alcohol use disorder: Evaluating effects of childhood trauma, perceived stress, and psychological comorbidity

The relationship between pain and alcohol use disorder (AUD) is complex and bidirectional. The current study examines risk factors for pain in a large comprehensively phenotyped sample including individuals from across the spectrum of alcohol use and misuse. Participants (n = 1101) were drawn from the National Institute on Alcohol Abuse and Alcoholism Natural History Protocol and included treatment-seeking AUD inpatients (AUD+Tx, n = 369), individuals with AUD not seeking treatment (AUD+, n = 161), and individuals without AUD (AUD-, n = 571). General linear models were utilized to test the effects of AUD status, history of childhood trauma exposure, perceived stress, and psychological comorbidity on daily percent time in pain, as well as change in daily percent time in pain across the inpatient stay in AUD+Tx individuals. Overall, 60.2% individuals reported any pain, with a significantly higher prevalence in the AUD+Tx group (82.1%) compared to the AUD+ (56.5%) and AUD- (47.1%) groups. Daily percent time in pain was also highest in the AUD+Tx group (30.2%) and was further increased in those with a history of childhood abuse and comorbid posttraumatic stress disorder (PTSD). Years of heavy drinking and craving were also associated with increased percent time in pain in the AUD+Tx group. Percent time in pain decreased following acute withdrawal in the AUD+Tx group but plateaued around 25% just prior to discharge. Individuals seeking inpatient treatment for AUD, especially those with a history of childhood trauma and/or comorbid PTSD, report greater percent time in pain compared to those not seeking treatment and those without AUD. The prolonged experience of pain in abstinent AUD inpatients after the resolution of acute withdrawal may signal the early stages of protracted withdrawal. Integrative treatments targeting pain and other symptoms of protracted withdrawal may be effective in improving overall function in people with severe AUD.

A CONSTRAINED CONSTRUCTIVE OPTIMIZATION MODEL OF BRANCHING ARTERIOLAR NETWORKS IN RAT SKELETAL MUSCLE

Blood flow regulation within the microvasculature reflects a complex interaction of regulatory mechanisms and varies spatially and temporally according to conditions such as metabolism, growth, injury, and disease. Understanding the role of microvascular flow distributions across conditions is of interest to investigators spanning multiple disciplines; however, data collection within networks can be labour-intensive and challenging due to limited resolution. To overcome these experimental challenges, computational network models which can accurately simulate vascular behavior are highly beneficial. Constrained Constructive Optimization (CCO) is a commonly used algorithm for vascular simulation, particularly well known for its adaptability towards vascular modelling across tissues. The present work demonstrates an implementation of CCO aimed to simulate a branching arteriolar microvasculature in healthy skeletal muscle, validated against literature including comprehensive rat gluteus maximus vasculature datasets, and reviews a list of user-specified adjustable model parameters to understand how their variability affects the simulated networks. Network geometric properties, including mean element diameters, lengths, and numbers of bifurcations per order, Horton's Law ratios, and fractal dimension, demonstrate good validation once model parameters are adjusted to experimental data. This model successfully demonstrates hemodynamic properties such as Murray's Law and the network Fahraeus effect. Application of centrifugal and Strahler ordering schemes results in divergent descriptions of identical simulated networks. This work introduces a novel CCO-based model focused on generating branching skeletal muscle microvascular arteriolar networks based on adjustable model parameters, thus making it a valuable tool for investigations into skeletal muscle microvascular structure and tissue perfusion.

Capillary oxygen regulates demand-supply coupling by triggering connexin40-mediated conduction: Rethinking the metabolic hypothesis

Coupling red blood cell (RBC) supply to O2 demand is an intricate process requiring O2 sensing, generation of a stimulus, and signal transduction that alters upstream arteriolar tone. Although actively debated, this process has been theorized to be induced by hypoxia and to involve activation of endothelial inwardly rectifying K+ channels (KIR) 2.1 by elevated extracellular K+ to trigger conducted hyperpolarization via connexin40 (Cx40) gap junctions to upstream resistors. This concept was tested in resting healthy skeletal muscle of Cx40-/- and endothelial KIR2.1-/- mice using state-of-the-art live animal imaging where the local tissue O2 environment was manipulated using a custom gas chamber. Second-by-second capillary RBC flow responses were recorded as O2 was altered. A stepwise drop in PO2 at the muscle surface increased RBC supply in capillaries of control animals while elevated O2 elicited the opposite response; capillaries were confirmed to express Cx40. The RBC flow responses were rapid and tightly coupled to O2; computer simulations did not support hypoxia as a driving factor. In contrast, RBC flow responses were significantly diminished in Cx40-/- mice. Endothelial KIR2.1-/- mice, on the other hand, reacted normally to O2 changes, even when the O2 challenge was targeted to a smaller area of tissue with fewer capillaries. Conclusively, microvascular O2 responses depend on coordinated electrical signaling via Cx40 gap junctions, and endothelial KIR2.1 channels do not initiate the event. These findings reconceptualize the paradigm of blood flow regulation in skeletal muscle and how O2 triggers this process in capillaries independent of extracellular K+.

Urine proteomic signatures of histological class, activity, chronicity, and treatment response in lupus nephritis

Lupus nephritis (LN) is a pathologically heterogenous autoimmune disease linked to end-stage kidney disease and mortality. Better therapeutic strategies are needed as only 30%-40% of patients completely respond to treatment. Noninvasive biomarkers of intrarenal inflammation may guide more precise approaches. Because urine collects the byproducts of kidney inflammation, we studied the urine proteomic profiles of 225 patients with LN (573 samples) in the longitudinal Accelerating Medicines Partnership in RA/SLE cohort. Urinary biomarkers of monocyte/neutrophil degranulation (i.e., PR3, S100A8, azurocidin, catalase, cathepsins, MMP8), macrophage activation (i.e., CD163, CD206, galectin-1), wound healing/matrix degradation (i.e., nidogen-1, decorin), and IL-16 characterized the aggressive proliferative LN classes and significantly correlated with histological activity. A decline of these biomarkers after 3 months of treatment predicted the 1-year response more robustly than proteinuria, the standard of care (AUC: CD206 0.91, EGFR 0.9, CD163 0.89, proteinuria 0.8). Candidate biomarkers were validated and provide potentially treatable targets. We propose these biomarkers of intrarenal immunological activity as noninvasive tools to diagnose LN and guide treatment and as surrogate endpoints for clinical trials. These findings provide insights into the processes involved in LN activity. This data set is a public resource to generate and test hypotheses and validate biomarkers.

Immune and molecular landscape behind non-response to Mycophenolate Mofetil and Azathioprine in lupus nephritis therapy

Lupus nephritis (LN) represents one of the most severe complications of systemic lupus erythematosus, leading to end-stage kidney disease in worst cases. Current first-line therapies for LN, including mycophenolate mofetil (MMF) and azathioprine (AZA), fail to induce long-term remission in 60-70% of the patients, evidencing the urgent need to delve into the molecular knowledge-gap behind the non-response to these therapies. A longitudinal cohort of treated LN patients including clinical, cellular and transcriptomic data, was analyzed. Gene-expression signatures behind non-response to different drugs were revealed by differential expression analysis. Drug-specific non-response mechanisms and cell proportion differences were identified. Blood cell subsets mediating non-response were described using single-cell RNASeq data. We show that AZA and MMF non-response implicates different cells and regulatory functions. Mechanistic models were used to suggest add-on therapies to improve their current performance. Our results provide new insights into the molecular mechanisms associated with treatment failures in LN.

Thromboxane-induced cerebral microvascular rarefaction predicts depressive symptom emergence in metabolic disease

Previous studies have suggested that the loss of microvessel density in the peripheral circulation with evolving metabolic disease severity represents a significant contributor to impaired skeletal muscle oxygenation and fatigue-resistance. Based on this and our recent work, we hypothesized that cerebral microvascular rarefaction was initiated from the increased prooxidant and proinflammatory environment with metabolic disease and is predictive of the severity of the emergence of depressive symptoms in obese Zucker rats (OZRs). In male OZR, cerebrovascular rarefaction followed the emergence of elevated oxidant and inflammatory environments characterized by increased vascular production of thromboxane A2 (TxA2). The subsequent emergence of depressive symptoms in OZR was associated with the timing and severity of the rarefaction. Chronic intervention with antioxidant (TEMPOL) or anti-inflammation (pentoxifylline) therapy blunted the severity of rarefaction and depressive symptoms, although the effectiveness was limited. Blockade of TxA2 production (dazmegrel) or action (SQ-29548) resulted in a stronger therapeutic effect, suggesting that vascular production and action represent a significant contributor to rarefaction and the emergence of depressive symptoms with chronic metabolic disease (although other pathways clearly contribute as well). A de novo biosimulation of cerebrovascular oxygenation in the face of progressive rarefaction demonstrates the increased probability of generating hypoxic regions within the microvascular networks, which could contribute to impaired neuronal metabolism and the emergence of depressive symptoms. The results of the present study also implicate the potential importance of aggressive prodromic intervention in reducing the severity of chronic complications arising from metabolic disease.NEW & NOTEWORTHY With clinical studies linking vascular disease risk to depressive symptom emergence, we used obese Zucker rats, a model of chronic metabolic disease, to identify potential mechanistic links between these two negative outcomes. Depressive symptom severity correlated with the extent of cerebrovascular rarefaction, after increased vascular oxidant stress/inflammation and TxA2 production. Anti-TxA2 interventions prevasculopathy blunted rarefaction and depressive symptoms, while biosimulation indicated that cerebrovascular rarefaction increased hypoxia within capillary networks as a potential contributing mechanism.

Clonal hematopoiesis related TET2 loss-of-function impedes IL1β-mediated epigenetic reprogramming in hematopoietic stem and progenitor cells

Clonal hematopoiesis (CH) is defined as a single hematopoietic stem/progenitor cell (HSPC) gaining selective advantage over a broader range of HSPCs. When linked to somatic mutations in myeloid malignancy-associated genes, such as TET2-mediated clonal hematopoiesis of indeterminate potential or CHIP, it represents increased risk for hematological malignancies and cardiovascular disease. IL1β is elevated in patients with CHIP, however, its effect is not well understood. Here we show that IL1β promotes expansion of pro-inflammatory monocytes/macrophages, coinciding with a failure in the demethylation of lymphoid and erythroid lineage associated enhancers and transcription factor binding sites, in a mouse model of CHIP with hematopoietic-cell-specific deletion of Tet2. DNA-methylation is significantly lost in wild type HSPCs upon IL1β administration, which is resisted by Tet2-deficient HSPCs, and thus IL1β enhances the self-renewing ability of Tet2-deficient HSPCs by upregulating genes associated with self-renewal and by resisting demethylation of transcription factor binding sites related to terminal differentiation. Using aged mouse models and human progenitors, we demonstrate that targeting IL1 signaling could represent an early intervention strategy in preleukemic disorders. In summary, our results show that Tet2 is an important mediator of an IL1β-promoted epigenetic program to maintain the fine balance between self-renewal and lineage differentiation during hematopoiesis.

Microglial depletion after brain injury prolongs inflammation and impairs brain repair, adult neurogenesis and pro-regenerative signaling

The adult zebrafish brain, unlike mammals, has a remarkable regenerative capacity. Although inflammation in part hinders regeneration in mammals, it is necessary for zebrafish brain repair. Microglia are resident brain immune cells that regulate the inflammatory response. To explore the microglial role in repair, we used liposomal clodronate or colony stimulating factor-1 receptor (csf1r) inhibitor to suppress microglia after brain injury, and also examined regeneration in two genetic mutant lines that lack microglia. We found that microglial ablation impaired telencephalic regeneration after injury. Microglial suppression attenuated cell proliferation at the intermediate progenitor cell amplification stage of neurogenesis. Notably, the loss of microglia impaired phospho-Stat3 (signal transducer and activator of transcription 3) and ß-Catenin signaling after injury. Furthermore, the ectopic activation of Stat3 and ß-Catenin rescued neurogenesis defects caused by microglial loss. Microglial suppression also prolonged the post-injury inflammatory phase characterized by neutrophil accumulation, likely hindering the resolution of inflammation. These findings reveal specific roles of microglia and inflammatory signaling during zebrafish telencephalic regeneration that should advance strategies to improve mammalian brain repair.

Does the use of corticosteroids and immunosuppressants increase the risk of COVID-19 infection among people with systemic lupus erythematosus?

OBJECTIVE

An important clinical question is whether the use of immunosuppressants or corticosteroids increases the risk of incident COVID-19 disease among patients with SLE. To address this question, we examined the incidence of COVID-19 infection in a large SLE cohort.

METHODS

This study was based on a single-centre cohort of patients with SLE seen quarterly from March 2020 to August 2022. Clinical information from these visits was augmented with information on COVID-19 infections and vaccinations obtained from the electronic medical records and by patient self-report. We compared treated and untreated patients with respect to the incidence of COVID-19 infection per person month. Statistical significance was assessed based on logistic regression models.

RESULTS

We observed 339 incident cases of COVID-19 experienced over 24 614 person-months of follow-up from 1052 different patients. The risk of infection per person-month of follow-up was similar among those not on prednisone (1.37%), on moderate doses of prednisone (<7 mg/day) (1.44%) and those on higher doses (1.52%) (p=0.87 for difference). We observed an elevated risk among those taking belimumab, however, after adjustment for potential confounding variables, the increased risk was not statistically significant (rate ratio 1.4, 95% CI 0.88 to 2.24, p=0.16) There was no evidence of an increased risk among those taking mycophenolate, methotrexate or azathioprine.

CONCLUSION

It is reassuring that there was not strong evidence of an increased risk of infection among those taking prednisone or other immunosuppressants. However, given the range of our CIs, moderate effects of these medications on COVID-19 risk cannot be completely ruled out.

Regulation of Skeletal Muscle Resistance Arteriolar Tone: Integration of Multiple Mechanisms

INTRODUCTION

Physiological system complexity represents an imposing challenge to gaining insight into how arteriolar behavior emerges. Further, mechanistic complexity in arteriolar tone regulation requires that a systematic determination of how these processes interact to alter vascular diameter be undertaken.

METHODS

The present study evaluated the reactivity of ex vivo proximal and in situ distal resistance arterioles in skeletal muscle with challenges across the full range of multiple physiologically relevant stimuli and determined the stability of responses over progressive alterations to each other parameter. The five parameters chosen for examination were (1) metabolism (adenosine concentration), (2) adrenergic activation (norepinephrine concentration), (3) myogenic activation (intravascular pressure), (4) oxygen (superfusate PO2), and (5) wall shear rate (altered intraluminal flow). Vasomotor tone of both arteriole groups following challenge with individual parameters was determined; subsequently, responses were determined following all two- and three-parameter combinations to gain deeper insight into how stimuli integrate to change arteriolar tone. A hierarchical ranking of stimulus significance for establishing arteriolar tone was performed using mathematical and statistical analyses in conjunction with machine learning methods.

RESULTS

Results were consistent across methods and indicated that metabolic and adrenergic influences were most robust and stable across all conditions. While the other parameters individually impact arteriolar tone, their impact can be readily overridden by the two dominant contributors.

CONCLUSION

These data suggest that mechanisms regulating arteriolar tone are strongly affected by acute changes to the local environment and that ongoing investigation into how microvessels integrate stimuli regulating tone will provide a more thorough understanding of arteriolar behavior emergence across physiological and pathological states.

Application of a novel index for understanding vascular health following pharmacological intervention in a pre-clinical model of metabolic disease

While a thorough understanding of microvascular function in health and how it becomes compromised with progression of disease risk is critical for developing effective therapeutic interventions, our ability to accurately assess the beneficial impact of pharmacological interventions to improve outcomes is vital. Here we introduce a novel Vascular Health Index (VHI) that allows for simultaneous assessment of changes to vascular reactivity/endothelial function, vascular wall mechanics and microvessel density within cerebral and skeletal muscle vascular networks with progression of metabolic disease in obese Zucker rats (OZR); under control conditions and following pharmacological interventions of clinical relevance. Outcomes are compared to "healthy" conditions in lean Zucker rats. We detail the calculation of vascular health index, full assessments of validity, and describe progressive changes to vascular health index over the development of metabolic disease in obese Zucker rats. Further, we detail the improvement to cerebral and skeletal muscle vascular health index following chronic treatment of obese Zucker rats with anti-hypertensive (15%-52% for skeletal muscle vascular health index; 12%-48% for cerebral vascular health index; p < 0.05 for both), anti-dyslipidemic (13%-48% for skeletal muscle vascular health index; p < 0.05), anti-diabetic (12%-32% for cerebral vascular health index; p < 0.05) and anti-oxidant/inflammation (41%-64% for skeletal muscle vascular health index; 29%-42% for cerebral vascular health index; p < 0.05 for both) drugs. The results present the effectiveness of mechanistically diverse interventions to improve cerebral or skeletal muscle vascular health index in obese Zucker rats and provide insight into the superiority of some pharmacological agents despite similar effectiveness in terms of impact on intended targets. In addition, we demonstrate the utility of including a wider, more integrative approach to the study of microvasculopathy under settings of elevated disease risk and following pharmacological intervention. A major benefit of integrating vascular health index is an increased understanding of the development, timing and efficacy of interventions through greater insight into integrated microvascular function in combination with individual, higher resolution metrics.

Assessments of Perfusion, Blood Flow, and Vascular Structure in Ambulatory Subjects: Guidance for Translational Research Scientists

Research involving human subjects in ambulatory settings is a critical link in the chain comprising translational research, spanning preclinical research to human subject and patient cohort studies. There are presently a wide array of techniques and approaches available to investigators wishing to study blood flow, perfusion, and vascular structure and function in human subjects. In this multi-sectioned review, we discuss capillaroscopy, carotid intima-media thickness, flow-mediated dilation, laser Doppler flowmetry, near-infrared spectroscopy, peripheral arterial tonometry, pulse wave velocity, retinal fundus imaging, and vascular plethysmography. Each section contains a general overview and the physical basis of the technique followed by a discussion of the procedures involved and the necessary equipment, with attention paid to specific requirements or limitations. Subsequently, we detail which aspects of vascular function can be studied with a given technique, the analytical approach to the collected data, and the appropriate application and limitation(s) to the interpretation of the data collected. Finally, a modified scoping review provides a summary of how each assessment technique has been applied in previous studies. It is anticipated that this review will provide an efficient source of information and insight for preclinical investigators seeking to add translational aspects to their research programs.

A novel vascular health index: Using data analytics and population health to facilitate mechanistic modeling of microvascular status

The study of vascular function across conditions has been an intensive area of investigation for many years. While these efforts have revealed many factors contributing to vascular health, challenges remain for integrating results across research groups, animal models, and experimental conditions to understand integrated vascular function. As such, the insights attained in clinical/population research from linking datasets, have not been fully realized in the basic sciences, thus frustrating advanced analytics and complex modeling. To achieve comparable advances, we must address the conceptual challenge of defining/measuring integrated vascular function and the technical challenge of combining data across conditions, models, and groups. Here, we describe an approach to establish and validate a composite metric of vascular function by comparing parameters of vascular function in metabolic disease (the obese Zucker rat) to the same parameters in age-matched, "healthy" conditions, resulting in a common outcome measure which we term the vascular health index (VHI). VHI allows for the integration of datasets, thus expanding sample size and permitting advanced modeling to gain insight into the development of peripheral and cerebral vascular dysfunction. Markers of vascular reactivity, vascular wall mechanics, and microvascular network density are integrated in the VHI. We provide a detailed presentation of the development of the VHI and provide multiple measures to assess face, content, criterion, and discriminant validity of the metric. Our results demonstrate how the VHI captures multiple indices of dysfunction in the skeletal muscle and cerebral vasculature with metabolic disease and provide context for an integrated understanding of vascular health under challenged conditions.

Scoring personalized molecular portraits identify Systemic Lupus Erythematosus subtypes and predict individualized drug responses, symptomatology and disease progression

OBJECTIVES

Systemic Lupus Erythematosus is a complex autoimmune disease that leads to significant worsening of quality of life and mortality. Flares appear unpredictably during the disease course and therapies used are often only partially effective. These challenges are mainly due to the molecular heterogeneity of the disease, and in this context, personalized medicine-based approaches offer major promise. With this work we intended to advance in that direction by developing MyPROSLE, an omic-based analytical workflow for measuring the molecular portrait of individual patients to support clinicians in their therapeutic decisions.

METHODS

Immunological gene-modules were used to represent the transcriptome of the patients. A dysregulation score for each gene-module was calculated at the patient level based on averaged z-scores. Almost 6100 Lupus and 750 healthy samples were used to analyze the association among dysregulation scores, clinical manifestations, prognosis, flare and remission events and response to Tabalumab. Machine learning-based classification models were built to predict around 100 different clinical parameters based on personalized dysregulation scores.

RESULTS

MyPROSLE allows to molecularly summarize patients in 206 gene-modules, clustered into nine main lupus signatures. The combination of these modules revealed highly differentiated pathological mechanisms. We found that the dysregulation of certain gene-modules is strongly associated with specific clinical manifestations, the occurrence of relapses or the presence of long-term remission and drug response. Therefore, MyPROSLE may be used to accurately predict these clinical outcomes.

CONCLUSIONS

MyPROSLE (https://myprosle.genyo.es) allows molecular characterization of individual Lupus patients and it extracts key molecular information to support more precise therapeutic decisions.

Urine proteomic insights from the belimumab in lupus nephritis trial

OBJECTIVE

Urine proteomic approaches have shown promise in identifying biological pathways in lupus nephritis (LN) which are not captured on renal histopathology or by measurement of proteinuria alone. We investigated how the urine proteome changes with treatment response and with belimumab therapy.

METHODS

Urine samples from 54 Belimumab International Systemic Lupus Erythematosus-Lupus Nephritis trial participants (all with biopsy-proven LN) were collected at weeks 0, 24 and 52. At each time point, 1000 urinary proteins were quantified using antibody microarrays (Raybiotech Kiloplex), and their abundance was compared in responders (n=31) versus non-responders (n=22) and with belimumab treatment (n=28) versus standard of care therapy (n=26). Response was defined as proteinuria <500 mg/g_{creatinine (cr)}, serum creatinine ≤1.25 times the week 0 value and prednisone ≤10 mg/day at week 52.

RESULTS

By week 52, CD163 was the urine protein with the most significant difference in abundance between complete responders (median 1.8 pg/mg_cr) versus non-responders (median 8.2 pg/mg_cr, p=4e-7) regardless of treatment arm. At week 24, five urinary proteins were present at a significantly lower (CD23 and Siglec-5) or higher (AIF, CRELD2 and ROR2) level in the belimumab group. Belimumab therapy was particularly associated with reduction in CD23 between week 0 and week 24 (p=0.0001).

CONCLUSIONS

Reduction in urinary CD163 was strongly associated with complete renal response, confirming the results of multiple prior studies. Treatment with belimumab can be detected in the urine proteome, and further study is needed to determine whether modulation of CD23-mediated immune enhancement pathways might be implicated in LN treatment response.

The development of peripheral microvasculopathy with chronic metabolic disease in obese Zucker rats: a retrograde emergence?

The study of peripheral vasculopathy with chronic metabolic disease is challenged by divergent contributions from spatial (the level of resolution or specific tissue being studied) and temporal origins (evolution of the developing impairments in time). Over many years of studying the development of skeletal muscle vasculopathy and its functional implications, we may be at the point of presenting an integrated conceptual model that addresses these challenges within the obese Zucker rat (OZR) model. At the early stages of metabolic disease, where systemic markers of elevated cardiovascular disease risk are present, the only evidence of vascular dysfunction is at postcapillary and collecting venules, where leukocyte adhesion/rolling is elevated with impaired venular endothelial function. As metabolic disease severity and duration increases, reduced microvessel density becomes evident as well as increased variability in microvascular hematocrit. Subsequently, hemodynamic impairments to distal arteriolar networks emerge, manifesting as increasing perfusion heterogeneity and impaired arteriolar reactivity. This retrograde "wave of dysfunction" continues, creating a condition wherein deficiencies to the distal arteriolar, capillary, and venular microcirculation stabilize and impairments to proximal arteriolar reactivity, wall mechanics, and perfusion distribution evolve. This proximal arteriolar dysfunction parallels increasing failure in fatigue resistance, hyperemic responses, and O2 uptake within self-perfused skeletal muscle. Taken together, these results present a conceptual model for the retrograde development of peripheral vasculopathy with chronic metabolic disease and provide insight into the timing and targeting of interventional strategies to improve health outcomes.NEW & NOTEWORTHY Working from an established database spanning multiple scales and times, we studied progression of peripheral microvascular dysfunction in chronic metabolic disease. The data implicate the postcapillary venular endothelium as the initiating site for vasculopathy. Indicators of dysfunction, spanning network structures, hemodynamics, vascular reactivity, and perfusion progress in an insidious retrograde manner to present as functional impairments to muscle blood flow and performance much later. The silent vasculopathy progression may provide insight into clinical treatment challenges.

Transfer from spatial education to verbal reasoning and prediction of transfer from learning-related neural change

Current debate surrounds the promise of neuroscience for education, including whether learning-related neural changes can predict learning transfer better than traditional performance-based learning assessments. Longstanding debate in philosophy and psychology concerns the proposition that spatial processes underlie seemingly nonspatial/verbal reasoning (mental model theory). If so, education that fosters spatial cognition might improve verbal reasoning. Here, in a quasi-experimental design in real-world STEM classrooms, a curriculum devised to foster spatial cognition yielded transfer to improved verbal reasoning. Further indicating a spatial basis for verbal transfer, students' spatial cognition gains predicted and mediated their reasoning improvement. Longitudinal fMRI detected learning-related changes in neural activity, connectivity, and representational similarity in spatial cognition-implicated regions. Neural changes predicted and mediated learning transfer. Ensemble modeling demonstrated better prediction of transfer from neural change than from traditional measures (tests and grades). Results support in-school "spatial education" and suggest that neural change can inform future development of transferable curricula.

Lipoprotein(a) in systemic lupus erythematosus is associated with history of proteinuria and reduced renal function

OBJECTIVE

Proteinuria is the clinical expression of lupus nephritis and despite recent advances in the therapeutic armamentarium for lupus nephritis, morbidity and mortality rates remain high. Therefore, the identification of factors that predict lupus nephritis is paramount in preventing damage accrual and disease progression. Lipoprotein (a) (Lp[a]) is a primarily genetically inherited plasma lipoprotein with pro-thrombotic and pro-atherosclerotic effects. Elevated Lp(a) has been observed at early stages of renal impairment in the general population and is associated with the development of chronic kidney disease. However, little is known about renal implications of Lp(a) in SLE. Thus, we evaluated Lp(a) and atherosclerotic events, thrombotic events, renal disease, and disease activity in patients with SLE.

METHODS

SLE patients fulfilling the revised American College of Rheumatology (ACR) or SLICC classification criteria with a measurement of Lp(a) were included in the analysis. A cutoff of 125 nmol/L was chosen based on expert opinion. Chi-square test was used to compare the differences between patient characteristics and Lp(a) levels. Logistic regression or linear regression were used, where appropriate, to assess the association between Lp(a) values and the measured outcomes.

RESULTS

Lp(a) levels from 562 patients were analyzed. There was an association between elevated Lp(a) and a history of proteinuria (OR 1.58, p-value = 0.02). This association remained significant following adjustment for age, sex, race, low C3, and elevated anti-dsDNA (OR = 1.55, p-value = 0.04). There was also an association with eGFR < 60 (p = 0.02). Patients with elevated Lp(a) had higher physician global activity (p = 0.01) and erythrocyte sediment rate (p = 0.03).

CONCLUSION

Elevated Lp(a) was associated with proteinuria, independent of known factors associated with lupus proteinuria, as well as reduced eGFR and physician global activity. Our findings highlight the potential role of Lp(a) as a noninvasive biomarker for early renal disease in SLE.

Arteriolar dysgenesis in ischemic, regenerating skeletal muscle revealed by automated micro-morphometry, computational modeling, and perfusion analysis

Rebuilding the local vasculature is central to restoring the health of muscles subjected to ischemic injury. Arteriogenesis yields remodeled collateral arteries that circumvent the obstruction, and angiogenesis produces capillaries to perfuse the regenerating myofibers. However, the vital intervening network of arterioles that feed the regenerated capillaries is poorly understood and an investigative challenge. We used machine learning and automated micro-morphometry to quantify the arteriolar landscape in distal hindlimb muscles in mice that have regenerated after femoral artery excision. Assessment of 1546 arteriolar sections revealed a striking (> 2-fold) increase in arteriolar density in regenerated muscle 14 and 28 days after ischemic injury. Lumen caliber was initially similar to that of control arterioles but after 4 weeks lumen area was reduced by 46%. In addition, the critical smooth muscle layer was attenuated throughout the arteriolar network, across a 150 to 5 µm diameter range. To understand the consequences of the reshaped distal hindlimb arterioles, we undertook computational flow modeling which revealed blunted flow augmentation. Moreover, impaired flow reserve was confirmed in vivo by laser Doppler analyses of flow in response to directly applied sodium nitroprusside. Thus, in hindlimb muscles regenerating after ischemic injury, the arteriolar network is amplified, inwardly remodels, and is diffusely under-muscularized. These defects and the associated flow restraints could contribute to the deleterious course of peripheral artery disease and merit attention when considering therapeutic innovations.

One-third of patients with lupus nephritis classified as complete responders continue to accrue progressive renal damage despite resolution of proteinuria

OBJECTIVE

Treatment response in lupus nephritis (LN) is defined based on proteinuria, yet protocol kidney biopsy studies have shown that patients with lupus can have active nephritis in the absence of proteinuria. Using estimated glomerular filtration rate (eGFR) trajectories, we characterised early chronic kidney disease in LN and examined whether certain patients continue to accrue renal damage despite proteinuric response.

METHODS

We conducted a single-centre study of patients diagnosed with their first episode of biopsy-proven class III, IV, and/or V LN (n=37). For each patient, eGFR trajectory was graphed over 5 years following renal biopsy. Participants were divided into those with progressive eGFR loss (eGFR slope <-5 mL/min/1.73 m2/year) versus those with stable eGFR. Participant demographics, renal biopsy features and response status at 1 year (urine protein to creatinine ratio <500 mg/g) were compared between eGFR trajectory groups.

RESULTS

Overall, 30% (n=11) of participants accrued progressive eGFR loss despite standard of care therapy over the first 5 years following renal biopsy. There were no significant differences in baseline renal biopsy features, medication regimens or comorbidities between eGFR trajectory groups. Resolution of proteinuria at 1 year did not differentiate between groups: 6 of 18 (33%) of complete responders continued to accrue renal damage compared with 5 of 17 (29%) of non-responders. Response status could not be assigned for two participants in the stable eGFR group due to missing clinical information at 1 year.

CONCLUSIONS

We identified an understudied category of patients with LN who accrue progressive renal damage despite apparent response to standard of care therapy. Better definitions and biomarkers of response are needed to improve renal outcomes and trial design.

A Role for Gastric Point of Care Ultrasound in Postoperative Delayed Gastrointestinal Functioning

INTRODUCTION

Delayed bowel function (DBF) and postoperative ileus (POI) are common gastrointestinal complications after surgery. There is no reliable imaging study to help diagnose these complications, forcing clinicians to rely solely on patient history and physical exam. Gastric point of care ultrasound (POCUS) is a simple bedside imaging technique to evaluate gastric contents but has not been evaluated in postoperative patients.

METHODS

Twenty colorectal patients were enrolled in this pilot study. Patients were categorized as either full or empty stomach based upon their postoperative day one gastric POCUS exams and previously published definitions. The primary outcome was GI-3 recovery, a dual end point defined as tolerance of solid food and either flatus or bowel movement. Secondary outcomes were length of stay, emesis, time to first flatus, time to first bowel movement, nasogastric tube placement, aspiration events, and mortality.

RESULTS

Nine of 20 patients had a full stomach postoperatively. Patients with full stomachs were younger and received greater perioperative opioid doses (74.0 ± 28.2 v 42.6 ± 32.9 morphine equivalents, P = 0.0363) compared to empty stomach patients. GI-3 recovery occurred significantly later for patients with postoperative day 1 full stomachs (2.1 ± 0.4 versus 1 ± 0 days, P = 0.00091).

CONCLUSIONS

Based upon this pilot study, gastric POCUS may hold promise as a noninvasive and simple bedside modality to potentially help identify colorectal patients at risk for postoperative DBF and POI and should be evaluated in a larger study.

Clinical and histopathological features of myositis in systemic lupus erythematosus

Objective

The objectives of this study were to compare the clinical features of patients with SLE with and without myopathy and to describe the muscle biopsy features of patients with SLE myopathy.

Methods

This nested case–control study included all subjects enrolled in the Hopkins Lupus Cohort database from May 1987 to June 2016. Subjects with elevated creatine kinase along with evidence of muscle oedema on MRI, myopathic electromyography and/or myopathic muscle biopsy features were defined as having SLE myopathy. Demographic, serological and clinical features were compared between patients with SLE with and without myopathy. Muscle biopsies were histologically classified as polymyositis, dermatomyositis, necrotising myopathy or non-specific myositis.

Results

From among 2437 patients with SLE, 179 (7.3%) had myopathy. African American patients were more likely to develop myositis than Caucasian patients (p<0.0001). Compared with those without myopathy, patients with SLE myopathy were more likely to have malar rash (OR 1.67, 1.22–2.29), photosensitivity (OR 1.43, 1.04–1.96), arthritis (OR 1.81, 1.21–2.69), pleurisy (OR 1.77, 1.3–2.42), pericarditis (OR 1.49, 1.06–2.08), acute confusional state (OR 2.07, 1.09–3.94), lymphopaenia (OR 1.64, 1.2–2.24), anti-double-stranded DNA antibodies (OR 1.52, 1.09–2.13), lupus anticoagulant (OR 1.42, 1–2), cognitive impairment (OR 1.87, 1.12–3.13), cataract (OR 1.5, 1.04–2.18), pulmonary hypertension (OR 1.98, 1.13–3.47), pleural fibrosis (OR 2.01, 1.27–3.18), premature gonadal failure (OR 1.9, 1.05–3.43), diabetes (OR 1.92, 1.22–3.02) or hypertension (OR 1.45, 1.06–2). Among 16 muscle biopsies available for review, the most common histological classifications were necrotising myositis (50%) and dermatomyositis (38%).

Conclusions

Patients with SLE myopathy have a higher prevalence of numerous SLE disease manifestations. Necrotising myopathy and dermatomyositis are the most prevalent histopathological features in SLE myopathy.

A two-layer continuously distributed capillary O2 transport model applied to blood flow regulation in resting skeletal muscle

The microcirculation is the site of direct oxygen transfer from blood to tissue, and also of oxygen delivery control via regulation of local blood flow. In addition, a number of diseases including type II diabetes mellitus (DMII) and sepsis are known to produce microcirculatory dysfunction in their early phases. Given the complexity of microvascular structure and physiology, and the difficulty of measuring tissue oxygenation at the micro-scale, mathematical modelling has been necessary for understanding the physiology and pathophysiology of O₂ transport in the microcirculation and for interpreting in vivo experiments. To advance this area, a model of blood-tissue O₂ transport in skeletal muscle was recently developed which uses continuously distributed capillaries and includes O₂ diffusion, convection, and consumption. The present work extends this model to two adjacent layers of skeletal muscle with different blood flow rates and applies it to study steady-state O₂ transport when flow regulation is stimulated using an O₂ exchange chamber. To generate a model which may be validated through in vivo experiments, an overlying O₂ permeable membrane is included. The model is solved using traditional methods including separation of variables and Fourier decomposition, and to ensure smooth profiles at the muscle-muscle and muscle-membrane interfaces matching conditions are developed. The study presents qualitative verification for the model, using visualizations of tissue PO₂ distributions for varying capillary density (CD), and presents capillary velocity response values in the near layer for varying chamber PO₂ under the assumption that outlet capillary O₂ saturation is equalized between adjacent layers. These compensatory velocity profiles, along with effective 'no-flux' chamber PO₂ values, are presented for varying CD and tissue O₂ consumption values. Insights gained from the two-layer model provide guidance for interpreting and planning future in-vivo experiments, and also provide motivation for further development of the model to improve understanding of the interaction between O₂ transport and blood flow regulation.

Salivary anti-nuclear antibody (ANA) mirrors serum ANA in systemic lupus erythematosus

OBJECTIVES

To assay salivary anti-nuclear antibody (ANA) and its isotypes in patients with systemic lupus erythematosus (SLE) and to investigate relevant clinical associations.

METHODS

Saliva samples were collected from SLE patients and assayed for salivary ANA using immunofluorescence (IF). Isotypes of salivary ANA, including IgG-ANA, IgA-ANA, and IgM-ANA, were quantified using enzyme-linked immunosorbent assay. The correlations between clinical parameters and levels of salivary ANA and isotypes were evaluated.

RESULTS

Salivary ANA IF intensities were significantly higher in SLE patients than in healthy controls, irrespective of SLE patient disease activity, and strongly correlated with serum ANA titers. Salivary ANA was detected in 67.14% of SLE patients and 10.00% of healthy controls (p < 0.001). Among ANA-positive samples, 80.85% exhibited a nuclear ANA pattern, and 42.55% exhibited a cytoplasmic ANA pattern. Salivary IgG-ANA, IgA-ANA, and IgM-ANA levels, as assayed by ELISA, were significantly increased in both active and less active SLE patients compared with healthy controls, and levels of each isotype were significantly correlated with serum ANA titer. Salivary IgM-ANA levels correlated with the physician global assessment (PGA), SLE disease activity index (SLEDAI), and negatively with serum C3 and C4. Salivary IgG-ANA also correlated with erythrocyte sedimentation rate (ESR), SLEDAI, and negatively with serum C3.

CONCLUSION

Salivary ANA levels correlate with serum ANA titer, and salivary IgM-ANA and IgG-ANA correlate variably with PGA, SLEDAI, ESR and complement levels. These findings underscore the potential of using salivary ANA and ANA isotypes as surrogates for serum ANA, particularly for future point-of-care applications since saliva is easier to obtain than blood.

The oral microbiome in alcohol use disorder: a longitudinal analysis during inpatient treatment

Background

Alcohol use disorder (AUD)-induced disruption of oral microbiota can lead to poor oral health; there have been no studies published examining the longitudinal effects of alcohol use cessation on the oral microbiome.

Aim

To investigate the oral microbiome during alcohol cessation during inpatient treatment for AUD.

Methods

Up to 10 oral tongue brushings were collected from 22 AUD patients during inpatient treatment at the National Institutes of Health. Alcohol use history, smoking, and periodontal disease status were measured. Oral microbiome samples were sequenced using 16S rRNA gene sequencing.

Results

Alpha diversity decreased linearly during treatment across the entire cohort (P = 0.002). Alcohol preference was associated with changes in both alpha and beta diversity measures. Characteristic tongue dorsum genera from the Human Microbiome Project such as Streptococcus, Prevotella, Veillonella and Haemophilus were highly correlated in AUD. Oral health-associated genera that changed longitudinally during abstinence included Actinomyces, Capnocytophaga, Fusobacterium, Neisseria and Prevotella.

Conclusion

The oral microbiome in AUD is affected by alcohol preference. Patients with AUD often have poor oral health but abstinence and attention to oral care improve dysbiosis, decreasing microbiome diversity and periodontal disease-associated genera while improving acute oral health.

Loss of antiphospholipid antibody positivity post-thrombosis in SLE

Background/Purpose

Loss of positivity of antiphospholipid antibodies has been observed in clinical practice post-thrombosis in patients with SLE with secondary antiphospholipid syndrome (APS). Our study defined the frequency of this loss and the duration before positivity recurred.

Methods

In this prospective study, patients with SLE having at least two positive antiphospholipid markers prior to thrombosis and at least 1 year of follow-up after thrombosis were included. Antiphospholipid markers included lupus anticoagulant (dilute Russell viper venom test >45 s followed by mixing and confirmatory tests) and/or anticardiolipin titre (aCL IgG ≥20, aCL IgM ≥20 and/or aCL IgA ≥20). The percentage of visits with positive antiphospholipid markers after thrombosis was calculated. For patients with a negative antiphospholipid marker any time after thrombosis, survival estimates were performed to calculate the time to return of antiphospholipid positivity.

Results

In APS due to SLE, complete loss of antiphospholipid positivity post-thrombosis was up to 41% for aCL IgG, 51% for IgM and 50% for IgA, but only 20% for those with lupus anticoagulant. Of those who at some point lost aCL IgG or became negative for lupus anticoagulant, the majority (60% and 76%, respectively) reacquired the antibody within 5 years. In contrast, of those who lost aCL IgM or IgA, fewer reacquired it within 5 years (37% and 17%, respectively).

Conclusion

Intermittent positivity of antiphospholipid antibodies is present in APS due to SLE. These fluctuations make it difficult to decide on length of anticoagulation. Lupus anticoagulant is more likely to persist post-thrombosis.

Notch signaling via Hey1 and Id2b regulates Müller glia's regenerative response to retinal injury

Zebrafish Müller glia (MG) respond to retinal injury by suppressing Notch signaling and producing progenitors for retinal repair. A certain threshold of injury-derived signal must be exceeded in order to engage MG in a regenerative response (MG's injury-response threshold). Pan-retinal Notch inhibition expands the zone of injury-responsive MG at the site of focal injury, suggesting that Notch signaling regulates MG's injury-response threshold. We found that Notch signaling enhanced chromatin accessibility and gene expression at a subset of regeneration-associated genes in the uninjured retina. Two Notch effector genes, hey1 and id2b, were identified that reflect bifurcation of the Notch signaling pathway, and differentially regulate MG's injury-response threshold and proliferation of MG-derived progenitors. Furthermore, Notch signaling component gene repression in the injured retina suggests a role for Dll4, Dlb, and Notch3 in regulating Notch signaling in MG and epistasis experiments confirm that the Dll4/Dlb-Notch3-Hey1/Id2b signaling pathway regulates MG's injury-response threshold and proliferation.

Association of cervical spine signs and symptoms with temporomandibular disorders in adults: a systematic review protocol

OBJECTIVE

The objective of this systematic review is to assess the evidence of association of cervical spine signs and symptoms with temporomandibular disorders (TMD). This will help to lend credence to mechanisms supporting the association in order to improve care strategies for this condition.

INTRODUCTION

The association of cervical spine impairments (in relation to neck posture, cervical spine mobility, muscle tenderness, muscle activity, and neck disability) with TMD has been widely discussed in the literature. Clarification of this relationship is important for health professionals to better assess and treat TMD.

INCLUSION CRITERIA

Eligible studies will include participants aged 18 years and over, with a diagnosis of TMD from the Research and Diagnostic Criteria for Temporomandibular Disorders or a revised version. Exclusion criteria will be participants with previous temporomandibular joint surgery, history of trauma or fracture in the temporomandibular joint or the craniomandibular system; serious comorbid conditions such as cancer, rheumatic disease, and neurological problems; primary cervical spine disorders such as disc herniation or spinal degenerative changes; or systemic disease such as ankylosing spondylitis.

METHODS

The search for articles will be conducted in the databases PubMed, PEDro, CINAHL, Web of Science, and Embase, without language or time restrictions. Two independent reviewers will review the title, abstract, and full texts of identified studies; select studies against the inclusion criteria; assess the methodological quality of eligible studies using critical appraisal tools; and perform data extraction. Relevant quantitative data will be pooled with statistical meta-analysis, when possible.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42019123698.

Evidence for role of capillaries in regulation of skeletal muscle oxygen supply

How oxygen (O₂ ) supply to capillaries is regulated to match the tissue's demand is unknown. Erythrocytes have been proposed as sensors in this regulatory mechanism since they release ATP, a vasodilator, in an oxygen saturation (SO₂ )-dependent manner. ATP causes hyperpolarization of endothelial cells resulting in conducted vasodilation to arterioles.

OBJECTIVE

We propose individual capillary units can regulate their own O₂ supply by direct communication to upstream arterioles via electrically coupled endothelium.

METHODS

To test this hypothesis, we developed a transparent micro-exchange device for localized O₂ exchange with surface capillaries of intact tissue. The device was fabricated with an O₂ permeable micro-outlet 0.2 × 1.0 mm. Experiments were performed on rat extensor digitorum longus (EDL) muscle using dual wavelength video microscopy to measure capillary hemodynamics and erythrocyte SO₂ . Responses to local O₂ perturbations were measured with only capillaries positioned over the micro-outlet.

RESULTS

Step changes in the gas mixture %O₂ caused physiological changes in erythrocyte SO₂ , and appropriate changes in flow to offset the O₂ challenge if at least 3-4 capillaries were stimulated.

CONCLUSION

These results support our hypothesis that individual capillary units play a role in regulating their erythrocyte supply in response to a changing O₂ environment.

The capillary fascicle in skeletal muscle: Structural and functional physiology of RBC distribution in capillary networks

KEY POINTS

The capillary module, consisting of parallel capillaries from arteriole to venule, is classically considered as the building block of complex capillary networks. In skeletal muscle, this structure fails to address how blood flow is regulated along the entire length of the synchronously contracting muscle fibres. Using intravital video microscopy of resting extensor digitorum longus muscle in rats, we demonstrated the capillary fascicle as a series of interconnected modules forming continuous columns that align naturally with the dimensions of the muscle fascicle. We observed structural heterogeneity for module topology, and functional heterogeneity in space and time for capillary-red blood cell (RBC) haemodynamics within a module and between modules. We found that module RBC haemodynamics were independent of module resistance, providing direct evidence for microvascular flow regulation at the level of the capillary module. The capillary fascicle is an updated paradigm for characterizing blood flow and RBC distribution in skeletal muscle capillary networks.

ABSTRACT

Capillary networks are the fundamental site of oxygen exchange in the microcirculation. The capillary module (CM), consisting of parallel capillaries from terminal arteriole (TA) to post-capillary venule (PCV), is classically considered as the building block of complex capillary networks. In skeletal muscle, this structure fails to address how blood flow is regulated along the entire length of the synchronously contracting muscle fibres, requiring co-ordination from numerous modules. It has previously been recognized that TAs and PCVs interact with multiple CMs, creating interconnected networks. Using label-free intravital video microscopy of resting extensor digitorum longus muscle in rats, we found that these networks form continuous columns of linked CMs spanning thousands of microns, herein denoted as the capillary fascicle (CF); this structure aligns naturally with the dimensions of the muscle fascicle. We measured capillary-red blood cell (RBC) haemodynamics and module topology (n = 9 networks, 327 modules, 1491 capillary segments). The average module had length 481 μm, width 157 μm and 9.51 parallel capillaries. We observed structural heterogeneity for CM topology, and functional heterogeneity in space and time for capillary-RBC haemodynamics within a module and between modules. There was no correlation between capillary RBC velocity and lineal density. A passive inverse relationship between module length and haemodynamics was remarkably absent, providing direct evidence for microvascular flow regulation at the level of the CM. In summary, the CF is an updated paradigm for characterizing RBC distribution in skeletal muscle, and strengthens the theory of capillary networks as major contributors to the signal that regulates capillary perfusion.

Association of systemic lupus erythematosus autoantibody diversity with breast cancer protection

Background

Epidemiologic data suggest that patients with systemic lupus erythematosus (SLE) have a lower risk of breast cancer than women in the general population. In light of mechanistic studies suggesting that anti-DNA antibodies have anti-cancer effects, we sought to examine breast cancer risk in autoantibody strata in a well-characterized SLE cohort.

Methods

SLE patients without a cancer diagnosis prior to entry in the Hopkins Lupus Cohort were studied (N = 2431). Overall and site-specific cancer incidence was calculated in racial strata and compared with the US Surveillance, Epidemiology and End Results (SEER) registry. Breast cancer incidence was further examined in autoantibody subsets. Patients were considered positive for an autoantibody if they were ever positive for a specificity during their disease course.

Results

Patients with SLE had a 37% lower risk of breast cancer (SIR 0.63, 95% CI 0.39–0.95). The risk of HPV-associated cancers (SIR 4.39, 95% CI 2.87–6.44) and thyroid cancer (SIR 2.27, 95% CI 1.04–4.30) was increased. Cancer risk varied by race, with breast cancer protection occurring in non-African Americans (SIR 0.29, 95% CI 0.11–0.63) and the increased risk of HPV-associated cancers occurring in African Americans (SIR 7.23, 95% CI 4.35–11.3). Breast cancer risk was decreased in patients ever positive for anti-dsDNA (SIR 0.55, 95% CI 0.29–0.96), anti-La (SIR 0.00, 95% CI 0.00–0.78), and lupus anticoagulant (SIR 0.37, 95% CI 0.10–0.94). Patients who were positive for fewer (0–2) SLE autoantibodies did not have a lower risk of breast cancer (SIR 0.84, 95% CI 0.47–1.39), but patients with 3+ autoantibodies had a 59% decreased risk (SIR 0.41, 95% CI 0.16–0.84).

Conclusions

Positivity for multiple SLE autoantibodies was associated with a lower risk of breast cancer, supporting the hypothesis that a highly diversified immune response may exert an anti-cancer effect against some cancers. Validation of racial differences in cancer risk in SLE is required to determine whether cancer screening strategies should be targeted to racial subgroups.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02449-3.

A two-compartment model of oxygen transport in skeletal muscle using continuously distributed capillaries

For future application to studying regulation of microvascular oxygen delivery, a model is developed for O₂ transport within an idealized volume of tissue, that is perfused by a continuous distribution of capillaries. Considering oxygen diffusion, convection, and consumption, an O₂-dependent transfer term between the capillaries and tissue is used to extend previous single-compartment approaches to include separate tissue and capillary compartments. The coupled tissue-capillary PDE system is considered for unidirectional capillary flow in z, as a simplified model of O₂ transport in skeletal muscle, and steady-state 2D solutions are obtained using boundary conditions in x that are consistent with two experimental situations of interest. To validate the continuous capillary model, comparisons are made of an exact nonlinear solution (for no flux at x=0) to results of an established discrete capillary model (solved via finite differences) for varying capillary density, O₂ consumption rate, and red blood cell velocity. In addition, comparisons of an approximate linearized solution (for fixed PO₂ at x=0) are made to the corresponding discrete capillary solution. Results of the continuous capillary model are presented for varying inlet O₂ saturation, showing the utility of the new model for studying physiological problems. Numerical solution of the new model for problems with time dependence and complex geometry is expected to be substantially more efficient than for the corresponding discrete capillary problems.

Perspectives of Veterans Affairs mental health providers on working with older adults with dementia and their caregivers

Continuing education directed at building providers' skills and knowledge in geriatrics represents a practical approach to addressing the geriatric mental health (MH) care workforce shortage. To inform the development of professional training curricula, we surveyed MH providers (N = 65) at a Veterans Affairs medical center on working with older persons with dementia (PwD) and informal caregivers. Providers rated service provision to PwD and caregivers as highly important but endorsed modest self-efficacy. Half of respondents were minimally confident in managing risk of harm to self or others in a PwD. Respondents believed PwD can benefit from MH treatments, yet identified several barriers to providing care, including inadequate time and staffing resources. Interest in geriatric training topics was high. Findings demonstrate that MH providers at this site value care provision to PwD and caregivers, and desire additional training to serve this population. System-level barriers to MH care for PwD should also be identified and addressed.

Voluntary Cyclical Distancing: A Potential Alternative to Constant Level Mandatory Social Distancing, Relying on an "Infection Weather Report"

COVID-19 has significantly changed our daily lives. Stay-at-home orders and forced closings of all non-essential businesses had a significant impact on our economy. While it is important to ensure that the healthcare system is not overwhelmed, there are many questions that remain about the efficacy of extreme social distancing, and whether there are alternatives to mandatory lockdowns. This paper analyzes the utility of various levels of social distancing, and suggests an alternative approach using voluntary distancing informed by an infectious load index or "infection weather report."

Steady-State Tissue Oxygen Distributions Calculated by a Green's Function Method and a Finite Difference Method: A Comparison

Simulations that are meant to determine the steady-state distribution of a diffusible solute such as oxygen in tissues have typically used finite difference methods to solve the diffusion equation. Finite difference methods require a tissue mesh with enough points to resolve oxygen gradients near and between discrete blood vessels. The large number of points that are typically required can make these calculations very slow. In this paper, we investigate a numerical method known as the Green's function method which is not bound by the same constraint. The Green's function method is expected to yield an accurate oxygen distribution more quickly by requiring fewer mesh points. Both methods were applied to calculate the steady state oxygen distribution in a model simulation region. When the Green's function calculation used meshes with 1/2, 1/4 and, 1/8 of the resolution required for the finite-difference mesh, there was good agreement with the finite difference calculation in all cases. When the volume of the domain was increased 8-fold the Green's function method was able to calculate the O₂ field in 22 minutes, whereas the finite difference calculation is expected to take approximately 1 week. The number of steps required for the Green's function calculation increases quadratically with the number of points in the tissue mesh. As a result, small meshes are calculated very quickly using Green's functions, while for larger mesh sizes this method experiences a significant decrease in efficiency.

Cutaneous vasculitis in SLE

Objectives

We determined the temporal association between clinical and serological disease manifestations and development of cutaneous small vessel vasculitis in a large prospective multiethnic cohort.

Methods

Patients with SLE diagnosed according to the Systemic Lupus International Collaborating Clinics (SLICC) classification criteria or the revised classification criteria as defined by the American College of Rheumatology (ACR) were enrolled in the Hopkins Lupus Cohort. Cutaneous small vessel vasculitis was determined as a component of the Systemic Lupus Erythematosus Disease Activity Index. SLE-associated cutaneous small vessel vasculitis lesions were reported clinically. They presented as punctate lesions, palpable purpura, tender erythematous plaques or macules with or without necrosis. No histopathological diagnosis was pursued to confirm the diagnosis of vasculitis or to differentiate it from other causes of digital lesions in patients with SLE. Disease manifestations that preceded the first occurrence of cutaneous small vessel vasculitis lesions were analysed using Kaplan-Meier. Cox regression analysis was used to assess the relationship between baseline clinical and immunological manifestations and the development of cutaneous small vessel vasculitis. We adjusted for gender, race and age at SLE diagnosis.

Results

A total of 2580 patients were studied: 52.4% were Caucasian and 39.4% were African-American. The mean age of the cohort was 45.5±14.5 years. The mean years of cohort follow-up was 7.9±7.6. Cutaneous small vessel vasculitis was observed in 449 (17.3%). The mean time to cutaneous vasculitis after SLE diagnosis was 4.78 years (95% CI 3.96 to 5.60). At least 159 (35%) patients had recurrences of cutaneous vasculitis lesions. Discoid rash, Raynaud’s phenomenon, myositis, anaemia, Coombs’ positivity, leucopenia, anti-Smith and anti-RNP (Ribonucleoprotein) were significantly associated with the development of cutaneous vasculitis. The SLICC/ACR Damage Index score was higher in patients with cutaneous vasculitis compared with those without cutaneous vasculitis.

Conclusions

Cutaneous vasculitis is frequent (17.3%) and often recurrent (35%). African-Americans are at higher risk of developing cutaneous small vessel vasculitis than Caucasians. Clinical presentations such as myositis and haematological manifestations are predictors of cutaneous vasculitis development. The presence of cutaneous vasculitis is associated with increased organ damage.