Novel Insights into the Pathobiology of Pulmonary Hypertension in Heart Failure with Preserved Ejection Fraction

Heart failure (HF) with preserved ejection fraction (HFpEF) is the most common cause of pulmonary hypertension (PH) worldwide and is strongly associated with adverse clinical outcomes. The American Heart Association recently highlighted a call to action regarding the distinct lack of evidence-based treatments for PH due to poorly understood pathophysiology of PH attributable to HFpEF (PH-HFpEF). Prior studies have described cardio-physiological mechanisms to explain the development of isolated postcapillary PH (ipc-PH); however, the consequent increased pulmonary vascular (PV) resistance (PVR) may lead to the less understood and more fatal combined pre- and postcapillary PH (cpc-PH). Metabolic disease and inflammatory dysregulation have been suggested to predispose cpc-PH, yet the molecular mechanisms are unknown. Although PH-HFpEF has been studied to partly share vasoactive neurohormonal mediators with primary pulmonary arterial hypertension (PAH), clinical trials that have targeted these pathways have been unsuccessful. The increased mortality of PH-HFpEF patients necessitates further study into viable mechanistic targets involved in disease progression. We aim to summarize the current pathophysiological and clinical understanding of PH-HFpEF, highlight the role of known molecular mechanisms in the progression of PV disease, and introduce a novel concept that lipid metabolism may be attenuating and propagating PH-HFpEF.

The Association Between Well-Being and Empathy in Medical Residents: A Cross-Sectional Survey

Objective: To evaluate the extent to which personal well-being may be associated with empathy, while controlling for potential confounders. Settings/Location: Residency programs throughout the United States. Subjects: A total of 407 medical residents from residencies including general medicine, surgery, specialized and diagnostic medicine participated in this study. Outcome Measures: Well-being was measured using the modified existential well-being subscale of the spiritual well-being scale. Empathy was measured using the Jefferson Scale of Empathy. Results: Well-being was found to be positively correlated with empathy when adjusted for possible confounders (p < 0.001). In addition to well-being, other factors noted to be statistically significant contributors to higher empathy scores while controlling for the others included age, gender, year in residency, specialty, and work-hours (p < 0.05 for each). After controlling for these factors, a resident's year in residency was not found to be a statistically significant contributor to empathy score. Conclusions: In this study, well-being was associated with empathy in medical and surgical residents. Empathy is a fundamental component of physician competency, and its development is an essential aspect of medical training. These findings suggest that efforts to increase well-being may promote empathy among medical residents.

A Case Series of Potential Pediatric Cyanotoxin Exposures Associated with Harmful Algal Blooms in Northwest Ohio

Cyanobacterial harmful algal blooms (CyanoHABs) are increasing in prevalence and severity in the Great Lakes region, as well as both globally and locally. CyanoHABs have the potential to cause adverse effects on human health due to the production of cyanotoxins from cyanobacteria. Common routes of exposure include recreational exposure (swimming, skiing, and boating), ingestion, and aerosolization of contaminated water sources. Cyanotoxins have been shown to adversely affect several major organ systems contributing to hepatotoxicity, gastrointestinal distress, and pulmonary inflammation. We present three pediatric case reports that coincided with CyanoHABs exposure with a focus on presentation of illness, diagnostic work-up, and treatment of CyanoHAB-related illnesses. Potential cyanotoxin exposure occurred while swimming in the Maumee River and Maumee Bay of Lake Erie in Ohio during the summer months with confirmed CyanoHAB activity. Primary symptoms included generalized macular rash, fever, vomiting, diarrhea, and severe respiratory distress. Significant labs included leukocytosis and elevated C-reactive protein. All patients ultimately recovered with supportive care. Symptoms following potential cyanotoxin exposure coincide with multiple disease states representing an urgent need to develop specific diagnostic tests of exposure.

Building a new regional home for implementation science: Annual Midwest Clinical & Translational Research Meetings

The vision of the Central Society for Clinical and Translational Research (CSCTR) is to "promote a vibrant, supportive community of multidisciplinary, clinical, and translational medical research to benefit humanity." Together with the Midwestern Section of the American Federation for Medical Research, CSCTR hosts an Annual Midwest Clinical & Translational Research Meeting, a regional multispecialty meeting that provides the opportunity for trainees and early-stage investigators to present their research to leaders in their fields. There is an increasing national and global interest in implementation science (IS), the systematic study of activities (or strategies) to facilitate the successful uptake of evidence-based health interventions in clinical and community settings. Given the growing importance of this field and its relevance to the goals of the CSCTR, in 2022, the Midwest Clinical & Translational Research Meeting incorporated new initiatives and sessions in IS. In this report, we describe the role of IS in the translational research spectrum, provide a summary of sessions from the 2022 Midwest Clinical & Translational Research Meeting, and highlight initiatives to complement national efforts to build capacity for IS through the annual meetings.

Novel Model of Oxalate Diet-Induced Chronic Kidney Disease in Dahl-Salt-Sensitive Rats

Diet-induced models of chronic kidney disease (CKD) offer several advantages, including clinical relevance and animal welfare, compared with surgical models. Oxalate is a plant-based, terminal toxic metabolite that is eliminated by the kidneys through glomerular filtration and tubular secretion. An increased load of dietary oxalate leads to supersaturation, calcium oxalate crystal formation, renal tubular obstruction, and eventually CKD. Dahl-Salt-Sensitive (SS) rats are a common strain used to study hypertensive renal disease; however, the characterization of other diet-induced models on this background would allow for comparative studies of CKD within the same strain. In the present study, we hypothesized that SS rats on a low-salt, oxalate rich diet would have increased renal injury and serve as novel, clinically relevant and reproducible CKD rat models. Ten-week-old male SS rats were fed either 0.2% salt normal chow (SS-NC) or a 0.2% salt diet containing 0.67% sodium oxalate (SS-OX) for five weeks.Real-time PCR demonstrated an increased expression of inflammatory marker interleukin-6 (IL-6) (p < 0.0001) and fibrotic marker Timp-1 metalloproteinase (p < 0.0001) in the renal cortex of SS-OX rat kidneys compared with SS-NC. The immunohistochemistry of kidney tissue demonstrated an increase in CD-68 levels, a marker of macrophage infiltration in SS-OX rats (p < 0.001). In addition, SS-OX rats displayed increased 24 h urinary protein excretion (UPE) (p < 0.01) as well as significant elevations in plasma Cystatin C (p < 0.01). Furthermore, the oxalate diet induced hypertension (p < 0.05). A renin-angiotensin-aldosterone system (RAAS) profiling (via liquid chromatography-mass spectrometry; LC-MS) in the SS-OX plasma showed significant (p < 0.05) increases in multiple RAAS metabolites including angiotensin (1-5), angiotensin (1-7), and aldosterone. The oxalate diet induces significant renal inflammation, fibrosis, and renal dysfunction as well as RAAS activation and hypertension in SS rats compared with a normal chow diet. This study introduces a novel diet-induced model to study hypertension and CKD that is more clinically translatable and reproducible than the currently available models.

Occupational Characteristics Associated With Professional Fulfillment and Burnout Among US Physiatrists

INTRODUCTION

Multiple national studies suggest that among physicians, physiatrists are at increased risk for occupational burnout.

OBJECTIVE

The aim of the study is to identify characteristics of the work environment associated with professional fulfillment and burnout among US physiatrists.

DESIGN

Between May and December 2021, a mixed qualitative and quantitative approach was used to identify factors contributing to professional fulfillment and burnout in physiatrists.

SETTING

Online interviews, focus groups, and survey were conducted.

PARTICIPANTS

The participants are physiatrists in the American Academy of Physical Medicine and Rehabilitation Membership Masterfile.

MAIN OUTCOME MEASURES

Burnout and professional fulfillment were assessed using the Stanford Professional Fulfillment Index.

RESULTS

Individual interviews with 21 physiatrists were conducted to identify domains that contributed to professional fulfillment followed by focus groups for further definition. Based on themes identified, scales were identified or developed to evaluate: control over schedule (6 items, Cronbach α = 0.86); integration of physiatry into patient care (3 items, Cronbach α = 0.71); personal-organizational values alignment (3 items, Cronbach α = 0.90); meaningfulness of physiatrist clinical work (6 items, Cronbach α = 0.90); teamwork and collaboration (3 items, Cronbach α = 0.89). Of 5760 physiatrists contacted in the subsequent national survey, 882 (15.4%) returned surveys (median age, 52 yrs; 46.1% women). Overall, 42.6% (336 of 788) experienced burnout and 30.6% (244 of 798) had high levels of professional fulfillment. In multivariable analysis, each one-point improvement in control over schedule (odds ratio = 1.96; 95% confidence interval = 1.45-2.69), integration of physiatry into patient care (odds ratio = 1.77; 95% confidence interval = 1.32-2.38), personal-organizational values alignment (odds ratio = 1.92; 95% confidence interval = 1.48-2.52), meaningfulness of physiatrist clinical work (odds ratio = 2.79; 95% confidence interval = 1.71-4.71), and teamwork and collaboration score (odds ratio = 2.11; 95% confidence interval = 1.48-3.03) was independently associated with higher likelihood of professional fulfillment.

CONCLUSIONS

Control over schedule, optimal integration of physiatry into clinical care, personal-organizational values alignment, teamwork, and meaningfulness of physiatrist clinical work are strong and independent drivers of occupational well-being in US physiatrists. Variation in these domains by practice setting and subspecialty suggests that tailored approaches are needed to promote professional fulfillment and reduce burnout among US physiatrists.

Paraoxonases at the Heart of Neurological Disorders

Paraoxonase enzymes serve as an important physiological redox system that participates in the protection against cellular injury caused by oxidative stress. The PON enzymes family consists of three members (PON-1, PON-2, and PON-3) that share a similar structure and location as a cluster on human chromosome 7. These enzymes exhibit anti-inflammatory and antioxidant properties with well-described roles in preventing cardiovascular disease. Perturbations in PON enzyme levels and their activity have also been linked with the development and progression of many neurological disorders and neurodegenerative diseases. The current review summarizes the available evidence on the role of PONs in these diseases and their ability to modify risk factors for neurological disorders. We present the current findings on the role of PONs in Alzheimer's disease, Parkinson's disease, and other neurodegenerative and neurological diseases.

Occupational Characteristics Associated with Professional Fulfillment and Burnout Among U.S. Physiatrists

INTRODUCTION

Multiple national studies suggest that, among physicians, physiatrists are at increased risk for occupational burnout.

OBJECTIVE

Identify characteristics of the work environment associated with professional fulfillment and burnout among U.S. physiatrists.

DESIGN

Between May and December 2021, a mixed qualitative and quantitative approach was used to identify factors contributing to professional fulfillment and burnout in physiatrists.

SETTING

Online interviews, focus groups, and survey PARTICIPANTS: physiatrists in the AAPM&R Membership Masterfile MAIN OUTCOME MEASURES: Burnout and professional fulfillment assessed using the Stanford Professional Fulfillment Index RESULTS: Individual interviews with 21 physiatrists were conducted to identify domains that contributed to professional fulfillment followed by focus groups for further definition. Based on themes identified, scales were identified or developed to evaluate: control over schedule (6 items; Cronbach's alpha=0.86); integration of physiatry into patient care (3 items; Cronbach's alpha=0.71); personal-organizational values alignment (3 items; Cronbach's alpha=0.90); meaningfulness of physiatrist clinical work (6 items; Cronbach's alpha=0.90); teamwork and collaboration (3 items; Cronbach's alpha=0.89). Of 5760 physiatrists contacted in the subsequent national survey, 882 (15.3%) returned surveys (median age 52 years; 46.1% women). Overall, 42.6% (336 or 788) experienced burnout and 30.6% (224 of 798) had high levels of professional fulfillment. In multivariable analysis, each one-point improvement in control over schedule (OR=2.00; 95%CI=1.45-2.69), integration of physiatry into patient care (OR=1.77; 95%CI=1.32-2.38), personal-organizational-values alignment (OR=1.92; 95%CI=1.48-2.52), meaningfulness of physiatrist clinical work (OR=2.79; 95%CI=1.71-4.71) and teamwork and collaboration score (OR=2.11; 95%CI=1.48-3.03) was independently associated with higher likelihood of professional fulfillment.

CONCLUSIONS

Control over schedule, optimal integration of physiatry into clinical care, personal-organizational values alignment, teamwork, and meaningfulness of physiatrist clinical work are strong and independent drivers of occupational well-being in U.S. physiatrists. Variation in these domains by practice setting and sub-specialty suggests tailored approaches are needed to promote professional fulfillment and reduce burnout among US physiatrists.

Eutherian-Specific Functions of BetaM Acquired through Atp1b4 Gene Co-Option in the Regulation of MyoD Expression

Vertebrate ATP1B4 genes represent a rare instance of orthologous gene co-option, resulting in radically different functions of the encoded BetaM proteins. In lower vertebrates, BetaM is a Na, K-ATPase β-subunit that is a component of ion pumps in the plasma membrane. In placental mammals, BetaM lost its ancestral role and, through structural alterations of the N-terminal domain, became a skeletal and cardiac muscle-specific protein of the inner nuclear membrane, highly expressed during late fetal and early postnatal development. We previously determined that BetaM directly interacts with the transcriptional co-regulator SKI-interacting protein (SKIP) and is implicated in the regulation of gene expression. This prompted us to investigate a potential role for BetaM in the regulation of muscle-specific gene expression in neonatal skeletal muscle and cultured C2C12 myoblasts. We found that BetaM can stimulate expression of the muscle regulatory factor (MRF), MyoD, independently of SKIP. BetaM binds to the distal regulatory region (DRR) of MyoD, promotes epigenetic changes associated with activation of transcription, and recruits the SWI/SNF chromatin remodeling subunit, BRG1. These results indicate that eutherian BetaM regulates muscle gene expression by promoting changes in chromatin structure. These evolutionarily acquired new functions of BetaM might be very essential and provide evolutionary advantages to placental mammals.

Radiofrequency Ablation for Chronic Lumbar Zygapophyseal Joint Pain Using a V-Shaped Active Tip Needle: An Observational Retrospective Study

Background

Lumbar zygapophyseal joint dysfunction represents one of the major sources of chronic low back pain. Radiofrequency ablation (RFA) using a V-shaped active tip needle may offer a larger lesion of the medial branch nerves, improving clinical outcome. The aim of our study is to evaluate the efficacy and the feasibility of RFA using V-shaped active tip needles.

Methods

This is a single-center observational retrospective study. Clinical records were screened and analyzed if they met the following inclusion criteria: adult patients (>18 years), diagnosis of chronic lumbar zygapophyseal joint pain, failure of conservative treatments, ability to provide informed consent for data analysis and publication. Exclusion criteria: lumbar pain not related to zygapophyseal joints, previous spinal/lumbar surgery, incomplete data, absence or withdrawal of informed consent. The primary outcome of the study was a change in pain intensity at follow-up. The secondary outcomes were the evaluation of quality-of-life improvement, the occurrence of adverse events and the impact on post-procedural analgesic consumption. For these purposes, pre- and post-treatment numeric rating scale (NRS), neuropathic pain 4 questions (DN4), EuroQoL - EQ-5D-3L, EQ-VAS, EQ-index and North American Spine Society (NASS) index were retrieved and analysed.

Results

Sixty-four patients were included. 7.8% of patients at 1-month (CI95% 0.026, 0.173), 37.5% at 3-month (CI95% 0.257, 0.505), 40.6% at 6-month (CI95% 0.285, 0.536) and 35.9% at 9-month (CI95% 0.243, 0.489) follow-up reported a reduction of more than 80% in NRS Statistical analysis indicated a significant change in NRS, DN4, EQ-index and EQ-5D-VAS (p-value <0.001) at the different time-points.

Conclusion

RFA using a V-shaped active tip needle might be a feasible and effective treatment for chronic lumbar zygapophyseal joint pain.

Quantification of Cardiotonic Steroids Potentially Regulated by Paraoxonase 3 in a Rat Model of Chronic Kidney Disease Using UHPLC-Orbitrap-MS

Endogenous cardiotonic steroids (CTSs), such as telocinobufagin (TCB) and marinobufagin (MBG) contain a lactone moiety critical to their binding and signaling through the Na+/K+-ATPase. Their concentrations elevate in response to sodium intake and under volume-expanded conditions. Paraoxonase 3 (PON3) is an enzyme that can hydrolyze lactone substrates. Here, we examine the role of PON3 in regulating CTS levels in a rat model of chronic kidney diseases (CKD). TCB and MBG were extracted from rat urine samples, and the analyses were carried out using ultra-high pressure liquid chromatography−Orbitrap-mass spectrometry (UHPLC-Orbitrap-MS). Ten-week-old Dahl salt-sensitive wild type (SS-WT) and Dahl salt-sensitive PON3 knockout (SS-PON3 KO) rats were maintained on a high-salt diet (8% NaCl) for 8 weeks to initiate salt-sensitive hypertensive renal disease characteristic of this model. CTS extraction recovery from urine >80% was achieved. For animals maintained on a normal chow diet, the baseline amount of TCB excreted in 24 h urine of SS-PON3 KO rats (6.08 ± 1.47 ng/24 h; or 15.09 ± 3.25 pmol) was significantly higher than for SS-WT rats (1.48 ± 0.69 ng/24 h; or 3.67 ± 1.54 pmol, p < 0.05). Similarly, for the same animals, the amount of excreted MBG was higher in the urine of SS-PON3 KO rats (4.74 ± 1.30 ng/24 h versus 1.03 ± 0.25 ng/24 h in SS-WT; or 11.83 ± 2.91 pmol versus 2.57 ± 0.56 pmol in SS-WT, p < 0.05). For animals on a high-salt diet, the SS-PON3 KO rats had significantly increased levels of TCB (714.52 ± 79.46 ng/24 h; or 1774.85 ± 175.55 pmol) compared to SS-WT control (343.84 ± 157.54 ng/24 h; or 854.09 ± 350.02 pmol, p < 0.05), and comparatively higher levels of MBG were measured for SS-PON3 KO (225.55 ± 82.61 ng/24 h; or 563.19 ± 184.5 pmol) versus SS-WT (157.56 ± 85.53 ng/24 h; or 393.43 ± 191.01 pmol, p > 0.05) rats. These findings suggest that the presence and absence of PON3 dramatically affect the level of endogenous CTSs, indicating its potential role in CTS regulation.

Microcystin-LR aerosol induces inflammatory responses in healthy human primary airway epithelium

Harmful algal blooms plague bodies of freshwater globally. These blooms are often composed of outgrowths of cyanobacteria capable of producing the heptapeptide Microcystin-LR (MC-LR) which is a well-known hepatotoxin. Recently, MC-LR has been detected in aerosols generated from lake water. However, the risk for human health effects due to MC-LR inhalation exposure have not been extensively investigated. In this study, we exposed a fully differentiated 3D human airway epithelium derived from 14 healthy donors to MC-LR-containing aerosol once a day for 3 days. Concentrations of MC-LR ranged from 100 pM to 1 µM. Although there were little to no detrimental alterations in measures of the airway epithelial function (i.e. cell survival, tissue integrity, mucociliary clearance, or cilia beating frequency), a distinct shift in the transcriptional activity was found. Genes related to inflammation were found to be upregulated such as C-C motif chemokine 5 (CCL5; log2FC = 0.57, p = 0.03) and C-C chemokine receptor type 7 (CCR7; log2FC = 0.84, p = 0.03). Functionally, conditioned media from MC-LR exposed airway epithelium was also found to have significant chemo-attractive properties for primary human neutrophils. Additionally, increases were found in the concentration of secreted chemokine proteins in the conditioned media such as CCL1 (log2FC = 5.07, p = 0.0001) and CCL5 (log2FC = 1.02, p = 0.046). These results suggest that MC-LR exposure to the human airway epithelium is capable of inducing an inflammatory response that may potentiate acute or chronic disease.

Cardioprotective Role for Paraoxonase-1 in Chronic Kidney Disease

Paraoxonase-1 (PON-1) is a hydrolytic enzyme associated with HDL, contributing to its anti-inflammatory, antioxidant, and anti-atherogenic properties. Deficiencies in PON-1 activity result in oxidative stress and detrimental clinical outcomes in the context of chronic kidney disease (CKD). However, it is unclear if a decrease in PON-1 activity is mechanistically linked to adverse cardiovascular events in CKD. We investigated the hypothesis that PON-1 is cardioprotective in a Dahl salt-sensitive model of hypertensive renal disease. Experiments were performed on control Dahl salt-sensitive rats (SSMcwi, hereafter designated SS-WT rats) and mutant PON-1 rats (SS-Pon1em1Mcwi, hereafter designated SS-PON-1 KO rats) generated using CRISPR gene editing technology. Age-matched 10-week-old SS and SS-PON-1 KO male rats were maintained on high-salt diets (8% NaCl) for five weeks to induce hypertensive renal disease. Echocardiography showed that SS-PON-1 KO rats but not SS-WT rats developed compensated left ventricular hypertrophy after only 4 weeks on the high-salt diet. RT-PCR analysis demonstrated a significant increase in the expression of genes linked to cardiac hypertrophy, inflammation, and fibrosis, as well as a significant decrease in genes essential to left ventricular function in SS-PON-1 KO rats compared to SS-WT rats. A histological examination also revealed a significant increase in cardiac fibrosis and immune cell infiltration in SS-PON-1 KO rats, consistent with their cardiac hypertrophy phenotype. Our data suggest that a loss of PON-1 in the salt-sensitive hypertensive model of CKD leads to increased cardiac inflammation and fibrosis as well as a molecular and functional cardiac phenotype consistent with compensated left ventricular hypertrophy.

Dirty Jobs: Macrophages at the Heart of Cardiovascular Disease

Cardiovascular disease (CVD) is one of the greatest public health concerns and is the leading cause of morbidity and mortality in the United States and worldwide. CVD is a broad yet complex term referring to numerous heart and vascular conditions, all with varying pathologies. Macrophages are one of the key factors in the development of these conditions. Macrophages play diverse roles in the maintenance of cardiovascular homeostasis, and an imbalance of these mechanisms contributes to the development of CVD. In the current review, we provide an in-depth analysis of the diversity of macrophages, their roles in maintaining tissue homeostasis within the heart and vasculature, and the mechanisms through which imbalances in homeostasis may lead to CVD. Through this review, we aim to highlight the potential importance of macrophages in the identification of preventative, diagnostic, and therapeutic strategies for patients with CVD.

Paraoxonase-1 Regulation of Renal Inflammation and Fibrosis in Chronic Kidney Disease

Papraoxonase-1 (PON1) is a hydrolytic lactonase enzyme that is synthesized in the liver and circulates attached to high-density lipoproteins (HDL). Clinical studies have demonstrated an association between diminished PON-1 and the progression of chronic kidney disease (CKD). However, whether decreased PON-1 is mechanistically linked to renal injury is unknown. We tested the hypothesis that the absence of PON-1 is mechanistically linked to the progression of renal inflammation and injury in CKD. Experiments were performed on control Dahl salt-sensitive rats (SSMcwi, hereafter designated SS rats) and Pon1 knock-out rats (designated SS-Pon1em1Mcwi, hereafter designated SS-PON-1 KO rats) generated by injecting a CRISPR targeting the sequence into SSMcwi rat embryos. The resulting mutation is a 7 bp frameshift insertion in exon 4 of the PON-1 gene. First, to examine the renal protective role of PON-1 in settings of CKD, ten-week-old, age-matched male rats were maintained on a high-salt diet (8% NaCl) for up to 5 weeks to initiate the salt-sensitive hypertensive renal disease characteristic of this model. We found that SS-PON-1 KO rats demonstrated several hallmarks of increased renal injury vs. SS rats including increased renal fibrosis, sclerosis, and tubular injury. SS-PON-1 KO also demonstrated increased recruitment of immune cells in the renal interstitium, as well as increased expression of inflammatory genes compared to SS rats (all p < 0.05). SS-PON-1 KO rats also showed a significant (p < 0.05) decline in renal function and increased renal oxidative stress compared to SS rats, despite no differences in blood pressure between the two groups. These findings suggest a new role for PON-1 in regulating renal inflammation and fibrosis in the setting of chronic renal disease independent of blood pressure.

A PON for All Seasons: Comparing Paraoxonase Enzyme Substrates, Activity and Action including the Role of PON3 in Health and Disease

Paraoxonases (PONs) are a family of hydrolytic enzymes consisting of three members, PON1, PON2, and PON3, located on human chromosome 7. Identifying the physiological substrates of these enzymes is necessary for the elucidation of their biological roles and to establish their applications in the biomedical field. PON substrates are classified as organophosphates, aryl esters, and lactones based on their structure. While the established native physiological activity of PONs is its lactonase activity, the enzymes’ exact physiological substrates continue to be elucidated. All three PONs have antioxidant potential and play an important anti-atherosclerotic role in several diseases including cardiovascular diseases. PON3 is the last member of the family to be discovered and is also the least studied of the three genes. Unlike the other isoforms that have been reviewed extensively, there is a paucity of knowledge regarding PON3. Thus, the current review focuses on PON3 and summarizes the PON substrates, specific activities, kinetic parameters, and their association with cardiovascular as well as other diseases such as HIV and cancer.

As We Drink and Breathe: Adverse Health Effects of Microcystins and Other Harmful Algal Bloom Toxins in the Liver, Gut, Lungs and Beyond

Freshwater harmful algal blooms (HABs) are increasing in number and severity worldwide. These HABs are chiefly composed of one or more species of cyanobacteria, also known as blue-green algae, such as Microcystis and Anabaena. Numerous HAB cyanobacterial species produce toxins (e.g., microcystin and anatoxin—collectively referred to as HAB toxins) that disrupt ecosystems, impact water and air quality, and deter recreation because they are harmful to both human and animal health. Exposure to these toxins can occur through ingestion, inhalation, or skin contact. Acute health effects of HAB toxins have been well documented and include symptoms such as nausea, vomiting, abdominal pain and diarrhea, headache, fever, and skin rashes. While these adverse effects typically increase with amount, duration, and frequency of exposure, susceptibility to HAB toxins may also be increased by the presence of comorbidities. The emerging science on potential long-term or chronic effects of HAB toxins with a particular emphasis on microcystins, especially in vulnerable populations such as those with pre-existing liver or gastrointestinal disease, is summarized herein. This review suggests additional research is needed to define at-risk populations who may be helped by preventative measures. Furthermore, studies are required to develop a mechanistic understanding of chronic, low-dose exposure to HAB toxins so that appropriate preventative, diagnostic, and therapeutic strategies can be created in a targeted fashion.

OUP accepted manuscript

Objective

The study sought to investigate the disease state–dependent risk profiles of patient demographics and medical comorbidities associated with adverse outcomes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections.

Materials and Methods

A covariate-dependent, continuous-time hidden Markov model with 4 states (moderate, severe, discharged, and deceased) was used to model the dynamic progression of COVID-19 during the course of hospitalization. All model parameters were estimated using the electronic health records of 1362 patients from ProMedica Health System admitted between March 20, 2020 and December 29, 2020 with a positive nasopharyngeal PCR test for SARS-CoV-2. Demographic characteristics, comorbidities, vital signs, and laboratory test results were retrospectively evaluated to infer a patient’s clinical progression.

Results

The association between patient-level covariates and risk of progression was found to be disease state dependent. Specifically, while being male, being Black or having a medical comorbidity were all associated with an increased risk of progressing from the moderate disease state to the severe disease state, these same factors were associated with a decreased risk of progressing from the severe disease state to the deceased state.

Discussion

Recent studies have not included analyses of the temporal progression of COVID-19, making the current study a unique modeling-based approach to understand the dynamics of COVID-19 in hospitalized patients.

Conclusion

Dynamic risk stratification models have the potential to improve clinical outcomes not only in COVID-19, but also in a myriad of other acute and chronic diseases that, to date, have largely been assessed only by static modeling techniques.

Budget constrained machine learning for early prediction of adverse outcomes for COVID-19 patients

The combination of machine learning (ML) and electronic health records (EHR) data may be able to improve outcomes of hospitalized COVID-19 patients through improved risk stratification and patient outcome prediction. However, in resource constrained environments the clinical utility of such data-driven predictive tools may be limited by the cost or unavailability of certain laboratory tests. We leveraged EHR data to develop an ML-based tool for predicting adverse outcomes that optimizes clinical utility under a given cost structure. We further gained insights into the decision-making process of the ML models through an explainable AI tool. This cohort study was performed using deidentified EHR data from COVID-19 patients from ProMedica Health System in northwest Ohio and southeastern Michigan. We tested the performance of various ML approaches for predicting either increasing ventilatory support or mortality. We performed post hoc analysis to obtain optimal feature sets under various budget constraints. We demonstrate that it is possible to achieve a significant reduction in cost at the expense of a small reduction in predictive performance. For example, when predicting ventilation, it is possible to achieve a 43% reduction in cost with only a 3% reduction in performance. Similarly, when predicting mortality, it is possible to achieve a 50% reduction in cost with only a 1% reduction in performance. This study presents a quick, accurate, and cost-effective method to evaluate risk of deterioration for patients with SARS-CoV-2 infection at the time of clinical evaluation.

Microcystin-LR (MC-LR) Triggers Inflammatory Responses in Macrophages

We were the first to previously report that microcystin-LR (MC-LR) has limited effects within the colons of healthy mice but has toxic effects within colons of mice with pre-existing inflammatory bowel disease. In the current investigation, we aimed to elucidate the mechanism by which MC-LR exacerbates colitis and to identify effective therapeutic targets. Through our current investigation, we report that there is a significantly greater recruitment of macrophages into colonic tissue with pre-existing colitis in the presence of MC-LR than in the absence of MC-LR. This is seen quantitatively through IHC staining and the enumeration of F4/80-positive macrophages and through gene expression analysis for Cd68, Cd11b, and Cd163. Exposure of isolated macrophages to MC-LR was found to directly upregulate macrophage activation markers Tnf and Il1b. Through a high-throughput, unbiased kinase activity profiling strategy, MC-LR-induced phosphorylation events were compared with potential inhibitors, and doramapimod was found to effectively prevent MC-LR-induced inflammatory responses in macrophages.

Characteristics of ambulatory spine care visits in the United States, 2009-2016

BACKGROUND

Back pain is a leading reason for seeking care in the United States (US), and is a major cause of morbidity.

OBJECTIVE

To analyze demographic, patient, and visit characteristics of adult ambulatory spine clinic visits in the United States from 2009-2016.

METHODS

Data from the National Ambulatory Medical Care Survey from 2009-2016 were used and were sample weighted.

RESULTS

Most patients presenting for ambulatory spine care were 45-64 years (45%), were most commonly female (56.8%), and private insurance (45%) and Medicare (26%) were most common payors. The percentage of visits for spine care done at a primary care setting was 50.1% in 2009-2010 and 48.3% in 2014-2015. Approximately 15.5% were seen in orthopedic surgery clinics in 2009-2010 and 7.3% in 2015-2016. MRI was utilized in 11.7% in 2009-2010 and 11.0% in 2015-2016. Physical therapy was prescribed in 13.2% and narcotic analgesic medications were prescribed in 36.2% of patients in 2015-2016.

CONCLUSIONS

MRI was used more frequently than guidelines recommended, and physical therapy was less frequently utilized despite evidence. A relatively high use of opiates in treatment of back pain was reported and is concerning. Although back pain represents a substantial public health burden in the United States, the delivery of care is not evidence-based.

Validity of Physical Exam Maneuvers in the Diagnosis of Sacroiliac Joint Pathology

BACKGROUND

A combination of physical examination maneuvers is currently considered necessary to help predict who will respond to injections in the sacroiliac joint. However, the literature on this topic currently consists of conflicting studies, with one showing the value of a combination of exam maneuvers and the other showing no real value.

OBJECTIVE

To determine the diagnostic validity of sacroiliac joint (SIJ) physical exam maneuvers using anesthetic intra-articular injection as a reference standard.

DESIGN

A single institution prospective study.

PARTICIPANTS

Patients with the clinical diagnosis of SIJ pain and referred for SIJ injection were enrolled.

MAIN OUTCOME MEASURE

Numeric rating scale (NRS) to assess pain intensity.

RESULTS

Participants underwent fluoroscopically guided SIJ intra-articular injection with 1 cc of 2% lidocaine and 1 cc of triamcinolone 40 mg. Patients' pain was assessed via 0-10 NRS pre-injection and immediately postinjection to determine positive anesthetic response to the injection. Six physical exam maneuvers (thigh thrust, Geanslen's test, FABER test, distraction test, compression test, and sacral thrust) were performed pre-injection and 15 minutes postinjection. The results of these SIJ physical exam maneuvers were evaluated singly and in combinations for diagnostic power in relation to a positive anesthetic response (>80% relief) to the injection. No association was found between a single SIJ physical exam maneuver or combination of maneuvers and anesthetic response to the injection.

CONCLUSIONS

In this cohort, patient physical exam maneuvers to identify intra-articular SIJ pain did not demonstrate diagnostic value when compared with the reference standard of an intra-articular anesthetic block.

Ultrasound-guided cervical selective nerve root injections: a narrative review of literature

BACKGROUND/IMPORTANCE

Ultrasound (US)-guided cervical selective nerve root injections (CSNRI) have been proposed as an alternative to fluoroscopic (FL) -guided injections. When choosing US guidance, the proceduralist should be aware of potential issues confirming vertebral level, be clear regarding terminology, and up to date regarding the advantages and disadvantages of US-guided CSNRI.

OBJECTIVE

Review the accuracy and effectiveness of US guidance in avoiding vascular puncture (VP) and/or intravascular injection (IVI) during CSNRI.

EVIDENCE REVIEW

Queries included PubMed, CINAHL and Embase databases from 2005 to 2019. Three authors reviewed references for eligibility, abstracted data, and appraised quality.

FINDINGS

The literature demonstrates distinct safety considerations and limited evidence of the effectiveness of US guidance in detecting VP and/or IVI. As vascular flow and desired injectate spread cannot be visualized with US, the use of real-time fluoroscopy, and if needed digitial subraction imaging, is indicated in cervical transforaminal epidural injections (CTFEIs). Given the risk of VP and/or IVI, the ability to perform and to retain FL images to document that the procedure was safely conducted is valuable in CTFEIs.

CONCLUSION

US guidance remains to be proven as a non-inferior alternative to FL guidance or other imaging modalities in the prevention of VP and/or IVI with CTFEIs or cervical selective nerve root blocks. There is a paucity of adequately powered clinical studies evaluating the accuracy and effectiveness of US guidance in avoiding VP and/or IVI. US-guided procedures to treat cervical radicular pain has limitations in visualization of anatomy, and currently with the evidence available is best used in a combined approach with FL guidance.

A strategic expression method of miR-29b and its anti-fibrotic effect based on RNA-sequencing analysis

Tissue fibrosis is a significant health issue associated with organ dysfunction and failure. Increased deposition of collagen and other extracellular matrix (ECM) proteins in the interstitial area is a major process in tissue fibrosis. The microRNA-29 (miR-29) family has been demonstrated as anti-fibrotic microRNAs. Our recent work showed that dysregulation of miR-29 contributes to the formation of cardiac fibrosis in animal models of uremic cardiomyopathy, whereas replenishing miR-29 attenuated cardiac fibrosis in these animals. However, excessive overexpression of miR-29 is a concern because microRNAs usually have multiple targets, which could result in unknown and unexpected side effect. In the current study, we constructed a novel Col1a1-miR-29b vector using collagen 1a1 (Col1a1) promoter, which can strategically express miR-29b-3p (miR-29b) in response to increased collagen synthesis and reach a dynamic balance between collagen and miR-29b. Our experimental results showed that in mouse embryonic fibroblasts (MEF cells) transfected with Col1a1-miR-29b vector, the miR-29b expression is about 1000 times less than that in cells transfected with CMV-miR-29b vector, which uses cytomegalovirus (CMV) as a promoter for miR-29b expression. Moreover, TGF-β treatment increased the miR-29b expression by about 20 times in cells transfected with Col1a1-miR-29b, suggesting a dynamic response to fibrotic stimulation. Western blot using cell lysates and culture media demonstrated that transfection of Col1a1-miR-29b vector significantly reduced TGF-β induced collagen synthesis and secretion, and the effect was as effective as the CMV-miR-29b vector. Using RNA-sequencing analysis, we found that 249 genes were significantly altered (180 upregulated and 69 downregulated, at least 2-fold change and adjusted p-value <0.05) after TGF-β treatment in MEF cells transfected with empty vector. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis using GAGE R-package showed that the top 5 upregulated pathways after TGF-β treatment were mostly fibrosis-related, including focal adhesion, ECM reaction, and TGF-β signaling pathways. As expected, transfection of Col1a1-miR-29b or CMV-miR-29b vector partially reversed the activation of these pathways. We also analyzed the expression pattern of the top 100 miR-29b targeting genes in these cells using the RNA-sequencing data. We identified that miR-29b targeted a broad spectrum of ECM genes, but the inhibition effect is mostly moderate. In summary, our work demonstrated that the Col1a1-miR-29b vector can be used as a dynamic regulator of collagen and other ECM protein expression in response to fibrotic stimulation, which could potentially reduce unnecessary side effect due to excessive miR-29b levels while remaining an effective potential therapeutic approach for fibrosis.

Regulation of Na/K-ATPase expression by cholesterol: isoform specificity and the molecular mechanism

We have reported that the reduction in plasma membrane cholesterol could decrease cellular Na/K-ATPase α1-expression through a Src-dependent pathway. However, it is unclear whether cholesterol could regulate other Na/K-ATPase α-isoforms and the molecular mechanisms of this regulation are not fully understood. Here we used cells expressing different Na/K-ATPase α isoforms and found that membrane cholesterol reduction by U18666A decreased expression of the α1-isoform but not the α2- or α3-isoform. Imaging analyses showed the cellular redistribution of α1 and α3 but not α2. Moreover, U18666A led to redistribution of α1 to late endosomes/lysosomes, while the proteasome inhibitor blocked α1-reduction by U18666A. These results suggest that the regulation of the Na/K-ATPase α-subunit by cholesterol is isoform specific and α1 is unique in this regulation through the endocytosis-proteasome pathway. Mechanistically, loss-of-Src binding mutation of A425P in α1 lost its capacity for regulation by cholesterol. Meanwhile, gain-of-Src binding mutations in α2 partially restored the regulation. Furthermore, through studies in caveolin-1 knockdown cells, as well as subcellular distribution studies in cell lines with different α-isoforms, we found that Na/K-ATPase, Src, and caveolin-1 worked together for the cholesterol regulation. Taken together, these new findings reveal that the putative Src-binding domain and the intact Na/K-ATPase/Src/caveolin-1 complex are indispensable for the isoform-specific regulation of Na/K-ATPase by cholesterol.

The effect of patient satisfaction scores on physician job satisfaction and burnout

Physician burnout is recognized as reversible with the potential to negatively influence quality of care and patient outcomes. The study objective was to evaluate associations between patient satisfaction scores (PSS) and physicians' perceptions of job satisfaction and burnout via a physician survey. Eighty two out of 107 report PSS are institutionally tracked, with 23/107 and 39/107 reporting PSS utilization in financial compensation or performance review, respectively. Fifty four out of 107, report pressure to emphasize PSS; 63/107, report PSS having negative effect on job satisfaction; 31/107 considered leaving their job or career due to PSS and 84/107 report PSS contribute to burnout. In the cohort of physicians treating patients with spine pain who responded to this survey, PSS are associated with decreased job satisfaction and increased burnout.

Investigation of Johne's disease in Tasmanian fallow deer (Dama dama)

In 2012 when many sheep flocks in northern-central Tasmania were experiencing a high prevalence of ovine Johne's disease, 34 wild adult fallow deer shot on or near infected properties were negative to microscopic Mptb lesions of the ileo-caecal valve, terminal ileum and ileo-caecal lymph nodes. This study demonstrated 95% confidence of detecting Johne's disease in this fallow deer population if ≥10% of animals were shedding Mycobacterium avium subsp. paratuberculosis in their faeces, or if ≥21% of animals were sub-clinically infected.

Assessment of diagnostic biomarkers of liver injury in the setting of microcystin-LR (MC-LR) hepatotoxicity

Microcystin-leucine arginine (MC-LR) is a potent liver toxin produced by freshwater cyanobacteria, also known as blue-green algae. While harmful algal blooms are increasing in frequency and severity worldwide, there is still no established method for the diagnosis and assessment of MC-LR induced liver damage. The guidelines for MC-LR safe exposure limits have been previously established based on healthy animal studies, however we have previously demonstrated that pre-existing non-alcoholic fatty liver disease (NAFLD) increases susceptiblity to the hepatotoxic effects of MC-LR. In this study, we sought to investigate the suitability of clinically used biomarkers of liver injury, specifically alanine aminotransferase (ALT) and alkaline phosphatase (ALP), as potential diagnostic tools for liver damage induced by chronic low dose administration of MC-LR in the setting of pre-existing NAFLD. In our Leprdb/J mouse model of NAFLD, we found that while MC-LR induced significant histopathologic damage in the setting of NAFLD, gene expression of ALT and ALP failed to increase with MC-LR exposure. Serum ALT and ALP also failed to increase with MC-LR exposure, except for a moderate increase in ALP with the highest dose of MC-LR used (100 μg/kg). In HepG2 human liver epithelial cells, we observed that increasing MC-LR exposure levels do not lead to an increase in ALT or ALP gene expression, intracellular enzyme activity, or extracellular activity, despite a significant increase in MC-LR induced cytotoxicity. These findings demonstrate that ALT and ALP may be unsuitable as diagnostic biomarkers for MC-LR induced liver damage.

Pain Management Best Practices from Multispecialty Organizations During the COVID-19 Pandemic and Public Health Crises

BACKGROUND

It is nearly impossible to overestimate the burden of chronic pain, which is associated with enormous personal and socioeconomic costs. Chronic pain is the leading cause of disability in the world, is associated with multiple psychiatric comorbidities, and has been causally linked to the opioid crisis. Access to pain treatment has been called a fundamental human right by numerous organizations. The current COVID-19 pandemic has strained medical resources, creating a dilemma for physicians charged with the responsibility to limit spread of the contagion and to treat the patients they are entrusted to care for.

METHODS

To address these issues, an expert panel was convened that included pain management experts from the military, Veterans Health Administration, and academia. Endorsement from stakeholder societies was sought upon completion of the document within a one-week period.

RESULTS

In these guidelines, we provide a framework for pain practitioners and institutions to balance the often-conflicting goals of risk mitigation for health care providers, risk mitigation for patients, conservation of resources, and access to pain management services. Specific issues discussed include general and intervention-specific risk mitigation, patient flow issues and staffing plans, telemedicine options, triaging recommendations, strategies to reduce psychological sequelae in health care providers, and resource utilization.

CONCLUSIONS

The COVID-19 public health crisis has strained health care systems, creating a conundrum for patients, pain medicine practitioners, hospital leaders, and regulatory officials. Although this document provides a framework for pain management services, systems-wide and individual decisions must take into account clinical considerations, regional health conditions, government and hospital directives, resource availability, and the welfare of health care providers.

Harmful Algal Bloom Toxicity in Lithobates catesbeiana Tadpoles

Harmful algal blooms (HAB) have become a major health concern worldwide, not just to humans that consume and recreate on contaminated waters, but also to the fauna that inhabit the environments surrounding affected areas. HABs contain heterotrophic bacteria, cyanobacterial lipopolysaccharide, and cyanobacterial toxins such as microcystins, that can cause severe toxicity in many aquatic species as well as bioaccumulation within various organs. Thus, the possibility of trophic transference of this toxin through the food chain has potentially important health implications for other organisms in the related food web. While some species have developed adaptions to attenuate the toxic effects of HAB toxins, there are still numerous species that remain vulnerable, including Lithobates catesbeiana (American bullfrog) tadpoles. In the current study we demonstrate that acute, short-term exposure of tadpoles to HAB toxins containing 1 µg/L (1 nmol/L) of total microcystins for only 7 days results in significant liver and intestinal toxicity within tadpoles. Exposed tadpoles had increased intestinal diameter, decreased intestinal fold heights, and a constant number of intestinal folds, indicating pathological intestinal distension, similar to what is seen in various disease processes, such as toxic megacolon. HAB-toxin-exposed tadpoles also demonstrated hepatocyte hypertrophy with increased hepatocyte binucleation consistent with carcinogenic and oxidative processes within the liver. Both livers and intestines of HAB-toxin-exposed tadpoles demonstrated significant increases in protein carbonylation consistent with oxidative stress and damage. These findings demonstrate that short-term exposure to HAB toxins, including microcystins, can have significant adverse effects in amphibian populations. This acute, short-term toxicity highlights the need to evaluate the influence HAB toxins may have on other vulnerable species within the food web and how those may ultimately also impact human health.

Consensus practice guidelines on interventions for lumbar facet joint pain from a multispecialty, international working group

BACKGROUND

The past two decades have witnessed a surge in the use of lumbar facet blocks and radiofrequency ablation (RFA) to treat low back pain (LBP), yet nearly all aspects of the procedures remain controversial.

METHODS

After approval by the Board of Directors of the American Society of Regional Anesthesia and Pain Medicine, letters were sent to a dozen pain societies, as well as representatives from the US Departments of Veterans Affairs and Defense. A steering committee was convened to select preliminary questions, which were revised by the full committee. Questions were assigned to 4-5 person modules, who worked with the Subcommittee Lead and Committee Chair on preliminary versions, which were sent to the full committee. We used a modified Delphi method, whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chair, who incorporated the comments and sent out revised versions until consensus was reached.

RESULTS

17 questions were selected for guideline development, with 100% consensus achieved by committee members on all topics. All societies except for one approved every recommendation, with one society dissenting on two questions (number of blocks and cut-off for a positive block before RFA), but approving the document. Specific questions that were addressed included the value of history and physical examination in selecting patients for blocks, the value of imaging in patient selection, whether conservative treatment should be used before injections, whether imaging is necessary for block performance, the diagnostic and prognostic value of medial branch blocks (MBB) and intra-articular (IA) injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for a prognostic block, how many blocks should be performed before RFA, how electrodes should be oriented, the evidence for larger lesions, whether stimulation should be used before RFA, ways to mitigate complications, if different standards should be applied to clinical practice and clinical trials and the evidence for repeating RFA (see table 12 for summary).

CONCLUSIONS

Lumbar medial branch RFA may provide benefit to well-selected individuals, with MBB being more predictive than IA injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of more false-negatives. Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

Digital Care for Chronic Musculoskeletal Pain: 10,000 Participant Longitudinal Cohort Study

BACKGROUND

Chronic musculoskeletal pain has a vast global prevalence and economic burden. Conservative therapies are universally recommended but require patient engagement and self-management to be effective.

OBJECTIVE

This study aimed to evaluate the efficacy of a 12-week digital care program (DCP) in a large population of patients with chronic knee and back pain.

METHODS

A longitudinal observational study was conducted using a remote DCP available through a mobile app. Subjects participated in a 12-week multimodal DCP incorporating education, sensor-guided exercise therapy (ET), and behavioral health support with 1-on-1 remote health coaching. The primary outcome was pain measured by the visual analog scale (VAS). Secondary measures included engagement levels, program completion, program satisfaction, condition-specific pain measures, depression, anxiety, and work productivity.

RESULTS

A total of 10,264 adults with either knee (n=3796) or low back (n=6468) pain for at least three months were included in the study. Participants experienced a 68.45% average improvement in VAS pain between baseline intake and 12 weeks. In all, 73.04% (7497/10,264) participants completed the DCP into the final month. In total, 78.60% (5893/7497) of program completers (7144/10,264, 69.60% of all participants) achieved minimally important change in pain. Furthermore, the number of ET sessions and coaching interactions were both positively associated with improvement in pain, suggesting that the amount of engagement influenced outcomes. Secondary outcomes included a 57.9% and 58.3% decrease in depression and anxiety scores, respectively, and 61.5% improvement in work productivity. Finally, 3 distinct clusters of pain response trajectories were identified, which could be predicted with a mean 76% accuracy using baseline measures.

CONCLUSIONS

These results support the efficacy and scalability of a DCP for chronic low back and knee pain in a large, diverse, real-world population. Participants demonstrated high completion and engagement rates and a significant positive relationship between engagement and pain reduction was identified, a finding that has not been previously demonstrated in a DCP. Furthermore, the large sample size allowed for the identification of distinct pain response subgroups, which may prove beneficial in predicting recovery and tailoring future interventions. This is the first longitudinal digital health study to analyze pain outcomes in a sample of this magnitude, and it supports the prospect for DCPs to serve the overwhelming number of musculoskeletal pain sufferers worldwide.

Antiplatelet and Anticoagulant Risk for Select Spine Interventions: A Retrospective Cohort

OBJECTIVES

To identify significant bleeding complications following spinal interventions in patients taking medications with antiplatelet or anticoagulation effect.

DESIGN

Retrospective chart review of a 12-month period.

SETTING

Outpatient academic medical practice.

INTERVENTIONS

Injections during outpatient interventional spine clinical encounters, including 14 cervical transforaminal epidural steroid injections, 26 cervical medial branch blocks, seven cervical radiofrequency neurotomies, three cervical facet joint injections, 88 lumbar transforaminal epidural steroid injections, 66 lumbosacral medial branch blocks, 18 lumbosacral radiofrequency neurotomies, 13 lumbar facet joint injections, one caudal epidural steroid injection, 11 sacral transforaminal epidural steroid injections, and 32 sacroiliac joint injections.

MAIN OUTCOME MEASURE

Epidural hematoma or other serious bleeding.

RESULTS

In this cohort of 275 consecutive encounters with available records in which patients underwent a spinal injection while continuing medications with antiplatelet or anticoagulant effect, zero of the 275 clinical encounters (0%, 95% confidence interval = 0-1.4%) resulted in epidural hematoma or other serious bleeding. For antiplatelet medication, nonsteroidal anti-inflammatory drugs were continued in 102 procedures, aspirin in 142, clopidogrel in 21, and meloxicam and/or Celebrex in 81; for anticoagulation medication, warfarin was continued in four procedures, apixaban in six, dabigatran in one, and fondaparinux in two. Of note, one patient suffered a deep vein thrombosis, which was identified at two-week follow-up despite continuing aspirin therapy.

CONCLUSIONS

This cohort adds to the growing evidence that the risk of serious bleeding complications from select spine interventions while continuing medications with antiplatelet or anticoagulant effect appears low.

Development and Application of Extraction Methods for LC-MS Quantification of Microcystins in Liver Tissue

A method was developed to extract and quantify microcystins (MCs) from mouse liver with limits of quantification (LOQs) lower than previously reported. MCs were extracted from 40-mg liver samples using 85:15 (v:v) CH₃CN:H₂O containing 200 mM ZnSO₄ and 1% formic acid. Solid-phase extraction with a C18 cartridge was used for sample cleanup. MCs were detected and quantified using HPLC-orbitrap-MS with simultaneous MS/MS detection of the 135.08 m/z fragment from the conserved Adda amino acid for structural confirmation. The method was used to extract six MCs (MC-LR, MC-RR, MC-YR, MC-LA, MC-LF, and MC-LW) from spiked liver tissue and the MC-LR cysteine adduct (MC-LR-Cys) created by the glutathione detoxification pathway. Matrix-matched internal standard calibration curves were constructed for each MC (R² ≥ 0.993), with LOQs between 0.25 ng per g of liver tissue (ng/g) and 0.75 ng/g for MC-LR, MC-RR, MC-YR, MC-LA, and MC-LR-Cys, and 2.5 ng/g for MC-LF and MC-LW. The protocol was applied to extract and quantify MC-LR and MC-LR-Cys from the liver of mice that had been gavaged with 50 µg or 100 µg of MC-LR per kg bodyweight and were euthanized 2 h, 4 h, or 48 h after final gavage. C57Bl/6J (wild type, control) and Lepr^db/J (experiment) mice were used as a model to study non-alcoholic fatty liver disease. The Lepr^db/J mice were relatively inefficient in metabolizing MC-LR into MC-LR-Cys, which is an important defense mechanism against MC-LR exposure. Trends were also observed as a function of MC-LR gavage amount and time between final MC-LR gavage and euthanasia/organ harvest.

Renal Fibrosis Is Significantly Attenuated Following Targeted Disruption of Cd40 in Experimental Renal Ischemia

Background

Renal artery stenosis is a common cause of renal ischemia, contributing to the development of chronic kidney disease. To investigate the role of local CD40 expression in renal artery stenosis, Goldblatt 2‐kidney 1‐clip surgery was performed on hypertensive Dahl salt‐sensitive rats (S rats) and genetically modified S rats in which CD40 function is abolished (Cd40^mutant).

Methods and Results

Four weeks following the 2‐kidney 1‐clip procedure, Cd40^mutant rats demonstrated significantly reduced blood pressure and renal fibrosis in the ischemic kidneys compared with S rat controls. Similarly, disruption of Cd40 resulted in reduced 24‐hour urinary protein excretion in Cd40^mutant rats versus S rat controls (46.2±1.9 versus 118.4±5.3 mg/24 h; P<0.01), as well as protection from oxidative stress, as indicated by increased paraoxonase activity in Cd40^mutant rats versus S rat controls (P<0.01). Ischemic kidneys from Cd40^mutant rats demonstrated a significant decrease in gene expression of the profibrotic mediator, plasminogen activator inhibitor‐1 (P<0.05), and the proinflammatory mediators, C‐C motif chemokine ligand 19 (P<0.01), C‐X‐C Motif Chemokine Ligand 9 (P<0.01), and interleukin‐6 receptor (P<0.001), compared with S rat ischemic kidneys, as assessed by quantitative PCR assay. Reciprocal renal transplantation documented that CD40 exclusively expressed in the kidney contributes to ischemia‐induced renal fibrosis. Furthermore, human CD40‐knockout proximal tubule epithelial cells suggested that suppression of CD40 signaling significantly inhibited expression of proinflammatory and ‐fibrotic genes.

Conclusions

Taken together, our data suggest that activation of CD40 induces a significant proinflammatory and ‐fibrotic response and represents an attractive therapeutic target for treatment of ischemic renal disease.

Intra-articular Steroids vs Saline for Lumbar Z-Joint Pain: A Prospective, Randomized, Double-Blind Placebo-Controlled Trial

OBJECTIVE

To determine if intra-articular (IA) injection of corticosteroids is effective in reducing the need for radiofrequency ablation (RFA) in those with dual comparative medial branch block (MBB)-confirmed lumbar z-joint pain.

DESIGN

This was a randomized, double blind, placebo-controlled study.

SETTING

Two academic medical centers.

SUBJECTS

Fifty-six consecutive subjects who had ≥80% pain relief during an initial screening MBB were recruited.

METHODS

Patients received a second confirmatory MBB and concurrent IA injection of either corticosteroid or saline per randomization. Twenty-nine of 56 received intra-articular corticosteroid (triamcinolone 20 mg), of whom 24 also had a positive confirmatory MBB per Spine Interventional Society guidelines, with ≥80% pain relief from both MBBs. Twenty-seven of 56 received IA saline into the z-joint during the confirmatory MBB, of whom 22 also had a positive confirmatory MBB. The primary outcome measure was the categorical need for RFA due to insufficient pain relief with intra-articular injection, and the secondary outcome was time to RFA.

RESULTS

There was no statistically significant difference in the need for an RFA between the groups (16/24 steroid, 67%, 95% confidence interval [CI] = 47-82%) vs 15/22 saline (68%, 95% CI = 47-84%, P = 1.00). The average time to RFA was also not different, at 6.00 weeks for steroids vs 6.55 weeks for saline (P = 0.82).

CONCLUSIONS

Intra-articular corticosteroids were not effective in reducing the need for or the time to a radiofrequency ablation of the medial branches in those with dual MBB-confirmed lumbar z-joint pain.

Epithelial and Endothelial Adhesion of Immune Cells Is Enhanced by Cardiotonic Steroid Signaling Through Na+/K+-ATPase-α-1

Background

Recent studies have highlighted a critical role for a group of natriuretic hormones, cardiotonic steroid (CTS), in mediating renal inflammation and fibrosis associated with volume expanded settings, such as chronic kidney disease. Immune cell adhesion is a critical step in the inflammatory response; however, little is currently understood about the potential regulatory role of CTS signaling in this setting. Herein, we tested the hypothesis that CTS signaling through Na⁺/K⁺‐ATPase α‐1 (NKA α‐1) enhances immune cell recruitment and adhesion to renal epithelium that ultimately advance renal inflammation.

Methods and Results

We demonstrate that knockdown of the α‐1 isoform of Na/K‐ATPase causes a reduction in CTS‐induced macrophage infiltration in renal tissue as well reduces the accumulation of immune cells in the peritoneal cavity in vivo. Next, using functional adhesion assay, we demonstrate that CTS‐induced increases in the adhesion of macrophages to renal epithelial cells were significantly diminished after reduction of NKA α‐1 in either macrophages or renal epithelial cells as well after inhibition of NKA α‐1‐Src signaling cascade with a specific peptide inhibitor, pNaKtide in vitro. Finally, CTS‐induced expression of adhesion markers in both endothelial and immune cells was significantly inhibited in an NKA α‐1‐Src signaling dependent manner in vitro.

Conclusions

These findings suggest that CTS potentiates immune cell migration and adhesion to renal epithelium through an NKA α‐1–dependent mechanism; our new findings suggest that pharmacological inhibition of this feed‐forward loop may be useful in the treatment of renal inflammation associated with renal disease.

Pain and Functional Outcomes After Sacroiliac Joint Injection with Anesthetic and Corticosteroid at Six Months, Stratified by Anesthetic Response and Physical Exam Maneuvers

OBJECTIVE

To evaluate sacroiliac joint (SIJ) injection outcomes with local anesthetic and corticosteroid.

DESIGN

Prospective cohort.

SETTING

Single academic medical center.

METHODS

Thirty-four patients referred for SIJ injection with a clinical diagnosis of SIJ pain underwent injections with 1:1 mixture of 2% lidocaine and triamcinolone 40 mg/mL. Pain provocation physical exam (PE) maneuvers were recorded immediately before and after injection. Outcome measures at two to four weeks and six months included pain numeric rating scale (NRS) and Oswestry Disability Index (ODI).

RESULTS

For the analysis of outcomes by the overall group (not stratified by PE and/or anesthetic block), a 58.8% (95% confidence interval [CI] = +/-16.5%) ≥2 NRS reduction, a 32.4% (95% CI = +/-15.7%) ≥50% NRS reduction, and a 38.2% (95% CI = +/-16.3%) ≥30% ODI reduction were observed at two to four weeks, with similar improvements at six months. Outcomes stratified based on pre-injection PE did not reveal significant differences at either time point. The stratification based on the presence of 100% postinjection anesthetic response demonstrated a significant difference at two to four weeks for ≥50% NRS improvement. The true positive/true negative group (TP/TN) stratification demonstrated a significant difference for ≥50% NRS improvement at two to four weeks, whereas six-month outcomes for TP/TN demonstrated significant differences for ≥50% NRS and ≥30% ODI improvement. An increased injection response was observed with stratification of patients more likely to have true SIJ pain (i.e., TP), with TP/TN stratification demonstrating a 75% (95% CI = +/-30.0%) ≥2 NRS improvement and a 62.5% (95% CI = +/-33.5%) improvement of ≥50% NRS and ≥30% ODI for the TP group at two to four weeks, with similar results at six months.

CONCLUSIONS

SIJ steroid injection based on referral clinical diagnosis is unlikely to demonstrate true injection efficacy, and more specific selection criteria are warranted.

Hyperglycemia induces key genetic and phenotypic changes in human liver epithelial HepG2 cells which parallel the Leprdb/J mouse model of non-alcoholic fatty liver disease (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) is a growing global health concern. With a propensity to progress towards non-alcoholic steatohepatitis (NASH), cirrhosis, and hepatocellular carcinoma, NAFLD is an important link amongst a multitude of comorbidities including obesity, diabetes, and cardiovascular and kidney disease. As several in vivo models of hyperglycemia and NAFLD are employed to investigate the pathophysiology of this disease process, we aimed to characterize an in vitro model of hyperglycemia that was amenable to address molecular mechanisms and therapeutic targets at the cellular level. Utilizing hyperglycemic cell culturing conditions, we induced steatosis within a human hepatocyte cell line (HepG2 cells), as confirmed by electron microscopy. The deposition and accumulation of lipids within hyperglycemic HepG2 cells is significantly greater than in normoglycemic cells, as visualized and quantified by Nile red staining. Alanine aminotransferase (ALT) and alkaline phosphatase (ALP), diagnostic biomarkers for liver damage and disease, were found to be upregulated in hyperglycemic HepG2 cells as compared with normoglycemic cells. Suppression of CEACAM1, GLUT2, and PON1, and elevation of CD36, PCK1, and G6PK were also found to be characteristic in hyperglycemic HepG2 cells compared with normoglycemic cells, suggesting insulin resistance and NAFLD. These in vitro findings mirror the characteristic genetic and phenotypic profile seen in Lepr^db/J mice, a well-established in vivo model of NAFLD. In conclusion, we characterize an in vitro model displaying several key genetic and phenotypic characteristics in common with NAFLD that may assist future studies in addressing the molecular mechanisms and therapeutic targets to combat this disease.

CD36 Enhances Vascular Smooth Muscle Cell Proliferation and Development of Neointimal Hyperplasia

Objective- Dysregulated proliferation of vascular smooth muscle cells (VSMC) plays an essential role in neointimal hyperplasia. CD36 functions critically in atherogenesis and thrombosis. We hypothesize that CD36 regulates VSMC proliferation and contributes to the development of obstructive vascular diseases. Approach and Results- We found by immunofluorescent staining that CD36 was highly expressed in human vessels with obstructive diseases. Using guidewire-induced carotid artery injury and shear stress-induced intima thickening models, we compared neointimal hyperplasia in Apoe^-/-, Cd36^-/- /Apoe^-/-, and CD36 specifically deleted in VSMC (VSMC ^cd36-/-) mice. CD36 deficiency, either global or VSMC-specific, dramatically reduced injury-induced neointimal thickening. Correspondingly, carotid artery blood flow was significantly increased in Cd36^-/- /Apoe^-/- compared with Apoe^-/- mice. In cultured VSMCs from thoracic aorta of wild-type and Cd36^-/- mice, we found that loss of CD36 significantly decreased serum-stimulated proliferation and increased cell populations in S phase, suggesting that CD36 is necessary for VSMC S/G2-M-phase transition. Treatment of VSMCs with a TSR (thrombospondin type 1 repeat) peptide significantly increased wild-type, but not Cd36^-/- VSMC proliferation. TSR or serum treatment significantly increased cyclin A expression in wild-type, but not in Cd36^-/- VSMCs. STAT3 (signal transducer and activator of transcription), which reportedly enhances both VSMC differentiation and maturation, was higher in Cd36^-/- VSMCs. CD36 deficiency significantly decreased expression of Col1A1 (type 1 collagen A1 chain) and TGF-β1 (transforming growth factor beta 1), and increased expression of contractile proteins, including calponin 1 and smooth muscle α actin, and dramatically increased cell contraction. Conclusions- CD36 promotes VSMC proliferation via upregulation of cyclin A expression that contributes to the development of neointimal hyperplasia, collagen deposition, and obstructive vascular diseases.

Na/K-ATPase/src complex mediates regulation of CD40 in renal parenchyma

Background

Recent studies have highlighted a critical role for CD40 in the pathogenesis of renal injury and fibrosis. However, little is currently understood about the regulation of CD40 in this setting.

Methods

We use novel Na/K-ATPase cell lines and inhibitors in order to demonstrate the regulatory function of Na/K-ATPase with regards to CD40 expression and function. We utilize 5/6 partial nephrectomy as well as direct infusion of a Na/K-ATPase ligand to demonstrate this mechanism exists in vivo.

Results

We demonstrate that knockdown of the α1 isoform of Na/K-ATPase causes a reduction in CD40 while rescue of the α1 but not the α2 isoform restores CD40 expression in renal epithelial cells. Second, because the major functional difference between α1 and α2 is the ability of α1 to form a functional signaling complex with Src, we examined whether the Na/K-ATPase/Src complex is important for CD40 expression. We show that a gain-of-Src binding α2 mutant restores CD40 expression while loss-of-Src binding α1 reduces CD40 expression. Furthermore, loss of a functional Na/K-ATPase/Src complex also disrupts CD40 signaling. Importantly, we show that use of a specific Na/K-ATPase/Src complex antagonist, pNaKtide, can attenuate cardiotonic steroid (CTS)-induced induction of CD40 expression in vitro.

Conclusions

Because the Na/K-ATPase/Src complex is also a key player in the pathogenesis of renal injury and fibrosis, our new findings suggest that Na/K-ATPase and CD40 may comprise a pro-fibrotic feed-forward loop in the kidney and that pharmacological inhibition of this loop may be useful in the treatment of renal fibrosis.

Building a Collaborative Model of Sacroiliac Joint Dysfunction and Pelvic Girdle Pain to Understand the Diverse Perspectives of Experts

BACKGROUND

Pelvic girdle pain (PGP) and sacroiliac joint (SIJ) dysfunction/pain are considered frequent contributors to low back pain (LBP). Like other persistent pain conditions, PGP is increasingly recognized as a multifactorial problem involving biological, psychological, and social factors. Perspectives differ between experts and a diversity of treatments (with variable degrees of evidence) have been utilized.

OBJECTIVE

To develop a collaborative model of PGP that represents the collective view of a group of experts. Specific goals were to analyze structure and composition of conceptual models contributed by participants, to aggregate them into a metamodel, to analyze the metamodel's composition, and to consider predicted efficacy of treatments.

DESIGN

To develop a collaborative model of PGP, models were generated by invited individuals to represent their understanding of PGP using fuzzy cognitive mapping (FCM). FCMs involved proposal of components related to causes, outcomes, and treatments for pain, disability, and quality of life, and their connections. Components were classified into thematic categories. Weighting of connections was summed for components to judge their relative importance. FCMs were aggregated into a metamodel for analysis of the collective opinion it represented and to evaluate expected efficacy of treatments.

RESULTS

From 21 potential contributors, 14 (67%) agreed to participate (representing six disciplines and seven countries). Participants' models included a mean (SD) of 22 (5) components each. FCMs were refined to combine similar terms, leaving 89 components in 10 categories. Biomechanical factors were the most important in individual FCMs. The collective opinion from the metamodel predicted greatest efficacy for injection, exercise therapy, and surgery for pain relief.

CONCLUSIONS

The collaborative model of PGP showed a bias toward biomechanical factors. Most efficacious treatments predicted by the model have modest to no evidence from clinical trials, suggesting a mismatch between opinion and evidence. The model enables integration and communication of the collection of opinions on PGP.

Circulating Lactonase Activity but Not Protein Level of PON-1 Predicts Adverse Outcomes in Subjects with Chronic Kidney Disease

The burden of cardiovascular disease and death in chronic kidney disease (CKD) outpaces that of the other diseases and is not adequately described by traditional risk factors alone. Diminished activity of paraoxonase (PON)-1 is associated with increased oxidant stress, a common feature underlying the pathogenesis of CKD. We aimed to assess the prognostic value of circulating PON-1 protein and PON lactonase activity on adverse clinical outcomes across various stages and etiologies of CKD. Circulating PON-1 protein levels and PON lactonase activity were measured simultaneously in patients with CKD as well as a cohort of apparently healthy non-CKD subjects. Both circulating PON-1 protein levels and PON lactonase activity were significantly lower in CKD patients compared to the non-CKD subjects. Similarly, across all stages of CKD, circulating PON-1 protein and PON lactonase activity were significantly lower in patients with CKD compared to the non-CKD controls. Circulating PON lactonase activity, but not protein levels, predicted future adverse clinical outcomes, even after adjustment for traditional risk factors. The combination of lower circulating protein levels and higher activity within the CKD subjects were associated with the best survival outcomes. These findings demonstrate that diminished circulating PON lactonase activity, but not protein levels, predicts higher risk of future adverse clinical outcomes in patients with CKD.