Tau molecular diversity contributes to clinical heterogeneity in Alzheimer's disease

Alzheimer's disease (AD) causes unrelenting, progressive cognitive impairments, but its course is heterogeneous, with a broad range of rates of cognitive decline1. The spread of tau aggregates (neurofibrillary tangles) across the cerebral cortex parallels symptom severity2,3. We hypothesized that the kinetics of tau spread may vary if the properties of the propagating tau proteins vary across individuals. We carried out biochemical, biophysical, MS and both cell- and animal-based-bioactivity assays to characterize tau in 32 patients with AD. We found striking patient-to-patient heterogeneity in the hyperphosphorylated species of soluble, oligomeric, seed-competent tau. Tau seeding activity correlates with the aggressiveness of the clinical disease, and some post-translational modification (PTM) sites appear to be associated with both enhanced seeding activity and worse clinical outcomes, whereas others are not. These data suggest that different individuals with 'typical' AD may have distinct biochemical features of tau. These data are consistent with the possibility that individuals with AD, much like people with cancer, may have multiple molecular drivers of an otherwise common phenotype, and emphasize the potential for personalized therapeutic approaches for slowing clinical progression of AD.

Synaptic Tau Seeding Precedes Tau Pathology in Human Alzheimer's Disease Brain

Alzheimer's disease (AD) is defined by the presence of intraneuronal neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau aggregates as well as extracellular amyloid-beta plaques. The presence and spread of tau pathology through the brain is classified by Braak stages and thought to correlate with the progression of AD. Several in vitro and in vivo studies have examined the ability of tau pathology to move from one neuron to the next, suggesting a "prion-like" spread of tau aggregates may be an underlying cause of Braak tau staging in AD. Using the HEK293 TauRD-P301S-CFP/YFP expressing biosensor cells as a highly sensitive and specific tool to identify the presence of seed competent aggregated tau in brain lysate-i.e., tau aggregates that are capable of recruiting and misfolding monomeric tau-, we detected substantial tau seeding levels in the entorhinal cortex from human cases with only very rare NFTs, suggesting that soluble tau aggregates can exist prior to the development of overt tau pathology. We next looked at tau seeding levels in human brains of varying Braak stages along six regions of the Braak Tau Pathway. Tau seeding levels were detected not only in the brain regions impacted by pathology, but also in the subsequent non-pathology containing region along the Braak pathway. These data imply that pathogenic tau aggregates precede overt tau pathology in a manner that is consistent with transneuronal spread of tau aggregates. We then detected tau seeding in frontal white matter tracts and the optic nerve, two brain regions comprised of axons that contain little to no neuronal cell bodies, implying that tau aggregates can indeed traverse along axons. Finally, we isolated cytosolic and synaptosome fractions along the Braak Tau Pathway from brains of varying Braak stages. Phosphorylated and seed competent tau was significantly enriched in the synaptic fraction of brain regions that did not have extensive cellular tau pathology, further suggesting that aggregated tau seeds move through the human brain along synaptically connected neurons. Together, these data provide further evidence that the spread of tau aggregates through the human brain along synaptically connected networks results in the pathogenesis of human Alzheimer's disease.

Clinical outcomes, risk stratification and practice patterns of unstable angina and myocardial infarction without ST elevation: Prospective Registry of Acute Ischaemic Syndromes in the UK (PRAIS-UK)

AIMS

To determine characteristics, outcomes, prognostic indicators and management of patients with acute coronary syndromes without ST elevation.

METHODS AND RESULTS

A prospective registry was carried out with follow-up for 6 months after index hospital admission. A history of acute cardiac chest pain was required plus ECG changes consistent with myocardial ischaemia and/or prior evidence of coronary heart disease. Patients with ST elevation or those receiving thrombolytic therapy were excluded. A total of 1046 patients were enrolled from 56 U.K. hospitals. The mean age was 66+/-12 years and 39% were female. The rate of death or non-fatal myocardial infarction at 6 months was 12.2% and of death, new myocardial infarction, refractory angina or re-admission for unstable angina at 6 months was 30%. In a multivariate analysis, patients >70 years had a threefold risk of death or new myocardial infarction compared with those <60 years (P<0.01) and those with ST depression or bundle branch block on the ECG had a five-fold greater risk than those with normal ECG (P<0.001). Aspirin was given to 87% and heparin to 72% of patients in hospital. At 6 months 56% received no lipid-lowering therapy at all. The 6-month rate of coronary angiography was 27% and any revascularization 15%.

CONCLUSIONS

In this cohort there was a one in eight chance of death or myocardial infarction, and a one in three chance of death, new myocardial infarction, refractory angina or re-admission for unstable angina, over 6 months. Age and baseline ECG were useful markers of risk. Aspirin, heparin and statins were not given to about one-sixth, one-third and one-half respectively. Rates of angiography and revascularization appear low. A review of treatment strategies of unstable angina and myocardial infarction without ST elevation is warranted in the U.K. to ensure that patients are receiving optimum treatments to reduce mortality and morbidity.

Laryngeal preservation with supracricoid partial laryngectomy results in improved quality of life when compared with total laryngectomy

OBJECTIVES/HYPOTHESES

Study 1: To assess the oncologic outcome following supracricoid partial laryngectomy (SCPL). Study 2: To compare the quality of life (QOL) following SCPL to total laryngectomy (TL) with tracheoesophageal puncture (TEP). Study 3: To analyze whole organ TL sections to determine the percentage of lesions amenable to SCPL STUDY DESIGN: Study 1: A retrospective review of patients who underwent SCPL. Study 2: A non-randomized, prospective study using QOL instruments to compare patients who underwent either SCPL or TL Study 3: A retrospective histopathologic study of TL specimens assessed for the possibility of performing an SCPL.

METHODS

Study 1: Twenty-five patients with carcinoma of the larynx underwent SCPL between June 1992 and June 1999. Various rates of oncologic outcome were calculated. Study 2: Thirty-one patients participated in the QOL assessment. This included the SF-36 general health status measure, the University of Michigan Head and Neck Quality of Life (HNQOL) instrument, and the University of Michigan Voice-Related Quality of Life (VRQOL) instrument. Study 3: Ninety surgical specimens were obtained and studied from the total laryngectomy cases in the Tucker Collection. Multiple sites were evaluated for the presence of carcinoma A computer program was written to classify whether the patient was amenable to SCPL.

RESULTS

Study 1: The overall local control rate was 96% (24/25). The local control rate following SCPL with cricohyoidoepiglottopexy (CHEP) was 95% (20/21). The local control rate following SCPL with cricohyoidopexy (CHP) was 100% (4/4). Study 2: The SCPL had significantly higher domain scores than TL and TEP in the following categories for the SF-36: physical function, physical limitations, general health, vitality, social functioning, emotional limitations, and physical health summary. The significantly higher domains for the SCPL when compared with the TL and TEP for the HNQOL were eating and pain. Finally, when voice-related QOL was assessed with the V-RQOL, the domains of physical functioning and the total score were significantly better with SCPL when compared with TL and TEP. Study 3: Forty of 90 (44%) laryngeal whole organ specimens were determined to be resectable by SCPL. In 16 (18%) specimens, the patients could have undergone SCPL with CHEP and in 24 (27%) specimens the patients could have undergone SCPL with CHP. Among the 40 (44%) specimens determined to be able to have undergone SCPL, 19 were glottic (1 T1, 15 T2, 3 T3) and 21 were supraglottic (9 T2, 12 T3).

CONCLUSIONS

1) A review of the literature and an analysis of the data in this study indicate that excellent local control may be expected following SCPL. 2) The QOL following SCPL, as measured by three validated QOL instruments, is superior to TL with TEP. 3) A histologic assessment of whole organ sections of TL specimens indicates that many patients who have been subjected to TL may have been candidates for SCPL. 4) If the indications and contraindications are rigorously adhered to, SCPLs are reasonable alternatives to TL in selected cases.

Tau reduction in the presence of amyloid-β prevents tau pathology and neuronal death in vivo

Several studies have now supported the use of a tau lowering agent as a possible therapy in the treatment of tauopathy disorders, including Alzheimer's disease. In human Alzheimer's disease, however, concurrent amyloid-β deposition appears to synergize and accelerate tau pathological changes. Thus far, tau reduction strategies that have been tested in vivo have been examined in the setting of tau pathology without confounding amyloid-β deposition. To determine whether reducing total human tau expression in a transgenic model where there is concurrent amyloid-β plaque formation can still reduce tau pathology and protect against neuronal loss, we have taken advantage of the regulatable tau transgene in APP/PS1 × rTg4510 mice. These mice develop both neurofibrillary tangles as well as amyloid-β plaques throughout the cortex and hippocampus. By suppressing human tau expression for 6 months in the APP/PS1 × rTg4510 mice using doxycycline, AT8 tau pathology, bioactivity, and astrogliosis were reduced, though importantly to a lesser extent than lowering tau in the rTg4510 alone mice. Based on non-denaturing gels and proteinase K digestions, the remaining tau aggregates in the presence of amyloid-β exhibit a longer-lived aggregate conformation. Nonetheless, lowering the expression of the human tau transgene was sufficient to equally ameliorate thioflavin-S positive tangles and prevent neuronal loss equally well in both the APP/PS1 × rTg4510 mice and the rTg4510 cohort. Together, these results suggest that, although amyloid-β stabilizes tau aggregates, lowering total tau levels is still an effective strategy for the treatment of tau pathology and neuronal loss even in the presence of amyloid-β deposition.

Assessment of Machine Learning vs Standard Prediction Rules for Predicting Hospital Readmissions

Importance

Hospital readmissions are associated with patient harm and expense. Ways to prevent hospital readmissions have focused on identifying patients at greatest risk using prediction scores.

Objective

To identify the type of score that best predicts hospital readmissions.

Design, Setting, and Participants

This prognostic study included 14 062 consecutive adult hospital patients with 16 649 discharges from a tertiary care center, suburban community hospital, and urban critical access hospital in Maryland from September 1, 2016, through December 31, 2016. Patients not included as eligible discharges by the Centers for Medicare & Medicaid Services or the Chesapeake Regional Information System for Our Patients were excluded. A machine learning rank score, the Baltimore score (B score) developed using a machine learning technique, for each individual hospital using data from the 2 years before September 1, 2016, was compared with standard readmission risk assessment scores to predict 30-day unplanned readmissions.

Main Outcomes and Measures

The 30-day readmission rate evaluated using various readmission scores: B score, HOSPITAL score, modified LACE score, and Maxim/RightCare score.

Results

Of the 10 732 patients (5605 [52.2%] male; mean [SD] age, 54.56 [22.42] years) deemed to be eligible for the study, 1422 were readmitted. The area under the receiver operating characteristic curve (AUROC) for individual rules was 0.63 (95% CI, 0.61-0.65) for the HOSPITAL score, which was significantly lower than the 0.66 for modified LACE score (95% CI, 0.64-0.68; P < .001). The B score machine learning score was significantly better than all other scores; 48 hours after admission, the AUROC of the B score was 0.72 (95% CI, 0.70-0.73), which increased to 0.78 (95% CI, 0.77-0.79) at discharge (all P < .001). At the hospital using Maxim/RightCare score, the AUROC was 0.63 (95% CI, 0.59-0.69) for HOSPITAL, 0.64 (95% CI, 0.61-0.68) for Maxim/RightCare, and 0.66 (95% CI, 0.62-0.69) for modified LACE score. The B score was 0.72 (95% CI, 0.69-0.75) 48 hours after admission and 0.81 (95% CI, 0.79-0.84) at discharge. In directly comparing the B score with the sensitivity at cutoff values for modified LACE, HOSPITAL, and Maxim/RightCare scores, the B score was able to identify the same number of readmitted patients while flagging 25.5% to 54.9% fewer patients.

Conclusions and Relevance

Among 3 hospitals in different settings, an automated machine learning score better predicted readmissions than commonly used readmission scores. More efficiently targeting patients at higher risk of readmission may be the first step toward potentially preventing readmissions.

Adaptation of mechanical properties of muscle to high force training in man

The first dorsal interosseus muscle of the hand was trained for 8 weeks using eighty maximal 10 s voluntary isometric contractions per day. As a result of this training the maximal voluntary force increased by 33%, but electrically evoked tetanic tension increased by only 11%. In other subjects the muscle was trained using electrical stimulation at 60 Hz to evoke eighty maximal 10 s tetani per day for 8 weeks. This training produced no increase in maximum voluntary force. Our results show that the increase in maximal voluntary force under these conditions may be due to a change in the voluntary neural drive to the muscle.

Diazepam-induced neuroprotection: dissociating the effects of hypothermia following global ischemia

Global cerebral ischemia produces hippocampal CA1 neuronal loss which in turn leads to deficits in memory related tasks. Previous studies have shown that the benzodiazepine diazepam is effective at attenuating this cell death and the related behavioural impairments. However these studies have been confounded by diazepam-induced hypothermia. In this study we sought to determine the neuroprotective efficacy of diazepam in the absence of hypothermia. Diazepam (10 mg/kg) was administered to two groups of gerbils at 30 and 90 min following a 5-min ischemic insult. In one group the brain temperature was monitored for 24 h post-ischemically but not regulated. In the second group, post-ischemic brain temperature was maintained at 36.5 degrees C to counteract the hypothermia produced by diazepam. Both behaviour (open field performance) and CA1 cell counts from these groups were compared to those from sham/normal, no drug ischemic and vehicle ischemic groups at 10 days survival. In animals treated with diazepam without temperature regulation, there was significant histological and behavioural protection at 10 days compared to untreated ischemic animals. Preventing hypothermia in diazepam-treated animals resulted in a decrease in the number of cells surviving (from 41.2 to 31.6% of sham) and abolished behavioural protection. Diazepam appears to have limited ability to attenuate neuronal loss and its neuroprotective efficacy is augmented by the concurrent hypothermic actions of the drug itself.

One year comparison of costs of coronary surgery versus percutaneous coronary intervention in the stent or surgery trial

OBJECTIVES

To compare initial and one year costs of coronary artery bypass grafting (CABG) versus percutaneous coronary intervention (PCI) in the stent or surgery trial.

DESIGN

Prospective, unblinded, randomised trial.

SETTING

Multicentre study.

PATIENTS

988 patients with multivessel disease.

INTERVENTIONS

CABG and stent assisted PCI.

MAIN OUTCOME MEASURES

Initial hospitalisation and one year follow up costs.

RESULTS

At one year mortality was 2.5% in the PCI arm and 0.8% in the CABG arm (p = 0.05). There was no difference in the composite of death or Q wave myocardial infarction (6.9% for PCI v 8.1% for CABG, p = 0.49). There were more repeat revascularisations with PCI (17.2% v 4.2% for CABG). There was no significant difference in utility between arms at six months or at one year. Quality adjusted life years were similar 0.6938 for PCI v 0.6954 for PCI, Delta = 0.00154, 95% confidence interval (CI) -0.0242 to 0.0273). Initial length of stay was longer with CABG (12.2 v 5.4 days with PCI, p < 0.0001) and initial hospitalisation costs were higher (7321 pounds sterling v 3884 pounds sterling for PCI, Delta = 3437 pounds sterling, 95% CI 3040 pounds sterling to 3848 pounds sterling). At one year the cost difference narrowed but costs remained higher for CABG (8905 pounds sterling v 6296 pounds sterling for PCI, Delta = 2609 pounds sterling, 95% CI 1769 pounds sterling to 3314 pounds sterling).

CONCLUSIONS

Over one year, CABG was more expensive and offered greater survival than PCI but little added benefit in terms of quality adjusted life years. The additional cost of CABG can be justified only if it offers continuing benefit at no further increase in cost relative to PCI over several years.

Competing processes of cell death and recovery of function following ischemic preconditioning

The goal of the present study was to determine the neuroprotective efficacy of ischemic preconditioning using behavioral, electrophysiological and histological endpoints at various time points up to 90 days postischemia. Gerbils were exposed to a brief, non-injurious episode of forebrain ischemia (1.5 min) on each of 2 consecutive days. Three days following this preconditioning procedure, the animals received a 5 min occlusion. Other animals underwent sham surgery or a 5 min occlusion without preconditioning. Ischemic preconditioning appeared to provide striking histological protection at both rostral (approximately 80% and approximately 67% of sham) and posterior levels of hippocampus (approximately 94% and approximately 78% of sham) at 3 and 10 days survival, respectively. However, in spite of the near normal number of CA1 neurons, animals displayed marked impairments in an open field test of habituation as well as reduced dendritic field potentials in the CA1 area. Additionally, in ischemic animals the basal and apical dendritic regions of CA1 were nearly devoid of the cytoskeletal protein microtubule associated protein 2 (MAP2). Staining levels of MAP2 in preconditioned and sham animals were similar. With increasing survival time, open field behavior as well as CA1 field potential amplitude recovered. Nonetheless, CA1 cell death in ischemic preconditioned animals continued over the 90-day survival period (P<0.05, vs. sham levels). Ischemic preconditioning provides a significant degree of neuroprotection characterized by a complex interplay of protracted cell death and neuroplasticity (recovery of function). These competing processes are best elucidated using a combination of functional and histological endpoints as well as multiple and extended survival times (i.e., greater than 7-10 days).

Targeting Tau Mitigates Mitochondrial Fragmentation and Oxidative Stress in Amyotrophic Lateral Sclerosis

Understanding the mechanisms underlying amyotrophic lateral sclerosis (ALS) is crucial for the development of new therapies. Previous studies have demonstrated that mitochondrial dysfunction is a key pathogenetic event in ALS. Interestingly, studies in Alzheimer's disease (AD) post-mortem brain and animal models link alterations in mitochondrial function to interactions between hyperphosphorylated tau and dynamin-related protein 1 (DRP1), the GTPase involved in mitochondrial fission. Recent evidence suggest that tau may be involved in ALS pathogenesis, therefore, we sought to determine whether hyperphosphorylated tau may lead to mitochondrial fragmentation and dysfunction in ALS and whether reducing tau may provide a novel therapeutic approach. Our findings demonstrated that pTau-S396 is mis-localized to synapses in post-mortem motor cortex (mCTX) across ALS subtypes. Additionally, the treatment with ALS synaptoneurosomes (SNs), enriched in pTau-S396, increased oxidative stress, induced mitochondrial fragmentation, and altered mitochondrial connectivity without affecting cell survival in vitro. Furthermore, pTau-S396 interacted with DRP1, and similar to pTau-S396, DRP1 accumulated in SNs across ALS subtypes, suggesting increases in mitochondrial fragmentation in ALS. As previously reported, electron microscopy revealed a significant decrease in mitochondria density and length in ALS mCTX. Lastly, reducing tau levels with QC-01-175, a selective tau degrader, prevented ALS SNs-induced mitochondrial fragmentation and oxidative stress in vitro. Collectively, our findings suggest that increases in pTau-S396 may lead to mitochondrial fragmentation and oxidative stress in ALS and decreasing tau may provide a novel strategy to mitigate mitochondrial dysfunction in ALS. pTau-S396 mis-localizes to synapses in ALS. ALS synaptoneurosomes (SNs), enriched in pTau-S396, increase oxidative stress and induce mitochondrial fragmentation in vitro. pTau-S396 interacts with the pro-fission GTPase DRP1 in ALS. Reducing tau with a selective degrader, QC-01-175, mitigates ALS SNs-induced mitochondrial fragmentation and increases in oxidative stress in vitro.

Novel genetic variants in MAPT and alterations in tau phosphorylation in amyotrophic lateral sclerosis post-mortem motor cortex and cerebrospinal fluid

Although the molecular mechanisms underlying amyotrophic lateral sclerosis (ALS) are not yet fully understood, several studies report alterations in tau phosphorylation in both sporadic and familial ALS. Recently, we have demonstrated that phosphorylated tau at S396 (pTau‐S396) is mislocalized to synapses in ALS motor cortex (mCTX) and contributes to mitochondrial dysfunction. Here, we demonstrate that while there was no overall increase in total tau, pTau‐S396, and pTau‐S404 in ALS post‐mortem mCTX, total tau and pTau‐S396 were increased in C9ORF72‐ALS. Additionally, there was a significant decrease in pTau‐T181 in ALS mCTX compared controls. Furthermore, we leveraged the ALS Knowledge Portal and Project MinE data sets and identified ALS‐specific genetic variants across MAPT, the gene encoding tau. Lastly, assessment of cerebrospinal fluid (CSF) samples revealed a significant increase in total tau levels in bulbar‐onset ALS together with a decrease in CSF pTau‐T181:tau ratio in all ALS samples, as reported previously. While increases in CSF tau levels correlated with a faster disease progression as measured by the revised ALS functional rating scale (ALSFRS‐R), decreases in CSF pTau‐T181:tau ratio correlated with a slower disease progression, suggesting that CSF total tau and pTau‐T181 ratio may serve as biomarkers of disease in ALS. Our findings highlight the potential role of pTau‐T181 in ALS, as decreases in CSF pTau‐T181:tau ratio may reflect the significant decrease in pTau‐T181 in post‐mortem mCTX. Taken together, these results indicate that tau phosphorylation is altered in ALS post‐mortem mCTX as well as in CSF and, importantly, the newly described pathogenic or likely pathogenic variants identified in MAPT in this study are adjacent to T181 and S396 phosphorylation sites further highlighting the potential role of these tau functional domains in ALS.

Although the molecular mechanisms underlying amyotrophic lateral sclerosis (ALS) are not yet fully understood, recent studies report alterations in tau phosphorylation in ALS. Our study builds on these findings and demonstrates that tau phosphorylation is altered in post‐mortem ALS motor cortex and highlights new and ALS‐specific variants in MAPT, the gene encoding tau. Lastly, we report alterations in phosphorylated tau in ALS cerebrospinal fluid that may function as a predictive biomarker for ALS.

PrP concentration in the central nervous system: regional variability, genotypic effects, and pharmacodynamic impact

Prion protein (PrP) concentration controls the kinetics of prion replication and is a genetically and pharmacologically validated therapeutic target for prion disease. In order to evaluate PrP concentration as a pharmacodynamic biomarker and assess its contribution to known prion disease risk factors, we developed and validated a plate-based immunoassay reactive for PrP across six species of interest and applicable to brain and cerebrospinal fluid (CSF). PrP concentration varies dramatically between different brain regions in mice, cynomolgus macaques, and humans. PrP expression does not appear to contribute to the known risk factors of age, sex, or common PRNP genetic variants. CSF PrP is lowered in the presence of rare pathogenic PRNP variants, with heterozygous carriers of P102L displaying 55% and of D178N just 31% the CSF PrP concentration of mutation-negative controls. In rodents, pharmacologic reduction of brain Prnp RNA is reflected in brain parenchyma PrP, and in turn in CSF PrP, validating CSF as a sampling compartment for the effect of PrP-lowering therapy. Our findings support the use of CSF PrP as a pharmacodynamic biomarker for PrP-lowering drugs, and suggest that relative reduction from individual baseline CSF PrP concentration may be an appropriate marker for target engagement.

Scleromyxedema (papular mucinosis): a surgical perspective

Scleromyxedema (papular mucinosis) is a rare systemic disorder with a poor prognosis that produces severe aesthetic and functional disability. A patient is presented for whom the hitherto undescribed use of aggressive surgical intervention for palliation is applied. Methods are described, including a discussion of the trial-and-error evolution of the treatment. Results are shown that suggest that there is a place for surgical intervention in the treatment of the cutaneous changes produced by this disease.

Temporal profile of magnetic resonance imaging changes following forebrain ischemia in the gerbil

Quantitative T2 magnetic resonance (MR) imaging was used to examine gerbil brains 1, 3, 10, and 30 days after 5 min forebrain ischemia. T2 was increased in the dorsal-lateral striatum 1 and 3 days post-ischemia, and in the hippocampus 3 days post-ischemia. T2 was normal 10 days post-ischemia, and decreased in the hippocampus and dorsal-lateral striatum 30 days post-ischemia. Neuronal counts in the dorsal-lateral striatum and CA1 hippocampal region were uniformly decreased 30 days post-ischemia. The increase in T2 shortly after ischemia is attributed to brain edema localized to regions where neuronal injury developed. The late decrease in T2 may be due to decreased water in gliotic tissue, or to ferritin-positive microglia, following forebrain ischemia. Tissue atrophy at later times gave enlarged ventricles on MR images.

Integrating peer support services into primary care-based OUD treatment: Lessons from the Penn integrated model

Opioid use disorder (OUD) is a major public health emergency in the United States. In 2020, 2.7 million individuals had an OUD. Medication for opioid use disorder is the evidence-based, standard of care for treating OUD in outpatient settings, especially buprenorphine because it is effective and has low toxicity. Buprenorphine is increasingly prescribed in primary care, a setting that provides greater anonymity and convenience than substance use disorder treatment centers. Yet two-thirds of people who begin buprenorphine treatment discontinue within the first six months. Treatment dropout elevates the risks of return to use, infections, higher levels of medical care and related costs, justice system involvement, and death. One promising form of retention support is peer service programs. Peers combine their lived experience of substance use and recovery with formal training to help patients engage and persist in OUD treatment. They provide a range of services, including health education, encouragement and empathy, coping skills, recovery modeling, and concrete assistance in overcoming the situational barriers to retention. However, guidance is needed to define the peer role in primary care, the specific tasks peers should perform, the competencies those tasks require, training and professional development needs, and peer performance standards. Guidance also is needed to integrate peers into the care team, allocate and coordinate responsibilities among care team members, manage peer operations and workflow, and facilitate effective team communication. Here we describe a peer support program in the University of Pennsylvania Health System (UPHS or Penn Medicine) network of primary care practices. This paper details the program's core components, values, and activities. We also report the organizational challenges, unresolved questions, and lessons for the field in administering a peer support program to meet the needs of patients served by a large, urban medical system with an extensive suburban and rural catchment area. CLINICAL TRIALS REGISTRATION: www.clinicaltrials.gov registration: NCT04245423.

Creating the Pick's disease International Consortium: Association study of MAPT H2 haplotype with risk of Pick's disease

Background

Pick's disease (PiD) is a rare and predominantly sporadic form of frontotemporal dementia that is classified as a primary tauopathy. PiD is pathologically defined by argyrophilic inclusion Pick bodies and ballooned neurons in the frontal and temporal brain lobes. PiD is characterised by the presence of Pick bodies which are formed from aggregated, hyperphosphorylated, 3-repeat tau proteins, encoded by the MAPT gene. The MAPT H2 haplotype has consistently been associated with a decreased disease risk of the 4-repeat tauopathies of progressive supranuclear palsy and corticobasal degeneration, however its role in susceptibility to PiD is unclear. The primary aim of this study was to evaluate the association between MAPT H2 and risk of PiD.

Methods

We established the Pick's disease International Consortium (PIC) and collected 338 (60.7% male) pathologically confirmed PiD brains from 39 sites worldwide. 1,312 neurologically healthy clinical controls were recruited from Mayo Clinic Jacksonville, FL (N=881) or Rochester, MN (N=431). For the primary analysis, subjects were directly genotyped for MAPT H1-H2 haplotype-defining variant rs8070723. In secondary analysis, we genotyped and constructed the six-variant MAPT H1 subhaplotypes (rs1467967, rs242557, rs3785883, rs2471738, rs8070723, and rs7521).

Findings

Our primary analysis found that the MAPT H2 haplotype was associated with increased risk of PiD (OR: 1.35, 95% CI: 1.12-1.64 P=0.002). In secondary analysis involving H1 subhaplotypes, a protective association with PiD was observed for the H1f haplotype (0.0% vs. 1.2%, P=0.049), with a similar trend noted for H1b (OR: 0.76, 95% CI: 0.58-1.00, P=0.051). The 4-repeat tauopathy risk haplotype MAPT H1c was not associated with PiD susceptibility (OR: 0.93, 95% CI: 0.70-1.25, P=0.65).

Interpretation

The PIC represents the first opportunity to perform relatively large-scale studies to enhance our understanding of the pathobiology of PiD. This study demonstrates that in contrast to its protective role in 4R tauopathies, the MAPT H2 haplotype is associated with an increased risk of PiD. This finding is critical in directing isoform-related therapeutics for tauopathies.

Validation of Risk Prediction Models for Pneumothorax and Intercostal Catheter Insertion Following CT-Guided Lung Biopsy

BACKGROUND

CT-guided percutaneous transthoracic needle biopsy is the primary method for diagnosing lung lesions. Widely accepted validated risk prediction models are yet to be developed. A recently published study conducted at Grampians Health Services (GHS) developed two risk prediction models for predicting pneumothorax and intercostal catheter (ICC) insertion. This study aims to validate these models.

METHODS

This is a single-centre, retrospective cohort study performed at GHS. Patients with a CT-guided lung biopsy between January 2020 and July 2023 were included, alongside target-lesion characteristics, procedural-related factors and complications. Predicted probabilities for pneumothorax and ICC insertion were generated for each patient, and the diagnostic accuracy of the previous risk prediction models was evaluated the area under the receiver operating characteristic. A Youden Index was used to determine the sensitivity and specificity at the optimal probability thresholds.

RESULTS

The validation found the model published by GHS demonstrated a diagnostic accuracy of 0.695 (95% CI: 0.601-0.695) for predicting pneumothorax following CT-guided percutaneous biopsy. The model for predicting intercostal catheter insertion had a diagnostic accuracy of 0.762 (95% CI: 0.642-0.762). The sensitivity for predicting pneumothorax and ICC insertion was 81.97% and 92.86%, respectively, for their optimum probability thresholds.

CONCLUSION

The findings suggest that the previously published models may be useful in predicting pneumothoraces and ICC insertion following CT-guided percutaneous biopsy. We recommend these models as an adjunctive tool to aid in clinical decision-making during the peri-procedural management of these patients pending further validation with an external cohort.

Divergent Molecular Pathways for Toxicity of Selected Mutant C9ORF72-derived Dipeptide Repeats

Expansion of a hexanucleotide repeat in a noncoding region of the C9ORF72 gene is responsible for a significant fraction of Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD) cases, but mechanisms linking mutant gene products to neuronal toxicity remain debatable. Pathogenesis was proposed to involve the production of toxic RNA species and/or accumulation of toxic dipeptide repeats (DPRs) but distinguishing between these mechanisms has been challenging. In this study, we first use complementary model systems for analyzing pathogenesis in adult-onset neurodegenerative diseases to characterize the pathogenicity of DPRs produced by Repeat Associated Non-ATG translation of C9ORF72 in specific cellular compartments: isolated axoplasm and giant synapse from the squid. Results showed selective axonal and presynaptic toxicity of GP-DPRs, independent of associated RNA. These effects involved a MAPK signaling pathway that affects fast axonal transport and synaptic function, a pathogenic mechanism shared with other mutant proteins associated with familial ALS, like SOD1 and FUS. In primary cultured neurons, GP but not other DPRs promote the "dying-back" axonopathy seen in ALS. Interestingly, GR- and PR-DPRs, which had no effect on axonal transport or synaptic transmission, were found to disrupt the nuclear membrane, promoting "dying-forward" neuropathy. All C9-DPR-mediated toxic effects observed in these studies are independent of whether the corresponding mRNAs contained hexanucleotide repeats or alternative codons. Finally, C9ORF72 human tissues confirmed a close association between GP and active P38 in degenerating motor neurons as well as GR-associated nuclear damage in the cortex. Collectively, our studies establish compartment-specific toxic effects of C9-DPRs associated with degeneration, suggesting that two independent pathogenic mechanisms may contribute to disease heterogeneity and/or synergize on disease progression in C9ORF72 patients with ALS and/or FTD symptoms.