Machine learning models for predicting blood pressure phenotypes by combining multiple polygenic risk scores.

We construct non-linear machine learning (ML) prediction models for systolic and diastolic blood pressure (SBP, DBP) using demographic and clinical variables and polygenic risk scores (PRSs). We developed a two-model ensemble, consisting of a baseline model, where prediction is based on demographic and clinical variables only, and a genetic model, where we also include PRSs. We evaluate the use of a linear versus a non-linear model at both the baseline and the genetic model levels and assess the improvement in performance when incorporating multiple PRSs. We report the ensemble model's performance as percentage variance explained (PVE) on a held-out test dataset. A non-linear baseline model improved the PVEs from 28.1 to 30.1% (SBP) and 14.3% to 17.4% (DBP) compared with a linear baseline model. Including seven PRSs in the genetic model computed based on the largest available GWAS of SBP/DBP improved the genetic model PVE from 4.8 to 5.1% (SBP) and 4.7 to 5% (DBP) compared to using a single PRS. Adding additional 14 PRSs computed based on two independent GWASs further increased the genetic model PVE to 6.3% (SBP) and 5.7% (DBP). PVE differed across self-reported race/ethnicity groups, with primarily all non-White groups benefitting from the inclusion of additional PRSs. In summary, non-linear ML models improves BP prediction in models incorporating diverse populations.

GPT-4 Performance for Neurologic Localization.

Background and Objectives: In health care, large language models such as Generative Pretrained Transformers (GPTs), trained on extensive text datasets, have potential applications in reducing health care disparities across regions and populations. Previous software developed for lesion localization has been limited in scope. This study aims to evaluate the capability of GPT-4 for lesion localization based on clinical presentation. Methods: GPT-4 was prompted using history and neurologic physical examination (H&P) from published cases of acute stroke followed by questions for clinical reasoning with answering for "single or multiple lesions," "side," and "brain region" using Zero-Shot Chain-of-Thought and Text Classification prompting. GPT-4 output on 3 separate trials for each of 46 cases was compared with imaging-based localization. Results: GPT-4 successfully processed raw text from H&P to generate accurate neuroanatomical localization and detailed clinical reasoning. Performance metrics across trial-based analysis for specificity, sensitivity, precision, and F1-score were 0.87, 0.74, 0.75, and 0.74, respectively, for side; 0.94, 0.85, 0.84, and 0.85, respectively, for brain region. Class labels within the brain region were similarly high for all regions except the cerebellum and were also similar when considering all 3 trials to examine metrics by case. Errors were due to extrinsic causes-inadequate information in the published cases, and intrinsic causes-failures of logic or inadequate knowledge base. Discussion: This study reveals capabilities of GPT-4 in the localization of acute stroke lesions, showing a potential future role as a clinical tool in neurology.

Activation of the insulin receptor by insulin-like growth factor 2.

Insulin receptor (IR) controls growth and metabolism. Insulin-like growth factor 2 (IGF2) has different binding properties on two IR isoforms, mimicking insulin's function. However, the molecular mechanism underlying IGF2-induced IR activation remains unclear. Here, we present cryo-EM structures of full-length human long isoform IR (IR-B) in both the inactive and IGF2-bound active states, and short isoform IR (IR-A) in the IGF2-bound active state. Under saturated IGF2 concentrations, both the IR-A and IR-B adopt predominantly asymmetric conformations with two or three IGF2s bound at site-1 and site-2, which differs from that insulin saturated IR forms an exclusively T-shaped symmetric conformation. IGF2 exhibits a relatively weak binding to IR site-2 compared to insulin, making it less potent in promoting full IR activation. Cell-based experiments validated the functional importance of IGF2 binding to two distinct binding sites in optimal IR signaling and trafficking. In the inactive state, the C-terminus of α-CT of IR-B contacts FnIII-2 domain of the same protomer, hindering its threading into the C-loop of IGF2, thus reducing the association rate of IGF2 with IR-B. Collectively, our studies demonstrate the activation mechanism of IR by IGF2 and reveal the molecular basis underlying the different affinity of IGF2 to IR-A and IR-B.

Antihypertensive medication persistence and adherence among non-Hispanic Asian US patients with hypertension and fee-for-service Medicare health insurance.

BACKGROUND: Less than 50% of non-Hispanic Asian adults taking antihypertensive medication have controlled blood pressure. METHODS: We compared non-persistence and low adherence to antihypertensive medication between non-Hispanic Asian and other race/ethnicity groups among US adults ≥66 years who initiated antihypertensive medication between 2011 and 2018 using a 5% random sample of Medicare beneficiaries (non-Hispanic Asian, n = 2,260; non-Hispanic White, n = 56,000; non-Hispanic Black, n = 5,792; Hispanic, n = 4,212; and Other, n = 1,423). Non-persistence was defined as not having antihypertensive medication available to take in the last 90 of 365 days following treatment initiation. Low adherence was defined as having antihypertensive medication available to take on <80% of the 365 days following initiation. RESULTS: In 2011-2012, 2013-2014, 2015-2016 and 2017-2018, the proportion of non-Hispanic Asian Medicare beneficiaries with non-persistence was 29.1%, 25.6%, 25.4% and 26.7% (p-trend = 0.381), respectively, and the proportion with low adherence was 58.1%, 54.2%, 53.4% and 51.6%, respectively (p-trend = 0.020). In 2017-2018, compared with non-Hispanic Asian beneficiaries, non-persistence was less common among non-Hispanic White beneficiaries (risk ratio 0.74 [95%CI, 0.64-0.85]), non-Hispanic Black beneficiaries (0.80 [95%CI 0.68-0.94]) and those reporting Other race/ethnicity (0.68 [95%CI, 0.54-0.85]) but not among Hispanic beneficiaries (1.04 [95%CI, 0.88-1.23]). Compared to non-Hispanic Asian beneficiaries, non-Hispanic White beneficiaries and beneficiaries reporting Other race/ethnicity were less likely to have low adherence to antihypertensive medication (relative risk 0.78 [95%CI 0.72-0.84] and 0.84 [95%CI 0.74-0.95], respectively); there was no association for non-Hispanic Black or Hispanic beneficiaries. CONCLUSIONS: Non-persistence and low adherence to antihypertensive medication were more common among older non-Hispanic Asian than non-Hispanic White adults.

Trends in All-Cause, Cardiovascular, and Noncardiovascular Mortality Among US Adults With Hypertension.

BACKGROUND: Death certificate data indicate that hypertension may have increased as a contributing cause of death among US adults. Hypertension is not commonly recorded on death certificates although it contributes to a substantial proportion of cardiovascular disease (CVD) deaths. METHODS: We estimated changes in all-cause, CVD, and non-CVD mortality over 5 years of follow-up among 4 cohorts of US adults with hypertension using mortality follow-up data from National Health and Nutrition Examination Survey III in 1988 to 1994, and National Health and Nutrition Examination Survey cycles from 1999 to 2000 through 2015 to 2016 (n=20 927). Hypertension was defined as systolic blood pressure ≥140 mm Hg, diastolic blood pressure ≥90 mm Hg, or antihypertensive medication use. Participants were grouped according to the date of their National Health and Nutrition Examination Survey study visit (1988-1994, 1999-2004, 2005-2010, 2011-2016). RESULTS: There were 2646, 1048, and 1598 all-cause, CVD, and non-CVD deaths, respectively. After age, gender, and race/ethnicity adjustment and compared with the 1988 to 1994 cohort, the hazard ratio of all-cause mortality was 0.88 (95% CI, 0.76-1.01) for the 1999 to 2004 cohort, 0.82 (95% CI, 0.70-0.95) for the 2005 to 2010 cohort, and 0.89 (95% CI, 0.75-1.05) for the 2011 to 2016 cohort (P trend=0.123). The age, gender, and race/ethnicity-adjusted hazard ratios for CVD mortality compared with the 1988 to 1994 cohort were 0.74 (95% CI, 0.60-0.90) for the 1999 to 2004 cohort, 0.61 (95% CI, 0.50-0.74) for the 2005 to 2010 cohort, and 0.57 (95% CI, 0.44-0.74) for the 2011 to 2016 cohort (P trend <0.001). There was no evidence of a change in CVD mortality between the 2005 to 2010 and 2011 to 2016 cohorts (P=0.661). Noncardiovascular mortality did not decline over the study period (P trend=0.145). CONCLUSIONS: The decline in CVD mortality among US adults with hypertension stalled after 2005 to 2010.

Diagnostic Accuracy of Office Blood Pressure Measurement and Home Blood Pressure Monitoring for Hypertension Screening Among Adults: Results From the IDH Study.

BACKGROUND: Using high awake blood pressure (BP; ≥130/80 mm Hg) on ambulatory BP monitoring (ABPM) as a reference, the purpose of this study was to determine the accuracy of high office BP (≥130/80 mm Hg) at an initial visit and high confirmatory office BP (≥130/80 mm Hg), and separately, high home BP (≥130/80 mm Hg) among participants with high office BP (≥130/80 mm Hg) at an initial office visit. METHODS AND RESULTS: The accuracy of office BP measurements using the oscillometric method for detecting high BP on ABPM was determined among 379 participants with complete office BP and ABPM data in the IDH (Improving the Detection of Hypertension) study. For detecting high BP on ABPM, the accuracy of high confirmatory office BP using the oscillometric method and, separately, high home BP was also determined among the subgroup of 122 participants with high office BP at an initial visit and complete home BP monitoring data. High office BP had moderate sensitivity (0.61 [95% CI, 0.53-0.68]) and high specificity (0.85 [95% CI, 0.80-0.90]) for high awake BP. High confirmatory office BP and high home BP had moderate sensitivity (0.69 [95% CI, 0.59-0.79] and 0.79 [95% CI, 0.71-0.87], respectively) and low and moderate specificity (0.44 [95% CI, 0.27-0.61] and 0.72 [95% CI, 0.56-0.88], respectively). CONCLUSIONS: Many individuals with high BP on ABPM do not have high office BP. Confirmatory office BP and home blood pressure monitoring also had limited ability to identify individuals with high BP on ABPM.

MAD2-Dependent Insulin Receptor Endocytosis Regulates Metabolic Homeostasis.

Insulin activates insulin receptor (IR) signaling and subsequently triggers IR endocytosis to attenuate signaling. Cell division regulators MAD2, BUBR1, and p31comet promote IR endocytosis on insulin stimulation. Here, we show that genetic ablation of the IR-MAD2 interaction in mice delays IR endocytosis, increases IR levels, and prolongs insulin action at the cell surface. This in turn causes a defect in insulin clearance and increases circulating insulin levels, unexpectedly increasing glucagon levels, which alters glucose metabolism modestly. Disruption of the IR-MAD2 interaction increases serum fatty acid concentrations and hepatic fat accumulation in fasted male mice. Furthermore, disruption of the IR-MAD2 interaction distinctly changes metabolic and transcriptomic profiles in the liver and adipose tissues. Our findings establish the function of cell division regulators in insulin signaling and provide insights into the metabolic functions of IR endocytosis. ARTICLE HIGHLIGHTS: The physiological role of IR endocytosis in insulin sensitivity remains unclear. Disruption of the IR-MAD2 interaction delays IR endocytosis and prolongs insulin signaling. IR-MAD2 controls insulin clearance and glucose metabolism. IR-MAD2 maintains energy homeostasis.

Structural basis of insulin fibrillation.

Insulin is a hormone responsible for maintaining normal glucose levels by activating insulin receptor (IR) and is the primary treatment for diabetes. However, insulin is prone to unfolding and forming cross-ß fibers. Fibrillation complicates insulin storage and therapeutic application. Molecular details of insulin fibrillation remain unclear, hindering efforts to prevent fibrillation process. Here, we characterized insulin fibrils using cryo-electron microscopy (cryo-EM), showing multiple forms that contain one or more of the protofilaments containing both the A and B chains of insulin linked by disulfide bonds. We solved the cryo-EM structure of one of the fibril forms composed of two protofilaments at 3.2-Å resolution, which reveals both the ß sheet conformation of the protofilament and the packing interaction between them that underlie the fibrillation. On the basis of this structure, we designed several insulin mutants that display reduced fibrillation while maintaining native IR signaling activity. These designed insulin analogs may be developed into more effective therapeutics for type 1 diabetes.

Metastatic Lung Adenocarcinoma: A Case of Unusual Presentation With a Skull Mass.

This case report describes an uncommon presentation of lung adenocarcinoma, which appeared as a skull mass. While not the first reported case in medical literature, it is still a rare occurrence for lung adenocarcinoma to present in this manner. This report focuses on the clinical presentation and treatment of an elderly male patient who had a progressively enlarging and painful skull mass. The initial imaging revealed an about 5 cm soft tissue mass at the dorsal midline of the parietal-occipital bone. Subsequent imaging identified a lung mass, and a biopsy of the skull bone confirmed that the mass was metastatic adenocarcinoma originating from the lung. For treatment, the patient underwent occipital partial resection of the mass, followed by wire mesh cranioplasty. Chemotherapy and external beam radiotherapy were administered to alleviate symptoms and control the spread of cancer. Lung carcinoma with distant metastasis is generally associated with a poorer prognosis. However, some supporting data suggest that early detection and aggressive management play crucial roles in preventing further metastasis and improving the patient's quality of life and overall survival rate. Skull bone metastasis from lung cancer is indeed a rare phenomenon, and cases like these contribute valuable knowledge to the field. By reporting such cases, healthcare professionals can gain a better understanding of the clinical manifestations, diagnostic challenges, and appropriate management strategies for these uncommon occurrences. This case report underscores the significance of maintaining a high index of suspicion and utilizing a multimodality approach to diagnose rare instances of calvarial metastasis.

Use of Different Blood Pressure Thresholds to Reduce the Number of Home Blood Pressure Monitoring Days Needed for Detecting Hypertension.

BACKGROUND: Home blood pressure (BP) monitoring over a 7-day period is recommended to confirm the diagnosis of hypertension. METHODS: We determined upper and lower home BP thresholds with >90% positive predictive value and >90% negative predictive value using 1 to 6 days of monitoring to identify high home BP (systolic BP ≥130 mm Hg or diastolic BP ≥80 mm Hg) based on 7 days of home BP monitoring. The sample included 361 adults from the Improving the Detection of Hypertension Study who were not taking antihypertensive medication. We used two 7-day periods, at least 3 days apart, the first being a sampling period and the second a reference period. For each number of days in the sampling period, we determined the percentage of participants who had a high likelihood of having (>90% positive predictive value) or not having (>90% negative predictive value) high BP and would not need to continue home BP monitoring. Only the participants in an uncertain category (ie, positive predictive value ≤90% and negative predictive value ≤90%) after each day were carried forward to the next day of home BP monitoring. RESULTS: Of the 361 participants (mean [SD] age of 41.3 [13.2] years; 60.4% women), 38.0% had high home BP during the reference period. There were 63.7%, 17.1%, 10.5%, 3.3%, 3.6%, and 1.4% participants who would not need to continue after 1, 2, 3, 4, 5, and 6 days of monitoring. CONCLUSIONS: In most people, high home BP can be identified or excluded with a high degree of confidence with 3 days or less of monitoring.

Clinical Outcomes in Hypertensive Emergency: A Systematic Review and Meta-Analysis.

Background To study the prevalence and types of hypertension-mediated organ damage and the prognosis of patients presenting to the emergency department (ED) with hypertensive emergencies. Methods and Results PubMed was queried from inception through November 30, 2021. Studies were included if they reported the prevalence or prognosis of hypertensive emergencies in patients presenting to the ED. Studies reporting data on hypertensive emergencies in other departments were excluded. The extracted data were arcsine transformed and pooled using a random-effects model. Fifteen studies (n=4370 patients) were included. Pooled analysis demonstrates that the prevalence of hypertensive emergencies was 0.5% (95% CI, 0.40%-0.70%) in all patients presenting to ED and 35.9% (95% CI, 26.7%-45.5%) among patients presenting in ED with hypertensive crisis. Ischemic stroke (28.1% [95% CI, 18.7%-38.6%]) was the most prevalent hypertension-mediated organ damage, followed by pulmonary edema/acute heart failure (24.1% [95% CI, 19.0%-29.7%]), hemorrhagic stroke (14.6% [95% CI, 9.9%-20.0%]), acute coronary syndrome (10.8% [95% CI, 7.3%-14.8%]), renal failure (8.0% [95% CI, 2.9%-15.5%]), subarachnoid hemorrhage (6.9% [95% CI, 3.9%-10.7%]), encephalopathy (6.1% [95% CI, 1.9%-12.4%]), and the least prevalent was aortic dissection (1.8% [95% CI, 1.1%-2.8%]). Prevalence of in-hospital mortality among patients with hypertensive emergency was 9.9% (95% CI, 1.4%-24.6%). Conclusions Our findings demonstrate a pattern of hypertension-mediated organ damage primarily affecting the brain and heart, substantial cardiovascular renal morbidity and mortality, as well as subsequent hospitalization in patients with hypertensive emergencies presenting to the ED.

Blood Pressure and Cardiovascular Disease Mortality Among US Adults: A Sex-Stratified Analysis, 1999-2019.

BACKGROUND: Most research examining the association between blood pressure (BP) and cardiovascular disease (CVD) is sex-agnostic. Our goal was to assess sex-specific associations between BP and CVD mortality. METHODS: We combined ten cycles of the National Health and Nutrition Examination Survey (1999-2018), N=53 289. Blood pressure was measured 3× and averaged. Data were linked to National Death Index data, and CVD mortality through December 31, 2019, was defined from International Classification of Diseases, Tenth Revision codes. We estimated sex-stratified, multivariable-adjusted incidence rate ratios (IRRs) for CVD mortality. RESULTS: Over a median follow-up of 9.5 years, there were 2405 CVD deaths. Associations between categories of systolic blood pressure (SBP) and diastolic blood pressure (DBP) with CVD mortality differed by sex (P<0.01). Among men, compared with SBP of 100 to <110 mm Hg, CVD mortality was 76% higher with SBP ≥160 mm Hg (IRR, 1.76 [95% CI, 1.27-2.44]). Among women, compared with SBP 100 to < 110 mm Hg, CVD mortality was 61% higher with SBP 130 to 139 mm Hg (IRR, 1.61 [95% CI, 1.02-2.55]), 75% higher with SBP 140 to 159 mm Hg (IRR, 1.75 [95% CI, 1.09-2.80]), and 113% higher with SBP≥160 mm Hg (IRR, 2.13 [95% CI, 1.35-3.36]). Compared with DBP 70 to <80 mm Hg, CVD mortality was higher with DBP <70 mm Hg and DBP≥80 mm Hg among men, and higher with DBP <50 mm Hg and DBP≥80 mm Hg among women. CONCLUSIONS: The association between BP and CVD mortality differed by sex, with increased CVD mortality risk present at lower levels of systolic blood pressure among women compared with men.

Structural basis of the alkaline pH-dependent activation of insulin receptor-related receptor.

The insulin receptor (IR) family is a subfamily of receptor tyrosine kinases that controls metabolic homeostasis and cell growth. Distinct from IR and insulin-like growth factor 1 receptor, whose activation requires ligand binding, insulin receptor-related receptor (IRR)-the third member of the IR family-is activated by alkaline pH. However, the molecular mechanism underlying alkaline pH-induced IRR activation remains unclear. Here, we present cryo-EM structures of human IRR in both neutral pH inactive and alkaline pH active states. Combined with mutagenesis and cellular assays, we show that, upon pH increase, electrostatic repulsion of the pH-sensitive motifs of IRR disrupts its autoinhibited state and promotes a scissor-like rotation between two protomers, leading to a T-shaped active conformation. Together, our study reveals an unprecedented alkaline pH-dependent activation mechanism of IRR, opening up opportunities to understand the structure-function relationship of this important receptor.

The Activation Mechanism of the Insulin Receptor: A Structural Perspective.

The insulin receptor (IR) is a type II receptor tyrosine kinase that plays essential roles in metabolism, growth, and proliferation. Dysregulation of IR signaling is linked to many human diseases, such as diabetes and cancers. The resolution revolution in cryo-electron microscopy has led to the determination of several structures of IR with different numbers of bound insulin molecules in recent years, which have tremendously improved our understanding of how IR is activated by insulin. Here, we review the insulin-induced activation mechanism of IR, including (a) the detailed binding modes and functions of insulin at site 1 and site 2 and (b) the insulin-induced structural transitions that are required for IR activation. We highlight several other key aspects of the activation and regulation of IR signaling and discuss the remaining gaps in our understanding of the IR activation mechanism and potential avenues of future research.

Discontinuation of Renin-Angiotensin System Inhibitors During the Early Stage of the COVID-19 Pandemic.

BACKGROUND: In March and April 2020, medical societies published statements recommending continued use of renin-angiotensin system (RAS) inhibitors despite theoretical concerns that these medications could increase COVID-19 severity. Determining if patients discontinued RAS inhibitors during the COVID-19 pandemic could inform responses to future public health emergencies. METHODS: We analyzed claims data from US adults with health insurance in the Marketscan database. We identified patients who filled a RAS inhibitor and were persistent, defined by not having a ≥30-day gap without medication available, and high adherence, defined by having medication available on ≥80% of days, from March 2019 to February 2020. Among these patients, we estimated the proportion who discontinued their RAS inhibitor (i.e., had ≥30 consecutive days without a RAS inhibitor available to take) between March and August 2020. For comparison, we estimated the proportion of patients that discontinued a RAS inhibitor between March and August 2019 after being persistent with high adherence from March 2018 to February 2019. RESULTS: Among 816,380 adults who were persistent and adherent to a RAS inhibitor from March 2019 to February 2020, 10.8% discontinued this medication between March and August 2020. Among 822,873 adults who were persistent and adherent to a RAS inhibitor from March 2018 to February 2019, 11.7% discontinued this medication between March and August 2019. The multivariable-adjusted relative risk for RAS inhibitor discontinuation in 2020 vs. 2019 was 0.94 (95% CI 0.93-0.95). CONCLUSIONS: There was no evidence of an increase in RAS inhibitor discontinuation during the early stage of the COVID-19 pandemic.

The insulin receptor endocytosis.

Insulin signaling controls multiple aspects of animal physiology. At the cell surface, insulin binds and activates the insulin receptor (IR), a receptor tyrosine kinase. Insulin promotes a large conformational change of IR and stabilizes the active conformation. The insulin-activated IR triggers signaling cascades, thus controlling metabolism, growth, and proliferation. The activated IR undergoes internalization by clathrin- or caveolae-mediated endocytosis. The IR endocytosis plays important roles in insulin clearance from blood, and distribution and termination of the insulin signaling. Despite decades of extensive studies, the mechanism and regulation of IR endocytosis and its contribution to pathophysiology remain incompletely understood. Here we discuss recent findings that provide insights into the molecular mechanisms and regulatory pathways that mediate the IR endocytosis.

Association of Clinical Setting With Sociodemographics and Outcomes Following Endovascular Femoropopliteal Artery Revascularization in the United States.

BACKGROUND: After the Centers for Medicare and Medicaid Services modified reimbursement rates for outpatient peripheral vascular intervention in 2008 with the intent of improving access to care, providers began to increasingly perform peripheral vascular interventions in privately owned office-based clinics. Little is known about the characteristics of patients treated in this setting and their long-term outcomes as compared with those treated in hospital-based centers. METHODS: In this retrospective cohort study, Medicare beneficiaries ≥66 years undergoing outpatient femoropopliteal peripheral vascular interventions in office-based clinics and hospital-based centers from 2015 to 2017 were identified. Sociodemographics, comorbidities, and institutional characteristics were compared across sites. Multivariable Cox proportional hazards models were used to estimate the adjusted associations between practice site location and outcomes. The primary outcome was the composite of major amputation or death analyzed through the end of follow-up. RESULTS: Among 134 869 patients, 29.9% were treated in office-based clinics and 70.1% in hospital-based centers. Patients treated in office-based clinics were more often Black (16.9% versus 11.9%), dually enrolled in Medicaid (26.3% versus 19.6%), and residents of lower-resourced regions (32.6% versus 25.6%). Over a median follow-up time of 800 days (interquartile range, 531-1119 days), patients treated in office-based clinics had reduced risks of major amputation or death compared with outpatients treated in hospital-based centers (hazard ratio, 0.92 [95% CI, 0.89-0.95]). They also had lower adjusted all-cause mortality (hazard ratio, 0.93 [95% CI, 0.90-0.96]), major lower extremity amputation (hazard ratio, 0.84 [95% CI, 0.79-0.89]), and all-cause hospitalization (hazard ratio, 0.86 [95% CI, 0.84-0.88]). These findings persisted after stratification by critical limb ischemia, race, dual enrollment, and regional socioeconomic status, as well as among operators treating patients in both clinical settings. CONCLUSIONS: In this large nationwide analysis of Medicare beneficiaries, office-based clinics treated a more socioeconomically disadvantaged population compared with hospital-based centers. Long-term outcomes were comparable between locations. As such, these clinics appear to be selecting lower-risk patients for outpatient peripheral vascular interventions, although there remains the possibility of unmeasured confounding.

Machine learning models for blood pressure phenotypes combining multiple polygenic risk scores.

We construct non-linear machine learning (ML) prediction models for systolic and diastolic blood pressure (SBP, DBP) using demographic and clinical variables and polygenic risk scores (PRSs). We developed a two-model ensemble, consisting of a baseline model, where prediction is based on demographic and clinical variables only, and a genetic model, where we also include PRSs. We evaluate the use of a linear versus a non-linear model at both the baseline and the genetic model levels and assess the improvement in performance when incorporating multiple PRSs. We report the ensemble model's performance as percentage variance explained (PVE) on a held-out test dataset. A non-linear baseline model improved the PVEs from 28.1% to 30.1% (SBP) and 14.3% to 17.4% (DBP) compared with a linear baseline model. Including seven PRSs in the genetic model computed based on the largest available GWAS of SBP/DBP improved the genetic model PVE from 4.8% to 5.1% (SBP) and 4.7% to 5% (DBP) compared to using a single PRS. Adding additional 14 PRSs computed based on two independent GWASs further increased the genetic model PVE to 6.3% (SBP) and 5.7% (DBP). PVE differed across self-reported race/ethnicity groups, with primarily all non-White groups benefitting from the inclusion of additional PRSs.

Molecular basis for the role of disulfide-linked αCTs in the activation of insulin-like growth factor 1 receptor and insulin receptor.

The insulin receptor (IR) and insulin-like growth factor 1 receptor (IGF1R) control metabolic homeostasis and cell growth and proliferation. The IR and IGF1R form similar disulfide bonds linked homodimers in the apo-state; however, their ligand binding properties and the structures in the active state differ substantially. It has been proposed that the disulfide-linked C-terminal segment of α-chain (αCTs) of the IR and IGF1R control the cooperativity of ligand binding and regulate the receptor activation. Nevertheless, the molecular basis for the roles of disulfide-linked αCTs in IR and IGF1R activation are still unclear. Here, we report the cryo-EM structures of full-length mouse IGF1R/IGF1 and IR/insulin complexes with modified αCTs that have increased flexibility. Unlike the Γ-shaped asymmetric IGF1R dimer with a single IGF1 bound, the IGF1R with the enhanced flexibility of αCTs can form a T-shaped symmetric dimer with two IGF1s bound. Meanwhile, the IR with non-covalently linked αCTs predominantly adopts an asymmetric conformation with four insulins bound, which is distinct from the T-shaped symmetric IR. Using cell-based experiments, we further showed that both IGF1R and IR with the modified αCTs cannot activate the downstream signaling potently. Collectively, our studies demonstrate that the certain structural rigidity of disulfide-linked αCTs is critical for optimal IR and IGF1R signaling activation.