Innate Immune Signaling and Its Role in Metabolic and Cardiovascular Diseases.

The innate immune system is an evolutionarily conserved system that senses and defends against infection and irritation. Innate immune signaling is a complex cascade that quickly recognizes infectious threats through multiple germline-encoded cell surface or cytoplasmic receptors and transmits signals for the deployment of proper countermeasures through adaptors, kinases, and transcription factors, resulting in the production of cytokines. As the first response of the innate immune system to pathogenic signals, inflammatory responses must be rapid and specific to establish a physical barrier against the spread of infection and must subsequently be terminated once the pathogens have been cleared. Long-lasting and low-grade chronic inflammation is a distinguishing feature of type 2 diabetes and cardiovascular diseases, which are currently major public health problems. Cardiometabolic stress-induced inflammatory responses activate innate immune signaling, which directly contributes to the development of cardiometabolic diseases. Additionally, although the innate immune elements are highly conserved in higher-order jawed vertebrates, lower-grade jawless vertebrates lack several transcription factors and inflammatory cytokine genes downstream of the Toll-like receptors (TLRs) and retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs) pathways, suggesting that innate immune signaling components may additionally function in an immune-independent way. Notably, recent studies from our group and others have revealed that innate immune signaling can function as a vital regulator of cardiometabolic homeostasis independent of its immune function. Therefore, further investigation of innate immune signaling in cardiometabolic systems may facilitate the discovery of new strategies to manage the initiation and progression of cardiometabolic disorders, leading to better treatments for these diseases. In this review, we summarize the current progress in innate immune signaling studies and the regulatory function of innate immunity in cardiometabolic diseases. Notably, we highlight the immune-independent effects of innate immune signaling components on the development of cardiometabolic disorders.

Structure of the essential inner membrane lipopolysaccharide-PbgA complex.

Lipopolysaccharide (LPS) resides in the outer membrane of Gram-negative bacteria where it is responsible for barrier function1,2. LPS can cause death as a result of septic shock, and its lipid A core is the target of polymyxin antibiotics3,4. Despite the clinical importance of polymyxins and the emergence of multidrug resistant strains5, our understanding of the bacterial factors that regulate LPS biogenesis is incomplete. Here we characterize the inner membrane protein PbgA and report that its depletion attenuates the virulence of Escherichia coli by reducing levels of LPS and outer membrane integrity. In contrast to previous claims that PbgA functions as a cardiolipin transporter6-9, our structural analyses and physiological studies identify a lipid A-binding motif along the periplasmic leaflet of the inner membrane. Synthetic PbgA-derived peptides selectively bind to LPS in vitro and inhibit the growth of diverse Gram-negative bacteria, including polymyxin-resistant strains. Proteomic, genetic and pharmacological experiments uncover a model in which direct periplasmic sensing of LPS by PbgA coordinates the biosynthesis of lipid A by regulating the stability of LpxC, a key cytoplasmic biosynthetic enzyme10-12. In summary, we find that PbgA has an unexpected but essential role in the regulation of LPS biogenesis, presents a new structural basis for the selective recognition of lipids, and provides opportunities for future antibiotic discovery.

Coordination between Two Branches of the Unfolded Protein Response Determines Apoptotic Cell Fate.

The kinases PERK and IRE1 alleviate endoplasmic reticulum (ER) stress by orchestrating the unfolded protein response (UPR). If stress mitigation fails, PERK promotes cell death by activating pro-apoptotic genes, including death receptor 5 (DR5). Conversely, IRE1-which harbors both kinase and endoribonuclease (RNase) modules-blocks apoptosis through regulated IRE1-dependent decay (RIDD) of DR5 mRNA. Under irresolvable ER stress, PERK activity persists, whereas IRE1 paradoxically attenuates, by mechanisms that remain obscure. Here, we report that PERK governs IRE1's attenuation through a phosphatase known as RPAP2 (RNA polymerase II-associated protein 2). RPAP2 reverses IRE1 phosphorylation, oligomerization, and RNase activation. This inhibits IRE1-mediated adaptive events, including activation of the cytoprotective transcription factor XBP1s, and ER-associated degradation of unfolded proteins. Furthermore, RIDD termination by RPAP2 unleashes DR5-mediated caspase activation and drives cell death. Thus, PERK attenuates IRE1 via RPAP2 to abort failed ER-stress adaptation and trigger apoptosis.

Targeted degradation via direct 26S proteasome recruitment.

Engineered destruction of target proteins by recruitment to the cell's degradation machinery has emerged as a promising strategy in drug discovery. The majority of molecules that facilitate targeted degradation do so via a select number of ubiquitin ligases, restricting this therapeutic approach to tissue types that express the requisite ligase. Here, we describe a new strategy of targeted protein degradation through direct substrate recruitment to the 26S proteasome. The proteolytic complex is essential and abundantly expressed in all cells; however, proteasomal ligands remain scarce. We identify potent peptidic macrocycles that bind directly to the 26S proteasome subunit PSMD2, with a 2.5-Å-resolution cryo-electron microscopy complex structure revealing a binding site near the 26S pore. Conjugation of this macrocycle to a potent BRD4 ligand enabled generation of chimeric molecules that effectively degrade BRD4 in cells, thus demonstrating that degradation via direct proteasomal recruitment is a viable strategy for targeted protein degradation.

Adapting Ferritin, a Naturally Occurring Protein Cage, to Modulate Intrinsic Agonism of OX40.

Ferritin is a multivalent, self-assembling protein scaffold found in most human cell types, in addition to being present in invertebrates, higher plants, fungi, and bacteria, that offers an attractive alternative to polymer-based drug delivery systems (DDS). In this study, the utility of the ferritin cage as a DDS was demonstrated within the context of T cell agonism for tumor killing. Members of the tumor necrosis factor receptor superfamily (TNFRSF) are attractive targets for the development of anticancer therapeutics. These receptors are endogenously activated by trimeric ligands that occur in transmembrane or soluble forms, and oligomerization and cell-surface anchoring have been shown to be essential aspects of the targeted agonism of this receptor class. Here, we demonstrated that the ferritin cage could be easily tailored for multivalent display of anti-OX40 antibody fragments on its surface and determined that these arrays are capable of pathway activation through cell-surface clustering. Together, these results confirm the utility, versatility, and developability of ferritin as a DDS.

Sodium-glucose co-transporter-2 inhibitors and the risk of venous thromboembolism: A nationwide population-based study and meta-analysis.

AIMS: Sodium-glucose cotransporter-2 inhibitors (SGLT-2i) have off-target effects on haemoconcentration and anti-inflammation. The impact of SGLT-2i on the risk of venous thromboembolism (VTE) in patients with diabetes mellitus (DM) remains unclear. This study aimed to evaluate the risk of newly diagnosed VTE in patients with DM using SGLT-2i in comparison to dipeptidyl peptidase-4 inhibitors (DPP-4i) or glucagon-like peptide-1 receptor agonists (GLP-1RA). MATERIALS AND METHODS: In this nationwide retrospective cohort study, we used data from Taiwan's National Health Insurance Research Database. Patients with diabetes aged 20 years or older who received SGLT-2i, DPP-4i, or GLP-1RA between 1 May 2016, and 31 December 2020, were included. The risks of VTE in SGLT-2i users were compared with those of DPP-4i and GLP-1RA users. A Cox regression model with stabilised inverse probability of treatment weighting was used to calculate hazard ratio (HR) for VTE risk. Additionally, a meta-analysis of relevant articles published before 23 May 2023, was conducted. RESULTS: Data from 136,530 SGLT-2i, 598,280 DPP-4i, and 5760 GLP-1RA users were analysed. SGLT-2i use was associated with a lower risk of VTE than DPP-4i (HR, 0.70; 95% CI, 0.59-0.84; p < 0·001), but not with GLP-1RA (HR, 1.39; 95% CI, 0.32-5.94; p = 0.66). Our meta-analysis further supported these findings (SGLT-2i vs. DPP-4i: HR, 0.71; 95% CI, 0.62-0.82; p < 0·001; SGLT-2i vs. GLP-1RA: HR, 0.91; 95% CI, 0.73-1.15; p = 0.43), suggesting the robustness of our retrospective analysis. CONCLUSIONS: In patients with DM, SGLT-2i was associated with a lower risk of VTE compared to DPP-4i, but not GLP-1RA.

Combining descriptive and predictive modeling to systematically design depth filtration-based harvest processes for biologics.

Advances in upstream production of biologics-particularly intensified fed-batch processes beyond 10% cell solids-have severely strained harvest operations, especially depth filtration. Bioreactors containing high amounts of cell debris (more than 40% particles <10 µm in diameter) are increasingly common and drive the need for more robust depth filtration processes, while accelerated timelines emphasize the need for predictive tools to accelerate development. Both needs are constrained by the current limited mechanistic understanding of the harvest filter-feedstream system. Historically, process development relied on screening scale-down depth filter devices and conditions to define throughput before fouling, indicated by increasing differential pressure and/or particle breakthrough (measured via turbidity). This approach is straightforward, but resource-intensive, and its results are inherently limited by the variability of the feedstream. Semi-empirical models have been developed from first principles to describe various mechanisms of filter fouling, that is, pore constriction, pore blocking, and/or surface deposit. Fitting these models to experimental data can assist in identifying the dominant fouling mechanism. Still, this approach sees limited application to guide process development, as it is descriptive, not predictive. To address this gap, we developed a hybrid modeling approach. Leveraging historical bench scale filtration process data, we built a partial least squares regression model to predict particle breakthrough from filter and feedstream attributes, and leveraged the model to demonstrate prediction of filter performance a priori. The fouling models are used to interpret and provide physical meaning to these computational models. This hybrid approach-combining the mechanistic insights of fouling models and the predictive capability of computational models-was used to establish a robust platform strategy for depth filtration of Chinese hamster ovary cell cultures. As new data continues to teach the computational models, in silico tools will become an essential part of harvest process development by enabling prospective experimental design, reducing total experimental load, and accelerating development under strict timelines.

Imaging after Pancreatic Surgery: Expected Findings and Postoperative Complications.

Pancreatic surgery is considered one of the most technically challenging surgical procedures, despite the evolution of modern techniques. Neoplasms remain the most common indication for pancreatic surgery, although inflammatory conditions may also prompt surgical evaluation. The choice of surgical procedure depends on the type and location of the pathologic finding because different parts of the pancreas have separate vascular supplies that may be shared by adjacent organs. The surgical approach could be conventional or minimally invasive (laparoscopic, endoscopic, or robotic assisted). Because of the anatomic complexity of the pancreatic bed, perioperative complications may be frequently encountered and commonly involve the pancreatic-biliary, vascular, lymphatic, or bowel systems, irrespective of the surgical technique used. Imaging plays an important role in the assessment of suspected postoperative complications, with CT considered the primary imaging modality, while MRI, digital subtraction angiography, and molecular imaging are considered ancillary diagnostic tools. Accurate diagnosis of postoperative complications requires a solid understanding of pancreatic anatomy, surgical indications, normal postoperative appearance, and expected postsurgical changes. The practicing radiologist should be familiar with the most common perioperative complications, such as anastomotic leak, abscess, and hemorrhage, and be able to differentiate these entities from normal anticipated postoperative changes such as seroma, edema and fat stranding at the surgical site, and perivascular soft-tissue thickening. In addition to evaluation of the primary operative fossa, imaging plays a fundamental role in assessment of the adjacent organ systems secondarily affected after pancreatic surgery, such as vascular, biliary, and enteric complications. Published under a CC BY 4.0 license. Test Your Knowledge questions are available in the supplemental material. See the invited commentary by Winslow in this issue.

Mid-Infrared Intersubband Cavity Polaritons in Flexible Single Quantum Well.

Strong and ultrastrong coupling between intersubband transitions in quantum wells and cavity photons have been realized in mid-infrared and terahertz spectral regions. However, most previous works employed a large number of quantum wells on rigid substrates to achieve coupling strengths reaching the strong or ultrastrong coupling regime. In this work, we experimentally demonstrate ultrastrong coupling between the intersubband transition in a single quantum well and the resonant mode of photonic nanocavity at room temperature. We also observe strong coupling between the nanocavity resonance and the second-order intersubband transition in a single quantum well. Furthermore, we implement for the first time such intersubband cavity polariton systems on soft and flexible substrates and demonstrate that bending of the single quantum well does not significantly affect the characteristics of the cavity polaritons. This work paves the way to broaden the range of potential applications of intersubband cavity polaritons including soft and wearable photonics.

Association of prior outpatient diabetes screening with cardiovascular events and mortality among people with incident diabetes: a population-based cohort study.

BACKGROUND: Outcomes of diabetes screening in contemporary, multi-ethnic populations are unknown. We examined the association of prior outpatient diabetes screening with the risks of cardiovascular events and mortality in Ontario, Canada. METHODS: We conducted a population-based cohort study using administrative databases among adults aged ≥ 20 years with incident diabetes diagnosed during 2014-2016. The exposure was outpatient diabetes screening performed within 3 years prior to diabetes diagnosis. The co-primary outcomes were (1) a composite of all-cause mortality and hospitalization for myocardial infarction, stroke, coronary revascularization, and (2) all-cause mortality (followed up until 2018). We calculated standardized rates of each outcome and conducted cause-specific hazard modelling to determine the adjusted hazard ratio (HR) of the outcomes, adjusting for prespecified confounders and accounting for the competing risk of death. RESULTS: We included 178,753 Ontarians with incident diabetes (70.2% previously screened). Individuals receiving prior screening were older (58.3 versus 53.4 years) and more likely to be women (49.6% versus 40.0%) than previously unscreened individuals. Individuals receiving prior screening had relatively lower standardized event rates than those without prior screening across all outcomes (composite: 12.8 versus 18.1, mortality: 8.2 versus 11.1 per 1000 patient-years). After multivariable adjustment, prior screening was associated with 34% and 32% lower risks of the composite (HR 0.66, 0.63-0.69) and mortality (0.68, 0.64-0.72) outcomes. Among those receiving prior screening, a result in the prediabetes range was associated with lower risks of the composite (0.82, 0.77-0.88) and mortality (0.71, 0.66-0.78) outcomes than a result in the normoglycemic range. CONCLUSIONS: Previously screened individuals with diabetes had lower risks of cardiovascular events and mortality versus previously unscreened individuals. Better risk assessment tools are needed to support wider and more appropriate uptake of diabetes screening, especially among young adults.

Risk of heart failure in elderly patients with atrial fibrillation and diabetes taking different oral anticoagulants: a nationwide cohort study.

BACKGROUND: Heart failure (HF) is a critical complication in elderly patients with atrial fibrillation (AF) and diabetes mellitus (DM). Recent preclinical studies suggested that non-vitamin K antagonist oral anticoagulants (NOACs) can potentially suppress the progression of cardiac fibrosis and ischemic cardiomyopathy. Whether different oral anticoagulants influence the risk of HF in older adults with AF and DM is unknown. This study aimed to evaluate the risk of HF in elderly patients with AF and DM who were administered NOACs or warfarin. METHODS: A nationwide retrospective cohort study was conducted based on claims data from the entire Taiwanese population. Target trial emulation design was applied to strengthen causal inference using observational data. Patients aged ≥ 65 years with AF and DM on NOAC or warfarin treatment between 2012 and 2019 were included and followed up until 2020. The primary outcome was newly diagnosed HF. Propensity score-based fine stratification weightings were used to balance patient characteristics between NOAC and warfarin groups. Hazard ratios (HRs) were estimated using Cox proportional hazard models. RESULTS: The study included a total of 24,835 individuals (19,710 NOAC and 5,125 warfarin users). Patients taking NOACs had a significantly lower risk of HF than those taking warfarin (HR = 0.80, 95% CI 0.74-0.86, p < 0.001). Subgroup analyses for individual NOACs suggested that dabigatran (HR = 0.86, 95% CI 0.80-0.93, p < 0.001), rivaroxaban (HR = 0.80, 95% CI 0.74-0.86, p < 0.001), apixaban (HR = 0.78, 95% CI 0.68-0.90, p < 0.001), and edoxaban (HR = 0.72, 95% CI 0.60-0.86, p < 0.001) were associated with lower risks of HF than warfarin. The findings were consistent regardless of age and sex subgroups and were more prominent in those with high medication possession ratios. Several sensitivity analyses further supported the robustness of our findings. CONCLUSIONS: This nationwide cohort study demonstrated that elderly patients with AF and DM taking NOACs had a lower risk of incident HF than those taking warfarin. Our findings suggested that NOACs may be the preferred oral anticoagulant treatment when considering the prevention of heart failure in this vulnerable population. Future research is warranted to elucidate causation and investigate the underlying mechanisms.

MRI assessment of rectal cancer response to neoadjuvant therapy: a multireader study.

OBJECTIVES: A watch and wait strategy with the goal of organ preservation is an emerging treatment paradigm for rectal cancer following neoadjuvant treatment. However, the selection of appropriate patients remains a challenge. Most previous efforts to measure the accuracy of MRI in assessing rectal cancer response used a small number of radiologists and did not report variability among them. METHODS: Twelve radiologists from 8 institutions assessed baseline and restaging MRI scans of 39 patients. The participating radiologists were asked to assess MRI features and to categorize the overall response as complete or incomplete. The reference standard was pathological complete response or a sustained clinical response for > 2 years. RESULTS: We measured the accuracy and described the interobserver variability of interpretation of rectal cancer response between radiologists at different medical centers. Overall accuracy was 64%, with a sensitivity of 65% for detecting complete response and specificity of 63% for detecting residual tumor. Interpretation of the overall response was more accurate than the interpretation of any individual feature. Variability of interpretation was dependent on the patient and imaging feature investigated. In general, variability and accuracy were inversely correlated. CONCLUSIONS: MRI-based evaluation of response at restaging is insufficiently accurate and has substantial variability of interpretation. Although some patients' response to neoadjuvant treatment on MRI may be easily recognizable, as seen by high accuracy and low variability, that is not the case for most patients. KEY POINTS: • The overall accuracy of MRI-based response assessment is low and radiologists differed in their interpretation of key imaging features. • Some patients' scans were interpreted with high accuracy and low variability, suggesting that these patients' pattern of response is easier to interpret. • The most accurate assessments were those of the overall response, which took into consideration both T2W and DWI sequences and the assessment of both the primary tumor and the lymph nodes.

Mesenchymal stem cells: A novel treatment option for primary sclerosing cholangitis.

Primary sclerosing cholangitis (PSC) is a progressive liver disease for which there is no effective therapy. Hepatocytes and cholangiocytes from a PSC patient were cocultured with mesenchymal stem cells (MSCs) to assess in vitro change. A single patient with progressive PSC was treated with 150 million MSCs via direct injection into the common bile duct. Coculture of MSCs with cholangiocytes and hepatocytes showed in vitro improvement. Local delivery of MSCs into a single patient with progressive PSC was safe. Radiographic and endoscopic evaluation showed stable distribution of multifocal structuring in the early postoperative period. MSCs may be effective for the treatment of PSC.

An Inhibitor of PIDDosome Formation.

The PIDDosome-PIDD-RAIDD-caspase-2 complex-is a proapoptotic caspase-activation platform of elusive significance. DNA damage can initiate complex assembly via ATM phosphorylation of the PIDD death domain (DD), which enables RAIDD recruitment to PIDD. In contrast, the mechanisms limiting PIDDosome formation have remained unclear. We identify the mitotic checkpoint factor BubR1 as a direct PIDDosome inhibitor, acting in a noncanonical role independent of Mad2. Following its phosphorylation by ATM at DNA breaks, "primed" PIDD relocates to kinetochores via a direct interaction with BubR1. BubR1 binds the PIDD DD, competes with RAIDD recruitment, and negates PIDDosome-mediated apoptosis after ionizing radiation. The PIDDosome thus sequentially integrates DNA damage and mitotic checkpoint signals to decide cell fate in response to genotoxic stress. We further show that by sequestering PIDD at the kinetochore, BubR1 acts to delay PIDDosome formation until the next cycle, defining a new mechanism by which cells evade apoptosis during mitosis.

Diabetes-Related Complications and Mortality in Patients With Atrial Fibrillation Receiving Different Oral Anticoagulants : A Nationwide Analysis.

BACKGROUND: Evidence about the association between types of oral anticoagulants and hazards of diabetes complications is limited in patients with atrial fibrillation (AF) and diabetes mellitus (DM). OBJECTIVE: To compare the hazards of diabetes complications and mortality between patients with AF and DM receiving non-vitamin K antagonist oral anticoagulants (NOACs) and those receiving warfarin. DESIGN: A retrospective cohort study. SETTING: Nationwide data obtained from Taiwan's National Health Insurance Research Database. PATIENTS: Patients with AF and DM receiving NOACs or warfarin between 2012 and 2017 in Taiwan were enrolled. Treatment groups were determined by patients' first initiation of oral anticoagulants. MEASUREMENTS: Hazards of diabetes complications (macrovascular complications, microvascular complications, and glycemic emergency) and mortality in the NOAC and warfarin users were investigated with a target trial design. Cause-specific Cox proportional hazards models were used to estimate hazard ratios (HRs). Propensity score methods with stabilized inverse probability of treatment weighting were applied to balance potential confounders between treatment groups. RESULTS: In total, 19 909 NOAC users and 10 300 warfarin users were included. Patients receiving NOACs had significantly lower hazards of developing macrovascular complications (HR, 0.84 [95% CI, 0.78 to 0.91]; P < 0.001), microvascular complications (HR, 0.79 [CI, 0.73 to 0.85]; P < 0.001), glycemic emergency (HR, 0.91 [CI, 0.83 to 0.99]; P = 0.043), and mortality (HR, 0.78 [CI, 0.75 to 0.82]; P < 0.001) than those receiving warfarin. Analyses with propensity score matching showed similar results. Several sensitivity analyses further supported the robustness of our findings. LIMITATION: The claims-based data did not allow for detailed data on patients' lifestyles and laboratory examinations to be obtained. CONCLUSION: Non-vitamin K antagonist oral anticoagulants were associated with lower hazards of diabetes complications and mortality than warfarin in patients with AF and DM. PRIMARY FUNDING SOURCE: Hualien Tzu Chi Hospital.

Design and Psychophysical Evaluation of a Novel Wearable Upper-Arm Tactile Display Device.

A novel wearable upper arm tactile display device, which can simultaneously provide three types of tactile stimuli (i.e., squeezing, stretching, and vibration) is presented. The squeezing and stretching stimulation of the skin is generated by two motors simultaneously driving the nylon belt in the opposite and the same direction, respectively. In addition, four evenly spaced vibration motors are fixed around the user's arm by an elastic nylon band. There is also a unique structural design for assembling the control module and actuator, powered by two lithium batteries, making it portable and wearable. Psychophysical experiments are conducted to investigate the effect of interference on the perception of squeezing and stretching stimulation by this device. Results show that (1) different tactile stimuli actually interfere with the user's perception compared to the case where only one stimulus is applied to the user; (2) the squeezing has a considerable impact on the stretch just noticeable difference (JND) values when both stimuli are exerted on the user, and when the squeezing is strong, while the impact of stretch on the squeezing JND values is negligible.

Event-Triggered Sliding Mode Neural Network Controller Design for Heterogeneous Multi-Agent Systems.

A class of heterogeneous second-order multi-agent consensus problems is studied, in which an event-triggered method is used to improve the feasibility of the control protocol. The sliding mode control method is used to achieve the robustness of the system. A special type of general radial basis function neural network is applied to estimate the uncertainties. The event-triggered mechanism is introduced to reduce the update frequency of the controller and the communication frequency among the agents. Zeno behavior is avoided by ensuring a lower bound between two adjacent trigger instants. Finally, the simulation results are provided to demonstrate that the time evolution of consensus errors eventually approaches zero. The consensus of multi-agent systems is achieved.

RIPK1 Expression Associates With Inflammation in Early Atherosclerosis in Humans and Can Be Therapeutically Silenced to Reduce NF-κB Activation and Atherogenesis in Mice.

BACKGROUND: Chronic activation of the innate immune system drives inflammation and contributes directly to atherosclerosis. We previously showed that macrophages in the atherogenic plaque undergo RIPK3 (receptor-interacting serine/threonine-protein kinase 3)-MLKL (mixed lineage kinase domain-like protein)-dependent programmed necroptosis in response to sterile ligands such as oxidized low-density lipoprotein and damage-associated molecular patterns and that necroptosis is active in advanced atherosclerotic plaques. Upstream of the RIPK3-MLKL necroptotic machinery lies RIPK1 (receptor-interacting serine/threonine-protein kinase 1), which acts as a master switch that controls whether the cell undergoes NF-κB (nuclear factor κ-light-chain-enhancer of activated B cells)-dependent inflammation, caspase-dependent apoptosis, or necroptosis in response to extracellular stimuli. We therefore set out to investigate the role of RIPK1 in the development of atherosclerosis, which is driven largely by NF-κB-dependent inflammation at early stages. We hypothesize that, unlike RIPK3 and MLKL, RIPK1 primarily drives NF-κB-dependent inflammation in early atherogenic lesions, and knocking down RIPK1 will reduce inflammatory cell activation and protect against the progression of atherosclerosis. METHODS: We examined expression of RIPK1 protein and mRNA in both human and mouse atherosclerotic lesions, and used loss-of-function approaches in vitro in macrophages and endothelial cells to measure inflammatory responses. We administered weekly injections of RIPK1 antisense oligonucleotides to Apoe-/- mice fed a cholesterol-rich (Western) diet for 8 weeks. RESULTS: We find that RIPK1 expression is abundant in early-stage atherosclerotic lesions in both humans and mice. Treatment with RIPK1 antisense oligonucleotides led to a reduction in aortic sinus and en face lesion areas (47.2% or 58.8% decrease relative to control, P<0.01) and plasma inflammatory cytokines (IL-1α [interleukin 1α], IL-17A [interleukin 17A], P<0.05) in comparison with controls. RIPK1 knockdown in macrophages decreased inflammatory genes (NF-κB, TNFα [tumor necrosis factor α], IL-1α) and in vivo lipopolysaccharide- and atherogenic diet-induced NF-κB activation. In endothelial cells, knockdown of RIPK1 prevented NF-κB translocation to the nucleus in response to TNFα, where accordingly there was a reduction in gene expression of IL1B, E-selectin, and monocyte attachment. CONCLUSIONS: We identify RIPK1 as a central driver of inflammation in atherosclerosis by its ability to activate the NF-κB pathway and promote inflammatory cytokine release. Given the high levels of RIPK1 expression in human atherosclerotic lesions, our study suggests RIPK1 as a future therapeutic target to reduce residual inflammation in patients at high risk of coronary artery disease.

Living Donor Liver Transplantation With Augmented Venous Outflow and Splenectomy: A Promised Land for Small Left Lobe Grafts.

OBJECTIVE: Living donor liver transplantation (LDLT) using small grafts, especially left lobe grafts (H1234-MHV) (LLG), continues to be a challenge due to small-for-size syndrome (SFSS). We herein demonstrate that with surgical modifications, outcomes with small grafts can be improved. METHODS: Between 2012 and 2020, we performed 130 adult LDLT using 61 (47%) LLG (H1234-MHV) in a single Enterprise. The median graft-to-recipient weight ratio was 0.84%, with graft-to-recipient weight ratio <0.7% accounting for 22%. Splenectomy was performed in 72 (56%) patients for inflow modulation before (n=50) or after (n=22) graft reperfusion. In LLG-LDLT, venous outflow was achieved using all three recipient hepatic veins. In right lobe graft (H5678) (RLG)-LDLT, the augmented graft right hepatic vein was anastomosed to the recipient's cava with a large cavotomy. Outcome measures include SFSS, early allograft dysfunction (EAD), and survival. RESULTS: Graft survival rates at 1, 3, and 5 years were 94%, 90%, and 83%, respectively, with no differences between LLG (H1234-MHV) and RLG (H5678). Splenectomy significantly reduced portal flow without increasing the complication rate. Despite the aggressive use of small grafts, SFSS and EAD developed in only 1 (0.8%) and 18 (13.8%) patients, respectively. Multivariable logistic regression revealed model for end-stage liver disease score and LLG (H1234-MHV) as independent risk factors for EAD and splenectomy as a protective factor (odds ratio: 0.09; P =0.03). For LLG (H1234-MHV)-LDLT, patients who underwent prereperfusion splenectomy tended to have better 1-year graft survival than those receiving postreperfusion splenectomy. CONCLUSIONS: LLG (H1234-MHV) are feasible in adult LDLT with excellent outcomes comparable to RLG (H5678). Venous outflow augmentation and splenectomy help lower the threshold of using small-for-size grafts without compromising graft survival.

Sleep, testosterone and cortisol balance, and ageing men.

Sleep serves important biological functions, and influences health and longevity through endocrine and metabolic related systems. Sleep debt, circadian misalignment and sleep disruption from obstructive sleep apnea is widespread in modern society and accumulates with life because recovery sleep is not completely restorative. Accumulated disordered sleep throughout life impacts the ageing process and the development of age-related diseases. When epidemiological and interventional studies are considered collectively, sleep loss and lower sleep duration are associated with lower morning, afternoon and 24-h testosterone; as well as higher afternoon, but not morning or 24-h cortisol. These reciprocal changes imbalances anabolic-catabolic signaling because testosterone and cortisol are respectively the main anabolic and catabolic signals in man. Fixing testosterone-cortisol balance by means of a novel dual-hormone clamp mitigates the induction of insulin resistance by sleep restriction and provided the first proof-of-concept that the metabolic harm from sleep loss can be ameliorated by approaches that do not require sleeping more. Obstructive sleep apnea is associated with lower testosterone, even after controlling for age and obesity whereas the conclusion that continuous positive airway pressure therapy has no effect on testosterone is premature because available studies are underpowered and better-quality studies suggest otherwise. High dose testosterone therapy induces OSA, but more physiological dosing may not; and this effect may be transient or may dissipate with longer term therapy. Studies investigating the origin of the diurnal testosterone rhythm, the effect of circadian misalignment on testosterone-cortisol balance, and methods to mitigate metabolic harm, are required.