Association of psychosocial risk factors and liver transplant evaluation outcomes in metabolic dysfunction-associated steatotic liver disease.

The Stanford Integrated Psychosocial Assessment for Transplantation (SIPAT) is a standardized psychosocial assessment tool used in liver transplantation (LT) evaluation and has been primarily studied in patients with alcohol-associated liver disease. We aimed to evaluate the relationship between SIPAT score and metabolic syndrome severity and LT waitlist outcomes in a large cohort of patients with metabolic dysfunction-associated steatotic liver disease (MASLD). We performed a single-center retrospective cohort study of patients with MASLD evaluated for LT from 2014-2021. The utility of the previously defined total SIPAT cut-off (<21 [excellent/good candidates] vs ≥21 [minimally acceptable/high risk candidates]) was studied. Multivariable logistic regression analyses examined associations between continuous SIPAT score and LT waitlisting outcomes. Youden's J statistic was used to identify the optimal SIPAT cut-off for MASLD patients. A total of 480 patients evaluated for transplant with MASLD were included. Only 9.4% of patients had SIPAT score ≥21. Patients with SIPAT score ≥21 had higher hemoglobin A1c compared to patients with lower psychosocial risk (median (IQR): 7.8 (6.0-9.7) vs 6.6 (5.8, 7.9); p=0.04). There were no other differences in metabolic comorbidities between SIPAT groups. Increasing SIPAT score was associated with decreased odds of listing (OR: 0.82 per five-point increase; p=0.003) in multivariable models. A SIPAT of ≥12 was identified as the optimal cut-off in this population, resulting in an adjusted OR for listing of 0.53 vs SIPAT <12 (p=0.001). In this large cohort of MASLD patients evaluated for LT, few patients met the previously defined high SIPAT cut-off for transplant suitability. Nevertheless, increasing SIPAT score was associated with waitlist outcome. Our suggested SIPAT cut-off of ≥12 for MASLD patients warrants further external validation using data from other centers.

Ultrasound evaluation of intraluminal magnets in an ex vivo model.

PURPOSE: The management of foreign body ingestion proves to be a challenge. Magnets pose a unique set of risks when ingested due to their attractive forces and subsequent risk of adherence, pressure necrosis, and perforation complications. Radiographs only provide a limited snapshot in the setting of multiple magnet ingestion when the risk of complication is highest. We hypothesize that abdominal ultrasound (US) has the potential to supplement radiographs in assessing ingested magnets by determining the presence of bowel loop entrapment and of any extraluminal fluid. METHODS: We recreated various scenarios of magnet configurations using animal cadaveric bowel models. X-ray and US images were obtained in various bowel-magnet orientations. RESULTS: We identified several key US features to suggest bowel wall tethering. These include direct visualization of bowel wall entrapment between magnets (what we term the "dangerous V sign"), anti-dependent positions of the magnets, and inability to separate loops of bowel with compression. CONCLUSION: These findings could potentially provide valuable information when directing the urgency of intervention in foreign body ingestion. Ultrasound may supplement and improve the current guidelines in management of magnet ingestion.

Development and Multicenter Case-Control Validation of Urinary Comprehensive Genomic Profiling for Urothelial Carcinoma Diagnosis, Surveillance, and Risk-Prediction.

PURPOSE: Urinary comprehensive genomic profiling (uCGP) uses next-generation sequencing to identify mutations associated with urothelial carcinoma and has the potential to improve patient outcomes by noninvasively diagnosing disease, predicting grade and stage, and estimating recurrence risk. EXPERIMENTAL DESIGN: This is a multicenter case-control study using banked urine specimens collected from patients undergoing initial diagnosis/hematuria workup or urothelial carcinoma surveillance. A total of 581 samples were analyzed by uCGP: 333 for disease classification and grading algorithm development, and 248 for blinded validation. uCGP testing was done using the UroAmp platform, which identifies five classes of mutation: single-nucleotide variants, copy-number variants, small insertion-deletions, copy-neutral loss of heterozygosity, and aneuploidy. UroAmp algorithms predicting urothelial carcinoma tumor presence, grade, and recurrence risk were compared with cytology, cystoscopy, and pathology. RESULTS: uCGP algorithms had a validation sensitivity/specificity of 95%/90% for initial cancer diagnosis in patients with hematuria and demonstrated a negative predictive value (NPV) of 99%. A positive diagnostic likelihood ratio (DLR) of 9.2 and a negative DLR of 0.05 demonstrate the ability to risk-stratify patients presenting with hematuria. In surveillance patients, binary urothelial carcinoma classification demonstrated an NPV of 91%. uCGP recurrence-risk prediction significantly prognosticated future recurrence (hazard ratio, 6.2), whereas clinical risk factors did not. uCGP demonstrated positive predictive value (PPV) comparable with cytology (45% vs. 42%) with much higher sensitivity (79% vs. 25%). Finally, molecular grade predictions had a PPV of 88% and a specificity of 95%. CONCLUSIONS: uCGP enables noninvasive, accurate urothelial carcinoma diagnosis and risk stratification in both hematuria and urothelial carcinoma surveillance patients.

Endocytosis in cancer and cancer therapy.

Endocytosis is a complex process whereby cell surface proteins, lipids and fluid from the extracellular environment are packaged, sorted and internalized into cells. Endocytosis is also a mechanism of drug internalization into cells. There are multiple routes of endocytosis that determine the fate of molecules, from degradation in the lysosomes to recycling back to the plasma membrane. The overall rates of endocytosis and temporal regulation of molecules transiting through endocytic pathways are also intricately linked with signalling outcomes. This process relies on an array of factors, such as intrinsic amino acid motifs and post-translational modifications. Endocytosis is frequently disrupted in cancer. These disruptions lead to inappropriate retention of receptor tyrosine kinases on the tumour cell membrane, changes in the recycling of oncogenic molecules, defective signalling feedback loops and loss of cell polarity. In the past decade, endocytosis has emerged as a pivotal regulator of nutrient scavenging, response to and regulation of immune surveillance and tumour immune evasion, tumour metastasis and therapeutic drug delivery. This Review summarizes and integrates these advances into the understanding of endocytosis in cancer. The potential to regulate these pathways in the clinic to improve cancer therapy is also discussed.

Predicting Septic Shock After Emergent Ureteral Stenting in Stone-Related Obstruction and Presumed Infections.

Introduction: Systemic inflammatory response syndrome (SIRS) criteria have long been used to predict septic shock. The sequential organ failure assessment and quick sequential organ failure assessment (qSOFA) scores have been suggested to be more accurate predictors. This study aims to compare SIRS and qSOFA for predicting of septic shock in the setting of retrograde ureteral stenting for obstructing stones and concomitant urinary tract infection. Methods: A retrospective review of records at two centers of consecutive patients was performed. Patients with unilateral ureteral obstruction by a stone who underwent ureteral stent placement and suspicion of urinary tract infection were identified. Primary endpoints were SIRS and qSOFA positive scores, intensive care unit admission, and vasopressor requirements. Results: A total of 187 patients were included. SIRS criteria were met in 103 patients (55.1%) and in 30 patients who experienced septic shock. qSOFA criteria were met for 24 patients (12.8%) and in 18 patients who experienced septic shock. Specificity for postoperative septic shock was significantly higher for qSOFA than for SIRS criteria (75 vs 29.1%, McNemar test p < 0.001). Both SIRS and qSOFA had significant areas under the curve (AUC), qSOFA had a fair AUC of 0.750, p = 0.001, whereas SIRS had a poor AUC of 0.659, p = 0.008. Univariate logistic regression of SIRS and qSOFA for septic shock showed: qSOFA (odds ratio [OR] 46 [0.25-228], p = 0.001) and SIRS (OR 2.29 [0.716-7.37], p = 0.162). Conclusion: Although SIRS offers higher sensitivity, qSOFA score may offer advantages over SIRS criteria in evaluation of risk for septic shock for patients who present with obstructing ureteral stone and urinary tract infection.

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

Rebuilding the local vasculature is central to restoring the health of muscles subjected to ischemic injury. Arteriogenesis yields remodeled collateral arteries that circumvent the obstruction, and angiogenesis produces capillaries to perfuse the regenerating myofibers. However, the vital intervening network of arterioles that feed the regenerated capillaries is poorly understood and is an investigative challenge. We used machine learning and automated micromorphometry to quantify the arteriolar landscape in distal hindlimb muscles in mice that have regenerated after femoral artery excision. Assessment of 1,546 arteriolar sections revealed a striking (>2-fold) increase in arteriolar density in regenerated muscle 14 and 28 days after ischemic injury. Lumen caliber was initially similar to that of control arterioles but after 4 wk lumen area was reduced by 46%. In addition, the critical smooth muscle layer was attenuated throughout the arteriolar network, across a 150- to 5-µm diameter range. To understand the consequences of the reshaped distal hindlimb arterioles, we undertook computational flow modeling, which revealed blunted flow augmentation. Moreover, impaired flow reserve was confirmed in vivo by laser-Doppler analyses of flow in response to directly applied sodium nitroprusside. Thus, in hindlimb muscles regenerating after ischemic injury, the arteriolar network is amplified, inwardly remodels, and is diffusely undermuscularized. These defects and the associated flow restraints could contribute to the deleterious course of peripheral artery disease and merit attention when considering therapeutic innovations.NEW & NOTEWORTHY We report a digital pipeline for interrogating the landscape of arterioles in mouse skeletal muscle, using machine learning and automated micromorphometry. This revealed that in muscle regenerating after ischemic injury, the arteriolar density is increased but lumen caliber and smooth muscle content are reduced. Computational modeling and experimental validation reveal this arteriolar network to be functionally compromised, with diminished microvascular flow reserve.

Incidental finding of lung hernia in a patient with a remote history of empyema status post video-assisted thoracoscopic surgery.

Lung hernia, the protrusion of pulmonary tissue outside of the thoracic cage, is a rare radiologic finding. The exact incidence of this condition is not well documented. The etiology is either secondary to underlying congenital conditions which weaken the supporting structures of the thoracic wall or more commonly, post-surgical changes. In this report, we describe the case of a 58-year-old male trauma patient who was involved in a motor vehicle collision. Computed tomography of the head, neck, body, and upper extremities was negative for acute injury, but an incidental left-sided herniation of the lingula between the fifth and sixth intercostal spaces was identified. Computed tomography is superior for identifying imaging lung herniations as chest radiographs may not visualize the defect. Upon further investigation, the patient had a remote history of pneumonia complicated by empyema treated by video-assisted thoracoscopic surgery (VATS). This history, coupled with the absence of traumatic injury to the thorax as well as the presence of pulmonary scarring suggests that the lung herniation was likely chronic and secondary to the VATS procedure. The patient was discharged home without surgical intervention. Asymptomatic lung herniations are typically managed conservatively, but patients and physicians should be aware of the risk of lung hernia after VATS as well as associated complications including strangulation or pulmonary infarct.

Low-flow intussusception and metastable VEGFR2 signaling launch angiogenesis in ischemic muscle.

Efforts to promote sprouting angiogenesis in skeletal muscles of individuals with peripheral artery disease have not been clinically successful. We discovered that, contrary to the prevailing view, angiogenesis following ischemic muscle injury in mice was not driven by endothelial sprouting. Instead, real-time imaging revealed the emergence of wide-caliber, primordial conduits with ultralow flow that rapidly transformed into a hierarchical neocirculation by transluminal bridging and intussusception. This process was accelerated by inhibiting vascular endothelial growth factor receptor-2 (VEGFR2). We probed this response by developing the first live-cell model of transluminal endothelial bridging using microfluidics. Endothelial cells subjected to ultralow shear stress could reposition inside the flowing lumen as pillars. Moreover, the low-flow lumen proved to be a privileged location for endothelial cells with reduced VEGFR2 signaling capacity, as VEGFR2 mechanosignals were boosted. These findings redefine regenerative angiogenesis in muscle as an intussusceptive process and uncover a basis for its launch.

Regenerated Microvascular Networks in Ischemic Skeletal Muscle.

Skeletal muscle is the largest organ in humans. The viability and performance of this metabolically demanding organ are exquisitely dependent on the integrity of its microcirculation. The architectural and functional attributes of the skeletal muscle microvasculature are acquired during embryonic and early postnatal development. However, peripheral vascular disease in the adult can damage the distal microvasculature, together with damaging the skeletal myofibers. Importantly, adult skeletal muscle has the capacity to regenerate. Understanding the extent to which the microvascular network also reforms, and acquires structural and functional competence, will thus be critical to regenerative medicine efforts for those with peripheral artery disease (PAD). Herein, we discuss recent advances in studying the regenerating microvasculature in the mouse hindlimb following severe ischemic injury. We highlight new insights arising from real-time imaging of the microcirculation. This includes identifying otherwise hidden flaws in both network microarchitecture and function, deficiencies that could underlie the progressive nature of PAD and its refractoriness to therapy. Recognizing and overcoming these vulnerabilities in regenerative angiogenesis will be important for advancing treatment options for PAD.

Flat Panel Detector c-Arms Are Associated with Dramatically Reduced Radiation Exposure During Ureteroscopy and Produce Superior Images.

Background: We wished to determine whether newly available flat panel detector (FPD) c-arms were (1) associated with lower radiation dose during ureteroscopy (URS) than conventional image intensifier (CII) c-arms and (2) to compare fluoroscopic image quality between the units. Materials and Methods: We retrospectively reviewed 44 consecutive patients undergoing URS at a pediatric hospital, with c-arms assigned by availability in the operating room. We performed dosimetry experiments using the same c-arms on standard phantoms. Results: Patient and case characteristics did not differ significantly between the two groups of patients. The median dose in the FPD group was less than a quarter of the dose in the CII group, 0.48 [0.42, 0.97] mGy vs 2.2 [1.1, 3.8] mGy, p < 0.0001. The FPD dose remained at less than one-third of the CII dose accounting for any difference in fluoroscopy time, and remained significant in a multivariate model including fluoroscopy time and patient weight (ß = 2.4, p = 0.007). Phantom studies showed higher image quality for FPDs at all simulated patient sizes, even at lower radiation doses. Conclusions: This is the first report comparing radiation dose from c-arms of image intensifiers and FPDs in adults or children. Use of an FPD during URS was associated with a substantially decreased absorbed dose for patients while simultaneously improving image quality.

Systematic Interrogation of Angiogenesis in the Ischemic Mouse Hind Limb: Vulnerabilities and Quality Assurance.

OBJECTIVE: There has been little success in translating preclinical studies of mouse hind limb ischemia into benefit for patients with peripheral artery disease. Using systematic strategies, we sought to define the injury and angiogenesis landscapes in mice subjected to hind limb ischemia and ascertain whether published studies to date have used an analysis strategy concordant with these data. Approach and Results: Maps of ischemic injury were generated from 22 different hind limb muscles and 33 muscle territories in 12-week-old C57BL/6 mice, based on loss or centralization of myofiber nuclei. Angiogenesis was similarly mapped based on CD (cluster of differentiation) 31-positive capillary content. Only 10 of 33 muscle territories displayed consistent muscle injury, with the distal anterior hind limb muscles most reliably injured. Angiogenesis was patchy and exclusively associated with zones of regenerated muscle (central nuclei). Angiogenesis was not observed in normal appearing muscle, necrotic muscle, or injury border zones. Systematic review of mouse hind limb angiogenesis studies identified 5147 unique publications, of which 509 met eligibility criteria for analysis. Only 7% of these analyzed manuscripts evaluated angiogenesis in distal anterior hind limb muscles and only 15% consistently examined for angiogenesis in zones of muscle regeneration. CONCLUSIONS: In 12-week C57BL/6 mice, angiogenesis postfemoral artery excision proceeds exclusively in zones of muscle regeneration. Only a minority of studies to date have analyzed angiogenesis in regions of demonstrably regenerating muscle or in high-likelihood territories. Quality assurance standards, informed by the atlas and mapping data herein, could augment data reliability and potentially help translate mouse hind limb ischemia studies to patient care.

Obstruction of Small Arterioles in Patients with Critical Limb Ischemia due to Partial Endothelial-to-Mesenchymal Transition.

Critical limb ischemia (CLI) is a hazardous manifestation of atherosclerosis and treatment failure is common. Abnormalities in the arterioles might underlie this failure but the cellular pathobiology of microvessels in CLI is poorly understood. We analyzed 349 intramuscular arterioles in lower limb specimens from individuals with and without CLI. Arteriolar densities were 1.8-fold higher in CLI muscles. However, 33% of small (<20 µm) arterioles were stenotic and 9% were completely occluded. The lumens were closed by bulky, re-oriented endothelial cells expressing abundant N-cadherin that uniquely localized between adjacent and opposing endothelial cells. S100A4 and SNAIL1 were also expressed, supporting an endothelial-to-mesenchymal transition. SMAD2/3 was activated in occlusive endothelial cells and TGFß1 was increased in the adjacent mural cells. These findings identify a microvascular closure process based on mesenchymal transitions in a hyper-TGFß environment that may, in part, explain the limited success of peripheral artery revascularization procedures.

Seno-destructive smooth muscle cells in the ascending aorta of patients with bicuspid aortic valve disease.

BACKGROUND: Ascending aortic aneurysms constitute an important hazard for individuals with a bicuspid aortic valve (BAV). However, the processes that degrade the aortic wall in BAV disease remain poorly understood. METHODS: We undertook in situ analysis of ascending aortas from 68 patients, seeking potentially damaging cellular senescence cascades. Aortas were assessed for senescence-associated-ß-galactosidase activity, p16Ink4a and p21 expression, and double-strand DNA breaks. The senescence-associated secretory phenotype (SASP) of cultured-aged BAV aortic smooth muscle cells (SMCs) was evaluated by transcript profiling and consequences probed by combined immunofluorescence and circular polarization microscopy. The contribution of p38 MAPK signaling was assessed by immunostaining and blocking strategies. FINDINGS: We uncovered SMCs at varying depths of cellular senescence within BAV- and tricuspid aortic valve (TAV)-associated aortic aneurysms. Senescent SMCs were also abundant in non-aneurysmal BAV aortas but not in non-aneurysmal TAV aortas. Multivariable analysis revealed that BAV disease independently associated with SMC senescence. Furthermore, SMC senescence was heightened at the convexity of aortas associated with right-left coronary cusp fusion. Aged BAV SMCs had a pronounced collagenolytic SASP. Moreover, senescent SMCs in the aortic wall were enriched with surface-localized MMP1 and surrounded by weakly birefringent collagen fibrils. The senescent-collagenolytic SMC phenotype depended on p38 MAPK signaling, which was chronically activated in BAV aortas. INTERPRETATION: We have identified a cellular senescence-collagen destruction axis in at-risk ascending aortas. This novel "seno-destructive" SMC phenotype could open new opportunities for managing BAV aortopathy. FUND: Canadian Institutes of Health Research, Lawson Health Research Institute, Heart and Stroke Foundation of Ontario/Barnett-Ivey Chair.

3D vessel-wall virtual histology of whole-body perfused mice using a novel heavy element stain.

Virtual histology - utilizing high-resolution three-dimensional imaging - is becoming readily available. Micro-computed tomography (micro-CT) is widely available and is often coupled with x-ray attenuating histological stains that mark specific tissue components for 3D virtual histology. In this study we describe a new tri-element x-ray attenuating stain and perfusion protocol that provides micro-CT contrast of the entire vasculature of an intact mouse. The stain - derived from an established histology stain (Verhoeff's) - is modified to enable perfusion through the vasculature; the attenuating elements of the stain are iodine, aluminum, and iron. After a 30-minute perfusion through the vasculature (10-minute flushing with detergent-containing saline followed by 15-minute perfusion with the stain and a final 5-minute saline flush), animals are scanned using micro-CT. We demonstrate that the new staining protocol enables sharp delineation of the vessel walls in three dimensions over the whole body; corresponding histological analysis verified that the CT stain is localized primarily in the endothelial cells and media of large arteries and the endothelium of smaller vessels, such as the coronaries. The rapid perfusion and scanning protocol ensured that all tissues are available for further analysis via higher resolution CT of smaller sections or traditional histological sectioning.

Silica-Supported Sterically Hindered Amines for CO2 Capture.

Most studies exploring the capture of CO2 on solid-supported amines have focused on unhindered amines or alkylimine polymers. It has been observed in extensive solution studies that another class of amines, namely sterically hindered amines, can exhibit enhanced CO2 capacity when compared to their unhindered counterparts. In contrast to solution studies, there has been limited research conducted on sterically hindered amines on solid supports. In this work, one hindered primary amine and two hindered secondary amines are grafted onto mesoporous silica at similar amine coverages, and their adsorption performances are investigated through fixed bed breakthrough experiments and thermogravimetric analysis. Furthermore, chemisorbed CO2 species formed on the sorbents under dry and humid conditions are elucidated using in situ Fourier-transform infrared spectroscopy. Ammonium bicarbonate formation and enhancement of CO2 adsorption capacity is observed for all supported hindered amines under humid conditions. Our experiments in this study also suggest that chemisorbed CO2 species formed on supported hindered amines are weakly bound, which may lead to reduced energy costs associated with regeneration if such materials were deployed in a practical separation process. However, overall CO2 uptake capacities of the solid supported hindered amines are modest compared to their solution counterparts. The oxidative and thermal stabilities of the supported hindered amine sorbents are also assessed to give insight into their operational lifetimes.

The "Missing" Bicarbonate in CO2 Chemisorption Reactions on Solid Amine Sorbents.

We have identified a hydrated bicarbonate formed by chemisorption of 13CO2 on both dimethylaminopropylsilane (DMAPS) and aminopropylsilane (APS) pendant molecules grafted on SBA-15 mesoporous silica. The most commonly used sequence in solid-state NMR, 13C CPMAS, failed to detect bicarbonate in these solid amine sorbent samples; here, we have employed a Bloch decay ("pulse-acquire") sequence (with 1H decoupling) to detect such species. The water that is present contributes to the dynamic motion of the bicarbonate product, thwarting CPMAS but enabling direct 13C detection by shortening the spin-lattice relaxation time. Since solid-state NMR plays a major role in characterizing chemisorption reactions, these new insights that allow for the routine detection of previously elusive bicarbonate species (which are also challenging to observe in IR spectroscopy) represent an important advance. We note that employing this straightforward NMR technique can reveal the presence of bicarbonate that has often otherwise been overlooked, as demonstrated in APS, that has been thought to only contain adsorbed CO2 as carbamate and carbamic acid species. As in other systems (e.g., proteins), dynamic species that sample multiple environments tend to broaden as their motion is frozen out. Here, we show two distinct bicarbonate species upon freezing, and coupling to different protons is shown through preliminary 13C-1H HETCOR measurements. This work demonstrates that bicarbonates have likely been formed in the presence of water but have gone unobserved by NMR due to the nature of the experiments most routinely employed, a perspective that will transform the way the sorption community will view CO2 capture by amines.

Probing Metal-Organic Framework Design for Adsorptive Natural Gas Purification.

Parent and amine-functionalized analogues of metal-organic frameworks (MOFs), UiO-66(Zr), MIL-125(Ti), and MIL-101(Cr), were evaluated for their hydrogen sulfide (H2S) adsorption efficacy and post-exposure acid gas stability. Adsorption experiments were conducted through fixed-bed breakthrough studies utilizing multicomponent 1% H2S/99% CH4 and 1% H2S/10% CO2/89% CH4 natural gas simulant mixtures. Instability of MIL-101(Cr) materials after H2S exposure was discovered through powder X-ray diffraction and porosity measurements following adsorbent pelletization, whereas other materials retained their characteristic properties. Linker-based amine functionalities increased H2S breakthrough times and saturation capacities from their parent MOF analogues. Competitive CO2 adsorption effects were mitigated in mesoporous MIL-101(Cr) and MIL-101-NH2(Cr), in comparison to microporous UiO-66(Zr) and MIL-125(Ti) frameworks. This result suggests that the installation of H2S binding sites in large-pore MOFs could potentially enhance H2S selectivity. In situ Fourier transform infrared measurements in 10% CO2 and 5000 ppm H2S environments suggest that framework hydroxyl and amine moieties serve as H2S physisorption sites. Results from this study elucidate design strategies and stability considerations for engineering MOFs in sour gas purification applications.