Pan-cancer Genomic Analysis of AXL Mutations Reveals a Novel, Recurrent, Functionally Activating AXL W451C Alteration Specific to Myxofibrosarcoma

Myxofibrosarcoma (MFS) is a common soft tissue sarcoma of the elderly that typically shows low tumor mutational burden, with mutations in TP53 and in genes associated with cell cycle checkpoints (RB1, CDKN2A). Unfortunately, no alterations or markers specific to MFS have been identified and, as a consequence, there are no effective targeted therapies. The receptor tyrosine kinase AXL, which drives cellular proliferation, is targetable by new antibody-based therapeutics. Expression of AXL messenger RNA is elevated in a variety of sarcoma types, with the highest levels reported in MFS, but the pathogenic significance of this finding remains unknown. To assess a role for AXL abnormalities in MFS, we undertook a search for AXL genomic alterations in a comprehensive genomic profiling database of 463,546 unique tumors (including 19,879 sarcomas, of which 315 were MFS) interrogated by targeted next-generation DNA and/or RNA sequencing. Notably, the only genomic alterations recurrent in a specific sarcoma subtype were AXL W451C (n = 8) and AXL W450C (n = 2) mutations. The tumors involved predominantly older adults (age: 44 to 81 [median: 72] y) and histologically showed epithelioid and spindle-shaped cells in a variably myxoid stroma, with 6 cases diagnosed as MFS, 3 as undifferentiated pleomorphic sarcoma (UPS), and 1 as low-grade sarcoma. The AXL W451C mutation was not identified in any non-sarcoma malignancy. A review of publicly available data sets revealed a single AXL W451C-mutant case of UPS that clustered with MFS/UPS by methylation profiling. Functional studies revealed a novel activation mechanism: the W451C mutation causes abnormal unregulated dimerization of the AXL receptor tyrosine kinase through disulfide bond formation between pairs of mutant proteins expressing ectopic cysteine residues. This dimerization triggers AXL autophosphorylation and activation of downstream ERK signaling. We further report sarcomas of diverse histologic subtypes with AXL gene amplifications, with the highest frequency of amplification identified in MFS cases without the W451C mutation. In summary, the activating AXL W451C mutation appears highly specific to MFS, with a novel mechanism to drive unregulated signaling. Moreover, AXL gene amplifications and messenger RNA overexpression are far more frequent in MFS than in other sarcoma subtypes. We conclude that these aberrations in AXL are distinct features of MFS and may aid diagnosis, as well as the selection of available targeted therapies.

Eradicating Atherosclerotic Events by Targeting Early Subclinical Disease: It Is Time to Retire the Therapeutic Paradigm of Too Much, Too Late

Recent decades have seen spectacular advances in understanding and managing atherosclerotic cardiovascular disease, but paradoxically, clinical progress has stalled. Residual risk of atherosclerotic cardiovascular disease events is particularly vexing, given recognized lifestyle interventions and powerful modern medications. Why? Atherosclerosis begins early in life, yet clinical trials and mechanistic studies often emphasize terminal, end-stage plaques, meaning on the verge of causing heart attacks and strokes. Thus, current clinical evidence drives us to emphasize aggressive treatments that are delayed until patients already have advanced arterial disease. I call this paradigm "too much, too late." This brief review covers exciting efforts that focus on preventing, or finding and treating, arterial disease before its end-stage. Also included are specific proposals to establish a new evidence base that could justify intensive short-term interventions (induction-phase therapy) to treat subclinical plaques that are early enough perhaps to heal. If we can establish that such plaques are actionable, then broad screening to find them in early midlife individuals would become imperative-and achievable. You have a lump in your coronaries! can motivate patients and clinicians. We must stop thinking of a heart attack as a disease. The real disease is atherosclerosis. In my opinion, an atherosclerotic heart attack is a medical failure. It is a manifestation of longstanding arterial disease that we had allowed to progress to its end-stage, despite knowing that atherosclerosis begins early in life and despite the availability of remarkably safe and highly effective therapies. The field needs a transformational advance to shift the paradigm out of end-stage management and into early interventions that hold the possibility of eradicating the clinical burden of atherosclerotic cardiovascular disease, currently the biggest killer in the world. We urgently need a new evidence base to redirect our main focus from terminal, end-stage atherosclerosis to earlier, and likely reversible, human arterial disease.

Pelvic floor symptoms among premenopausal women with pelvic organ prolapse in the Democratic Republic of the Congo

INTRODUCTION AND HYPOTHESIS

Most of the literature on pelvic organ prolapse (POP) has been generated from postmenopausal patients in high-income countries. In the Democratic Republic of the Congo (DRC), a significant proportion of patients who present for surgical management of POP are premenopausal. Little is known about the impact of POP on pelvic floor symptoms in this population. The objective was to describe pelvic floor symptoms and sexual function among premenopausal patients presenting for POP surgery in DRC.

METHODS

We performed a prospective cohort study of symptomatic premenopausal patients undergoing fertility-sparing POP surgery at a large referral hospital in the DRC. Pelvic floor symptoms were evaluated with the Pelvic Floor Distress Inventory Questionnaire and sexual function with the Pelvic organ prolapse/urinary Incontinence Sexual Questionnaire. Data are presented as means with standard deviations or counts with percentages.

RESULTS

A total of 107 patients were recruited between April 2019 and December 2021. All had either stage III (95.3%) or stage IV (4.7%) prolapse. Ages were 34.2 ± 6.7 years; 78.5% were married. A majority of patients experienced low abdominal pain (82.2%), heaviness or dullness (95.3%), and bulging or protrusion of the prolapse (92.5%). Almost two-thirds of patients reported no longer being sexually active, and 80% stated that they were not sexually active because of POP. Of the 37 sexually active patients (34.6%), nearly all reported significant sexual impairment because of the prolapse, with only 4 reporting no sexual impairment.

CONCLUSIONS

This study represents one of the largest prospective series of patients with premenopausal POP. Our results highlight the severity of pelvic floor symptoms and the negative effects on sexual function among this patient population with POP.

Novel SOX10 indel mutations drive schwannomas through impaired transactivation of myelination gene programs

BACKGROUND

Schwannomas are common peripheral nerve sheath tumors that can cause severe morbidity given their stereotypic intracranial and paraspinal locations. Similar to many solid tumors, schwannomas and other nerve sheath tumors are primarily thought to arise due to aberrant hyperactivation of the RAS growth factor signaling pathway. Here, we sought to further define the molecular pathogenesis of schwannomas.

METHODS

We performed comprehensive genomic profiling on a cohort of 96 human schwannomas, as well as DNA methylation profiling on a subset. Functional studies including RNA sequencing, chromatin immunoprecipitation-DNA sequencing, electrophoretic mobility shift assay, and luciferase reporter assays were performed in a fetal glial cell model following transduction with wildtype and tumor-derived mutant isoforms of SOX10.

RESULTS

We identified that nearly one-third of sporadic schwannomas lack alterations in known nerve sheath tumor genes and instead harbor novel recurrent in-frame insertion/deletion mutations in SOX10, which encodes a transcription factor responsible for controlling Schwann cell differentiation and myelination. SOX10 indel mutations were highly enriched in schwannomas arising from nonvestibular cranial nerves (eg facial, trigeminal, vagus) and were absent from vestibular nerve schwannomas driven by NF2 mutation. Functional studies revealed these SOX10 indel mutations have retained DNA binding capacity but impaired transactivation of glial differentiation and myelination gene programs.

CONCLUSIONS

We thus speculate that SOX10 indel mutations drive a unique subtype of schwannomas by impeding proper differentiation of immature Schwann cells.

State of current management of the heightened risk for atherosclerotic cardiovascular events in an established cohort of patients with lupus erythematosus

OBJECTIVE

Patients with lupus erythematosus (LE) are at heightened risk for clinical events, chiefly heart attacks and strokes, from atherosclerotic cardiovascular disease (ASCVD). We recently proposed new guidelines to assess and manage ASCVD event risk specifically in LE. Here, we examined current cardiovascular management in light of these new recommendations.

METHODS

We studied our entire UPenn Longitudinal Lupus Cohort of patients with cutaneous LE, without (CLE-only) or with (CLE+SLE) concurrent systemic LE, for whom we had full access to medical records (n=370, LE-ASCVD Study Cohort).

RESULTS

Of our LE-ASCVD Study Cohort, 336 out of 370 (90.8%) had a designated primary-care physician. By the new guidelines, the most recent low-density lipoprotein (LDL) levels were above-goal for 249 out of 370 (67.3%). Two-hundred sixty-six (71.9%) had hypertension, which was undertreated or untreated in 198 out of 266 (74.4%). Of current smokers, 51 out of 63 (81.0%) had no documented smoking cessation counselling or referrals. Diabetes and triglyceridaemia were generally well managed. Of the cohort, 278 qualified for two widely used online estimators of ASCVD event risk in primary prevention: the ACC-ASCVD Risk Estimator Plus and QRisk3. We also stratified these 278 patients into our recently defined categories of ASCVD event risk in LE. These three methods for estimating ASCVD event risk showed clinically meaningful discordance for 169 out of 278 (60.8%). The documented rate of ASCVD events in the first 10 years after enrolment was 13.5% (95% CI 8.9%, 17.9%), similar between CLE-only and CLE+SLE, indicating an at-risk population despite the preponderance of women and an average age at enrolment of only 47 years.

CONCLUSION

Patients with CLE-only or CLE+SLE are undertreated compared with the new guidelines and, accordingly, they experience a significant burden of ASCVD events. Moreover, it is unclear how to accurately assess their future ASCVD event risk, except that it is substantial. Efforts are underway to improve ASCVD event risk estimation and guideline implementation in patients with lupus.

HPV51-associated Leiomyosarcoma: A Novel Class of TP53/RB1-Wildtype Tumor With Predilection for the Female Lower Reproductive Tract

Inactivating mutations in tumor suppressor genes TP53 and RB1 are considered central drivers in leiomyosarcomas (LMSs). In high-risk human papillomavirus (HPV)-related tumors, a similar functional outcome is achieved through oncoproteins E6 and E7, which inactivate the p53 and RB1 proteins, respectively. Here, we hypothesized that HPV infection could provide an alternative mechanism for tumorigenesis in a subset of TP53/RB1-wildtype LMS. We evaluated tumor samples from 2585 consecutive unique patients carrying a diagnosis of gynecologic or soft tissue LMS. Tumor DNA and available RNA were analyzed by hybrid-capture-based next-generation sequencing/comprehensive genomic profiling of 406 genes and transcripts (FoundationOneHeme). Of the initial 2585 cases, we excluded 16 based on the presence of molecular alterations that are considered defining for sarcomas other than LMS. In the remaining 2569 cases, we searched for LMS that were TP53/RB1-wildtype (n=486 of 2569; 18.9%). We also searched LMS tumors for HPV sequences that we then classified into genotypes by de novo assembly of nonhuman sequencing reads followed by alignment to the RefSeq database. Among TP53/RB1-wildtype LMS, we identified 18 unique cases harboring HPV sequences. Surprisingly, most (n=11) were HPV51-positive, and these 11 represented all HPV51-positive tumors in our entire LMS database (n=11 of 2569; 0.4%). The absence of genomic alterations in TP53 or RB1 in HPV51-positive LMS represented a marked difference from HPV51-negative LMS (n=2558; 0% vs. 72% [P<0.00001], 0% vs. 53% [P=0.0002]). In addition, compared with HPV51-negative LMS, HPV51-positive LMS were significantly enriched for genomic alterations in ATRX (55% vs. 24%, P=0.027) and TSC1 (18% vs. 0.6%, P=0.0047). All HPV51-positive LMS were in women; median age was 54 years at surgery (range: 23 to 74 y). All known primary sites were from the gynecologic tract or adjacent anogenital area, including 5 cases of vaginal primary site. Histology was heterogeneous, with evaluable cases showing predominant epithelioid (n=5) and spindle (n=5) morphology. In situ hybridization confirmed the presence of high-risk HPV E6/E7 mRNA in tumor cells in three of three evaluable cases harboring HPV51 genomic sequences. Overall, in our pan-LMS analysis, HPV reads were identified in a subset of TP53/RB1-wildtype LMS. For all HPV51-associated LMS, the striking absence of any detectable TP53 or RB1 mutations and predilection for the female lower reproductive tract supports our hypothesis that high-risk HPV can be an alternative tumorigenic mechanism in this distinct class of LMS.

Assessment and management of the heightened risk for atherosclerotic cardiovascular events in patients with lupus erythematosus or dermatomyositis

For patients with lupus erythematosus (LE) or dermatomyositis (DM), there is an urgent need to address a heightened risk of clinical events, chiefly heart attacks and strokes, caused by atherosclerotic cardiovascular disease (ASCVD). Patients with LE or DM frequently exhibit high levels of conventional risk factors for ASCVD events, particularly dyslipoproteinemia and hypertension; an amplified burden of atherosclerotic plaques; and increased age- and sex-adjusted rates of ASCVD events compared with the general population. The rate of ASCVD events exceeds what would be expected from conventional risk factors, suggesting that disease-specific autoimmune processes exacerbate specific, known pathogenic steps in atherosclerosis. Importantly, despite their heightened risk, patients with LE or DM are often undertreated for known causative agents and exacerbators of ASCVD. Herein, we propose an approach to assess and manage the heightened risk of ASCVD events in patients with LE or DM. Our approach is modeled in large part on established approaches to patients with diabetes mellitus or stage 3 or 4 chronic kidney disease, which are well-studied conditions that also show heightened risk for ASCVD events and have been explicitly incorporated into standard clinical guidelines for ASCVD. Based on the available evidence, we conclude that patients with LE or DM require earlier and more aggressive screening and management of ASCVD. We suggest that physicians consider implementing multipliers of conventional risk calculators to trigger earlier initiation of lifestyle modifications and medical therapies in primary prevention of ASCVD events, employ vascular imaging to quantify the burden of subclinical plaques, and treat to lower lipid targets using statins and newer therapies, such as PCSK9 inhibitors, that decrease ASCVD events in nonautoimmune cohorts. More clinical vigilance is needed regarding surveillance, prevention, risk modification, and treatment of dyslipidemias, hypertension, and smoking in patients with LE or DM. All of these goals are achievable.

A randomized controlled trial of an innovative, user-friendly, interactive smartphone app-based lifestyle intervention for weight loss

OBJECTIVES

Most electronically delivered lifestyle interventions are labor intensive, requiring logging onto websites and manually recording activity and diet. Cumbersome technology and lack of a human coach may have contributed to the limitations of prior interventions. In response, the current program of research created a comprehensive electronically delivered lifestyle intervention using a user-friendly, interactive, smartphone app-based model, and evaluated it in a randomized controlled trial.

METHODS

Twenty-eight adults, body mass index 25-42 kg/m2, with smartphones and sedentary jobs, were randomized to the intervention, along with conventional outpatient weight-management visits every 3 months, or to a wait-listed control group that received only weight-management visits. The intervention included wearable activity trackers, smartscales, food photography logs, physician-driven app-based behavioral coaching, and peer support via the app. The prespecified primary outcome was a comparison of change in weight in kilograms, in the intervention versus control group at 6 months.

RESULTS

At 6 months, the intervention group experienced a statistically significant weight change of -7.16 ± 1.78 kg (mean ± SE, 95% CI -11.05 to -3.26, p < 0.01), which differed from the weight change in controls by -4.16 ± 2.01 kg (95% CI -8.29 to -0.02, p < 0.05, prespecified primary outcome). Weight change in the control group was -3.00 ± 1.05 kg (95% CI -5.27 to -0.73, p < 0.05). Waist circumference and hemoglobin A1c significantly improved (intervention vs. control: p < 0.01, p < 0.05, respectively, prespecified secondary outcomes). Weight change in the intervention group correlated with numbers of food photographs participants shared (rho = -0.86, p < 0.01), numbers of their text messages (rho = -0.80, p < 0.01), number of times and days each participant stepped on the smartscale (rho = -0.73, p < 0.01; rho = -0.608, p < 0.05, respectively), and mean daily step counts (rho = -0.55, p < 0.05).

CONCLUSION

This app-based electronically delivered lifestyle intervention produced statistically significant, clinically meaningful weight loss and improved metabolic health. Engagement with the intervention correlated strongly with weight loss. Given the limited sample size, larger and longer studies of this intervention are needed.

Prevalence of High-Risk Nonvaccine Human Papillomavirus Types in Advanced Squamous Cell Carcinoma Among Individuals of African vs Non-African Ancestry

This cross-sectional study assesses the prevalence of high-risk human papillomavirus (hrHPV) types not covered by the 9-valent HPV vaccine among patients of African vs non-African ancestry with advanced squamous cell carcinoma.

CYLD-mutant cylindroma-like basaloid carcinoma of the anus: a genetically and morphologically distinct class of HPV-related anal carcinoma

Rare reports of anal carcinoma (AC) describe histologic resemblance to cutaneous cylindroma, but mutations in the tumor suppressor CYLD, the gene responsible for familial and sporadic cylindromas, have not been systematically investigated in AC. Here, we investigate CYLD-mutant AC, focusing on molecular correlates of distinct histopathology. Comprehensive genomic profiling (hybrid-capture-based DNA sequencing) was performed on 574 ACs, of which 75 unique cases (13%) harbored a CYLD mutation. Clinical data, pathology reports, and histopathology were reviewed for each CYLD-mutant case. The spectrum of CYLD mutations included truncating (n = 50; 67%), homozygous deletion (n = 10; 13%), missense (n = 16; 21%), and splice-site (n = 3; 4%) events. Compared with CYLD-wildtype AC (n = 499), CYLD-mutant ACs were significantly enriched for females (88% vs. 67%, p = 0.0001), slightly younger (median age 59 vs. 61 years, p = 0.047), and included near-universal detection of high-risk HPV sequences (97% vs. 88%, p = 0.014), predominantly HPV16 (96%). The CYLD-mutant cohort also showed significantly lower tumor mutational burden (TMB; median 2.6 vs. 5.2 mut/Mb, p < 0.00001) and less frequent alterations in PIK3CA (13% vs. 31%, p = 0.0015). On histopathologic examination, 73% of CYLD-mutant AC (55/75 cases) showed a striking cylindroma-like histomorphology, composed of aggregates of basaloid cells surrounded by thickened basement membranes and containing characteristic hyaline globules, while only 8% of CYLD-wildtype tumors (n = 34/409) contained cylindroma-like hyaline globules (p < 0.0001). CYLD-mutant carcinomas with cylindroma-like histomorphology (n = 55) showed significantly lower TMB compared with CYLD-mutant cases showing basaloid histology without the distinctive hyaline globules (n = 14) (median 1.7 vs. 4.4 mut/Mb, p = 0.0058). Only five CYLD-mutant cases (7%) showed nonbasaloid conventional squamous cell carcinoma histology (median TMB = 5.2 mut/Mb), and a single CYLD-mutant case showed transitional cell carcinoma-like histology. Within our cohort of ACs, CYLD mutations characterize a surprisingly large subset (13%), with distinct clinical and genomic features and, predominantly, a striking cylindroma-like histopathology, representing a genotype-phenotype correlation which may assist in classification of AC.

Melanoma with in-frame deletion of MAP2K1: a distinct molecular subtype of cutaneous melanoma mutually exclusive from BRAF, NRAS, and NF1 mutations

While the genomics of BRAF, NRAS, and other key genes influencing MAP kinase (MAPK) activity have been thoroughly characterized in melanoma, mutations in MAP2K1 (MEK1) have received significantly less attention and have consisted almost entirely of missense mutations considered secondary oncogenic drivers of melanoma. Here, we investigated melanomas with in-frame deletions of MAP2K1, alterations characterized as MAPK-activating in recent experimental models. Our case archive of clinical melanoma samples with comprehensive genomic profiling by a hybrid capture-based DNA sequencing platform was searched for MAP2K1 genetic alterations. Clinical data, pathology reports, and histopathology were reviewed for each case. From a cohort of 7119 advanced melanomas, 37 unique cases (0.5%) featured small in-frame deletions in MAP2K1. These included E102_I103del (n = 11 cases), P105_A106del (n = 8), Q58_E62del (n = 6), I103_K104del (n = 5), I99_K104del (n = 3), L98_I103del (n = 3), and E41_F53del (n = 1). All 37 were wild type for BRAF, NRAS, and NF1 genomic alterations ("triple wild-type"), representing 2.0% of triple wild-type melanomas overall (37/1882). Median age was 66 years and 49% were male. The majority arose from primary cutaneous sites (35/37; 95%) and demonstrated a UV signature when available (21/25; 84%). Tumor mutational burden was typical for cutaneous melanoma (median = 9.6 mut/Mb, range 0-35.7), and frequently mutated genes included TERTp (63%), CDKN2A (46%), TP53 (11%), PTEN (8%), APC (8%), and CTNNB1 (5%). Histopathology revealed a spectrum of appearances typical of melanoma. For comparison, we evaluated 221 cases with pathogenic missense single nucleotide variants in MAP2K1. The vast majority of melanomas with missense SNVs in MAP2K1 showed co-mutations in BRAF (58%), NF1 (23%), or NRAS (18%). In-frame deletions in MAP2K1, previously shown in experimental models to be strongly MAPK-activating, characterized a significant subset of triple wild-type melanoma (2.0%), suggesting a primary oncogenic role for these mutations. Comprehensive genomic profiling of melanomas enables detection of this alteration, which may have implications for potential therapeutic options.

CDKN2C-Null Leiomyosarcoma: A Novel, Genomically Distinct Class of TP53/RB1-Wild-Type Tumor With Frequent CIC Genomic Alterations and 1p/19q-Codeletion

PURPOSE

Leiomyosarcoma (LMS) harbors frequent mutations in TP53 and RB1 but few actionable genomic alterations. Here, we searched for recurrent actionable genomic alterations in LMS that occur in the absence of common untreatable oncogenic drivers.

METHODS

Tissues from 276,645 unique advanced cancers, including 2,570 uterine and soft tissue LMS, were sequenced by hybrid-capture-based next-generation DNA and RNA sequencing/comprehensive genomic profiling of up to 406 genes. We characterized clinicopathologic features of relevant patient cases.

RESULTS

Overall, 77 LMS exhibited homozygous copy loss of CDKN2C at chromosome 1p32.3 (3.0% of LMS). Genomic alterations (GAs) in TP53, RB1, and ATRX were rare compared with the remainder of the LMS cohort (11.7% v 73.4%, 0% v 54.5%, 2.6% v 24.5%, respectively; all P < .0001). CDKN2C-null LMS patient cases were significantly enriched for GAs in CIC (40.3% v 1.4%) at 19q13.2, CDKN2A (46.8% v 7.0%), and RAD51B (16.9% v 1.7%; all P < .0001). Chromosome arm-level aneuploidy analysis of available LMS patient cases (n = 1,284) found that 81% (58 of 72) of CDKN2C-null LMS exhibited 1p/19q-codeletion, a significant enrichment compared with 5.1% in the remainder of the LMS cohort (P < .0001). In total, 99% of CDKN2C-null LMS were in women; the median age was 61 years at surgery (range, 36-81 years). Fifty-five patient cases were uterine primary, four were nonuterine, and the remaining 18 were of uncertain primary site. Sixty percent of cases showed at least focal epithelioid variant histology. Most patients had advanced-stage disease, with 62% of confirmed uterine primary LMS at International Federation of Gynecology and Obstetrics stage IVB. We further validated our findings in two publicly available datasets: The Cancer Genome Atlas and the Project GENIE initiative.

CONCLUSION

CDKN2C-null LMS defines a genomically distinct tumor that may have prognostic and/or therapeutic clinical implications, including possible use of specific cyclin-dependent kinase inhibitors.

Vulvar Squamous Cell Carcinoma: Comprehensive Genomic Profiling of HPV+ Versus HPV- Forms Reveals Distinct Sets of Potentially Actionable Molecular Targets

PURPOSE

Vulvar squamous cell carcinoma (vSCC) encompasses two predominant variants: one associated with detectable high-risk strains of human papillomavirus (hrHPV) and a second form often occurring in the context of chronic dermatitis in postmenopausal women. Genomic assessment of a large-scale cohort of patients with aggressive vSCC may identify distinct mutational signatures.

MATERIALS AND METHODS

Tumor samples from a total of 280 patients with vSCC underwent hybridization capture with analysis of up to 406 cancer-related genes. Human papillomavirus (HPV) sequences were detected by de novo assembly of nonhuman sequencing reads and aligned to the RefSeq database. Immunohistochemistry for programmed death-ligand 1 (PD-L1) was assessed.

RESULTS

One hundred two of 280 vSCCs (36%) contained hrHPV sequences, predominantly HPV 16 (88%). The HPV-positive (HPV+) group was significantly younger (median age, 59 v 64 years; P = .001). Compared with HPV-negative (HPV–) vSCCs, HPV+ tumors showed more frequent pathogenic alterations in PIK3CA (31% v 16%; P = .004), PTEN (14% v 2%; P < .0001), EP300 (14% v 1%; P < .0001), STK11 (14% v 1%; P < .0001), AR (5% v 0%; P = .006), and FBXW7 (10% v 3%; P = .03). In contrast, HPV– vSCCs showed more alterations in TP53 (83% v 6%; P < .0001), TERTp (71% v 9%; P < .0001), CDKN2A (55% v 2%; P < .0001), CCND1 amplification (22% v 2%; P < .0001), FAT1 (25% v 4%; P < .0001), NOTCH1 (19% v 6%; P = .002), and EGFR amplification (11% v 0%; P < .0001), as well as a higher rate of 9p24.1 (PDL1/PDL2) amplification (5% v 1%) and PD-L1 immunohistochemistry high-positive tumor staining (33% v 9%; P = .04).

CONCLUSION

Comprehensive molecular profiles of vSCC vary considerably with hrHPV status and may inform patient selection into clinical trials. Sixty-one percent of HPV+ vSCCs had a pathogenic alteration in the PI3K/mTOR pathway, whereas HPV– vSCCs showed alterations in TP53, TERTp, CDKN2A, CCND1, and EGFR, and biomarkers associated with responsiveness to immunotherapy.

Pan-sarcoma genomic analysis of KMT2A rearrangements reveals distinct subtypes defined by YAP1-KMT2A-YAP1 and VIM-KMT2A fusions

Sarcomas are driven by diverse pathogenic mechanisms, including gene rearrangements in a subset of cases. Rare soft tissue sarcomas containing KMT2A fusions have recently been reported, characterized by a predilection for young adults, sclerosing epithelioid fibrosarcoma-like morphology, and an often aggressive course. Nonetheless, clinicopathologic and molecular descriptions of KMT2A-rearranged sarcomas remain limited. In this study, we identified by targeted next-generation RNA sequencing an index patient with KMT2A fusion-positive soft tissue sarcoma. In addition, we systematically searched for KMT2A structural variants in a comprehensive genomic profiling database of 14,680 sarcomas interrogated by targeted next-generation DNA and/or RNA sequencing. We characterized the clinicopathologic and molecular features of KMT2A fusion-positive sarcomas, including KMT2A breakpoints, rearrangement partners, and concurrent genetic alterations. Collectively, we identified a cohort of 34 sarcomas with KMT2A fusions (0.2%), and YAP1 was the predominant partner (n = 16 [47%]). Notably, a complex rearrangement with YAP1 consistent with YAP1-KMT2A-YAP1 fusion was detected in most cases, with preservation of KMT2A CxxC-binding domain in the YAP1-KMT2A-YAP1 fusion and concurrent deletions of corresponding exons in KMT2A. The tumors often affected younger adults (age 20-66 [median 40] years) and histologically showed variably monomorphic epithelioid-to-spindle shaped cells embedded in a dense collagenous stroma. Ultrastructural evidence of fibroblastic differentiation was noted in one tumor examined. Our cohort also included two sarcomas with VIM-KMT2A fusions, each harboring concurrent mutations in CTNNB1, SMARCB1, and ARID1A and characterized histologically by sheets of spindle-to-round blue cells. The remaining 16 KMT2A-rearranged sarcomas in our cohort exhibited diverse histologic subtypes, each with unique novel fusion partners. In summary, KMT2A-fusion-positive sarcomas most commonly exhibit sclerosing epithelioid fibrosarcoma-like morphology and complex YAP1-KMT2A-YAP1 fusions. Cases also include rare spindle-to-round cell sarcomas with VIM-KMT2A fusions and tumors of diverse histologic subtypes with unique KMT2A fusions to non-YAP1 non-VIM partners.

Susceptibility of low-density lipoprotein particles to aggregate depends on particle lipidome, is modifiable, and associates with future cardiovascular deaths

Aims

Low-density lipoprotein (LDL) particles cause atherosclerotic cardiovascular disease (ASCVD) through their retention, modification, and accumulation within the arterial intima. High plasma concentrations of LDL drive this disease, but LDL quality may also contribute. Here, we focused on the intrinsic propensity of LDL to aggregate upon modification. We examined whether inter-individual differences in this quality are linked with LDL lipid composition and coronary artery disease (CAD) death, and basic mechanisms for plaque growth and destabilization.

Methods and results

We developed a novel, reproducible method to assess the susceptibility of LDL particles to aggregate during lipolysis induced ex vivo by human recombinant secretory sphingomyelinase. Among patients with an established CAD, we found that the presence of aggregation-prone LDL was predictive of future cardiovascular deaths, independently of conventional risk factors. Aggregation-prone LDL contained more sphingolipids and less phosphatidylcholines than did aggregation-resistant LDL. Three interventions in animal models to rationally alter LDL composition lowered its susceptibility to aggregate and slowed atherosclerosis. Similar compositional changes induced in humans by PCSK9 inhibition or healthy diet also lowered LDL aggregation susceptibility. Aggregated LDL in vitro activated macrophages and T cells, two key cell types involved in plaque progression and rupture.

Conclusion

Our results identify the susceptibility of LDL to aggregate as a novel measurable and modifiable factor in the progression of human ASCVD.

Diabetes-Related Fracture Risk Is Different in African Americans Compared With Hispanics and Caucasians

CONTEXT

Diabetes mellitus (DM) has been associated with a 60% to 90% increased risk of fracture but few studies have been performed in African American and Hispanic subjects.

OBJECTIVE

The aim of the present study was to quantify the risk of incident major osteoporotic fractures (MOFs) of the hip, wrist, and humerus in African Americans, Hispanics, and Caucasians with DM compared with those with hypertension (HTN).

METHODS

We performed a retrospective cohort study of 19,153 subjects with DM (7618 Caucasians, 7456 African Americans, and 4079 Hispanics) and 26,217 with HTN (15,138 Caucasians, 8301 African Americans, and 2778 Hispanics) aged ≥40 years, treated at a large health care system in Philadelphia, Pennsylvania. All information about the subjects was obtained from electronic health records.

RESULTS

The unadjusted MOF rates for each race/ethnicity were similar among those with DM and those with HTN (Caucasians, 1.85% vs 1.84%; African Americans, 1.07% vs 1.29%; and Hispanics, 1.69% vs 1.33%; P = NS for all). However, the MOF rates were higher for Caucasians and Hispanics with DM than for African Americans with DM (P < 0.01). In a multivariable model controlled for age, body mass index, sex, and previous MOF, DM was a statistically significant predictor of MOFs only for Caucasians and Hispanics [hazard ratio (HR), 1.23; 95% CI, 1.02 to 1.48; P = 0.026] but not for African Americans (HR, 0.92; 95% CI, 0.68 to 1.23; P = 0.56).

CONCLUSIONS

Hispanics had a DM-related fracture risk similar to that of Caucasians, but AAs did not have an additional fracture risk conferred by DM.

Novel phase I trial design to evaluate the addition of cediranib or selumetinib to preoperative chemoradiotherapy for locally advanced rectal cancer: the DREAMtherapy trial

BACKGROUND

The DREAMtherapy (Dual REctal Angiogenesis MEK inhibition radiotherapy) trial is a novel intertwined design whereby two tyrosine kinase inhibitors (cediranib and selumetinib) were independently evaluated with rectal chemoradiotherapy (CRT) in an efficient manner to limit the extended follow-up period often required for radiotherapy studies.

PATIENTS AND METHODS

Cediranib or selumetinib was commenced 10 days before and then continued with RT (45 Gy/25#/5 wks) and capecitabine (825 mg/m2 twice a day (BID)). When three patients in the cediranib 15-mg once daily (OD) cohort were in the surveillance period, recruitment to the selumetinib cohort commenced. This alternating schedule was followed throughout. Three cediranib (15, 20 and 30 mg OD) and two selumetinib cohorts (50 and 75 mg BID) were planned. Circulating and imaging biomarkers of inflammation/angiogenesis were evaluated.

RESULTS

In case of cediranib, dose-limiting diarrhoea, fatigue and skin reactions were seen in the 30-mg OD cohort, and therefore, 20 mg OD was defined as the maximum tolerated dose. Forty-one percent patients achieved a clinical or pathological complete response (7/17), and 53% (9/17) had an excellent clinical or pathological response (ECPR). Significantly lower level of pre-treatment plasma tumour necrosis factor alpha (TNFα) was found in patients who had an ECPR. In case of selumetinib, the 50-mg BID cohort was poorly tolerated (fatigue and diarrhoea); a reduced dose cohort of 75-mg OD was opened which was also poorly tolerated, and further recruitment was abandoned. Of the 12 patients treated, two attained an ECPR (17%).

CONCLUSIONS

This novel intertwined trial design is an effective way to independently investigate multiple agents with radiotherapy. The combination of cediranib with CRT was well tolerated with encouraging efficacy. TNFα emerged as a potential predictive biomarker of response and warrants further evaluation.

A new method for the high-precision assessment of tumor changes in response to treatment

Motivation

Imaging demonstrates that preclinical and human tumors are heterogeneous, i.e. a single tumor can exhibit multiple regions that behave differently during both development and also in response to treatment. The large variations observed in control group, tumors can obscure detection of significant therapeutic effects due to the ambiguity in attributing causes of change. This can hinder development of effective therapies due to limitations in experimental design rather than due to therapeutic failure. An improved method to model biological variation and heterogeneity in imaging signals is described. Specifically, linear Poisson modeling (LPM) evaluates changes in apparent diffusion co-efficient between baseline and 72 h after radiotherapy, in two xenograft models of colorectal cancer. The statistical significance of measured changes is compared to those attainable using a conventional t-test analysis on basic apparent diffusion co-efficient distribution parameters.

Results

When LPMs were applied to treated tumors, the LPMs detected highly significant changes. The analyses were significant for all tumors, equating to a gain in power of 4-fold (i.e. equivalent to having a sample size 16 times larger), compared with the conventional approach. In contrast, highly significant changes are only detected at a cohort level using t-tests, restricting their potential use within personalized medicine and increasing the number of animals required during testing. Furthermore, LPM enabled the relative volumes of responding and non-responding tissue to be estimated for each xenograft model. Leave-one-out analysis of the treated xenografts provided quality control and identified potential outliers, raising confidence in LPM data at clinically relevant sample sizes.

Availability and implementation

TINA Vision open source software is available from www.tina-vision.net.

Supplementary information

Supplementary data are available at Bioinformatics online.

Novel Insights into How Overnutrition Disrupts the Hypothalamic Actions of Leptin

Obesity has become a worldwide health problem, but we still do not understand the molecular mechanisms that contribute to overeating and low expenditure of energy. Leptin has emerged as a major regulator of energy balance through its actions in the hypothalamus. Importantly, obese people exhibit high circulating levels of leptin, yet the hypothalamus no longer responds normally to this hormone to suppress appetite or to increase energy expenditure. Several well-known hypotheses have been proposed to explain impaired central responsiveness to the effects of leptin in obesity, including defective transit across the blood-brain barrier at the arcuate nucleus, hypothalamic endoplasmic reticulum stress, maladaptive sterile inflammation in the hypothalamus, and overexpression of molecules that may inhibit leptin signaling. We also discuss a new explanation that is based on our group's recent discovery of a signaling pathway that we named "NSAPP" after its five main protein components. The NSAPP pathway consists of an oxide transport chain that causes a transient, targeted burst in intracellular hydrogen peroxide (H₂O₂) to inactivate redox-sensitive members of the protein tyrosine phosphatase gene family. The NSAPP oxide transport chain is required for full activation of canonical leptin signaling in neurons but fails to function normally in states of overnutrition. Remarkably, leptin and insulin both require the NSAPP oxide transport chain, suggesting that a defect in this pathway could explain simultaneous resistance to the appetite-suppressing effects of both hormones in obesity.

Suppression of Hepatic FLOT1 (Flotillin-1) by Type 2 Diabetes Mellitus Impairs the Disposal of Remnant Lipoproteins via Syndecan-1

OBJECTIVE

Type 2 diabetes mellitus (T2DM) and the atherometabolic syndrome exhibit a deadly dyslipoproteinemia that arises in part from impaired hepatic disposal of C-TRLs (cholesterol- and triglyceride-rich remnant apoB [apolipoprotein B] lipoproteins). We previously identified syndecan-1 as a receptor for C-TRLs that directly mediates endocytosis via rafts, independent from coated pits. Caveolins and flotillins form rafts but facilitate distinct endocytotic pathways. We now investigated their participation in syndecan-1-mediated disposal of C-TRLs and their expression in T2DM liver.

APPROACH AND RESULTS

In cultured liver cells and nondiabetic murine livers, we found that syndecan-1 coimmunoprecipitates with FLOT1 (flotillin-1) but not with CAV1 (caveolin-1). Binding of C-TRLs to syndecan-1 on the surface of liver cells enhanced syndecan-1/FLOT1 association. The 2 molecules then trafficked together into the lysosomes, implying limited if any recycling back to the cell surface. The interaction requires the transmembrane/cytoplasmic region of syndecan-1 and the N-terminal hydrophobic domain of FLOT1. Knockdown of FLOT1 in cultured liver cells substantially inhibited syndecan-1 endocytosis. Livers from obese, T2DM KKA^y mice exhibited 60% to 70% less FLOT1 protein and mRNA than in nondiabetic KK livers. An adenoviral construct to enhance hepatic expression of wild-type FLOT1 in T2DM mice normalized plasma triglycerides, whereas a mutant FLOT1 missing its N-terminal hydrophobic domain had no effect. Moreover, the adenoviral vector for wild-type FLOT1 lowered plasma triglyceride excursions and normalized retinyl excursions in T2DM KKA^y mice after a corn oil gavage, without affecting postprandial production of C-TRLs.

CONCLUSIONS

FLOT1 is a novel participant in the disposal of harmful C-TRLs via syndecan-1. Low expression of FLOT1 in T2DM liver may contribute to metabolic dyslipoproteinemia.

In vivo characterisation of a therapeutically relevant self-assembling 18 F-labelled β-sheet forming peptide and its hydrogel using positron emission tomography

Positron emission tomography (PET) and fluorescence labelling have been used to assess the pharmacokinetics, biodistribution and eventual fate of a hydrogel‐forming nonapeptide, FEFKFEFKK (F9), in healthy mice, using ¹⁸F‐labelled and fluorescein isothiocyanate (FITC)‐labelled F9 analogues. F9 was site‐specifically radiolabelled with 2‐[¹⁸F]fluoro‐3‐pyridinecarboxaldehyde ([¹⁸F]FPCA) via oxime bond formation. [¹⁸F]FPCA‐F9 in vivo fate was evaluated both as a solution, following intravenous administration, and as a hydrogel when subcutaneously injected. The behaviour of FITC‐F9 hydrogel was assessed following subcutaneous injection. [¹⁸F]FPCA‐F9 demonstrated high plasma stability and primarily renal excretion; [¹⁸F]FPCA‐F9 when in solution and injected into the bloodstream displayed prompt bladder uptake (53.4 ± 16.6 SUV at 20 minutes postinjection) and rapid renal excretion, whereas [¹⁸F]FPCA‐F9 hydrogel, formed by co‐assembly of [¹⁸F]FPCA‐F9 monomer with unfunctionalised F9 peptide and injected subcutaneously, showed gradual bladder accumulation of hydrogel fragments (3.8 ± 0.4 SUV at 20 minutes postinjection), resulting in slower renal excretion. Gradual disaggregation of the F9 hydrogel from the site of injection was monitored using FITC‐F9 hydrogel in healthy mice (60 ± 3 over 96 hours), indicating a biological half‐life between 1 and 4 days. The in vivo characterisation of F9, both as a gel and a solution, highlights its potential as a biomaterial.

Vasoproliferative process resembling pulmonary capillary hemangiomatosis in a cat

BACKGROUND

Pulmonary capillary hemangiomatosis is a rare, vascular obstructive disorder that uniformly causes pulmonary arterial hypertension. Clinically, pulmonary capillary hemangiomatosis is indistinguishable from primary pulmonary arterial hypertension and histology is required for definitive diagnosis. The distinctive histologic feature of pulmonary capillary hemangiomatosis is non-malignant extensive proliferation of capillaries in the alveolar septae. Vasodilator treatment of humans with primary arterial hypertension due to pulmonary capillary hemangiomatosis can result in fatal acute pulmonary edema. Computed tomography is thus critical to discern pulmonary capillary hemangiomatosis from other causes of pulmonary arterial hypertension prior to vasodilator therapy. This is the first report of a vasoproliferative process resembling pulmonary capillary hemangiomatosis in the feline species.

CASE PRESENTATION

A 15-year-old, male castrated, domestic shorthair cat presented for persistent labored breathing presumptively due to congestive heart failure despite treatment with diuretics for 7 days. Echocardiography showed evidence of hypertrophic cardiomyopathy with severe pulmonary hypertension; however, a normal sized left atrium was not consistent with congestive heart failure. Thoracic computed tomography was performed and showed evidence of diffuse ill-defined nodular ground glass opacities, enlarged pulmonary arteries, and filling defects consistent with pulmonary thromboembolism. The cat acutely decompensated after a single dose of sildenafil and was euthanized. Histopathology of the lungs showed severe multifocal alveolar capillary proliferation with respiratory bronchiolar infiltration, marked type II pneumocyte hyperplasia and multifocal pulmonary arterial thrombosis.

CONCLUSION

This is the first description in a cat of a vasoproliferative disorder resembling pulmonary capillary hemangiomatosis complicated by multifocal pulmonary arterial thrombosis. Inspiratory and expiratory ventilator-driven breath holds with angiography revealed lesions predominantly characterized by ground glass opacification and vascular filling defects with absence of air trapping. The results from this report suggest that, as in humans, the cat can develop a pulmonary capillary hemangiomatosis-like disease in which vasodilator therapy to address pulmonary hypertension may lead to fatal pulmonary edema.

Genome-wide RNAi screen reveals ALK1 mediates LDL uptake and transcytosis in endothelial cells

In humans and animals lacking functional LDL receptor (LDLR), LDL from plasma still readily traverses the endothelium. To identify the pathways of LDL uptake, a genome-wide RNAi screen was performed in endothelial cells and cross-referenced with GWAS-data sets. Here we show that the activin-like kinase 1 (ALK1) mediates LDL uptake into endothelial cells. ALK1 binds LDL with lower affinity than LDLR and saturates only at hypercholesterolemic concentrations. ALK1 mediates uptake of LDL into endothelial cells via an unusual endocytic pathway that diverts the ligand from lysosomal degradation and promotes LDL transcytosis. The endothelium-specific genetic ablation of Alk1 in Ldlr-KO animals leads to less LDL uptake into the aortic endothelium, showing its physiological role in endothelial lipoprotein metabolism. In summary, identification of pathways mediating LDLR-independent uptake of LDL may provide unique opportunities to block the initiation of LDL accumulation in the vessel wall or augment hepatic LDLR-dependent clearance of LDL.

Atherosclerosis is caused by low-density lipoprotein (LDL) buildup in the vessel wall, a process thought to be mediated by LDL receptor alone. Here, the authors show that the endothelium can uptake LDL via ALK1, a TGFβ signalling receptor, suggesting new therapies for blocking LDL accumulation in the vessel wall.

The central role of arterial retention of cholesterol-rich apolipoprotein-B-containing lipoproteins in the pathogenesis of atherosclerosis: a triumph of simplicity

PURPOSE OF REVIEW

Today, it is no longer a hypothesis, but an established fact, that increased plasma concentrations of cholesterol-rich apolipoprotein-B (apoB)-containing lipoproteins are causatively linked to atherosclerotic cardiovascular disease (ASCVD) and that lowering plasma LDL concentrations reduces cardiovascular events in humans. Here, we review evidence behind this assertion, with an emphasis on recent studies supporting the 'response-to-retention' model - namely, that the key initiating event in atherogenesis is the retention, or trapping, of cholesterol-rich apoB-containing lipoproteins within the arterial wall.

RECENT FINDINGS

New clinical trials have shown that ezetimibe and anti-PCSK9 antibodies - both nonstatins - lower ASCVD events, and they do so to the same extent as would be expected from comparable plasma LDL lowering by a statin. These studies demonstrate beyond any doubt the causal role of apoB-containing lipoproteins in atherogenesis. In addition, recent laboratory experimentation and human Mendelian randomization studies have revealed novel information about the critical role of apoB-containing lipoproteins in atherogenesis. New information has also emerged on mechanisms for the accumulation in plasma of harmful cholesterol-rich and triglyceride-rich apoB-containing remnant lipoproteins in states of overnutrition. Like LDL, these harmful cholesterol-rich and triglyceride-rich apoB-containing remnant lipoprotein remnants become retained and modified within the arterial wall, causing atherosclerosis.

SUMMARY

LDL and other cholesterol-rich, apoB-containing lipoproteins, once they become retained and modified within the arterial wall, cause atherosclerosis. This simple, robust pathophysiologic understanding may finally allow us to eradicate ASCVD, the leading killer in the world.

Coronary Arteriosclerosis with Myocardial Atrophy in a 13-year-old Dog

Myocardial ischemia, an uncommon cause of sudden death in dogs, usually results in infarction and fibrosis of the myocardium. Necropsy examination of a 13-year-old German Shepherd dog that died suddenly demonstrated multifocal myocardial thinning and loss in the left and right ventricular free wall and right atrium. Histopathologic examination confirmed the myocardial thinning to be sites of myocyte atrophy and loss, with loose reticulin-positive fibrovascular tissue and adipocytes and little fibrosis. Many intramural coronary arteries were irregularly thickened and partially occluded by segmental intimal and medial deposits of periodic acid-Schiff-positive, Congo red-negative amorphous extracellular material. This finding is consistent with hyaline arteriosclerosis. These vascular lesions likely lead to insufficient perfusion of the affected myocardium and gradual loss of myofibers without the acute necrosis and fibrosis characteristic of infarction.

Non-Invasive Management of Peripheral Arterial Disease

BACKGROUND

Peripheral arterial disease (PAD) is common and symptoms can be debilitating and lethal. Risk management, exercise, radiological and surgical intervention are all valuable therapies, but morbidity and mortality rates from this disease are increasing. Circulatory enhancement can be achieved using simple medical electronic devices, with claims of minimal adverse side effects. The evidence for these is variable, prompting a review of the available literature.

METHODS

Embase and Medline were interrogated for full text articles in humans and written in English. Any external medical devices used in the management of peripheral arterial disease were included if they had objective outcome data.

RESULTS

Thirty-one papers met inclusion criteria, but protocols were heterogenous. The medical devices reported were intermittent pneumatic compression (IPC), electronic nerve (NMES) or muscle stimulators (EMS), and galvanic electrical dressings. In patients with intermittent claudication, IPC devices increase popliteal artery velocity (49-70 %) and flow (49-84 %). Gastrocnemius EMS increased superficial femoral artery flow by 140 %. Over 4.5-6 months IPC increased intermittent claudication distance (ICD) (97-150 %) and absolute walking distance (AWD) (84-112 %), with an associated increase in quality of life. NMES of the calf increased ICD and AWD by 82 % and 61-150 % at 4 weeks, and 26 % and 34 % at 8 weeks. In patients with critical limb ischaemia IPC reduced rest pain in 40-100 % and was associated with ulcer healing rates of 26 %. IPC had an early limb salvage rate of 58-83 % at 1-3 months, and 58-94 % at 1.5-3.5 years. No studies have reported the use of EMS or NMES in the management of CLI.

CONCLUSION

There is evidence to support the use of IPC in the management of claudication and CLI. There is a building body of literature to support the use of electrical stimulators in PAD, but this is low level to date. Devices may be of special benefit to those with limited exercise capacity, and in non-reconstructable critical limb ischaemia. Galvanic stimulation is not recommended.

Proteolytically active ADAM10 and ADAM17 carried on membrane microvesicles in human abdominal aortic aneurysms

The intraluminal thrombus (ILT) of human abdominal aortic aneurysm (AAA) has been suggested to damage the underlying aortic wall, but previous work found scant activity of soluble proteases in the abluminal layer of the ILT, adjacent to the aneurysm. We hypothesised that transmembrane proteases carried by membrane microvesicles (MV) from dying cells remain active in the abluminal ILT. ILTs and AAA segments collected from 21 patients during surgical repair were assayed for two major transmembrane proteases, ADAM10 (a disintegrin and metalloprotease-10) and ADAM17. We also exposed cultured cells to tobacco smoke and assessed ADAM10 and ADAM17 expression and release on MVs. Immunohistochemistry showed abundant ADAM10 and ADAM17 protein in the ILT and underlying aneurysmal aorta. Domain-specific antibodies indicated both transmembrane and shed ADAM17. Importantly, ADAM10 and ADAM 17 in the abluminal ILT were enzymatically active. Electron microscopy of abluminal ILT and aortic wall showed MVs with ADAM10 and ADAM17. By flow cytometry, ADAM-positive microvesicles from abluminal ILT carried the neutrophil marker CD66, but not the platelet marker CD61. Cultured HL60 neutrophils exposed to tobacco smoke extract showed increased ADAM10 and ADAM17 content, cleavage of these molecules into active forms, and release of MVs carrying mature ADAM10 and detectable ADAM17. In conclusion, our results implicate persistent, enzymatically active ADAMs on MVs in the abluminal ILT, adjacent to the aneurysmal wall. The production of ADAM10- and ADAM17-positive MVs from smoke-exposed neutrophils provides a novel molecular mechanism for the vastly accelerated risk of AAA in smokers.

Compression Stockings versus Neuromuscular Electrical Stimulation Devices in the Management of Occupational Leg Swelling

Background Occupational edema is reported to occur in healthy individuals after working in a sitting or standing position for extensive periods of time. It can be associated with feelings of tiredness, heaviness of the legs, and pain. Three licensed medical devices were compared in their management of occupational edema. Subjects and Methods A total of 10 subjects were recruited from a clinical workspace. Right leg volume and great saphenous vein diameter was measured in the morning, and 6 hours later. On subsequent separate days, grade 2 graduated compression stockings (Active Compression Socks, Mediven, United Kingdom), geko (Firstkind Ltd, United Kingdom), and Revitive (Actegy Ltd, United Kingdom) were used bilaterally according to manufacturer's instructions. Results Leg volumes increased by median 41 mL (p < 0.05) with no intervention. Percentage increase in leg volume was found to be significantly reduced by stockings compared with control (-1.7%, p < 0.01), and were more effective than electrical devices. Changes in vein diameter poorly correlate with leg volume changes. Conclusion Occupational edema can occur over as little as 6 hours. All devices were well tolerated and reduced leg swelling. Stockings were the only device to significantly reduce leg swelling in this small trial.

Decreased secretion of adiponectin through its intracellular accumulation in adipose tissue during tobacco smoke exposure

Background

Cigarette smoking is associated with an increased risk of type 2 diabetes mellitus (T2DM). Smokers exhibit low circulating levels of total adiponectin (ADPN) and high-molecular-weight (HMW) ADPN multimers. Blood concentrations of HMW ADPN multimers closely correlate with insulin sensitivity for handling glucose. How tobacco smoke exposure lowers blood levels of ADPN, however, has not been investigated. In the current study, we examined the effects of tobacco smoke exposure in vitro and in vivo on the intracellular and extracellular distribution of ADPN and its HMW multimers, as well as potential mechanisms.

Findings

We found that exposure of cultured adipocytes to tobacco smoke extract (TSE) suppressed total ADPN secretion, and TSE administration to mice lowered their plasma ADPN concentrations. Surprisingly, TSE caused intracellular accumulation of HMW ADPN in cultured adipocytes and in the adipose tissue of wild-type mice, while preferentially decreasing HMW ADPN in culture medium and in plasma. Importantly, we found that TSE up-regulated the ADPN retention chaperone ERp44, which colocalized with ADPN in the endoplasmic reticulum. In addition, TSE down-regulated DsbA-L, a factor for ADPN secretion.

Conclusions

Tobacco smoke exposure traps HMW ADPN intracellularly, thereby blocking its secretion. Our results provide a novel mechanism for hypoadiponectinemia, and may help to explain the increased risk of T2DM in smokers.

Longitudinal study of Escherichia coli O157 shedding and super shedding in dairy heifers

A longitudinal study was conducted to assess the methods available for detection of Escherichia coli O157 and to investigate the prevalence and occurrence of long-term shedding and super shedding in a cohort of Australian dairy heifers. Samples were obtained at approximately weekly intervals from heifers at pasture under normal management systems. Selective sampling techniques were used with the aim of identifying heifers with a higher probability of shedding or super shedding. Rectoanal mucosal swabs (RAMS) and fecal samples were obtained from each heifer. Direct culture of feces was used for detection and enumeration. Feces and RAMS were tested by enrichment culture. Selected samples were further tested retrospectively by immunomagnetic separation of enriched samples. Of 784 samples obtained, 154 (19.6%) were detected as positive using culture methods. Adjusting for selective sampling, the prevalence was 71 (15.6%) of 454. In total, 66 samples were detected as positive at >10(2) CFU/g of which 8 were >10(4) CFU/g and classed as super shedding. A significant difference was observed in detection by enriched culture of RAMS and feces. Dairy heifers within this cohort exhibited variable E. coli O157 shedding, consistent with previous estimates of shedding. Super shedding was detected at a low frequency and inconsistently from individual heifers. All detection methods identified some samples as positive that were not detected by any other method, indicating that the testing methods used will influence survey results.

Imaging tumour hypoxia with positron emission tomography

Hypoxia, a hallmark of most solid tumours, is a negative prognostic factor due to its association with an aggressive tumour phenotype and therapeutic resistance. Given its prominent role in oncology, accurate detection of hypoxia is important, as it impacts on prognosis and could influence treatment planning. A variety of approaches have been explored over the years for detecting and monitoring changes in hypoxia in tumours, including biological markers and noninvasive imaging techniques. Positron emission tomography (PET) is the preferred method for imaging tumour hypoxia due to its high specificity and sensitivity to probe physiological processes in vivo, as well as the ability to provide information about intracellular oxygenation levels. This review provides an overview of imaging hypoxia with PET, with an emphasis on the advantages and limitations of the currently available hypoxia radiotracers.

Coagulation-driven platelet activation reduces cholestatic liver injury and fibrosis in mice

BACKGROUND

The coagulation cascade has been shown to participate in chronic liver injury and fibrosis, but the contribution of various thrombin targets, such as protease activated receptors (PARs) and fibrin(ogen), has not been fully described. Emerging evidence suggests that in some experimental settings of chronic liver injury, platelets can promote liver repair and inhibit liver fibrosis. However, the precise mechanisms linking coagulation and platelet function to hepatic tissue changes following injury remain poorly defined.

OBJECTIVES

To determine the role of PAR-4, a key thrombin receptor on mouse platelets, and fibrin(ogen) engagement of the platelet αII b β3 integrin (αIIb β3 ) in a model of cholestatic liver injury and fibrosis.

METHODS

Biliary and hepatic injury was characterized following 4 week administration of the bile duct toxicant α-naphthylisothiocyanate (ANIT) (0.025%) in PAR-4-deficient mice, mice expressing a mutant form of fibrin(ogen) incapable of binding integrin αII b β3 (Fibγ(Δ5) ), and wild-type mice.

RESULTS

Elevated plasma thrombin-antithrombin and serotonin levels, hepatic fibrin deposition, and platelet accumulation in liver accompanied hepatocellular injury and fibrosis in ANIT-treated wild-type mice. PAR-4 deficiency reduced plasma serotonin levels, increased serum bile acid concentration, and exacerbated ANIT-induced hepatocellular injury and peribiliary fibrosis. Compared with PAR-4-deficient mice, ANIT-treated Fibγ(Δ5) mice displayed more widespread hepatocellular necrosis accompanied by marked inflammation, robust fibroblast activation, and extensive liver fibrosis.

CONCLUSIONS

Collectively, the results indicate that PAR-4 and fibrin-αII b β3 integrin engagement, pathways coupling coagulation to platelet activation, each exert hepatoprotective effects during chronic cholestasis.

Targeting hypoxia in the treatment of small cell lung cancer

Small cell lung cancer (SCLC) is an extremely aggressive disease for which minimal therapeutic improvements have been made over the last few decades. Patients still rely on non-targeted, chemotherapeutic drugs complemented by irradiation. Although initial response is very good, the majority of SCLC patients invariably relapse with therapy-resistant tumours. Despite the link between pathologically low oxygen levels and therapy resistant tumours, hypoxia has gained little attention in the development of novel therapies for SCLC. In contrast, the advantages of targeting hypoxic cells in many other cancer types have been studied extensively. This review describes the reasons for targeting hypoxia in SCLC and outlines strategies undertaken to enhance hypoxic tumour cell death, including the use of bioreductive prodrugs, the targeting of HIF-1α and the induction of cell death through acidosis. Therapy directed towards hypoxic tumour regions has the potential to greatly enhance the response of SCLC tumours to current treatment regimens and represents an area of research in need of greater attention. Such research could lead to the much sought after development of targeted drugs against SCLC tumours.

Biglycan deficiency: increased aortic aneurysm formation and lack of atheroprotection

Proteoglycans of the arterial wall play a critical role in vascular integrity and the development of atherosclerosis owing to their ability to organize extracellular matrix molecules and to bind and retain atherogenic apolipoprotein (apo)-B containing lipoproteins. Prior studies have suggested a role for biglycan in aneurysms and in atherosclerosis. Angiotensin II (angII) infusions into mice have been shown to induce abdominal aortic aneurysm development, increase vascular biglycan content, increase arterial retention of lipoproteins, and accelerate atherosclerosis. The goal of this study was to determine the role of biglycan in angII-induced vascular diseases. Biglycan-deficient or biglycan wildtype mice crossed to LDL receptor deficient (Ldlr-/-) mice (C57BL/6 background) were infused with angII (500 or 1000ng/kg/min) or saline for 28days while fed on normal chow, then pumps were removed, and mice were switched to an atherogenic Western diet for 6weeks. During angII infusions, biglycan-deficient mice developed abdominal aortic aneurysms, unusual descending thoracic aneurysms, and a striking mortality caused by aortic rupture (76% for males and 48% for females at angII 1000ng/kg/min). Histological analyses of non-aneurysmal aortic segments from biglycan-deficient mice revealed a deficiency of dense collagen fibers and the aneurysms demonstrated conspicuous elastin breaks. AngII infusion increased subsequent atherosclerotic lesion development in both biglycan-deficient and biglycan wildtype mice. However, the biglycan genotype did not affect the atherosclerotic lesion area induced by the Western diet after treatment with angII. Biglycan-deficient mice exhibited significantly increased vascular perlecan content compared to biglycan wildtype mice. Analyses of the atherosclerotic lesions demonstrated that vascular perlecan co-localized with apoB, suggesting that increased perlecan compensated for biglycan deficiency in terms of lipoprotein retention. Biglycan deficiency increases aortic aneurysm development and is not protective against the development of atherosclerosis. Biglycan deficiency leads to loosely packed aortic collagen fibers, increased susceptibility of aortic elastin fibers to angII-induced stress, and up-regulation of vascular perlecan content.

Relative sensitivity of Escherichia coli O157 detection from bovine feces and rectoanal mucosal swabs

The need to quantify the potential human health risk posed by the bovine reservoir of Escherichia coli O157 has led to a wealth of prevalence studies and improvements in detection methods over the last two decades. Rectoanal mucosal swabs have been used for the detection of E. coli O157 fecal shedding, colonized animals, and those predisposed to super shedding. We conducted a longitudinal study to compare the detection of E. coli O157 from feces and rectoanal mucosal swabs (RAMS) from a cohort of dairy heifers. We collected 820 samples that were tested by immunomagnetic separation of both feces and RAMS. Of these, 132 were detected as positive for E. coli O157 from both samples, 66 were detected as positive from RAMS only, and 117 were detected as positive from feces only. The difference in results between the two sample types was statistically significant (P < 0.001). The relative sensitivities of detection by immunomagnetic separation were 53% (confidence interval, 46.6 to 59.3) from RAMS and 67% (confidence interval, 59.6 to 73.1) from fecal samples. No association between long-term shedding (P = 0.685) or super shedding (P = 0.526) and detection by RAMS only was observed.

The meaning, measurement and modification of hypoxia in the laboratory and the clinic

Hypoxia was identified as a microenvironmental component of solid tumours over 60 years ago and was immediately recognised as a potential barrier to therapy through the reliance of radiotherapy on oxygen to elicit maximal cytotoxicity. Over the last two decades both clinical and experimental studies have markedly enhanced our understanding of how hypoxia influences cellular behaviour and therapy response. Furthermore, they have confirmed early assumptions that low oxygenation status in tumours is an exploitable target in cancer therapy. Generally such approaches will be more beneficial to patients with hypoxic tumours, necessitating the use of biomarkers that reflect oxygenation status. Tissue biomarkers have shown utility in many studies. Further significant advances have been made in the non-invasive measurement of tumour hypoxia with positron emission tomography, magnetic resonance imaging and other imaging modalities. Here, we describe the complexities of defining and measuring tumour hypoxia and highlight the therapeutic approaches to combat it.

SULF2 strongly prediposes to fasting and postprandial triglycerides in patients with obesity and type 2 diabetes mellitus

OBJECTIVE

Hepatic overexpression of sulfatase-2 (SULF2), a heparan sulfate remodeling enzyme, strongly contributes to high triglyceride (TG) levels in obese, type 2 diabetic (T2DM) db/db mice. Nevertheless, data in humans are lacking. Here, the association of human hepatic SULF2 expression and SULF2 gene variants with TG metabolism in patients with obesity and/or T2DM was investigated.

METHODS

Liver biopsies from 121 obese subjects were analyzed for relations between hepatic SULF2 mRNA levels and plasma TG. Associations between seven SULF2 tagSNPs and TG levels were assessed in 210 obese T2DM subjects with dyslipidemia. Replication of positive findings was performed in 1,316 independent obese T2DM patients. Postprandial TRL clearance was evaluated in 29 obese T2DM subjects stratified by SULF2 genotype.

RESULTS

Liver SULF2 expression was significantly associated with fasting plasma TG (r = 0.271; P = 0.003) in obese subjects. The SULF2 rs2281279(A>G) SNP was reproducibly associated with lower fasting plasma TG levels in obese T2DM subjects (P < 0.05). Carriership of the minor G allele was associated with lower levels of postprandial plasma TG (P < 0.05) and retinyl esters levels (P < 0.001).

CONCLUSIONS

These findings implicate SULF2 as potential therapeutic target in the atherogenic dyslipidemia of obesity and T2DM.

Abstract 413: Metabolic Channeling from the Insulin Receptor to a Novel Class II Phosphatidylinositol 3’-Kinase and Then to the Threonine-308 Site on AKT Drives Overactive de Novo Lipogenesis in the Obese Liver

Patients with the atherometabolic syndrome develop fatty liver and dysglycemia. Both arise from pathway- se lective i nsulin r esistance and r esponsiveness (SEIRR): insulin still drives hepatic de-novo lipogenesis, but controls glucose poorly. We reported that injection of insulin into obese db/db mice fails to inactivate hepatic PTEN, a crucial action of NOX4. Insulin-stimulated db/db livers produce an unusual monophosphorylated form of AKT at Thr308 (pT308-AKT) with only weak phosphorylation at Ser473. Importantly, pT308-AKT activates downstream lipogenic pathways, but fails to phosphorylate FOXO1 or regulate glucose handling. All of these features are recapitulated in cultured hepatocytes by disrupting NOX4.

Any signal from insulin to AKT in the presence of active PTEN is a surprise. Canonically, insulin activates class I PI3 kinases to generate PtdIns(3,4,5)P 3 . This lipid binds pleckstrin homology (PH) domains in AKT and in the two enzymes that phosphorylate AKT (PDPK1 at Thr308 and mTORC2 at Ser473). Persistent PTEN consumes PtdIns(3,4,5)P 3 , blocking this pathway.

To explain insulin-stimulated generation of pT308-AKT, we hypothesized a role for the liver-specific class II PI3K, PI3K-C2γ. Insulin stimulates PI3K-C2γ to generate PtdIns(3,4)P 2 , a lipid that binds PH domains but is a poor substrate for destruction by PTEN. Knock-down of PI3K-C2γ in NOX4-deficient hepatocytes blocked insulin-stimulated formation of pT308-AKT and activation of downstream lipogenic targets.

Here, we explored why PI3K-C2γ activates phosphorylation of AKT at Thr308 over Ser473, even though PDPK1 and mTORC2 both have PH domains. Co-immunoprecipitations revealed a striking difference: PI3K-C2γ robustly associates with PDPK1, but not with SIN1, the component of mTORC2 that contains the PH domain.

Our results demonstrate a parallel, noncanonical signaling pathway in hepatocytes, in which the insulin receptor activates PI3K-C2γ, to generate PtdIns(3,4)P 2 . Because PI3K-C2γ closely associates with PDPK1, not mTORC2, it selectively triggers AKT phosphorylation at Thr308, not Ser473. The result is SEIRR: continued stimulation of hepatic lipogenesis, but a failure of glucose control. This is the clinical picture of the atherometabolic syndrome.