Fund Black scientists.

Our nationwide network of BME women faculty collectively argue that racial funding disparity by the National Institutes of Health (NIH) remains the most insidious barrier to success of Black faculty in our profession. We thus refocus attention on this critical barrier and suggest solutions on how it can be dismantled.

Widespread monoclonal IgE antibody convergence to an immunodominant, proanaphylactic Ara h 2 epitope in peanut allergy.

BACKGROUND: Despite their central role in peanut allergy, human monoclonal IgE antibodies have eluded characterization. OBJECTIVE: We sought to define the sequences, affinities, clonality, and functional properties of human monoclonal IgE antibodies in peanut allergy. METHODS: We applied our single-cell RNA sequencing-based SEQ SIFTER discovery platform to samples from allergic individuals who varied by age, sex, ethnicity, and geographic location in order to understand commonalities in the human IgE response to peanut allergens. Select antibodies were then recombinantly expressed and characterized for their allergen and epitope specificity, affinity, and functional properties. RESULTS: We found striking convergent evolution of IgE monoclonal antibodies (mAbs) from several clonal families comprising both memory B cells and plasmablasts. These antibodies bound with subnanomolar affinity to the immunodominant peanut allergen Ara h 2, specifically a linear, repetitive motif. Further characterization of these mAbs revealed their ability to single-handedly cause affinity-dependent degranulation of human mast cells and systemic anaphylaxis on peanut allergen challenge in humanized mice. Finally, we demonstrated that these mAbs, reengineered as IgGs, inhibit significant, but variable, amounts of Ara h 2- and peanut-mediated degranulation of mast cells sensitized with allergic plasma. CONCLUSIONS: Convergent evolution of IgE mAbs in peanut allergy is a common phenomenon that can reveal immunodominant epitopes on major allergenic proteins. Understanding the functional properties of these molecules is key to developing therapeutics, such as competitive IgG inhibitors, that are able to stoichiometrically outcompete endogenous IgE for allergen and thereby prevent allergic cascade in cases of accidental allergen exposure.

Genetic Architecture of Acute Myocarditis and the Overlap With Inherited Cardiomyopathy.

BACKGROUND: Acute myocarditis is an inflammatory condition that may herald the onset of dilated cardiomyopathy (DCM) or arrhythmogenic cardiomyopathy (ACM). We investigated the frequency and clinical consequences of DCM and ACM genetic variants in a population-based cohort of patients with acute myocarditis. METHODS: This was a population-based cohort of 336 consecutive patients with acute myocarditis enrolled in London and Maastricht. All participants underwent targeted DNA sequencing for well-characterized cardiomyopathy-associated genes with comparison to healthy controls (n=1053) sequenced on the same platform. Case ascertainment in England was assessed against national hospital admission data. The primary outcome was all-cause mortality. RESULTS: Variants that would be considered pathogenic if found in a patient with DCM or ACM were identified in 8% of myocarditis cases compared with <1% of healthy controls (P=0.0097). In the London cohort (n=230; median age, 33 years; 84% men), patients were representative of national myocarditis admissions (median age, 32 years; 71% men; 66% case ascertainment), and there was enrichment of rare truncating variants (tv) in ACM-associated genes (3.1% of cases versus 0.4% of controls; odds ratio, 8.2; P=0.001). This was driven predominantly by DSP-tv in patients with normal LV ejection fraction and ventricular arrhythmia. In Maastricht (n=106; median age, 54 years; 61% men), there was enrichment of rare truncating variants in DCM-associated genes, particularly TTN-tv, found in 7% (all with left ventricular ejection fraction <50%) compared with 1% in controls (odds ratio, 3.6; P=0.0116). Across both cohorts over a median of 5.0 years (interquartile range, 3.9-7.8 years), all-cause mortality was 5.4%. Two-thirds of deaths were cardiovascular, attributable to worsening heart failure (92%) or sudden cardiac death (8%). The 5-year mortality risk was 3.3% in genotype-negative patients versus 11.1% for genotype-positive patients (Padjusted=0.08). CONCLUSIONS: We identified DCM- or ACM-associated genetic variants in 8% of patients with acute myocarditis. This was dominated by the identification of DSP-tv in those with normal left ventricular ejection fraction and TTN-tv in those with reduced left ventricular ejection fraction. Despite differences between cohorts, these variants have clinical implications for treatment, risk stratification, and family screening. Genetic counseling and testing should be considered in patients with acute myocarditis to help reassure the majority while improving the management of those with an underlying genetic variant.

Strengths and weaknesses of alternative noninvasive imaging approaches for microvascular ischemia.

Structural and functional abnormalities of coronary microvasculature are highly prevalent in several clinical settings and often associated with worse clinical outcomes. Therefore, there is a growing interest in the detection and treatment of this, often overlooked, disease. Coronary angiography allows the assessment of the Coronary flow reserve (CFR) and the index of microcirculatory resistance (IMR). However, the measurement of these parameters is not always feasible because of limited technical availability and the need for a cardiac catheterization with a small but real risk of potential complications. Recent advances in non-invasive imaging techniques allow the assessment of coronary microvascular function with good accuracy and reproducibility. The objective of this review is to discuss the strengths and weaknesses of alternative non-invasive approaches used in the diagnosis of coronary microvascular dysfunction (CMD), highlighting the most recent advances for each imaging modality.

A long noncoding RNA, LncMyoD, modulates chromatin accessibility to regulate muscle stem cell myogenic lineage progression.

Epigenetics regulation plays a critical role in determining cell identity by controlling the accessibility of lineage-specific regulatory regions. In muscle stem cells, epigenetic mechanisms of how chromatin accessibility is modulated during cell fate determination are not fully understood. Here, we identified a long noncoding RNA, LncMyoD, that functions as a chromatin modulator for myogenic lineage determination and progression. The depletion of LncMyoD in muscle stem cells led to the down-regulation of myogenic genes and defects in myogenic differentiation. LncMyoD exclusively binds with MyoD and not with other myogenic regulatory factors and promotes transactivation of target genes. The mechanistic study revealed that loss of LncMyoD prevents the establishment of a permissive chromatin environment at myogenic E-box-containing regions, therefore restricting the binding of MyoD. Furthermore, the depletion of LncMyoD strongly impairs the reprogramming of fibroblasts into the myogenic lineage. Taken together, our study shows that LncMyoD associates with MyoD and promotes myogenic gene expression through modulating MyoD accessibility to chromatin, thereby regulating myogenic lineage determination and progression.

Magnetic Resonance Perfusion or Fractional Flow Reserve in Coronary Disease.

BACKGROUND: In patients with stable angina, two strategies are often used to guide revascularization: one involves myocardial-perfusion cardiovascular magnetic resonance imaging (MRI), and the other involves invasive angiography and measurement of fractional flow reserve (FFR). Whether a cardiovascular MRI-based strategy is noninferior to an FFR-based strategy with respect to major adverse cardiac events has not been established. METHODS: We performed an unblinded, multicenter, clinical-effectiveness trial by randomly assigning 918 patients with typical angina and either two or more cardiovascular risk factors or a positive exercise treadmill test to a cardiovascular MRI-based strategy or an FFR-based strategy. Revascularization was recommended for patients in the cardiovascular-MRI group with ischemia in at least 6% of the myocardium or in the FFR group with an FFR of 0.8 or less. The composite primary outcome was death, nonfatal myocardial infarction, or target-vessel revascularization within 1 year. The noninferiority margin was a risk difference of 6 percentage points. RESULTS: A total of 184 of 454 patients (40.5%) in the cardiovascular-MRI group and 213 of 464 patients (45.9%) in the FFR group met criteria to recommend revascularization (P = 0.11). Fewer patients in the cardiovascular-MRI group than in the FFR group underwent index revascularization (162 [35.7%] vs. 209 [45.0%], P = 0.005). The primary outcome occurred in 15 of 421 patients (3.6%) in the cardiovascular-MRI group and 16 of 430 patients (3.7%) in the FFR group (risk difference, -0.2 percentage points; 95% confidence interval, -2.7 to 2.4), findings that met the noninferiority threshold. The percentage of patients free from angina at 12 months did not differ significantly between the two groups (49.2% in the cardiovascular-MRI group and 43.8% in the FFR group, P = 0.21). CONCLUSIONS: Among patients with stable angina and risk factors for coronary artery disease, myocardial-perfusion cardiovascular MRI was associated with a lower incidence of coronary revascularization than FFR and was noninferior to FFR with respect to major adverse cardiac events. (Funded by the Guy's and St. Thomas' Biomedical Research Centre of the National Institute for Health Research and others; MR-INFORM ClinicalTrials.gov number, NCT01236807.).

Mechanisms of aortic carboxypeptidase-like protein secretion and identification of an intracellularly retained variant associated with Ehlers-Danlos syndrome.

Aortic carboxypeptidase-like protein (ACLP) is a collagen-binding extracellular matrix protein that has important roles in wound healing and fibrosis. ACLP contains thrombospondin repeats, a collagen-binding discoidin domain, and a catalytically inactive metallocarboxypeptidase domain. Recently, mutations in the ACLP-encoding gene, AE-binding protein 1 (AEBP1), have been discovered, leading to the identification of a new variant of Ehlers-Danlos syndrome causing connective tissue disruptions in multiple organs. Currently, little is known about the mechanisms of ACLP secretion or the role of post-translational modifications in these processes. We show here that the secreted form of ACLP contains N-linked glycosylation and that inhibition of glycosylation results in its intracellular retention. Using site-directed mutagenesis, we determined that glycosylation of Asn-471 and Asn-1030 is necessary for ACLP secretion and identified a specific N-terminal proteolytic ACLP fragment. To determine the contribution of secreted ACLP to extracellular matrix mechanical properties, we generated and mechanically tested wet-spun collagen ACLP composite fibers, finding that ACLP enhances the modulus (or stiffness), toughness, and tensile strength of the fibers. Some AEBP1 mutations were null alleles, whereas others resulted in expressed proteins. We tested the hypothesis that a recently discovered 40-amino acid mutation and insertion in the ACLP discoidin domain regulates collagen binding and assembly. Interestingly, we found that this protein variant is retained intracellularly and induces endoplasmic reticulum stress identified with an XBP1-based endoplasmic reticulum stress reporter. Our findings highlight the importance of N-linked glycosylation of ACLP for its secretion and contribute to our understanding of ACLP-dependent disease pathologies.

On Force and Form: Mechano-Biochemical Regulation of Extracellular Matrix.

The extracellular matrix is well-known for its structural role in supporting cells and tissues, and its important biochemical role in providing signals to cells has increasingly become apparent. These structural and biochemical roles are closely coupled through mechanical forces: the biochemistry of the extracellular matrix determines its mechanical properties, mechanical forces control release or display of biochemical signals from the extracellular matrix, and the mechanical properties of the matrix in turn influence the mechanical set point at which signals are sent. In this Perspective, we explain how the extracellular matrix is regulated by strain and mechanical forces. We show the impact of biochemistry and mechanical forces on in vivo assembly of extracellular matrix and illustrate how matrix can be generated in vitro using a variety of methods. We cover how the matrix can be characterized in terms of mechanics, composition, and conformation to determine its properties and to predict interactions. Finally, we explore how extracellular matrix remodeling, ligand binding, and hemostasis are regulated by mechanical forces. These recently discovered mechano-biochemical interactions have important functions in wound healing and disease progression. It is likely that mechanically altered extracellular matrix interactions are a commonly recurring theme, but due to limited tools to generate extracellular matrix fibers in vitro and lack of high-throughput methods to detect these interactions, it is hypothesized that many of these interactions have yet to be discovered.

Development of a bio-MEMS device for electrical and mechanical conditioning and characterization of cell sheets for myocardial repair.

Here we propose a bio-MEMS device designed to evaluate contractile force and conduction velocity of cell sheets in response to mechanical and electrical stimulation of the cell source as it grows to form a cellular sheet. Moreover, the design allows for the incorporation of patient-specific data and cell sources. An optimized device would allow cell sheets to be cultured, characterized, and conditioned to be compatible with a specific patient's cardiac environment in vitro, before implantation. This design draws upon existing methods in the literature but makes an important advance by combining the mechanical and electrical stimulation into a single system for optimized cell sheet growth. The device has been designed to achieve cellular alignment, electrical stimulation, mechanical stimulation, conduction velocity readout, contraction force readout, and eventually cell sheet release. The platform is a set of comb electrical contacts consisting of three-dimensional walls made of polydimethylsiloxane and coated with electrically conductive metals on the tops of the walls. Not only do the walls serve as a method for stimulating cells that are attached to the top, but their geometry is tailored such that they are flexible enough to be bent by the cells and used to measure force. The platform can be stretched via a linear actuator setup, allowing for simultaneous electrical and mechanical stimulation that can be derived from patient-specific clinical data.

Effect of Polymer Surface Modification of Superparamagnetic Iron Oxide Nanoparticle Dispersions in High Salinity Environments.

Superparamagnetic nanoparticles (SPIONs) can be used as nuclear magnetic resonance (NMR) signal enhancement agents for petroleum exploration. This enhancement effect is uniform if SPIONs are monodisperse in size and in composition; yet it is challenging to synthesize monodisperse particles that do not aggregate in high salinity petroleum brine. Here, we report a method to synthesize individual SPIONs coated with tunable surface coating densities of poly(2-acrylamido-2-methyl-1-propanesulfonic acid (pAMPS) with a catechol end-group (pAMPS*). To establish parameters under which pAMPS*-coated SPIONS do not aggregate, we compared computational predictions with experimental results for variations in pAMPS* chain length and surface coverage. Using this combined theoretical and experimental approach, we show that singly dispersed SPIONs remained stabilized in petroleum brine for up to 75 h with high surface density pAMPS*.

Fibrin-Targeted Polymerized Shell Microbubbles as Potential Theranostic Agents for Surgical Adhesions.

The development of new therapies for surgical adhesions has proven to be difficult as there is no consistently effective way to assess treatment efficacy in clinical trials without performing a second surgery, which can result in additional adhesions. We have developed lipid microbubble formulations that use a short peptide sequence, CREKA, to target fibrin, the molecule that forms nascent adhesions. These targeted polymerized shell microbubbles (PSMs) are designed to allow ultrasound imaging of early adhesions for diagnostic purposes and for evaluating the success of potential treatments in clinical trials while acting as a possible treatment. In this study, we show that CREKA-targeted microbubbles preferentially bind fibrin over fibrinogen and are stable for long periods of time (∼48 h), that these bound microbubbles can be visualized by ultrasound, and that neither these lipid-based bubbles nor their diagnostic-ultrasound-induced vibrations damage mesothelial cells in vitro. Moreover, these bubbles show the potential to identify adhesionlike fibrin formations and may hold promise in blocking or breaking up fibrin formations in vivo.

Structure and stabilization of the Hendra virus F glycoprotein in its prefusion form.

Hendra virus (HeV) is one of the two prototypical members of the Henipavirus genus of paramyxoviruses, which are designated biosafety level 4 (BSL-4) organisms due to the high mortality rate of Nipah virus (NiV) and HeV in humans. Paramyxovirus cell entry is mediated by the fusion protein, F, in response to binding of a host receptor by the attachment protein. During posttranslational processing, the fusion peptide of F is released and, upon receptor-induced triggering, inserts into the host cell membrane. As F undergoes a dramatic refolding from its prefusion to postfusion conformation, the fusion peptide brings the host and viral membranes together, allowing entry of the viral RNA. Here, we present the crystal structure of the prefusion form of the HeV F ectodomain. The structure shows very high similarity to the structure of prefusion parainfluenza virus 5 (PIV5) F, with the main structural differences in the membrane distal apical loops and the fusion peptide cleavage loop. Functional assays of mutants show that the apical loop can tolerate perturbation in length and surface residues without loss of function, except for residues involved in the stability and conservation of the F protein fold. Structure-based disulfide mutants were designed to anchor the fusion peptide to conformationally invariant residues of the F head. Two mutants were identified that inhibit F-mediated fusion by stabilizing F in its prefusion conformation.

Vascular smooth muscle cell durotaxis depends on extracellular matrix composition.

Mechanical compliance has been demonstrated to be a key determinant of cell behavior, directing processes such as spreading, migration, and differentiation. Durotaxis, directional migration from softer to more stiff regions of a substrate, has been observed for a variety of cell types. Recent stiffness mapping experiments have shown that local changes in tissue stiffness in disease are often accompanied by an altered ECM composition in vivo. However, the importance of ECM composition in durotaxis has not yet been explored. To address this question, we have developed and characterized a polyacrylamide hydrogel culture platform featuring highly tunable gradients in mechanical stiffness. This feature, together with the ability to control ECM composition, allows us to isolate the effects of mechanical and biological signals on cell migratory behavior. Using this system, we have tracked vascular smooth muscle cell migration in vitro and quantitatively analyzed differences in cell migration as a function of ECM composition. Our results show that vascular smooth muscle cells undergo durotaxis on mechanical gradients coated with fibronectin but not on those coated with laminin. These findings indicate that the composition of the adhesion ligand is a critical determinant of a cell's migratory response to mechanical gradients.

Design Approaches to Myocardial and Vascular Tissue Engineering.

Engineered tissues represent an increasingly promising therapeutic approach for correcting structural defects and promoting tissue regeneration in cardiovascular diseases. One of the challenges associated with this approach has been the necessity for the replacement tissue to promote sufficient vascularization to maintain functionality after implantation. This review highlights a number of promising prevascularization design approaches for introducing vasculature into engineered tissues. Although we focus on encouraging blood vessel formation within myocardial implants, we also discuss techniques developed for other tissues that could eventually become relevant to engineered cardiac tissues. Because the ultimate solution to engineered tissue vascularization will require collaboration between wide-ranging disciplines such as developmental biology, tissue engineering, and computational modeling, we explore contributions from each field.

Synergistic Integration of Experimental and Simulation Approaches for the de Novo Design of Silk-Based Materials.

Tailored biomaterials with tunable functional properties are crucial for a variety of task-specific applications ranging from healthcare to sustainable, novel bio-nanodevices. To generate polymeric materials with predictive functional outcomes, exploiting designs from nature while morphing them toward non-natural systems offers an important strategy. Silks are Nature's building blocks and are produced by arthropods for a variety of uses that are essential for their survival. Due to the genetic control of encoded protein sequence, mechanical properties, biocompatibility, and biodegradability, silk proteins have been selected as prototype models to emulate for the tunable designs of biomaterial systems. The bottom up strategy of material design opens important opportunities to create predictive functional outcomes, following the exquisite polymeric templates inspired by silks. Recombinant DNA technology provides a systematic approach to recapitulate, vary, and evaluate the core structure peptide motifs in silks and then biosynthesize silk-based polymers by design. Post-biosynthesis processing allows for another dimension of material design by controlled or assisted assembly. Multiscale modeling, from the theoretical prospective, provides strategies to explore interactions at different length scales, leading to selective material properties. Synergy among experimental and modeling approaches can provide new and more rapid insights into the most appropriate structure-function relationships to pursue while also furthering our understanding in terms of the range of silk-based systems that can be generated. This approach utilizes nature as a blueprint for initial polymer designs with useful functions (e.g., silk fibers) but also employs modeling-guided experiments to expand the initial polymer designs into new domains of functional materials that do not exist in nature. The overall path to these new functional outcomes is greatly accelerated via the integration of modeling with experiment. In this Account, we summarize recent advances in understanding and functionalization of silk-based protein systems, with a focus on the integration of simulation and experiment for biopolymer design. Spider silk was selected as an exemplary protein to address the fundamental challenges in polymer designs, including specific insights into the role of molecular weight, hydrophobic/hydrophilic partitioning, and shear stress for silk fiber formation. To expand current silk designs toward biointerfaces and stimuli responsive materials, peptide modules from other natural proteins were added to silk designs to introduce new functions, exploiting the modular nature of silk proteins and fibrous proteins in general. The integrated approaches explored suggest that protein folding, silk volume fraction, and protein amino acid sequence changes (e.g., mutations) are critical factors for functional biomaterial designs. In summary, the integrated modeling-experimental approach described in this Account suggests a more rationally directed and more rapid method for the design of polymeric materials. It is expected that this combined use of experimental and computational approaches has a broad applicability not only for silk-based systems, but also for other polymer and composite materials.

A feasibility and safety study of intracoronary hemodilution during primary coronary angioplasty in order to reduce reperfusion injury in myocardial infarction.

OBJECTIVES: We designed a pilot study to evaluate safety and feasibility of an inexpensive and simple approach to intracoronary hemodilution during primary angioplasty (PPCI) to reduce reperfusion injury. INTRODUCTION: Early revascularization in acute myocardial infarction decreases infarct size and improves outcomes. However, abrupt restoration of coronary flow results in myocardial reperfusion injury and increased final infarct size. Dilution of coronary blood during revascularization may help reduce this damage. If proved effective, such an approach would need to be simple and suitable for widespread adoption. METHODS: Ten patients presenting with STEMI underwent intracoronary dilution with room temperature Hartmann's solution delivered through the guiding catheter during primary angioplasty (PPCI). Infusion of perfusate began prior to crossing the occluded artery with the guidewire, continuing until 10 min after completion of the balloon and stenting procedure. Infusion was briefly interrupted for contrast injection and pressure monitoring. The outcome measures were safety, including intracoronary temperature reduction and volume of intracoronary perfusate infused, and technical feasibility. RESULTS: There were no significant symptomatic, hemodynamic, ECG ST/T segment or rhythm changes observed during perfusate administration. The median (interquartile range) volume of perfusate administered was 550 mL (350-725 mL) and the median intracoronary temperature reduction observed was 3.4°Celsius. Myocardial salvage was 0.54 (0.43-0.65). CONCLUSIONS: Transcatheter intracoronary hemodilution with room temperature perfusate during PPCI is feasible and appears safe. Such a strategy is simple and inexpensive, with potential to be widely applied. Further mechanistic and subsequent outcome powered studies are required to evaluate whether this strategy can reduce reperfusion injury in STEMI.

Extracellular matrix type modulates cell migration on mechanical gradients.

Extracellular matrix composition and stiffness are known to be critical determinants of cell behavior, modulating processes including differentiation, traction generation, and migration. Recent studies have demonstrated that the ECM composition can modulate how cells migrate in response to gradients in environmental stiffness, altering a cell's ability to undergo durotaxis. These observations were limited to single varieties of extracellular matrix, but typically cells are exposed to environments containing complex mixtures of extracellular matrix proteins. Here, we investigate migration of NIH 3T3 fibroblasts on mechanical gradients coated with one or more type of extracellular matrix protein. Our results show that NIH 3T3 fibroblasts exhibit durotaxis on fibronectin-coated mechanical gradients but not on those coated with laminin, demonstrating that extracellular matrix type can act as a regulator of cell response to mechanical gradients. Interestingly, NIH 3T3 fibroblasts were also observed to migrate randomly on gradients coated with a mixture of both fibronectin and laminin, suggesting that there may be a complex interplay in the cellular response to mechanical gradients in the presence of multiple extracellular matrix signals. These findings indicate that specific composition of available adhesion ligands is a critical determinant of a cell's migratory response to mechanical gradients.

Minimally invasive surgical approaches offer earlier time to adjuvant chemotherapy but not improved survival in resected pancreatic cancer.

BACKGROUND: Pancreatic surgery encompasses complex operations with significant potential morbidity. Greater experience in minimally invasive surgery (MIS) has allowed resections to be performed laparoscopically and robotically. This study evaluates the impact of surgical approach in resected pancreatic cancer. METHODS: The National Cancer Data Base (2010-2012) was reviewed for patients with stages 1-3 resected pancreatic carcinoma. Open approaches were compared to MIS. A sub-analysis was then performed comparing robotic and laparoscopic approaches. RESULTS: Of the 9047 patients evaluated, surgical approach was open in 7511 (83%), laparoscopic in 992 (11%), and robotic in 131 (1%). The laparoscopic and robotic conversion rate to open was 28% (n = 387) and 17% (n = 26), respectively. Compared to open, MIS was associated with more distal resections (13.5, 24.3%, respectively, p < 0.0001), shorter hospital length of stay (LOS) (11.3, 9.5 days, respectively, p < 0.0001), more margin-negative resections (75, 79%, p = 0.038), and quicker time to initiation of chemotherapy (TTC) (59.1, 56.3 days, respectively, p = 0.0316). There was no difference in number of lymph nodes obtained based on surgical approach (p = 0.5385). When stratified by type of resection (head, distal, or total), MIS offered significantly shorter LOS in all types. Multivariate analysis demonstrated no survival benefit for any MIS approach relative to open (all, p > 0.05). When adjusted for patient, disease, and treatment characteristics, TTC was not an independent prognostic factor (HR 1.09, p = 0.084). CONCLUSION: MIS appears to offer comparable surgical oncologic benefit with improved LOS and shorter TTC. This effect, however, was not associated with improved survival.

Greater lymph node retrieval and lymph node ratio impacts survival in resected pancreatic cancer.

BACKGROUND: Surgical resection is the mainstay of pancreatic cancer treatment; however, the ideal lymphadenectomy remains unsettled. This study sought to determine whether number of examined lymph nodes (eLNs) and lymph node ratio (LNR) impact survival. METHODS: The U.S. National Cancer Data Base (2003-2011) was reviewed for patients who underwent initial resection for clinical stage I and II pancreatic adenocarcinoma. Univariate and multivariate survival analyses were performed. RESULTS: Of 14,007 patients, 15.6% had 0-6 eLN, 27.1% 7-12, 13.4% 13-15, and 38.6% > 15 eLN. Median eLN was 11 for pancreaticoduodenectomy, and 14 for distal, total pancreatectomy, or other procedure. ELN >15 was associated with significantly improved survival in both node negative and positive disease (P < 0.001, both). In multivariable analysis, 7-12, 13-15, and >15 eLN had improved survival relative to 0-6 eLN (HR 0.87, P < 0.001, HR 0.89, P = 0.002, HR 0.82, P < 0.001, respectively). A total of 34.5% of patients had an LNR of 0, 31.5% ≤ 0.2, 20.3% 0.2-0.4, 11.7% 0.4-0.8, and 2.0% had an LNR >0.8. Patients with LNR 0 had improved survival in T1-T3 disease (P < 0.01). In multivariable analysis, higher LNR was negatively associated with survival (LNR 0-0.2: HR 1.44, P < 0.001, LNR 0.2-0.4: HR 1.82, P < 0.001, LNR 0.4-0.8: 2.03, P < 0.001, LNR >0.8, P < 0.001). Even with suboptimal eLN (eLN ≤6 or ≤12), higher LNR remained an independent predictor of mortality. CONCLUSIONS: Greater lymph node retrieval in stage I & II pancreatic adenocarcinoma may have prognostic value, even in node-negative disease. Lymph node ratio is inversely related to survival and may be useful with suboptimal eLN.

Impact of chromogranin A, differentiation, and mitoses in nonfunctional pancreatic neuroendocrine tumors ≤ 2 cm.

BACKGROUND: Small pancreatic neuroendocrine tumors (PNETs) are a unique subset of pancreatic neoplasms. Chromogranin A (CgA) levels, mitotic rate, and histologic differentiation are often used to characterize PNET behavior. This study evaluates the impact of these factors on survival in patients with PNETs. METHODS: The US National Cancer Data Base (1998-2012) was reviewed for patients with stages I-III, nonfunctional PNETs ≤2 cm. Clinicopathologic characteristics were collected, and univariate and multivariate survival analyses were performed. RESULTS: Of 1159 patients, 872 had tumor differentiation recorded, 403 had mitotic rate, and 217 patients had CgA. Mitotic rate >20 mitoses per 10 high-power microscopic fields was significantly associated with survival (hazard ratio [HR] = 10.6, P = 0.002) in multivariate analysis. Of those who underwent resection, there was no significant difference in positive lymph nodes between high (>100 ng/mL) and low (≤100 ng/mL) CgA levels (0.27 versus 0.37, P = 0.4440). Multivariate analyses of patients with both grade and CgA recorded found poorly differentiated tumors and very high CgA (>400 ng/mL) negatively impacted survival (HR = 2.99, P < 0.0001, HR = 3.47, P < 0.0001, respectively). Propensity score matching demonstrated improved 5-y survival in patients who underwent surgical resection, P < 0.0001. CONCLUSIONS: Poorly differentiated disease should be considered an indicator of worse prognosis in nonfunctional PNETs ≤2 cm. Surgical resection appears to improve survival in these patients.