Painful Diabetic Neuropathy: The Need for New Approaches

Painful diabetic neuropathy is a common vexing problem for people with diabetes and a costly problem for society. The pathophysiology is not well understood, and no safe and effective mechanistically-based treatment has been identified. Poor glycemic control is a risk factor for painful diabetic neuropathy. Excessive intraneuronal glucose in people with diabetes can be shunted away from physiological glycolysis into multiple pathological pathways associated with neuropathy and pain. The first three treatments that are traditionally offered consist of risk factor reduction, lifestyle modifications, and pharmacological therapy, which includes only three drugs that are approved for this indication by the United States Food and Drug Administration. All of these traditional treatments are often inadequate for relieving neuropathic pain, and thus, new approaches are needed. Modern devices based on neuromodulation technology, which act directly on the nervous system, have been recently cleared by the United States Food and Drug Administration for painful diabetic neuropathy and offer promise as next-in-line therapy when traditional therapies fail.

Spinal Cord Stimulation for Painful Diabetic Neuropathy

Spinal cord stimulation (SCS) technology has been recently approved by the US Food and Drug Administration (FDA) for painful diabetic neuropathy (PDN). The treatment involves surgical implantation of electrodes and a power source that delivers electrical current to the spinal cord. This treatment decreases the perception of pain in many chronic pain conditions, such as PDN. The number of patients with PDN treated with SCS and the amount of data describing their outcomes is expected to increase given four factors: (1) the large number of patients with this diagnosis, (2) the poor results that have been obtained for pain relief with pharmacotherapy and noninvasive non-pharmacotherapy, (3) the results to date with investigational SCS technology, and (4) the recent FDA approval of systems that deliver this treatment. Whereas traditional SCS replaces pain with paresthesias, a new form of SCS, called high-frequency 10-kHz SCS, first used for pain in 2015, can relieve PDN pain without causing paresthesias, although not all patients experience pain relief by SCS. This article describes (1) an overview of SCS technology, (2) the use of SCS for diseases other than diabetes, (3) the use of SCS for PDN, (4) a comparison of high-frequency 10-kHz and traditional SCS for PDN, (5) other SCS technology for PDN, (6) deployment of SCS systems, (7) barriers to the use of SCS for PDN, (8) risks of SCS technology, (9) current recommendations for using SCS for PDN, and (10) future developments in SCS.

Retained Diabetes Devices-A Literature Review

BACKGROUND

Diabetes management and treatment requires the use of many devices that frequently must puncture the skin, creating a risk of unintentional retention in the body as a retained diabetes device. In this article, we reviewed case studies about retained diabetes devices and presented analyses of the success rate of current imaging techniques in identifying retained devices and the success rate of device removal.

METHODS

PubMed and Google Scholar were searched for articles about retained diabetes devices. Relevant articles that included sufficient details about discovery and removal of the device were included. The success rate of identification and the success rate of removal of retained devices were both calculated as percentages.

RESULTS

Sixteen case studies of retained diabetes devices were identified. These devices included parts of continuous glucose monitors and infusion sets, a lancet, and various types of needles for insulin injection. Each case is presented with details about the year of publication, the retained diabetes device, the company that produced the device, the age and gender of the patient, the type of diabetes that the patient had, the location of the device, the reason for initial discovery of the retained device, the process of locating the device, the success rate for removal of the device, and the removal procedure of the device. Analysis revealed a 100% success rate for the use of imaging technology including X-rays and computed tomography to identify a retained diabetes device. The patients with retained diabetes devices had a 62.5% success rate for eventual removal of the device.

CONCLUSIONS

With the increasing use of injected, inserted, and implanted diabetes wearables for digital health, it is likely that some of the devices will detach, break apart, or otherwise become retained in the body. It is important to be aware of available technologies to identify retained diabetes devices so that it will be possible in most cases to surgically remove these devices if they detach or become retained.

Use of Continuous Glucose Monitors by People Without Diabetes: An Idea Whose Time Has Come?

BACKGROUND

Continuous glucose monitor (CGM) systems were originally intended only for people with diabetes. Recently, there has been interest in monitoring glucose concentrations in a variety of other situations. As data accumulate to support the use of CGM systems in additional states unrelated to diabetes, the use of CGM systems is likely to increase accordingly.

METHODS

PubMed and Google Scholar were searched for articles about the use of CGM in individuals without diabetes. Relevant articles that included sufficient details were queried to identify what cohorts of individuals were adopting CGM use and to define trends of use.

RESULTS

Four clinical user cases were identified: (1) metabolic diseases related to diabetes with a primary dysregulation of the insulin-glucose axis, (2) metabolic diseases without a primary pathophysiologic derangement of the insulin-glucose axis, (3) health and wellness, and (4) elite athletics. Seven trends in the use of CGM systems in people without diabetes were idenfitied which pertained to both FDA-cleared medical grade products as well as anticipated future products, which may be regulated differently based on intended populations and indications for use.

CONCLUSIONS

Wearing a CGM has been used not only for diabetes, but with a goal of improving glucose patterns to avoid diabetes, improving mental or physical performance, and promoting motivate healthy behavioral changes. We expect that clinicians will become increasingly aware of (1) glycemic patterns from CGM tracings that predict an increased risk of diabetes, (2) specific metabolic glucotypes from CGM tracings that predict an increased risk of diabetes, and (3) new genetic and genomic biomarkers in the future.

A Glycemia Risk Index (GRI) of Hypoglycemia and Hyperglycemia for Continuous Glucose Monitoring Validated by Clinician Ratings

BACKGROUND

A composite metric for the quality of glycemia from continuous glucose monitor (CGM) tracings could be useful for assisting with basic clinical interpretation of CGM data.

METHODS

We assembled a data set of 14-day CGM tracings from 225 insulin-treated adults with diabetes. Using a balanced incomplete block design, 330 clinicians who were highly experienced with CGM analysis and interpretation ranked the CGM tracings from best to worst quality of glycemia. We used principal component analysis and multiple regressions to develop a model to predict the clinician ranking based on seven standard metrics in an Ambulatory Glucose Profile: very low-glucose and low-glucose hypoglycemia; very high-glucose and high-glucose hyperglycemia; time in range; mean glucose; and coefficient of variation.

RESULTS

The analysis showed that clinician rankings depend on two components, one related to hypoglycemia that gives more weight to very low-glucose than to low-glucose and the other related to hyperglycemia that likewise gives greater weight to very high-glucose than to high-glucose. These two components should be calculated and displayed separately, but they can also be combined into a single Glycemia Risk Index (GRI) that corresponds closely to the clinician rankings of the overall quality of glycemia (r = 0.95). The GRI can be displayed graphically on a GRI Grid with the hypoglycemia component on the horizontal axis and the hyperglycemia component on the vertical axis. Diagonal lines divide the graph into five zones (quintiles) corresponding to the best (0th to 20th percentile) to worst (81st to 100th percentile) overall quality of glycemia. The GRI Grid enables users to track sequential changes within an individual over time and compare groups of individuals.

CONCLUSION

The GRI is a single-number summary of the quality of glycemia. Its hypoglycemia and hyperglycemia components provide actionable scores and a graphical display (the GRI Grid) that can be used by clinicians and researchers to determine the glycemic effects of prescribed and investigational treatments.

Continuous Subcutaneous Infusion Versus Multiple Daily Injections of Insulin for Pregestational Diabetes in Pregnancy: A Systematic Review and Meta-Analysis

BACKGROUND

The use of continuous subcutaneous insulin infusion (CSII) therapy in pregnancies affected by pregestational diabetes mellitus (DM) has generated mixed outcome data worthy of further investigation. This systematic review and meta-analysis aims to evaluate clinical outcomes associated with CSII versus multiple daily injections (MDIs) in pregnant persons with pregestational DM.

METHODS

A predefined, systematic, librarian-assisted search of MEDLINE (PubMed), Embase, Cochrane Library, Scopus, ClinicalTrials.gov, and World Health Organization International Clinical Trial Registry Platform (published from 2010 to 2022) yielded 3003 studies describing pregnancy outcomes associated with CSII and/or MDI for pregestational DM. The primary exposure was mode of insulin administration, with cesarean delivery and neonatal hypoglycemia as the primary maternal and neonatal outcomes, respectively. Secondary outcomes included hypertensive disorders of pregnancy, first and third-trimester glycemic control, large-for-gestational age (LGA) neonate, preterm birth, neonatal intensive care unit admission, need for respiratory support, hyperbilirubinemia, 5-minute Apgar <7, shoulder dystocia, and perinatal mortality. We calculated pooled odds ratios (OR) with 95% confidence intervals (CI) using random-effects models.

RESULTS

Among 39 eligible studies, 39% of the 5518 pregnancies included were exposed to CSII. Odds of cesarean delivery were higher with CSII (20 studies: 63% vs 56%, odds ratio [OR] 1.3 [95% confidence interval (CI) 1.2-1.5]), but we did not identify a difference in the odds of neonatal hypoglycemia (23 studies: 31% vs 34%, OR 1.1 [95% CI 0.9-1.5]). Among secondary outcomes, only the odds of LGA (20 studies: 47% vs 38%, OR 1.4 [95% CI 1.2-1.6]) were higher in individuals using CSII versus MDI.

CONCLUSIONS

Use of CSII (vs MDI) for pregestational DM in pregnancy is associated with higher odds of cesarean delivery and delivery of an LGA neonate. Further evaluation of how CSII use may influence neonatal size and delivery route is warranted.

Diabetes Research and Resource Sharing During the COVID-19 Pandemic: A Systematic Review and Experience from an Academic/Non-Profit Resource Website

BACKGROUND

The magnitude of the response of the diabetes professional community to the COVID-19 pandemic is not known. We aimed to examine diabetes technology research trends and resources offered by professional organizations during this period.

METHODS

We explored patterns of the response from the professional diabetes community to the pandemic by (1) systematically searching for articles related to diabetes, COVID-19, and diabetes technologies; (2) examining publication trends of research protocols (clinicaltrials.gov) and preprints (medRxiv); and (3) reviewing online resources from professional organizations including our website (COVIDinDiabetes.org; an Emory University-Diabetes Technology Society collaboration).

RESULTS

We identified 492 articles published between December 2019 and December 2022 meeting our inclusion criteria. Telemedicine and continuous glucose monitoring were the most common reported technologies from most parts of the world. The largest number of preprint articles was published in 2020, with a decline in 2021 and 2022. The number of research protocols related to COVID-19 was the highest in 2020 and declined in 2021 and 2022. Resources from organizations included protocols adapted to treat patients with diabetes and COVID-19, training programs, emergency preparedness, and literature on diabetes and COVID-19. On our website (COVIDinDiabetes.org), there were 12 236 visits and 18 149 pageviews, with 1.6 actions per visits, with most visits coming from North America (N = 7233, 54.2%), South America (N = 2663, 21.8%), and Europe (N = 1219).

CONCLUSIONS

We conclude that the COVID-19 pandemic promoted unprecedented global research productivity related to diabetes and COVID-19 and that the transition to the use of technology resources has been evident during this period.

The Need for Data Standards and Implementation Policies to Integrate CGM Data into the Electronic Health Record

The current lack of continuous glucose monitor (CGM) data integration into the electronic health record (EHR) is holding back the use of this wearable technology for patient-generated health data (PGHD). This failure to integrate with other healthcare data inside the EHR disrupts workflows, removes the data from critical patient context, and overall makes the CGM data less useful than it might otherwise be. Many healthcare organizations (HCOs) are either struggling with or delaying designing and implementing CGM data integrations. In this article, the current status of CGM integration is reviewed, goals for integration are proposed, and a consensus plan to engage key stakeholders to facilitate integration is presented.

Six Digital Health Technologies That Will Transform Diabetes

The digital health revolution is transforming the landscape of medicine through innovations in sensor data, software, and wireless communication tools. As one of the most prevalent chronic diseases in the United States, diabetes is particularly impactful as a model disease for which to apply innovation. As with any other newly developed technologies, there are three key questions to consider: 1) How can the technology benefit people with diabetes?, 2) What barriers must be overcome to further advance the technology?, and 3) How will the technology be applied in the future?. In this article, we highlight six areas of innovation that have the potential to reduce the burden of diabetes for individuals living with the condition and their families as well as provide measurable benefits for all stakeholders involved in diabetes care. The six technologies which have the potential to transform diabetes care are (i) telehealth, (ii) incorporation of diabetes digital data into the electronic health record, (iii) qualitative hypoglycemia alarms, (iv) artificial intelligence, (v) cybersecurity of diabetes devices, and (vi) diabetes registries. To be successful, a new digital health technology must be accessible and affordable. Furthermore, the people and communities that would most likely benefit from the technology must be willing to use the innovation in their management of diabetes.

Hospital Diabetes Meeting 2022

The annual Virtual Hospital Diabetes Meeting was hosted by Diabetes Technology Society on April 1 and April 2, 2022. This meeting brought together experts in diabetes technology to discuss various new developments in the field of managing diabetes in hospitalized patients. Meeting topics included (1) digital health and the hospital, (2) blood glucose targets, (3) software for inpatient diabetes, (4) surgery, (5) transitions, (6) coronavirus disease and diabetes in the hospital, (7) drugs for diabetes, (8) continuous glucose monitoring, (9) quality improvement, (10) diabetes care and educatinon, and (11) uniting people, process, and technology to achieve optimal glycemic management. This meeting covered new technology that will enable better care of people with diabetes if they are hospitalized.

Diabetes Technology Meeting 2021

Diabetes Technology Society hosted its annual Diabetes Technology Meeting on November 4 to November 6, 2021. This meeting brought together speakers to discuss various developments within the field of diabetes technology. Meeting topics included blood glucose monitoring, continuous glucose monitoring, novel sensors, direct-to-consumer telehealth, metrics for glycemia, software for diabetes, regulation of diabetes technology, diabetes data science, artificial pancreas, novel insulins, insulin delivery, skin trauma, metabesity, precision diabetes, diversity in diabetes technology, use of diabetes technology in pregnancy, and green diabetes. A live demonstration on a mobile app to monitor diabetic foot wounds was presented.

The Launch of the iCoDE Standard Project

INTRODUCTION

The first meeting of the Integration of Continuous Glucose Monitor Data into the Electronic Health Record (iCoDE) project, organized by Diabetes Technology Society, took place virtually on January 27, 2022.

METHODS

Clinicians, government officials, data aggregators, attorneys, and standards experts spoke in panels and breakout groups. Three themes were covered: 1) why digital health data integration into the electronic health record (EHR) is needed, 2) what integrated continuously monitored glucose data will look like, and 3) how this process can be achieved in a way that will satisfy clinicians, healthcare organizations, and regulatory experts.

RESULTS

The meeting themes were addressed within eight sessions: 1) What Do Inpatient Clinicians Want to See With Integration of CGM Data into the EHR?, 2) What Do Outpatient Clinicians Want to See With Integration of CGM Data into the EHR?, 3) Why Are Data Standards and Guidances Useful?, 4) What Value Can Data Integration Services Add?, 5) What Are Examples of Successful Integration?, 6) Which Privacy, Security, and Regulatory Issues Must Be Addressed to Integrate CGM Data into the EHR?, 7) Breakout Group Discussions, and 8) Presentation of Breakout Group Ideas.

CONCLUSIONS

Creation of data standards and workflow guidance are necessary components of the Integration of Continuous Glucose Monitor Data into the Electronic Health Record (iCoDE) standard project. This meeting, which launched iCoDE, will be followed by a set of working group meetings intended to create the needed standard.

Improving the Patient Experience With Longer Wear Infusion Sets Symposium Report

Continuous subcutaneous insulin infusion (CSII) therapy is becoming increasingly popular. CSII provides convenient insulin delivery, precise dosing, easy adjustments for physical activity, stress, or illness, and integration with continuous glucose monitors in hybrid or other closed-loop systems. However, even as insulin pump hardware and software have advanced, technology for insulin infusion sets (IISs) has stayed relatively stagnant over time and is often referred to as the "Achilles heel" of CSII. To discuss barriers to insulin pump therapy and present information about advancements in, and results from clinical trials of extended wear IISs, Diabetes Technology Society virtually hosted the "Improving the Patient Experience with Longer Wear Infusion Sets Symposium" on December 1, 2021. The symposium featured experts in the field of IISs, including representatives from Steno Diabetes Center Copenhagen, University of California San Francisco, Stanford University, Medtronic Diabetes, and Science Consulting in Diabetes. The webinar's seven speakers covered (1) advancements in insulin pump therapy, (2) efficacy of longer wear infusion sets, and (3) innovations to reduce plastics and insulin waste.

Continuous Ketone Monitoring Consensus Report 2021

This article is the work product of the Continuous Ketone Monitoring Consensus Panel, which was organized by Diabetes Technology Society and met virtually on April 20, 2021. The panel consisted of 20 US-based experts in the use of diabetes technology, representing adult endocrinology, pediatric endocrinology, advanced practice nursing, diabetes care and education, clinical chemistry, and bioengineering. The panelists were from universities, hospitals, freestanding research institutes, government, and private practice. Panelists reviewed the medical literature pertaining to ten topics: (1) physiology of ketone production, (2) measurement of ketones, (3) performance of the first continuous ketone monitor (CKM) reported to be used in human trials, (4) demographics and epidemiology of diabetic ketoacidosis (DKA), (5) atypical hyperketonemia, (6) prevention of DKA, (7) non-DKA states of fasting ketonemia and ketonuria, (8) potential integration of CKMs with pumps and automated insulin delivery systems to prevent DKA, (9) clinical trials of CKMs, and (10) the future of CKMs. The panelists summarized the medical literature for each of the ten topics in this report. They also developed 30 conclusions (amounting to three conclusions for each topic) about CKMs and voted unanimously to adopt the 30 conclusions. This report is intended to support the development of safe and effective continuous ketone monitoring and to apply this technology in ways that will benefit people with diabetes.

Green Diabetes Summit 2021

On July 21, 2021, Diabetes Technology Society convened the virtual Green Diabetes Summit. The event consisted of 23 representatives from key stakeholder groups based in both the United States and Europe. The purposes of the summit were to (1) provide background on the complexity of addressing sustainability-related issues, including waste management, of diabetes devices from many different perspectives along the products' life cycle stages, and (2) determine the feasibility and role of a coalition of stakeholders to find solutions, particularly in the design, use, and proper disposal of diabetes devices used in home care that no one stakeholder can resolve on their own.

The Impact of Stressor Exposure and Glucocorticoids on Anxiety and Fear

Anxiety disorders and trauma- and stressor-related disorders, such as posttraumatic stress disorder (PTSD), are common and are associated with significant economic and social burdens. Although trauma and stressor exposure are recognized as a risk factors for development of anxiety disorders and trauma or stressor exposure is recognized as essential for diagnosis of PTSD, the mechanisms through which trauma and stressor exposure lead to these disorders are not well characterized. An improved understanding of the mechanisms through which trauma or stressor exposure leads to development and persistence of anxiety disorders or PTSD may result in novel therapeutic approaches for the treatment of these disorders. Here, we review the current state-of-the-art theories, with respect to mechanisms through which stressor exposure leads to acute or chronic exaggeration of avoidance or anxiety-like defensive behavioral responses and fear, endophenotypes in both anxiety disorders and trauma- and stressor-related psychiatric disorders. In this chapter, we will explore physiological responses and neural circuits involved in the development of acute and chronic exaggeration of anxiety-like defensive behavioral responses and fear states, focusing on the role of the hypothalamic-pituitary-adrenal (HPA) axis and glucocorticoid hormones.

P2-quinazolinones and bis-macrocycles as new templates for next-generation hepatitis C virus NS3/4a protease inhibitors: discovery of MK-2748 and MK-6325

With the goal of identifying inhibitors of hepatitis C virus (HCV) NS3/4a protease that are potent against a wide range of genotypes and clinically relevant mutant viruses, several subseries of macrocycles were investigated based on observations made during the discovery of MK-5172. Quinazolinone-containing macrocycles were identified as promising leads, and optimization for superior cross-genotype and mutant enzyme potency as well as rat liver and plasma concentrations following oral dosing, led to the development of MK-2748. Additional investigation of a series of bis-macrocycles containing a fused 18- and 15-membered ring system were also optimized for the same properties, leading to the discovery of MK-6325. Both compounds display the broad genotype and mutant potency necessary for clinical development as next-generation HCV NS3/4a protease inhibitors.

Tumor size predicts vascular invasion and histologic grade among patients undergoing resection of intrahepatic cholangiocarcinoma

The association between tumor size and survival in patients with intrahepatic cholangiocarcinoma (ICC) undergoing surgical resection is controversial. We sought to define the incidence of major and microscopic vascular invasion relative to ICC tumor size, and identify predictors of microscopic vascular invasion in patients with ICC ≥5 cm. A total of 443 patients undergoing surgical resection for ICC between 1973 and 2011 at one of 11 participating institutions were identified. Clinical and pathologic data were evaluated using uni- and multivariate analyses. As tumor sized increased, the incidence of microscopic vascular invasion increased: <3 cm, 3.6 %; 3-5 cm, 24.7 %; 5-7 cm, 38.3 %; 7-15 cm, 32.9 %, ≥15 cm, 55.6 %; (p < 0.001). Increasing tumor size was also found to be associated with worsening tumor grade. The incidence of poorly differentiated tumors increased with increasing ICC tumor size: <3 cm, 9.7 %; 3-5 cm, 19.8 %; 5-7 cm, 24.2 %; 7-15 cm, 21.1 %; >15 cm, 31.6 % (p = 0.04). The presence of perineural invasion (odds ratio [OR] = 2.98) and regional lymph node metastasis (OR = 4.43) were independently associated with an increased risk of microscopic vascular invasion in tumors ≥5 cm (both p < 0.05). Risk of microscopic vascular invasion and worse tumor grade increased with tumor size. Large tumors likely harbor worse pathologic features; this information should be considered when determining therapy and prognosis of patients with large ICC.

Quantitative phosphoproteomic analysis identifies activation of the RET and IGF-1R/IR signaling pathways in neuroblastoma

Neuroblastoma is an embryonal tumor of childhood with a heterogenous clinical presentation that reflects differences in activation of complex biological signaling pathways. Protein phosphorylation is a key component of cellular signal transduction and plays a critical role in processes that control cancer cell growth and survival. We used shotgun LC/MS to compare phosphorylation between a human MYCN amplified neuroblastoma cell line (NB10), modeling a resistant tumor, and a human neural precursor cell line (NPC), modeling a normal baseline neural crest cell. 2181 unique phosphorylation sites representing 1171 proteins and 2598 phosphopeptides were found. Protein kinases accounted for 6% of the proteome, with a predominance of tyrosine kinases, supporting their prominent role in oncogenic signaling pathways. Highly abundant receptor tyrosine kinase (RTK) phosphopeptides in the NB10 cell line relative to the NPC cell line included RET, insulin-like growth factor 1 receptor/insulin receptor (IGF-1R/IR), and fibroblast growth factor receptor 1 (FGFR1). Multiple phosphorylated peptides from downstream mediators of the PI3K/AKT/mTOR and RAS pathways were also highly abundant in NB10 relative to NPC. Our analysis highlights the importance of RET, IGF-1R/IR and FGFR1 as RTKs in neuroblastoma and suggests a methodology that can be used to identify potential novel biological therapeutic targets. Furthermore, application of this previously unexploited technology in the clinic opens the possibility of providing a new wide-scale molecular signature to assess disease progression and prognosis.

Recurrence after operative management of intrahepatic cholangiocarcinoma

INTRODUCTION

Data on recurrence after operation for intrahepatic cholangiocarcinoma (ICC) are limited. We sought to investigate rates and patterns of recurrence in patients after operative intervention for ICC.

METHODS

We identified 301 patients who underwent operation for ICC between 1990 and 2011 from an international, multi-institutional database. Clinicopathologic data, recurrence patterns, and recurrence-free survival (RFS) were analyzed.

RESULTS

During the median follow up duration of 31 months (range 1-208), 53.5% developed a recurrence. Median RFS was 20.2 months and 5-year actuarial disease-free survival, 32.1%. The most common site for initial recurrence after operation of ICC was intrahepatic (n = 98; 60.9%), followed by simultaneous intra- and extrahepatic disease (n = 30; 18.6%); 33 (21.0%) patients developed extrahepatic recurrence only as the first site of recurrence. Macrovascular invasion (hazard ratio [HR], 2.08; 95% confidence interval [CI], 1.34-3.21; P < .001), nodal metastasis (HR, 1.55; 95% CI, 1.01-2.45; P = .04), unknown nodal status (HR, 1.57; 95% CI, 1.10-2.25; P = .04), and tumor size ≥ 5 cm (HR, 1.84; 95% CI, 1.28-2.65; P < .001) were independently associated with increased risk of recurrence. Patients were assigned a clinical score from 0 to 3 according to the presence of these risk factors. The 5-year RFS for patients with scores of 0, 1, 2, and 3 was 61.8%, 36.2%, 19.5%, and 9.6%, respectively.

CONCLUSION

Recurrence after operative intervention for ICC was common. Disease recurred both at intra- and extrahepatic sites with roughly the same frequency. Factors such as lymph node metastasis, tumor size, and vascular invasion predict highest risk of recurrence.

The CRM1 nuclear export protein in normal development and disease

CRM1 (Chromosomal Maintenance 1, also known as Exportin 1) is the major mammalian export protein that facilitates the transport of large macromolecules including RNA and protein across the nuclear membrane to the cytoplasm. The gene encoding CRM1 was originally identified in yeast as required to maintain higher order chromosome structure. In mammalian cells, CRM1 was found to bind several nuclear pore proteins hence its role in nuclear-cytosolic transport was discovered. In addition to nuclear-cytosolic transport, CRM1 also plays a role in centrosome duplication and spindle assembly, especially in response to DNA damage. The crystal structure of CRM1 suggests a complex protein that binds the Ran protein bound to GTP, allowing for a conformational change that facilitates binding to different cargo proteins through a nuclear export signal (NES). Included in the cadre of cargo are multiple tumor suppressor and oncoproteins as p53, BRCA1, Survivin, NPM, and APC, which function in the nucleus to regulate transcription or aid in chromosomal assembly and movement. An imbalance in the cytosolic level of these proteins has been observed in cancer cells, resulting in either inactivation (tumor suppressor) or an excess of anti-apoptotic activity (oncoprotein). Thus, the concept of inhibiting CRM1 has been explored as a potential therapeutic intervention. Indeed, inhibition of CRM1 by a variety of small molecules that interfere with cargo-NES binding results in cancer cell death. Whether all of these proteins together are responsible for this phenotype or whether specific proteins are required for this effect is unclear at this time.

Discovery of MK-5172, a Macrocyclic Hepatitis C Virus NS3/4a Protease Inhibitor

A new class of HCV NS3/4a protease inhibitors containing a P2 to P4 macrocyclic constraint was designed using a molecular modeling-derived strategy. Building on the profile of previous clinical compounds and exploring the P2 and linker regions of the series allowed for optimization of broad genotype and mutant enzyme potency, cellular activity, and rat liver exposure following oral dosing. These studies led to the identification of clinical candidate 15 (MK-5172), which is active against genotype 1-3 NS3/4a and clinically relevant mutant enzymes and has good plasma exposure and excellent liver exposure in multiple species.

Intrahepatic cholangiocarcinoma: an international multi-institutional analysis of prognostic factors and lymph node assessment

PURPOSE

To identify factors associated with outcome after surgical management of intrahepatic cholangiocarcinoma (ICC) and examine the impact of lymph node (LN) assessment on survival.

PATIENTS AND METHODS

From an international multi-institutional database, 449 patients who underwent surgery for ICC between 1973 and 2010 were identified. Clinical and pathologic data were evaluated using uni- and multivariate analyses.

RESULTS

Median tumor size was 6.5 cm. Most patients had a solitary tumor (73%) and no vascular invasion (69%). Median survival was 27 months, and 5-year survival was 31%. Factors associated with adverse prognosis included positive margin status (hazard ratio [HR], 2.20; P < .001), multiple lesions (HR, 1.80; P = .001), and vascular invasion (HR, 1.59; P = .015). Tumor size was not a prognostic factor (HR, 1.03; P = .23). Patients were stratified using the American Joint Committee on Cancer/International Union Against Cancer T1, T2a, and T2b categories (seventh edition) in a discrete step-wise fashion (P < .001). Lymphadenectomy was performed in 248 patients (55%); 74 of these (30%) had LN metastasis. LN metastasis was associated with worse outcome (median survival: N0, 30 months v N1, 24 months; P = .03). Although patients with no LN metastasis were able to be stratified by tumor number and vascular invasion (N0; P < .001), among patients with N1 disease, multiple tumors and vascular invasion, either alone or together, failed to discriminate patients into discrete prognostic groups (P = .34).

CONCLUSION

Although tumor size provides no prognostic information, tumor number, vascular invasion, and LN metastasis were associated with survival. N1 status adversely affected overall survival and also influenced the relative effect of tumor number and vascular invasion on prognosis. Lymphadenectomy should be strongly considered for ICC, because up to 30% of patients will have LN metastasis.

Discovery of MK-1220: A Macrocyclic Inhibitor of Hepatitis C Virus NS3/4A Protease with Improved Preclinical Plasma Exposure

The discovery of MK-1220 is reported along with the development of a series of HCV NS3/4A protease inhibitors containing a P2 to P4 macrocyclic constraint with improved preclinical pharmacokinetics. Optimization of the P2 heterocycle substitution pattern as well as the P3 amino acid led to compounds with greatly improved plasma exposure following oral dosing in both rats and dogs while maintaining excellent enzyme potency and cellular activity. These studies led to the identification of MK-1220.

A rapid and sensitive fluorometric method for the quantitative analysis of snake venom metalloproteases and their inhibitors

Metalloproteases are responsible for the hemorrhagic effects of many snake venoms and contribute to other pathways that lead to local tissue damage. Methods that quantify snake venom metalloproteases (SVMP) are therefore valuable tools in research on the clinical, physiological, and biochemical effects of envenomation. Comparative analysis of individual, population, and species differences requires screening of large numbers of samples and treatments, and therefore require a method of quantifying SVMP activity that is simple, rapid, and sensitive. This paper demonstrates the properties of a new fluorometric assay of SVMP activity that can provide a measure of metalloprotease activity in 1 h. The assay is reliable, with variation among replicates sufficiently small to reliably detect differences in between species (F(19,60) = 2924, p < 0.001), even for those venoms with low overall activity. It is also sensitive enough to detect differences among venoms using <2 ng of whole venom protein. We provide an example use of this assay to detect the presence of natural SVMP inhibitors in minute samples of blood plasma from rock squirrels (S. variegatus), a natural prey species for North American rattlesnakes. We propose this assay is a useful addition to the set of tools used to characterize venoms, as well as high-throughput screening of natural or synthetic inhibitors, or other novel therapeutic agents against SVMP effects.

Robotic-assisted major pancreatic resection and reconstruction

HYPOTHESIS

Robotic-assisted pancreatic resection and reconstruction are safe and can reproduce perioperative results seen in open surgery.

DESIGN

Single-institution retrospective review.

SETTING

Tertiary care center.

PATIENTS

Patients undergoing completed robotic-assisted pancreatic resection and reconstruction at the University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, between October 3, 2008, and February 26, 2010.

MAIN OUTCOME MEASURES

Primary pathology, operative time, operative blood loss, perioperative blood transfusions, pancreatic fistula, 90-day morbidity and mortality, and readmission rate.

RESULTS

Thirty patients with a median age of 70 years (range, 32-85 years) underwent completed robotic-assisted pancreatic resection and reconstruction. Procedures were robotic-assisted non-pylorus-preserving pancreaticoduodenectomy (n = 24), robotic-assisted central pancreatectomy (n = 4), and the robotic-assisted Frey procedure (n = 2). The median operative time was 512 minutes (range, 327-848 minutes). The median blood loss was 320 mL (range, 50-1000 mL), with a median length of hospital stay of 9 days (range, 4-87 days). The final diagnoses included periampullary adenocarcinoma (n = 7), pancreatic ductal adenocarcinoma (n = 6), pancreatic neuroendocrine tumor (n = 5), intraductal papillary mucinous neoplasm (n = 4), mucinous cystic neoplasm (n = 3), serous cystic adenoma (n = 2), chronic pancreatitis (n = 2), and solid pseudopapillary neoplasm (n = 1). There was 1 postoperative death. The overall pancreatic fistula rate was 27% (n = 8). The clinically significant pancreatic fistula rate (International Study Group on Pancreatic Fistula grades B and C) was 10% (n = 3). Clavien grade III and IV complications occurred in 7 patients (23%), while Clavien grade I and II complications occurred in 8 patients (27%).

CONCLUSIONS

Robotic-assisted complex pancreatic surgery can be performed safely in a high-volume pancreatic tertiary care center with perioperative outcomes comparable to those of open surgery. Advances in robotic technology and increasing experience may improve long operative times.

Identification of undiagnosed type 2 diabetes by systolic blood pressure and waist-to-hip ratio

AIMS/HYPOTHESIS

We estimated the current prevalence of type 2 diabetes in the Vietnamese population and developed simple diagnostic models for identifying individuals at high risk of undiagnosed type 2 diabetes.

METHODS

The study was designed as a cross-sectional investigation with 721 men and 1,421 women, who were aged between 30 and 72 years and were randomly sampled from Ho Chi Minh City (formerly Saigon) in Vietnam. A 75 g oral glucose tolerance test to assess fasting and 2 h plasma glucose concentrations were determined for each individual. The ADA diagnostic criteria were used to determine the prevalence of type 2 diabetes. WHR and blood pressure were also measured in all individuals.

RESULTS

The prevalence of type 2 diabetes was 10.8% in men and 11.7% in women. Higher WHR and blood pressure were independently associated with a greater risk of type 2 diabetes. Compared with participants without central obesity and hypertension, the odds of diabetes was increased by 6.4-fold (95% CI 3.2-13.0) in men and 4.1-fold (2.2-7.6) in women with central obesity and hypertension. Two nomograms were developed that help identify men and women at high risk of type 2 diabetes.

CONCLUSIONS/INTERPRETATION

The current prevalence of type 2 diabetes in the Vietnamese population is high. Simple field measurements such as waist-to-hip ratio and systolic blood pressure can identify individuals at high risk of undiagnosed type 2 diabetes.

Synergistic effect between EGF and TGF-beta1 in inducing oncogenic properties of intestinal epithelial cells

Transforming growth factor (TGF)-beta1 has a biphasic effect on rat intestinal epithelial (RIE) cells. By itself, TGF-beta1 functions as a tumor suppressor by inhibiting the growth, migration and invasion of RIE cells. We show in this study that in conjunction with epidermal growth factor (EGF), TGF-beta1 helped to augment migration, invasion and anchorage-independent growth (AIG) compared to that by EGF alone. EGF plus TGF-beta1 induced a dramatic morphological change characteristic of epithelial-mesenchymal transition (EMT). The mechanism for this enhanced effect of TGF-beta1 and EGF on oncogenic properties was explored by analysis of EGF- and TGF-beta1-mediated signaling pathways and complementary DNA arrays. TGF-beta1 augmented EGF-mediated signaling of mitogen-activated protein kinase (MAPK) and AKT by enhancing and prolonging the activation of the former and prolonging the activation of the latter. Inhibition of MAPK, but not phosphoinositide-3 kinase (PI3K), abolished TGF-beta1 plus EGF-induced EMT and downregulation of E-cadherin at mRNA and protein levels. By contrast, cell migration and invasion were sensitive to inhibition of either MAPK or PI3 kinase. TGF-beta1 plus EGF-induced AIG was significantly more resistant to inhibition of PI3K and MAPK compared to that induced by EGF alone. EGF and TGF-beta1 synergistically induced the expression of a series of proteases including matrix metalloproteinase (MMP) 1 (collagenase), MMP3, MMP9, MMP10, MMP14 and cathepsin. Among them, the expression of MMP1, MMP3, MMP9 and MMP10 was MAPK dependent. Inhibition of the MMPs or cathepsin significantly blocked EGF plus TGF-beta1-induced invasion, but had no effect on colony formation. Phospholipase C (PLC) and Cox2 induced by EGF plus TGF-beta1 also played a significant role in invasion, whereas PLC was also important for colony formation. Our study reveals specific signaling functions and induction of genes differentially required for enhanced effect of EGF- and TGF-beta1-induced oncogenic properties, and helps to explain the tumor-promoting effect of TGF-beta1 in human cancer with elevated expression or activation of TGF-beta1 and receptor protein tyrosine kinases.

Cyclic benzamidines as orally efficacious NR2B-selective NMDA receptor antagonists

A novel series of cyclic benzamidines was synthesized and shown to exhibit NR2B-subtype selective NMDA antagonist activity. Compound 29 is orally active in a carrageenan-induced rat hyperalgesia model of pain.

Identification and characterization of 4-methylbenzyl 4-[(pyrimidin-2-ylamino)methyl]piperidine-1-carboxylate, an orally bioavailable, brain penetrant NR2B selective N-methyl-D-aspartate receptor antagonist

The discovery of a novel series of NR2B subtype selective N-methyl-d-aspartate (NMDA) antagonists is reported. Initial optimization of a high-throughput screening lead afforded an aminopyridine derivative 13 with significant NR2B antagonist potency but limited selectivity over hERG-channel and other off-target activities. Further structure-activity studies on the aminoheterocycle moiety and optimization of the carbamate led to the highly potent 2-aminopyrimidine derivative 20j with a significantly improved off-target activity profile and oral bioavailability in multiple species coupled with good brain penetration. Compound 20j demonstrated efficacy in in vivo rodent models of antinociception, allodynia, and Parkinson's disease.

In vitro hemocompatibility studies of drug-loaded poly-(L-lactic acid) fibers

Our objective was to evaluate the hemocompatibility of biodegradable stent fibers, employing a closed-loop circulation system filled with human blood. We also investigated the effects of the anti-inflammatory and anti-proliferative drugs curcumin and paclitaxel, incorporated into stent fibers. Fresh whole blood was circulated in four parallel closed-loop systems: the empty tube circuit (control) and tubes containing either a PLLA fiber coil (PLLA), a curcumin-loaded PLLA coil (C-PLLA) or a paclitaxel-loaded PLLA coil (P-PLLA). The influence of PLLA fiber, alone or loaded with drug incorporated during melt-extrusion, on leukocyte and platelet adhesion and activation was determined by flow cytometry. The effects of blood flow and fiber properties on cell deposition were assessed by scanning electron microscopy (SEM). The flow cytometry results clearly demonstrated that PLLA triggers blood cell activation at the site of deployment, as shown by increases in CD11b, CD62P and leukocyte-platelet aggregates, compared to controls. Curcumin and paclitaxel treatments both significantly reduced leukocyte and platelet activation and adhesion to PLLA fibers, as shown by flow cytometry and SEM. Activated leukocytes and platelets revealed significantly lower CD11b and CD62P receptor binding for C-PLLA compared with PLLA alone, and slightly lower for P-PLLA. Reductions in platelet-leukocyte aggregates were observed as well. In addition, there was less leukocyte and platelet adhesion to C-PLLA, compared with PLLA fiber controls, as shown by SEM. A continuous linear thrombus, composed of platelets, leukocytes, red blood cells and fibrin was occasionally detected along the line of tangency between the coil and the tube wall. Flow separation and eddying, proximal and distal to the line of tangency of coil and tube, is thought to contribute to this deposit. Curcumin was more effective than paclitaxel in reducing leukocyte and platelet activation and adhesion to PLLA stent fibers in this setting. However there was evidence of paclitaxel degeneration during melt extrusion that may have inhibited its effectiveness. Incorporation of the anti-inflammatory and anti-proliferative drug curcumin into bioresorbable stent fibers is proposed to prevent thrombosis and in-stent restenosis.

The role of phosphatidylinositol 3-kinase, rho family GTPases, and STAT3 in Ros-induced cell transformation

Using loss-of-function mutants of Ros and inducible epidermal growth factor receptor-Ros chimeras we investigated the role of various signaling pathways in Ros-induced cell transformation. Inhibition of the mitogen-activated protein kinase (MAPK) pathway with the MEK (MAP/extracellular signal-regulated kinase kinase) inhibitor PD98059 had little effect on the Ros-induced monolayer and anchorage-independent growth of chicken embryo fibroblasts and NIH3T3 cells even though more than 70% of the MAPK was inhibited. In contrast, inhibiting the phosphatidylinositol 3-kinase (PI3K) pathway with the drug LY294002, a dominant negative mutant of PI3K, Deltap85, or the phosphatidylinositol phosphatase PTEN (phosphatase and tensin homologue deleted in chromosome ten) resulted in a dramatic reduction of v-Ros- and epidermal growth factor receptor-Ros-promoted anchorage-independent growth of chicken embryo fibroblasts and NIH3T3 cells, respectively. Parallel and downstream components of PI3K signaling such as the Rho family GTPases (Rac, Rho, Cdc42) and the survival factor Akt were all shown to contribute to Ros-induced anchorage-independent growth, although Rac appeared to be less important for Ros-induced colony formation in NIH3T3 cells. Furthermore, the transformation-attenuated v-Ros mutants F419 and DI could be complemented by constitutively active mutants of PI3K and Akt. Finally, we found that overexpressing a constitutively active mutant of STAT3 (STAT3C) conferred a resistance to the inhibition of Ros-induced anchorage-independent growth by LY294002, suggesting a possible overlap of functions between PI3K and STAT3 signaling in mediating Ros-induced anchorage-independent growth.

Characterization of an eukaryotic peptide deformylase from Plasmodium falciparum

Ribosomal protein synthesis in eubacteria and eukaryotic organelles initiates with an N-formylmethionyl-tRNA(i), resulting in N-terminal formylation of all nascent polypeptides. Peptide deformylase (PDF) catalyzes the subsequent removal of the N-terminal formyl group from the majority of bacterial proteins. Until recently, PDF has been thought as an enzyme unique to the bacterial kingdom. Searches of the genomic DNA databases identified several genes that encode proteins of high sequence homology to bacterial PDF from eukaryotic organisms. The cDNA encoding Plasmodium falciparum PDF (PfPDF) has been cloned and overexpressed in Escherichia coli. The recombinant protein is catalytically active in deformylating N-formylated peptides, shares many of the properties of bacterial PDF, and is inhibited by specific PDF inhibitors. Western blot analysis indicated expression of mature PfPDF in trophozoite, schizont, and segmenter stages of intraerythrocytic development. These results provide strong evidence that a functional PDF is present in P. falciparum. In addition, PDF inhibitors inhibited the growth of P. falciparum in the intraerythrocytic culture.

Pleiotropic functions of a Streptomyces pristinaespiralis autoregulator receptor in development, antibiotic biosynthesis, and expression of a superoxide dismutase

In Streptomyces, a family of related butyrolactones and their corresponding receptor proteins serve as quorum-sensing systems that can activate morphological development and antibiotic biosynthesis. Streptomyces pristinaespiralis contains a gene cluster encoding enzymes and regulatory proteins for the biosynthesis of pristinamycin, a clinically important streptogramin antibiotic complex. One of these proteins, PapR1, belongs to a well known family of Streptomyces antibiotic regulatory proteins. Gel shift assays using crude cytoplasmic extracts detected SpbR, a developmentally regulated protein that bound to the papR1 promoter. SpbR was purified, and its gene was cloned using reverse genetics. spbR encoded a 25-kDa protein similar to Streptomyces autoregulatory proteins of the butyrolactone receptor family, including scbR from Streptomyces coelicolor. In Escherichia coli, purified SpbR and ScbR produced bound sequences immediately upstream of papR1, spbR, and scbR. SpbR DNA-binding activity was inhibited by an extracellular metabolite with chromatographic properties similar to those of the well known gamma-butyrolactone signaling compounds. DNase I protection assays mapped the SpbR-binding site in the papR1 promoter to a sequence homologous to other known butyrolactone autoregulatory elements. A nucleotide data base search showed that these binding motifs were primarily located upstream of genes encoding Streptomyces antibiotic regulatory proteins and butyrolactone receptors in various Streptomyces species. Disruption of the spbR gene in S. pristinaespiralis resulted in severe defects in growth, morphological differentiation, pristinamycin biosynthesis, and expression of a secreted superoxide dismutase.

Cyclic strain increases protease-activated receptor-1 expression in vascular smooth muscle cells

Cyclic strain regulates many vascular smooth muscle cell (VSMC) functions through changing gene expression. This study investigated the effects of cyclic strain on protease-activated receptor-1 (PAR-1) expression in VSMCs and the possible signaling pathways involved, on the basis of the hypothesis that cyclic strain would enhance PAR-1 expression, reflecting increased thrombin activity. Uniaxial cyclic strain (1 Hz, 20%) of cells cultured on elastic membranes induced a 2-fold increase in both PAR-1 mRNA and protein levels. Functional activity of PAR-1, as assessed by cell proliferation in response to thrombin, was also increased by cyclic strain. In addition, treatment of cells with antioxidants or an NADPH oxidase inhibitor blocked strain-induced PAR-1 expression. Preincubation of cells with protein kinase inhibitors (staurosporine or Ro 31-8220) enhanced strain-increased PAR-1 expression, whereas inhibitors of NO synthase, tyrosine kinase, and mitogen-activated protein kinases had no effect. Cyclic strain in the presence of basic fibroblast growth factor induced PAR-1 mRNA levels beyond the effect of cyclic strain alone, whereas no additive effect was observed between cyclic strain and platelet-derived growth factor-AB. Our findings that cyclic strain upregulates PAR-1 mRNA expression but that shear stress downregulates this gene in VSMCs provide an opportunity to elucidate signaling differences by which VSMCs respond to different mechanical forces.

Roles of aconitase in growth, metabolism, and morphological differentiation of Streptomyces coelicolor

The studies of aconitase presented here, along with those of citrate synthase (P. H. Viollier, W. Minas, G. E. Dale, M. Folcher, and C. J. Thompson, J. Bacteriol. 183:3184-3192, 2001), were undertaken to investigate the role of the tricarboxylic acid (TCA) cycle in Streptomyces coelicolor development. A single aconitase activity (AcoA) was detected in protein extracts of cultures during column purification. The deduced amino acid sequence of the cloned acoA gene constituted the N-terminal sequence of semipurified AcoA and was homologous to bacterial A-type aconitases and bifunctional eukaryotic aconitases (iron regulatory proteins). The fact that an acoA disruption mutant (BZ4) did not grow on minimal glucose media in the absence of glutamate confirmed that this gene encoded the primary vegetative aconitase catalyzing flux through the TCA cycle. On glucose-based complete medium, BZ4 had defects in growth, antibiotic biosynthesis, and aerial hypha formation, partially due to medium acidification and accumulation of citrate. The inhibitory effects of acids and citrate on BZ4 were partly suppressed by buffer or by introducing a citrate synthase mutation. However, the fact that growth of an acoA citA mutant remained impaired, even on a nonacidogenic carbon source, suggested alternative functions of AcoA. Immunoblots revealed that AcoA was present primarily during substrate mycelial growth on solid medium. Transcription of acoA was limited to the early growth phase in liquid cultures from a start site mapped in vitro and in vivo.

Intrathecal HIV-1 envelope glycoprotein gp120 induces enhanced pain states mediated by spinal cord proinflammatory cytokines

Perispinal (intrathecal) injection of the human immunodeficiency virus-1 (HIV-1) envelope glycoprotein gp120 creates exaggerated pain states. Decreases in response thresholds to both heat stimuli (thermal hyperalgesia) and light tactile stimuli (mechanical allodynia) are rapidly induced after gp120 administration. gp120 is the portion of HIV-1 that binds to and activates microglia and astrocytes. These glial cells have been proposed to be key mediators of gp120-induced hyperalgesia and allodynia because these pain changes are blocked by drugs thought to affect glial function preferentially. The aim of the present series of studies was to determine whether gp120-induced pain changes involve proinflammatory cytokines [interleukin-1beta (IL-1) and tumor necrosis factor-alpha (TNF-alpha)], substances released from activated glia. IL-1 and TNF antagonists each prevented gp120-induced pain changes. Intrathecal gp120 produced time-dependent, site-specific increases in TNF and IL-1 protein release into lumbosacral CSF; parallel cytokine increases in lumbar dorsal spinal cord were also observed. Intrathecal administration of fluorocitrate (a glial metabolic inhibitor), TNF antagonist, and IL-1 antagonist each blocked gp120-induced increases in spinal IL-1 protein. These results support the concept that activated glia in dorsal spinal cord can create exaggerated pain states via the release of proinflammatory cytokines.

Endogenous glucocorticoids play a positive regulatory role in the anti-keyhole limpet hemocyanin in vivo antibody response

Glucocorticoids (GCs) are commonly reported to be immunosuppressive. Studies that support this involve the administration of synthetic GCs such as dexamethasone at high pharmacological doses and using in vitro assay systems that may have limited relevance to the role of GCs during normal in vivo immune responses. Therefore, the following experiments tested the conclusion that GCs are generally immunosuppressive. Adult male Sprague Dawley rats received adrenalectomy (ADX) or sham surgery. ADX rats were given either basal corticosterone (CORT) replacement in their drinking water (25 microg/ml) or no CORT. Rats were immunized with keyhole limpet hemocyanin (KLH), and blood samples were taken. ADX rats with no CORT replacement had reduced anti-KLH IgM and IgG responses compared with sham-operated controls. ADX rats that received basal CORT replacement had partially restored anti-KLH IgM, but still had suppressed anti-KLH IgG. Administration of GC receptor type I (RU28318) and type II (RU40555) receptor antagonists also reduced the anti-KLH IgM and IgG responses. ADX rats that received both basal CORT replacement and low dose injections of CORT on days 5 and 7 after KLH had anti-KLH IgG levels equal to those of sham-operated controls. Finally, the GC elevation 4-7 days after immunization may play a role in stimulating the IgM to IgG2a switch. GC receptor blockade reduced the anti-KLH IgG2a and splenic IFN-gamma, but not the anti-KLH IgG1, response. Given that IFN-gamma is an important regulator of the IgM to IgG2a switch, it is possible that the small rise in GC found 4-7 days after KLH facilitates IgG2a isotype switching.

Shear stress reduces protease activated receptor-1 expression in human endothelial cells

Shear stress has been shown to regulate several genes involved in the thrombotic and proliferative functions of endothelial cells. Thrombin receptor (protease-activated receptor-1: PAR-1) increases at sites of vascular injury, which suggests an important role for PAR-1 in vascular diseases. However, the effect of shear stress on PAR-1 expression has not been previously studied. This work investigates effects of shear stress on PAR-1 gene expression in both human umbilical vein endothelial cells (HUVECs) and microvascular endothelial cells (HMECs). Cells were exposed to different shear stresses using a parallel plate flow system. Northern blot and flow cytometry analysis showed that shear stress down-regulated PAR-1 messenger RNA (mRNA) and protein levels in both HUVECs and HMECs but with different thresholds. Furthermore, shear-reduced PAR-1 mRNA was due to a decrease of transcription rate, not increased mRNA degradation. Postshear stress release of endothelin-1 in response to thrombin was reduced in HUVECs and HMECs. Moreover, inhibitors of potential signaling pathways applied during shear stress indicated mediation of the shear-decreased PAR-1 expression by protein kinases. In conclusion, shear stress exposure reduces PAR-1 gene expression in HMECs and HUVECs through a mechanism dependent in part on protein kinases, leading to altered endothelial cell functional responses to thrombin.

Effects of vagotomy on lipopolysaccharide-induced brain interleukin-1beta protein in rats

The production of interleukin-1beta (IL-1beta) in brain is thought to be a critical step in the induction of central manifestations of the acute phase response, and the vagus nerve has been implicated in immune-to-brain communication. Thus, this study examined the effects of intraperitoneal (i.p.) injections of lipopolysaccharide (LPS) on brain IL-1beta protein levels in control and subdiaphragmatically vagotomized rats. In the first experiment, vagotomized and sham-operated male Sprague-Dawley rats were injected i.p. with one of three doses (10, 50, 100 microg/kg) of LPS or vehicle (sterile, pyrogen-free saline) and sacrificed 2 h after the injection. In the second experiment, vagotomized and sham-operated rats were injected i.p. with 100 microg/kg LPS or vehicle and sacrificed 1 h after the injection. The i.p. injection of LPS dose-dependently increased IL-1beta protein levels in the hypothalamus, hippocampus, dorsal vagal complex, cerebellum, posterior cortex, and pituitary 2 h after the injection. Brain and pituitary IL-1beta levels were also significantly increased 1 h after the injection of 100 microg/kg LPS. There were no significant differences in brain IL-1beta levels between sham-operated and vagotomized rats at either the 2 h or 1 h time points. The current data are consistent with previous studies showing increases in brain IL-1beta after peripheral injections of LPS, and support the notion that brain IL-1beta is a mediator in the illness-induction pathway. Furthermore, these data indicate that, at the doses and times tested, subdiaphragmatic vagal afferents are not crucial for LPS-induced brain IL-1beta protein.