Reduced prescription of TNF-inhibitors in chronic arthritis based on therapeutic drug monitoring: A randomized controlled trial

OBJECTIVE

Dosing of tumour necrosis factor-α inhibitors (TNFis) is not personalized causing interindividual variation in serum drug levels; however, dose optimization is not widely implemented. We hypothesized that some patients are overdosed; thus, drug prescription could be reduced by therapeutic drug monitoring (TDM).

METHOD

Independent of disease activity, 239 adults treated for rheumatoid arthritis (n = 99), psoriatic arthritis 15 (n = 48), or spondyloarthritis (n = 92) were recruited for a 48-week prospective, randomized open-label trial. Standard care alone or plus TDM was applied in chronic arthritis patients treated with infliximab (IFX), (n = 81), etanercept (ETN) (n = 79), or adalimumab (ADA) (n = 79). Serum TNFi trough levels assessed at inclusion and every 4 months determined patients within/outside predefined therapeutic intervals, supporting change in prescription or drug switch. The primary endpoint was reduced drug prescription.

RESULTS

Compared to standard care, TDM reduced prescribed IFX [-12% (95% confidence interval -20, -3); p = 0.001] and ETN (-15% (-29, 1); p = 0.01], and prolonged the interdosing intervals of ETN [+235% (38, 432); p = 0.02] and ADA [+28% (6, 51); p = 0.04]. Time to drug switch was accelerated (χ2 = 6.03, p = 0.01). No group differences in adverse events, disease activity, or self-reported outcomes were shown, indicating equally sustained remission.

CONCLUSIONS

TDM reduced prescription of IFX, ETN, and ADA and identified patients benefiting from accelerated drug switch, thereby minimizing treatment failure, risk of toxicity, and unnecessary adverse events.

Abstract 3200: Examining the role of obesity and leptin signaling in triple negative breast cancer

Individuals with a high body mass index (BMI) have an increased risk of developing many adult cancers, including breast cancer. In triple negative breast cancer (TNBC), a clinically aggressive subtype of breast cancer, increased BMI is associated with more aggressive tumor types and a higher risk of recurrence. The differences in outcomes between obese and non-obese breast cancer patients is a consequence of the complex interplay between social, environmental, and physiological factors that contribute to the etiology of breast cancer. Therefore, understanding the complex signaling events in the obese tumor microenvironment is essential. Adipose stem cells (ASCs) are a component of the breast microenvironment, and are a subset of mesenchymal stem cells. ASCs from obese patients (obASCs) secrete higher levels various cytokines and adipokines that induce a more invasive phenotype in triple negative breast cancer cells compared to ASCs from lean individuals. Leptin, an adipokine that is expressed proportionally to fat mass, has been implicated in many cancers. Increased leptin and leptin receptor expression is associated with worse prognosis. This study seeks to examine the role of leptin signaling in triple negative breast cancer.

Previous work in conjunction with a collaborating lab has shown that leptin signaling promotes metastasis and increased expression of epithelial-mesenchymal transition (EMT) markers in triple negative breast cancer. This project expands upon this work through using both patient-derived cell lines and and patient-derived xenografts (PDX), and examines the role of leptin signaling both in vitro and in vivo. To determine the effects of obesity upon a PDX model, a high fat diet was used to induce obesity in vivo. Exposure to conditioned media harvested from obASCs increased the percentage of TNBC cells that expressed cancer stem cell markers, whereas exposure to a small peptide antagonist of the leptin receptor decreased the percentage of cells with CSC markers. PDX tumors implanted into diet-induced obesity mice had an increased volume compared to tumors implanted into lean controls. Conclusions: These molecular differences may contribute to the differences in cancer outcomes between obese and lean individuals with breast cancer, and further study of the crosstalk between obASCs and TNBC is critical.

Citation Format: Courtney Brock, Maryl Wright, Khoa Nguyen, Katherine Hebert, Madlin Alzoubi, Thomas Cheng, Bridgette Collins-Burow, Matthew Burow. Examining the role of obesity and leptin signaling in triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3200.

Abstract 185: Monitoring metabolite dynamics in patient-derived tumoroids using automated microfluidic Pu·MA System

Introduction: Cancer cells are characterized by metabolic modifications to meet high bioenergetic and anabolic demand during tumorigenesis. For most tumors aerobic glycolysis is a major driver of cancer progression, resistance to therapy, poor patient outcome. Lactate, a product of glycolysis, plays a role in tumor progression and is linked to drug resistance in breast cancer. Patient-derived 3D cell models are valuable tools for research, drug development and personalized medicine, because they recapitulate features of tumor microenvironment. Therefore, monitoring metabolite dynamics and lactate production in physiologically relevant patient-derived models provides valuable data for understanding metabolic perturbations during disease progression, drug response and resistance. In this study we assayed the glucometabolic changes in response to anti-cancer drugs in triple negative breast cancer (TNBC) tumoroids. Our approach utilizes an automated 3D assay system. The Pu·MA system with microfluidic flowchips allows for in situ supernatant sampling, sensitive luminescence Lactate-Glo assay and high content imaging.

Methods: Tumoroids were formed in ULA plate from primary cells from a TNBC biopsy, TU-BcX-4IC (4IC). Single tumoroids were assayed in flowchips in the Pu·MA system. The workflow comprised of a) measuring pre-treatment tumoroid viability with RT-Glo assay b) time-course automated supernatant sampling for measuring lactate using Lactate-Glo assay and c) post-treatment imaging of viability response for IC50 calculation.

Results: RT-Glo assay of 4IC tumoroids showed sufficient signal-to-background ratio of 44 and signal-to-noise ratio of 690. Before treatment, the coefficient of variation of signal from samples was 26% indicating high starting uniformity of tumoroid size and viability, which is important for the validity of the conclusions. Treatment of 4IC tumoroids for 48 hr with paclitaxel, romidepsin (HDAC1/2 inhibitor) and trametinib (MEK1/2 inhibitor) showed varying sensitivities to these drugs. IC50 values for romidepsin and trametinib were ~10 nM, as compared to paclitaxel >1 μM, which is much greater than typically reported for breast cancer models. This is consistent with previously published taxane resistance of 4IC primary tumor. Tumoroid treatment of over 9 - 12 hr also resulted in statistically significant increase in lactate secretion for paclitaxel (p < 0.05) and romidepsin (p < 0.01) indicating drug-induced shift toward glycolysis. These results corroborate previous publications linking treatment with paclitaxel to increased lactate production and chemoresistance in breast cancer.

Conclusions: Profiling of patient-derived tumoroids using the automated Pu·MA System for dynamic metabolic changes shows great potential for studying disease progression, drug resistance, identifying new therapies and advancing personalized medicine.

Citation Format: Ekaterina Nikolov, Oksana Sirenko, Matthew Hammer, Courtney Brock, Anthony Thai, Matthew Burow, Bridgette Collins-Burow, Evan Cromwell. Monitoring metabolite dynamics in patient-derived tumoroids using automated microfluidic Pu·MA System [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 185.

Splenogonadal fusion: aiding detection and avoiding radical orchidectomy

Splenogonadal fusion is a rare benign congenital anomaly in which there is an abnormal connection between the gonad and the spleen. It was first described over 100 years ago with limited reports in the literature since then. Its similarity in presentation to testicular neoplasia poses a significant challenge in diagnosis and management, often resulting in radical orchidectomy. We present the case of a 31-year-old man who presented with a rapidly growing left-sided testicular mass and suspicious ultrasound findings; histology from the subsequent radical inguinal orchidectomy showed findings consistent with splenogonadal fusion. We describe points for consideration in the clinical history, examination and imaging that could suggest splenogonadal fusion, including preoperative technetium-99m-sulfur colloid imaging and intraoperative frozen section evaluation, which may confirm the diagnosis and prevent unnecessary orchidectomy.

Interventions to prevent preterm delivery in women with short cervix before fetoscopic laser surgery for twin-twin transfusion syndrome

OBJECTIVE

Preoperative short cervical length (CL) remains a major risk factor for preterm birth after laser surgery for twin-twin transfusion syndrome (TTTS), but the optimal intervention to prolong pregnancy remains elusive. The objective of this study was to compare secondary methods for the prevention of preterm birth in twin pregnancies with TTTS undergoing fetoscopic laser photocoagulation (FLP), in the setting of a short cervix at the time of FLP, in five North American Fetal Treatment Network (NAFTNet) centers.

METHODS

This was a secondary analysis of data collected prospectively at five NAFTNet centers, conducted from January 2013 to March 2020. Inclusion criteria were a monochorionic diamniotic twin pregnancy complicated by TTTS, undergoing FLP, with preoperative CL < 30 mm. Management options for a short cervix included expectant management, vaginal progesterone, pessary (Arabin, incontinence or Bioteque cup), cervical cerclage or a combination of two or more treatments. Patients were not included if the intervention was initiated solely on the basis of having a twin gestation rather than at the diagnosis of a short cervix. Demographics, ultrasound characteristics, operative data and outcomes were compared. The primary outcome was FLP-to-delivery interval. Propensity-score matching was performed, with each treatment group matched (1:1) to the expectant-management group for CL, in order to estimate the effect of each treatment on the FLP-to-delivery interval.

RESULTS

A total of 255 women with a twin pregnancy complicated by TTTS and a short cervix undergoing FLP were included in the study. Of these, 151 (59%) were managed expectantly, 32 (13%) had vaginal progesterone only, 21 (8%) had pessary only, 21 (8%) had cervical cerclage only and 30 (12%) had a combination of treatments. A greater proportion of patients in the combined-treatment group had had a prior preterm birth compared with those in the expectant-management group (33% vs 9%; P = 0.01). Mean preoperative CL was shorter in the pessary, cervical-cerclage and combined-treatment groups (14-16 mm) than in the expectant-management and vaginal-progesterone groups (22 mm for both) (P < 0.001). There was no significant difference in FLP-to-delivery interval between the groups, nor in gestational age at delivery or the rate of live birth or neonatal survival. Vaginal progesterone was associated with a decrease in the risk of delivery before 28 weeks' gestation compared with cervical cerclage and combined treatment (P = 0.03). Using propensity-score matching for CL, cervical cerclage was associated with a reduction in FLP-to-delivery interval of 13 days, as compared with expectant management.

CONCLUSIONS

A large proportion of pregnancies with TTTS and a short maternal cervix undergoing FLP were managed expectantly for a short cervix, establishing a high (62%) risk of delivery before 32 weeks in this condition. No treatment that significantly improved outcome was identified; however, there were significant differences in potential confounders and there were also likely to be unmeasured confounders. Cervical cerclage should not be offered as a secondary prevention for preterm birth in twin pregnancies with TTTS and a short cervix undergoing FLP. A large randomized controlled trial is urgently needed to determine the effects of treatments for the prevention of preterm birth in these pregnancies. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Cardiovascular Neuroendocrinology: Emerging Role for Neurohypophyseal Hormones in Pathophysiology

Arginine vasopressin (AVP) and oxytocin (OXY) are released by magnocellular neurosecretory cells that project to the posterior pituitary. While AVP and OXY currently receive more attention for their contributions to affiliative behavior, this mini-review discusses their roles in cardiovascular function broadly defined to include indirect effects that influence cardiovascular function. The traditional view is that neither AVP nor OXY contributes to basal cardiovascular function, although some recent studies suggest that this position might be re-evaluated. More evidence indicates that adaptations and neuroplasticity of AVP and OXY neurons contribute to cardiovascular pathophysiology.

Constitutive activation of MEK5 promotes a mesenchymal and migratory cell phenotype in triple negative breast cancer

Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer with limited targeted therapeutic options. A defining feature of TNBC is the propensity to metastasize and acquire resistance to cytotoxic agents. Mitogen activated protein kinase (MAPK) and extracellular regulated kinase (ERK) signaling pathways have integral roles in cancer development and progression. While MEK5/ERK5 signaling drives mesenchymal and migratory cell phenotypes in breast cancer, the specific mechanisms underlying these actions remain under-characterized. To elucidate the mechanisms through which MEK5 regulates the mesenchymal and migratory phenotype, we generated stably transfected constitutively active MEK5 (MEK5-ca) TNBC cells. Downstream signaling pathways and candidate targets of MEK5-ca cells were based on RNA sequencing and confirmed using qPCR and Western blot analyses. MEK5 activation drove a mesenchymal cell phenotype independent of cell proliferation effects. Transwell migration assays demonstrated MEK5 activation significantly increased breast cancer cell migration. In this study, we provide supporting evidence that MEK5 functions through FRA-1 to regulate the mesenchymal and migratory phenotype in TNBC.

Splenogonadal fusion: aiding detection and avoiding radical orchidectomy

Splenogonadal fusion is a rare benign congenital anomaly in which there is an abnormal connection between the gonad and the spleen. It was first described over 100 years ago with limited reports in the literature since then. Its similarity in presentation to testicular neoplasia poses a significant challenge in diagnosis and management, often resulting in radical orchidectomy. We present the case of a 31-year-old man who presented with a rapidly growing left-sided testicular mass and suspicious ultrasound findings; histology from the subsequent radical inguinal orchidectomy showed findings consistent with splenogonadal fusion. We describe points for consideration in the clinical history, examination and imaging that could suggest splenogonadal fusion, including preoperative technetium-99m-sulfur colloid imaging and intraoperative frozen section evaluation, which may confirm the diagnosis and prevent unnecessary orchidectomy.

Trend in ventricle size during pregnancy and its use for prediction of ventriculoperitoneal shunt in fetal open neural tube defect

OBJECTIVES

Fetal surgery for repair of open neural tube defect (ONTD) typically results in decreased need for a ventriculoperitoneal shunt (VPS). Our objectives were to determine the trend in ventricle size (VS) during pregnancy and whether VS and change in VS, as assessed by ultrasound, were predictive of the need for VPS in pregnancy with ONTD.

METHODS

This was a retrospective analysis of prospectively collected data of consecutive pregnancies with ONTD, evaluated in a single center from January 2012 to May 2018. Two groups were identified: the first consisted of pregnancies that underwent in-utero repair (IUR) and the second those that had postnatal repair (PNR). Penalized B splines were used to determine the trend in VS, across 2-week gestational-age (GA) epochs, between 24 and 36 weeks of gestation. VS at each GA epoch and the change in VS between each GA epoch were compared between the IUR and PNR groups. To determine whether VS at any GA was predictive of VPS, receiver-operating-characteristics (ROC) curves were used and the optimal cut-off at each GA epoch was identified. Univariate analysis and multiple logistic regression were used for further analysis.

RESULTS

ONTD was diagnosed in 110 fetuses, of whom 69 underwent IUR and 41 had PNR. Fetuses in the IUR group were more likely to have Chiari II malformation (100.0% vs 82.9%; P < 0.01), lower GA at delivery (34.9 ± 3.2 vs 37.1 ± 2.1 weeks; P < 0.01) and lower rates of VPS within the first year postpartum (36.2% vs 61.0%; P = 0.02) compared with the PNR group. In both groups, VS increased steadily with GA from the initial evaluation to delivery. In the IUR group, there was a significant change in VS between the 24 + 0 to 25 + 6-week and the 26 + 0 to 27 + 6-week epochs (2.3 (95% CI, 0.4-4.1) mm; P = 0.02). There was a positive trend in the change in VS at later GAs, but this was not significant. Although there was no significant change in VS in the PNR group before 30 weeks, there was a positive trend after that time. On multivariate analysis, each week of advancing GA was associated with a mean increase of 0.74 mm in VS (P < 0.0001) in both groups. VS was not associated with the level or type of lesion, but presence of Chiari II malformation was associated with a mean increase of 5.88 mm (P < 0.0001) in VS in both the IUR and PNR groups. VS was modestly predictive of need for VPS in both groups, with area under ROC curves between 0.68 and 0.76 at the different GA epochs. Change in VS between the first and last measurements was also modestly predictive of the need for VPS, with better performance in the PNR group.

CONCLUSIONS

VS increased with advancing GA in all fetuses with ONTD, although in the IUR group this increase occurred immediately after fetal surgery and in the PNR group it occurred after 30 weeks of gestation. In-utero surgery was associated with a decreased rate of VPS and was more predictive of need for VPS than was VS. Postnatal factors resulting in increased need for VPS in the PNR group need to be assessed further. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Short-term transcutaneous non-invasive vagus nerve stimulation may reduce disease activity and pro-inflammatory cytokines in rheumatoid arthritis: results of a pilot study

Objective: Rheumatoid arthritis (RA) is a chronic, autoimmune, inflammatory disease. Studies suggest that pro-inflammatory cytokines may be attenuated by the vagus nerve through the cholinergic anti-inflammatory pathway. We aimed to evaluate the anti-inflammatory effects of short-term transcutaneous non-invasive vagus nerve stimulation (n-VNS) applied to the cervical vagus nerve in patients with RA. Method: We conducted a single-centre, open-label, preliminary proof-of-concept study of n-VNS in two cohorts of participants with RA: one with high disease activity (n = 16) and one with low disease activity (n = 20). Disease Activity Score based on 28-joint count-C-reactive protein (DAS28-CRP), cardiac vagal tone, and pro-inflammatory cytokines were measured at baseline and after 1 and 4 days of n-VNS. Results: In the high disease activity group, n-VNS resulted in reductions in DAS28-CRP (4.1 to 3.8, p = 0.02), CRP (8.2 to 6 mg/mL, p = 0.01), and interferon-γ (29.8 to 22.5 pg/mL, p = 0.02). In the low disease activity group, there was no effect on DAS28-CRP, and n-VNS was associated with a decrease in cardiac vagal tone (p = 0.03) and a reduction in interleukin-10 (0.8 to 0.6 pg/mL, p = 0.02). Participants with high disease activity had lower baseline cardiac vagal tone than those with low disease activity (3.6 ± 2 vs 4.9 ± 3 linear vagal scale, p = 0.03). Cardiac vagal tone was negatively associated with DAS28-CRP (r = -0.37, p = 0.03). Overall, n-VNS was well tolerated. Conclusion: This study provides preliminary support for an anti-inflammatory effect of n-VNS in patients with RA. These findings warrant further investigation in larger placebo-controlled trials.

Cortical processing to anorectal stimuli after rectal resection with and without radiotherapy

BACKGROUND

Bowel dysfunction is common after surgery for rectal cancer, especially when neoadjuvant radiotherapy is used. The role of sensory function in the pathogenesis remains obscure, and the aim of the present study was to characterize the sensory pathways of the brain-gut axis in rectal cancer patients treated with resection ± radiotherapy compared with healthy volunteers.

METHODS

Sensory evaluation by (neo)rectal distensions was performed and sensory evoked potentials (SEPs) were recorded during rapid balloon distensions of the (neo)rectum and anal canal in resected patients with (n = 8) or without (n = 12) radiotherapy. Twenty healthy volunteers were included for comparison. (Neo)rectal latencies and amplitudes of SEPs were compared and spectral band analysis from (neo)rectal and anal distensions was used as a proxy of neuronal processing.

RESULTS

Neorectal sensation thresholds were significantly increased in both patient categories (all p < 0.008). There were no differences in (neo)rectal SEP latencies and amplitudes between groups. However, spectral analysis of (neo)rectal SEPs showed significant differences between all groups in all bands (all p < 0.01). On the other hand, anal SEP analyses only showed significant differences between the delta (0-4 Hz), theta (4-8 Hz) and, gamma 32-50 Hz) bands (all p < 0.02) between the subgroup of patients that also received radiotherapy and healthy volunteers.

CONCLUSIONS

Surgery for rectal cancer leads to abnormal cortical processing of neorectal sensation. Additional radiotherapy leads to a different pattern of central sensory processing of neorectal and anal sensations. This may play a role in the functional outcome of these patients.

Regional gastrointestinal pH profile is altered in patients with type 1 diabetes and peripheral neuropathy

BACKGROUND

Gastrointestinal (GI) symptoms, such as nausea and bloating, are common in people with type 1 diabetes (T1DM). Autonomic dysfunction can lead to changes in the GI secreto-motor function which can be associated with GI symptom development. We hypothesized that regional pH profiles in T1DM differs from health and would be associated with objective physiological/clinical markers.

METHODS

Forty-seven T1DM with confirmed diabetic sensory peripheral neuropathy and 41 healthy age-matched subjects underwent standardized wireless motility capsule testing. T1DM completed the gastroparesis cardinal symptom index (GCSI) and the gastrointestinal symptom rating scale. Disease duration, glycemic control, insulin usage, and 24-hour heart rate variability testing were evaluated.

KEY RESULTS

In comparison to healthy subjects, gastric, and large bowel median pH were lower in T1DM (1.8 ± 1.6 vs 2.9 ± 1.5, P = 0.001 and 6.7 ± 0.6 vs 7.0 ± 0.5, P = 0.003, respectively). Additionally, change in pH across the pylorus was lower while change in pH across the ileocecal junction was higher in T1DM (5.2 ± 1.5 vs 5.8 ± 0.5, P = 0.003 and 1.8 ± 0.4 vs 1.3 ± 0.4, P < 0.0001, respectively). No difference was found in small bowel median pH. Gastric median pH was associated with small bowel transit time (r = 0.30, P = 0.049). Change in pH across the pylorus was negatively associated with fasting glycose (r = -0.35, P = 0.027). Small bowel median pH was associated with nausea (r = 0.42, P = 0.005) and small bowel transit time (r = 0.48, P = 0.0007). Large bowel median pH was associated with nausea (r = 0.35, P = 0.018) and the total GCSI score (r = 0.34, P = 0.023).

CONCLUSIONS AND INFERENCES

The GI pH profile in T1DM with DSPN is different from healthy subjects. Changes in pH profile may have important therapeutic implications and influence pharmacotherapeutic bioavailability.

Regional gastrointestinal contractility parameters using the wireless motility capsule: inter-observer reproducibility and influence of age, gender and study country

BACKGROUND

The wireless motility capsule concurrently measures temperature, pH and pressure as it traverses the gastrointestinal tract.

AIMS

To describe normative values for motility/contractility parameters across age, gender and testing centres.

METHODS

Healthy participants underwent a standardised wireless motility capsule assessment following an overnight fast and consumption of a meal of known nutritional content. Traces were divided into regions of interest and analysed using 2 software packages (MotiliGI and GIMS Data Viewer). Inter-observer agreement was independently assessed by 2 investigators.

RESULTS

Normative data for motility/contractility parameters (maximum amplitude, mean peak amplitude, contraction frequency and motility index) are presented for 107 individuals (62 male, median age 40 years, range 18-78). MotiliGI-Gastric, small bowel and colonic maximal contraction amplitude correlated with age (r = .24, P = .01; r = .22, P = .02; and r = .2, P = .04 respectively). Small bowel motility index was higher in females than males (150.4 ± 12 vs 122 ± 7.6, P = .04). Inter-observer agreement was excellent for transit times, pH and contractility/motility parameters. GIMS Data viewer-Gastric, small bowel and colonic log_e motility index correlated with the respective area under the contraction curve, total contractions, sum of amplitudes and contraction frequency (all r>.35, P < .0003) but not with transit times.

CONCLUSIONS

Our analysis provides normative data for motility/contractility parameters. Log motility index summarises a number of measures. In future, the measurement of contractile activity with the wireless motility capsule may potentially aid in the diagnosis of disease states such as visceral myopathic disorders.

Cardiac vagal tone, a non-invasive measure of parasympathetic tone, is a clinically relevant tool in Type 1 diabetes mellitus

AIMS

To compare a novel index of parasympathetic tone, cardiac vagal tone, with established autonomic variables and to test the hypotheses that (1) cardiac vagal tone would be associated with established time and frequency domain measures of heart rate and (2) cardiac vagal tone would be lower in people with Type 1 diabetes than in a matched healthy cohort and lower still in people with established neuropathy.

METHODS

Cardiac vagal tone is a validated cardiometrically derived index of parasympathetic tone. It is measured using a standard three-lead electrocardiogram which connects, via Bluetooth, to a smartphone application. A 5-min resting recording of cardiac vagal tone was undertaken and observational comparisons were made between 42 people with Type 1 diabetes and peripheral neuropathy and 23 without peripheral neuropathy and 65 healthy people. In those with neuropathy, 24-h heart rate variability values were compared with cardiac vagal tone. Correlations between cardiac vagal tone and clinical variables were also made.

RESULTS

Cardiac vagal tone was lower in people with established neuropathy and Type 1 diabetes in comparison with healthy participants [median (interquartile range) linear vagal scale 3.4 (1.6-5.5 vs 7.0 (5.5-9.6); P < 0.0001]. Cardiac vagal tone was positively associated with time (r = 0.8, P < 0.0001) and frequency domain markers of heart rate variability (r = 0.75, P < 0.0001), representing established measures of parasympathetic function. Cardiac vagal tone was negatively associated with age (r=-0.32, P = 0.003), disease duration (r=-0.43, P < 0.0001) and cardiovascular risk score (r=-0.32, P = 0.006).

CONCLUSIONS

Cardiac vagal tone represents a convenient, clinically relevant method of assessing parasympathetic nervous system tone, potentially facilitating the earlier identification of people with Type 1 diabetes who should undergo formal autonomic function testing.

Vagal influences in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic immune-mediated inflammatory disease with a prevalence of 0.5-1% in Western populations. Conventionally, it is treated with therapeutic interventions that include corticosteroids, disease-modifying anti-rheumatic drugs, and biological agents. RA exerts a significant socio-economic burden and despite the use of existing treatments some patients end up with disabling symptoms. The autonomic nervous system (ANS) is a brain-body interface that serves to regulate homeostasis by integrating the external environment with the internal milieu. The main neural substrate of the parasympathetic branch of the ANS is the vagus nerve (VN). The discovery of the role of the ANS and the VN in mediating and dampening the inflammatory response has led to the proposal that modulation of neural circuits may serve as a valuable therapeutic tool. Recent studies have explored the role of the VN in this inflammatory reflex and have provided evidence that stimulation may represent a novel new therapeutic intervention. Accumulating evidence suggests that modulation of the parasympathetic tone results in a broad physiological multi-level response, including decreased pro-inflammatory cytokine response in terms of tumour necrosis factor-α, interleukin-1 (IL-1), and IL-6, and may result in an enhanced macrophage switch from M1 to M2 cells and potentially an increased level of the anti-inflammatory cytokine IL-10. Therefore, therapeutic electrical modulation of the VN may serve as an alternative, non-pharmacological, neuroimmunomodulatory intervention in RA in the future. This review gives a focused introduction to the mechanistic link between the ANS and the immune system.

The impact of naloxegol treatment on gastrointestinal transit and colonic volume

Aims

Opioid treatment is associated with gastrointestinal (GI) side effects, known as opioid-induced bowel dysfunction (OIBD). Symptoms of OIBD are caused by opioid receptor activation in the enteric nervous system, which results in increased GI transit time and increased faecal volume in the colon. OIBD can be experimentally induced in healthy participants through oral oxycodone treatment. The aim of this study was to investigate whether administration of naloxegol, a peripherally restricted opioid antagonist, could reduce GI symptoms, GI transit time, and colorectal volume, using an experimental model of OIBD.

Methods

In a double blind crossover trial, twenty-five healthy males were randomly assigned to a six day treatment of oral oxycodone in combination with either oral naloxegol or placebo. At baseline and at day six, participants filled in the Patient Assessment of Constipation Symptom questionnaire, and colorectal volume was quantified with a magnetic resonance imaging method. Participants swallowed a small electromagnetic capsule, which allowed determination of total and segmental GI transit times, using the 3D-Transit system.

Results

In the established model of oxycodone induced OIBD, fewer GI symptoms were observed during naloxegol treatment, compared to placebo (P <0.01). Naloxegol decreased median total transit time by 27% (56 vs 71 h, P < 0.05) and decreased colorectal transit time by 33% (45 vs 59 h, P < 0.01), compared to placebo. No difference in colorectal volume was found between the two treatments.

Conclusions

In an experimental model of OIBD, GI symptoms and GI transit time were reduced during treatment with naloxegol, compared to placebo. However, naloxegol treatment did not reduce colorectal volume. These findings add information on the potential of naloxegol to be used in prevention and treatment of OIBD.

Transcutaneous cervical vagal nerve stimulation modulates cardiac vagal tone and tumor necrosis factor-alpha

The vagus nerve is a central component of cholinergic anti-inflammatory pathways. We sought to evaluate the effect of bilateral transcutaneous cervical vagal nerve stimulation (t-VNS) on validated parameters of autonomic tone and cytokines in 20 healthy subjects. 24 hours after t-VNS, there was an increase in cardiac vagal tone and a reduction in tumor necrosis factor-α in comparison to baseline. No change was seen in blood pressure, cardiac sympathetic index or other cytokines. These preliminary data suggest that t-VNS exerts an autonomic and a subtle antitumor necrosis factor-α effect, which warrants further evaluation in larger controlled studies.

The impact of opioid treatment on regional gastrointestinal transit

Aims

To employ a human experimental model of opioid-induced bowel dysfunction (OIBD) in healthy volunteers, and evaluate the impact of opioid treatment compared to placebo on gastrointestinal (GI) symptoms and motility, assessed by questionnaires and regional GI transit times.

Methods

Twenty-five healthy males were randomly assigned to oxycodone or placebo for five days in a double-blind, crossover design. Adverse GI effects were measured with bowel function index, gastrointestinal symptom rating scale, patient assessment of constipation symptoms questionnaire, and bristol stool form scale. Regional GI transit times were determined using the 3D-Transit system and segmental colonic transit times were determined using a custom Matlab® graphical user interface.

Results

GI symptom scores increased significantly across all applied questionnaires during opioid treatment. Oxycodone increased median total GI transit time from 22.2 to 43.9 h (P< 0.01), segmental transit times in the cecum and ascending colon from 5.7 to 9.9 h (P<0.05), rectosigmoid transit time from 2.7 to 9.0 h (P<0.05), and colorectal transit time from 18.6 to 38.6 h (P<0.01). No association between questionnaire scores and segmental transit times were detected.

Conclusions

Self-assessed adverse GI effects and increased GI transit times in different segments were induced during oxycodone treatment. This detailed information about segmental changes in motility has great potential for future interventional head-to-head trials of different laxative regimes for prevention and treatment of OIBD.

Modulation of vagal tone enhances gastroduodenal motility and reduces somatic pain sensitivity

BACKGROUND

The parasympathetic nervous system, whose main neural substrate is the vagus nerve, exerts a fundamental antinociceptive role and influences gastrointestinal sensori-motor function. Our research question was to whether combined electrical and physiological modulation of vagal tone, using transcutaneous electrical vagal nerve stimulation (t-VNS) and deep slow breathing (DSB) respectively, could increase musculoskeletal pain thresholds and enhance gastroduodenal motility in healthy subjects.

METHODS

Eighteen healthy subjects were randomized to a subject-blinded, sham-controlled, cross-over study with an active protocol including stimulation of auricular branch of the vagus nerve, and breathing at full inspiratory capacity and forced full expiration. Recording of cardiac derived parameters including cardiac vagal tone, moderate pain thresholds to muscle, and bone pressure algometry, conditioned pain modulation using a cold pressor test and a liquid meal ultrasonographic gastroduodenal motility test were performed.

KEY RESULTS

Cardiac vagal tone increased during active treatment with t-VNS and DSB compared to sham (p = 0.009). In comparison to sham, thresholds to bone pain increased (p = 0.001), frequency of antral contractions increased (p = 0.004) and gastroduodenal motility index increased (p = 0.016) with active treatment. However, no effect on muscle pain thresholds and conditioned pain modulation was seen.

CONCLUSIONS & INFERENCES

This experimental study suggests that this noninvasive approach with combined electrical and physiological modulation of vagal tone enhances gastroduodenal motility and reduces somatic pain sensitivity. These findings warrant further investigation in patients with disorders characterized with chronic pain and gastrointestinal dysmotility such as functional dyspepsia and irritable bowel syndrome.

Quantification and variability in colonic volume with a novel magnetic resonance imaging method

BACKGROUND

Segmental distribution of colorectal volume is relevant in a number of diseases, but clinical and experimental use demands robust reliability and validity. Using a novel semi-automatic magnetic resonance imaging-based technique, the aims of this study were to describe: (i) inter-individual and intra-individual variability of segmental colorectal volumes between two observations in healthy subjects and (ii) the change in segmental colorectal volume distribution before and after defecation.

METHODS

The inter-individual and intra-individual variability of four colorectal volumes (cecum/ascending colon, transverse, descending, and rectosigmoid colon) between two observations (separated by 52 ± 10) days was assessed in 25 healthy males and the effect of defecation on segmental colorectal volumes was studied in another seven healthy males.

KEY RESULTS

No significant differences between the two observations were detected for any segments (All p > 0.05). Inter-individual variability varied across segments from low correlation in cecum/ascending colon (intra-class correlation coefficient [ICC] = 0.44) to moderate correlation in the descending colon (ICC = 0.61) and high correlation in the transverse (ICC = 0.78), rectosigmoid (ICC = 0.82), and total volume (ICC = 0.85). Overall intra-individual variability was low (coefficient of variance = 9%). After defecation the volume of the rectosigmoid decreased by 44% (p = 0.003). The change in rectosigmoid volume was associated with the true fecal volume (p = 0.02).

CONCLUSIONS & INFERENCES

Imaging of segmental colorectal volume, morphology, and fecal accumulation is advantageous to conventional methods in its low variability, high spatial resolution, and its absence of contrast-enhancing agents and irradiation. Hence, the method is suitable for future clinical and interventional studies and for characterization of defecation physiology.

Abnormal neuronal response to rectal and anal stimuli in patients with idiopathic fecal incontinence

BACKGROUND

The pathophysiology behind idiopathic fecal incontinence (IFI) is poorly understood. We hypothesized abnormal sensory pathways along the brain-gut axis as a key player in this disease, reflected in cortical evoked potentials (CEP) from mechanical stimuli of the rectum and the anal canal.

METHODS

CEPs were recorded during repeated rapid balloon distensions of the rectum and anal canal in 19 women with IFI (mean age: 60 ± 14, mean Wexner score: 14.7 ± 2.9) and in 19 healthy women (mean age: 56 ± 11, mean Wexner score: 1.1 ± 1.3). Latencies, amplitudes and topography of CEPs elicited by rectal distension were compared between the groups. CEPs from both rectal and anal distensions were examined using spectral band analysis of single sweeps determining the relative amplitude of five spectral bands as a proxy of neuronal processing.

KEY RESULTS

Compared to controls IFI patients had prolonged latency of CEPs from rectal distension by up to 27% (p < 0.001) while amplitudes and topography were similar (all p > 0.7 and all p > 0.23). Spectral analysis of CEPs from rectal distensions showed no difference (all p > 0.1) between groups. However, analysis of CEPs following distension of the anal canal resulted in abnormally low activity in beta (8-12 Hz; p < 0.001) band and high activity in the gamma (32-70 Hz; p = 0.04) band in patients.

CONCLUSIONS & INFERENCES

IFI seems to be associated with impaired ano-rectal sensory functions in both the afferent fibers to the brain and the cortical processing of anal sensory pathways. This may play a central role for the pathogenesis of IFI.

Rapid balloon distension as a tool to study cortical processing of visceral sensations and pain

BACKGROUND

The processing of discomfort and pain in the central nervous system is normally studied with experimental methods, but it is mandatory that they are reliable over time to ensure that any interventions will result in valid results. We investigated reliability of rapid balloon distension in the rectum to elicit cortical evoked potentials (CEPs) to study the reliability of central processing of visceral sensation and discomfort/pain.

METHODS

Eighteen healthy volunteers had two series of rectal balloon distensions performed on two separate days. Individualized balloon pressure, corresponding to pain detection threshold or to the maximum possible distension (30 psi), was used. Within- and between days reliability was measured in terms of amplitudes and latencies of the CEP global field power, topography and underlying brain networks.

KEY RESULTS

There were two prominent peaks in the CEP recordings at mean latencies of 157 and 322 ms. There were no differences in latencies or amplitudes (p = 0.3) and they passed the Bland-Altman test for reproducibility. There were no differences in topographies (p > 0.7). Brain source connectivity revealed the cingulate-operculum network as the most consistent network within and between subjects. There were no differences in the location of brain sources in this network (p = 0.9) and the source coordinates were reproducible. Finally, the cingulate source generally had higher strength than operculum source (p < 0.001).

CONCLUSIONS & INFERENCES

A reliable method to study central mechanisms underlying visceral sensation and pain was established. The method may improve our understanding of visceral pain and could be an objective method for studying efficacy of analgesics on visceral pain.

Effect of protein overfeeding on energy expenditure measured in a metabolic chamber

BACKGROUND

Energy expenditure (EE) increases with overfeeding, but it is unclear how rapidly this is related to changes in body composition, increased body weight, or diet.

OBJECTIVE

The objective was to quantify the effects of excess energy from fat or protein on energy expenditure of men and women living in a metabolic chamber.

DESIGN

We conducted a randomized controlled trial in 25 participants who ate ∼40% excess energy for 56 d from 5%, 15%, or 25% protein diets. Twenty-four-hour EE (24EE) and sleeping EE (SleepEE) were measured on days 1, 14, and 56 of overfeeding and on day 57 while consuming the baseline diet (usually day 57). Metabolic and molecular markers of muscle metabolism were measured in skeletal muscle biopsy specimens.

RESULTS

In the low-protein diet group whose excess energy was fat, the 24EE and SleepEE did not increase during the first day of overfeeding. When extra energy contained protein, both 24EE and SleepEE increased in relation to protein intake (r = 0.50, P = 0.02). The 24EE over 8 wk in all 3 groups was correlated with protein intake (r = 0.60, P = 0.004) but not energy intake (r = 0.16; P = 0.70). SleepEE was unchanged by overfeeding in the low-protein diet group, and baseline surface area predicted increased 24EE in this group. Protein and fat oxidation were reciprocally related during overfeeding. Observed 24EE was higher than predicted on days 1 (P ≤ 0.05), 14 (P = 0.0001), and 56 (P = 0.0007). There was no relation between change in fat mass and change in EE.

CONCLUSIONS

Excess energy, as fat, does not acutely increase 24EE, which rises slowly as body weight increases. Excess energy as protein acutely stimulates 24EE and SleepEE. The strongest relation with change in 24EE was the change in energy expenditure in tissue other than muscle or fat-free mass.

Sacral nerve stimulation changes rectal sensitivity and biomechanical properties in patients with irritable bowel syndrome

BACKGROUND

Sacral nerve stimulation (SNS) has been demonstrated to alleviate symptoms and improve quality of life in selected patients with irritable bowel syndrome (IBS). The mechanisms of action, however, remain unknown. The aim of the study was to evaluate the effects of SNS on rectal sensitivity and biomechanical properties in patients with IBS.

METHODS

Twenty patients with diarrhea-predominant (n = 11) or mixed (n = 9) IBS were treated with SNS in a controlled, randomized crossover trial. They were randomized to either 1 month of SNS (ON) or placebo (OFF) with the opposite setting for the next month. Sensory and biomechanical parameters were assessed by multimodal rectal stimulation at the end of each period. IBS-specific symptoms were evaluated at baseline and at the end of each treatment period.

KEY RESULTS

Cold stimuli were better tolerated in the ON period (19.9 °C[± 0.6]) compared to the OFF period (21.8 °C[± 0.6]; p = 0.03). Significantly lower cross-sectional areas were needed to elicit sensory responses in the ON period (1545 mm(2) [± 95]) compared to the OFF period (1869 mm(2) [± 92]; p = 0.015). The association between reduced sensory threshold and improvement of constipation was of borderline significance (p = 0.05). Wall stiffness was significantly lower in the ON period (192 mmHg[± 10]) compared to the OFF period (234 mmHg[± 10]; p = 0.004). Reduced wall stiffness was significantly associated with improved overall GSRS-IBS symptom score (p = 0.01). Reduced sensory threshold to stretch (p = 0.02) and reduced wall stiffness (p < 0.001) were predictors of the GSRS-IBS symptom score.

CONCLUSIONS & INFERENCES

SNS for diarrhea-predominant and mixed IBS relaxes the rectal wall, while making it more sensitive to stretch and less sensitive to cold. Reduced wall stiffness and increased sensitivity to stretch are associated with improved GSRS-IBS symptom score.

Cortical evoked potentials in response to rapid balloon distension of the rectum and anal canal

BACKGROUND

Neurophysiological evaluation of anorectal sensory function is hampered by a paucity of methods. Rapid balloon distension (RBD) has been introduced to describe the cerebral response to rectal distension, but it has not successfully been applied to the anal canal.

METHODS

Nineteen healthy women received 30 RBDs in the rectum and the anal canal at intensities corresponding to sensory and unpleasantness thresholds, and response was recorded as cortical evoked potentials (CEPs) in 64-channels. The anal canal stimulations at unpleasantness level were repeated after 4 min to test the within-day reproducibility. CEPs were averaged, and to overcome latency variation related to jitter the spectral content of single sweeps was also computed.

KEY RESULTS

Repeated stimulation of the anal canal generated CEPs with similar latencies but smaller amplitudes compared to those from the rectum. Due to latency jitter, reproducibility of averaged CEPs was lower than what was found in the rectum. The most reproducible feature was N2P2 peak-to-peak amplitude with intra-class correlation coefficient (ICC) of 0.7 and coefficient of variation (CV) of 18%. Spectral content of the single sweeps showed reproducibility with ICCs for all bands >0.8 and corresponding CVs <7%.

CONCLUSIONS & INFERENCES

Cortical potentials evoked from the anal canal are challenged by latency jitter likely related to variability in muscle tone due to the distensions. Using single-sweep analysis, anal CEPs proved to be reproducible and should be used in future evaluation of the anal function.

The brain networks encoding visceral sensation in patients with gastrointestinal symptoms due to diabetic neuropathy

BACKGROUND

Increasing evidence points to association between long-term diabetes mellitus and abnormal brain processing. The aim of this study was to investigate central changes due to electrical stimulation in esophagus in patients with upper gastrointestinal (GI) symptoms due to diabetic neuropathy.

METHODS

Twenty-three diabetes patients with upper GI symptoms and 27 healthy controls were included. A standard ambulatory 24-h electrocardiography was carried out. 122-channel esophageal evoked brain potentials to electrical stimulation were acquired. Brain source/network analysis was performed. Gastroparesis Cardinal Symptom Index was used to evaluate upper GI symptoms and SF-36 questionnaire was utilized to assess patients' quality of life (QOL).

KEY RESULTS

Diabetes patients with GI symptoms showed modifications in three brain networks: (i) brainstem/operculum/frontal cortex, (ii) operculum/cingulate, and (iii) mid-cingulate/anterior-cingulate/operculum/deep limbic structures. Operculum brain source in patients was localized deeper and more anterior in all three networks. The shift of operculum source was correlated with the severity of upper GI symptoms, decreased heart beat-to-beat interval, and decreased SD of the intervals. The activation of the first network was delayed in patients. Operculum source had higher activity than cingulate in the second network in patients, and this was correlated with decreased physical QOL. Deep limbic source was localized deeper in patients, which also correlated with decreased physical QOL.

CONCLUSIONS & INFERENCES

This study indicates involvement of central nervous system in diabetes. Reorganization within opercular cortex was correlated with GI symptoms suggesting that operculo-cingulate cortex could contribute to development and maintenance of GI symptoms in diabetes patients.

Central response to painful electrical esophageal stimulation in well-defined patients suffering from functional chest pain

BACKGROUND

Functional chest pain (FCP) of presumed esophageal origin is considered a common cause for chest pain in which central nervous system hyperexcitability is thought to play an important role. We aimed to compare cerebral responses with painful esophageal stimuli between FCP patients and healthy subjects (HS).

METHODS

Thirteen patients with FCP (seven females, mean age 50.4 ± 7.5 years) and 15 HS (eight females, mean age 49.1 ± 12.9 years) were enrolled. Inclusion criteria consisted of typical chest pain, normal coronary angiogram, and normal upper gastrointestinal evaluation. Electrical stimulations evoking the pain threshold were applied in the distal esophagus, while cortical evoked potentials were recorded from the scalp. Pain scores, resting electroencephalogram (EEG), evoked potential characteristics and brain electrical sources to pain stimulation were compared between groups.

KEY RESULTS

No differences were seen between patients and HS regarding (i) pain thresholds (patients: 20.1 ± 7.4 mA vs HS: 22.4 ± 8.3 mA, all P > 0.05), (ii) resting-EEG (P > 0.05), (iii) evoked brain potential latencies (N2: patients 181.7 ± 25.7 mS vs HS 182.2 ± 25.8 mS, all P > 0.05) and amplitudes (N2P2: patients 8.2 ± 7.2 μV vs HS: 10.1 ± 3.4 μV, all P > 0.05), (iv) topography (P > 0.05), and (v) brain source location (P > 0.05).

CONCLUSIONS & INFERENCES

No differences in activation of brain areas to painful esophageal stimulation were seen in this group of well characterized patients with FCP compared with sex- and age-matched HS. The mechanism of pain in FCP and whether it originates in the esophagus remains unsolved.

Support vector regression correlates single-sweep evoked brain potentials to gastrointestinal symptoms in diabetes mellitus patients

Diabetes mellitus (DM) is a multi-factorial and complex disease causing autonomic neuropathy and gastrointestinal symptoms in some patients. The neural mechanisms behind these symptoms are poorly understood, but it is believed that both peripheral and central mechanisms are involved. To gain further knowledge of the central mechanisms, the aim of this study was to identify biomarkers for the altered brain activity in type-1 DM patients compared to healthy volunteers (HV), and to correlate the obtained biomarkers to clinical patient scores. The study included 14 DM patients and 15 HV, with brain activity recorded as multi-channel electroencephalography evoked brain potentials (EPs) elicited by painful electrical stimulations in the esophagus. The single-sweep EPs were decomposed by an optimized discrete wavelet transform (DWT), and averaged for each channel. The DWT features from the DM patients were discriminated from the HV by a support vector machine (SVM) applied in regression mode. For the optimal DWT, the discriminative features were extracted and the SVM regression value representing the overall alteration of the EP was correlated to the clinical scores. A classification performance of 86.2% (P=0.01) was obtained by applying a majority voting scheme to the 5 best performing channels. The biomarker was identified as decreased theta band activity. The regression value was correlated to symptoms reported by the patients (P=0.04). The methodology is an improvement of the present approach to study central mechanisms in diabetes mellitus, and may provide a future application for a clinical tool to optimize treatment in individual patients.

Macrostructural brain changes in patients with longstanding type 1 diabetes mellitus - a cortical thickness analysis study

Longstanding diabetes mellitus (DM) is associated with the risk of complications affecting the central nervous system. The aims were to study brain volume and cortical thickness in regional brain areas in DM patients and to correlate the findings with relevant clinical data.15 patients with longstanding (average 24.6 years) type 1 DM and 20 healthy controls were studied in a 3T magnetic resonance scanner. Using an automated surface based cortical segmentation method, cortical thickness was assessed in anatomical regions including total and lobe-wise grey and white matter volumes. Also morphological changes were evaluated.No differences between patients and controls were found in regard to number of white matter lesions (P=0.50), grey and white matter volumes (P=0.25) and overall cortical thickness (P=0.64). Subanalysis revealed exclusively reduced cortical thickness of the postcentral (P=0.03) and superior parietal gyrus (P=0.008) in patients. The cortical thickness of these regions was not associated with diabetes duration, age at diabetes onset or to HbA1c (all P>0.08). Patients with peripheral neuropathy showed reduced right postcentral gyrus cortical thickness compared to patients without peripheral neuropathy (P=0.02).Patients with longstanding type 1 diabetes showed cortical thinning involving sensory related areas, even though no overall macrostructural brain alterations were detected. This could possibly have underlying functional significance since cortical thinning was associated to presence of peripheral neuropathy. The absence of universal macrostructural changes might illustrate that more pronounced brain pathology is likely to be preceded by more subtle microstructural changes as reported in other studies.

Measurement of gastric emptying by radiopaque markers in patients with diabetes: correlation with scintigraphy and upper gastrointestinal symptoms

BACKGROUND

Scintigraphy, the gold standard to measure gastric emptying, is expensive and not widely available. Therefore, we compared emptying of radiopaque markers (ROM) from the stomach, by use of fluoroscopy, with scintigraphy in patients with insulin-treated diabetes.

METHODS

On the same day we measured gastric emptying of 20 ROM using fluoroscopy and scintigraphic emptying of a standard solid meal. The subjects also completed a validated gastrointestinal (GI) symptom questionnaire.

KEY RESULTS

We included 115 patients with insulin-treated diabetes (median age 53, range 21-69 years; 59 women). A moderately strong correlation was demonstrated between scintigraphic (% retained at 2 h) and ROM emptying (markers retained at 6 h) (r = 0.47; P < 0.0001). Eighty-three patients had delayed gastric emptying with scintigraphy, whereas only 29 patients had delayed emptying of ROM. Of the 29 patients with delayed emptying of ROM, 28 also had delayed scintigraphic emptying. The sensitivity and specificity of the ROM test was 34% and 97%, respectively. Significant correlations were only noted between scintigraphic gastric emptying and GI symptom severity, with the strongest correlations for fullness/early satiety (r = 0.34; P < 0.001) and nausea/vomiting (r = 0.30; P < 0.001).

CONCLUSIONS & INFERENCES

A gastric emptying test with ROM is a widely available screening method to detect delayed gastric emptying in patients with diabetes, where a positive result seems reliable. However, a normal ROM test does not exclude delayed gastric emptying, and if the clinical suspicion of gastroparesis remains, scintigraphy should be performed. Results from scintigraphy also correlate with GI symptom severity, which ROM test did not.

Peripheral and central nervous contribution to gastrointestinal symptoms in diabetic patients with autonomic neuropathy

BACKGROUND & AIMS

Long-term diabetes mellitus (DM) has been associated with neuronal changes in the enteric, peripheral and/or central nervous system. Moreover, abnormal visceral sensation and gastrointestinal (GI) symptoms are seen in up to 75% of patients. To explore the role of diabetic autonomic neuropathy (DAN) in patients with long-standing DM, we investigated psychophysical responses and neuronal activity recorded as evoked brain potentials and dipolar source modelling.

METHODS

Fifteen healthy volunteers and 14 type-1 DM patients with DAN were assessed with a symptom score index characterizing upper GI abnormalities. Multichannel (62) electroencephalography was recorded during painful electrical stimulation of the lower oesophagus. Brain activity to painful stimulations was modelled using Brain Electrical Source Analysis (besa).

RESULTS

Diabetic patients had higher stimulus intensities to evoke painful sensation (p ≤ 0.001), longer latencies of N2 and P2 components (both p ≤ 0.001), and lower amplitudes of P1-N2 and N2-P2 complexes (p ≤ 0.001; p = 0.02). Inverse modelling of brain sources showed deeper bilateral insular dipolar source localization (p = 0.002). Symptom score index was negatively correlated with the depth of insular activity (p = 0.004) and positively correlated with insular dipole strength (p = 0.03).

CONCLUSION

DM patients show peripheral and central neuroplastic changes. Moreover, the role of abnormal insular processing may explain the appearance and persistence of GI symptoms related to DAN. This enhanced understanding of DAN may have future clinical and therapeutical implications.

Esophageal distension parameters as potential biomarkers of impaired gastrointestinal function in diabetes patients

BACKGROUND

Gastrointestinal (GI) symptoms, such as nausea, vomiting, bloating, postprandial fullness, and abdominal pain, are frequent in patients with diabetes mellitus (DM). The pathogenesis is complex and multi-factorial. To determine easy accessible and valid biomarkers for disordered GI function in DM patients, we aimed to study esophageal mechanical parameters and their relation to symptoms typically arising from the digestive tract.

METHODS

Seventeen patients with longstanding DM and GI symptoms and 13 healthy controls were studied using ultrasound monitored esophageal distension. The sensory response was recorded and their symptoms registered. Biomechanical parameters, such as compliance and stiffness were computed from luminal diameters during distension based on the ultrasound images and from pressure data. Biomechanical and sensory parameters were correlated with the clinical data.

KEY RESULTS

Diabetes patients had reduced esophageal sensitivity compared with controls (P = 0.046). The esophageal compliance was reduced (P = 0.004) and the esophageal stiffness was increased (P = 0.004) in the diabetes patients. Among patients, both postprandial fullness/early satiety and bloating correlated negatively to the esophageal compliance parameters (all P < 0.05).

CONCLUSIONS & INFERENCES

Patients with long-standing DM and GI symptoms had reduced esophageal sensitivity together with reduced compliance and increased stiffness, which were correlated to the patients' GI symptoms. Biomechanical parameters obtained during distension may serve as biomarker for similar pathophysiologic effects of diabetes in the stomach and small bowel. They may contribute to our understanding of the pathophysiology underlying GI dysfunction and symptoms in patients with longstanding DM.

Neuroprotection and estrogen receptors

This review is intended to assess the state of current knowledge on the role of estrogen receptors (ERs) in the neuroprotective effects of estrogens in models for acute neuronal injury and death. We evaluate the overall evidence that estrogens are neuroprotective in acute injury and critically assess the role of ERα, ERβ, GPR 30, and nonreceptor-mediated mechanisms in these robust neuroprotective effects of this ovarian steroid hormone. We conclude that all three receptors, as well as nonreceptor-mediated mechanisms can be involved in neuroprotection, depending on the model used, the level of estrogen administrated, and the mode of administration of the steroid. Also, the signaling pathways used by both ER-dependent and ER-independent mechanisms to exert neuroprotection are considered. Finally, further studies that are needed to parse out the relative contribution of receptor versus nonreceptor-mediated signaling are discussed.

Effect of dietary protein content on weight gain, energy expenditure, and body composition during overeating: a randomized controlled trial

CONTEXT

The role of diet composition in response to overeating and energy dissipation in humans is unclear.

OBJECTIVE

To evaluate the effects of overconsumption of low, normal, and high protein diets on weight gain, energy expenditure, and body composition.

DESIGN, SETTING, AND PARTICIPANTS

A single-blind, randomized controlled trial of 25 US healthy, weight-stable male and female volunteers, aged 18 to 35 years with a body mass index between 19 and 30. The first participant was admitted to the inpatient metabolic unit in June 2005 and the last in October 2007.

INTERVENTION

After consuming a weight-stabilizing diet for 13 to 25 days, participants were randomized to diets containing 5% of energy from protein (low protein), 15% (normal protein), or 25% (high protein), which they were overfed during the last 8 weeks of their 10- to 12-week stay in the inpatient metabolic unit. Compared with energy intake during the weight stabilization period, the protein diets provided approximately 40% more energy intake, which corresponds to 954 kcal/d (95% CI, 884-1022 kcal/d).

MAIN OUTCOME MEASURES

Body composition was measured by dual-energy x-ray absorptiometry biweekly, resting energy expenditure was measured weekly by ventilated hood, and total energy expenditure by doubly labeled water prior to the overeating and weight stabilization periods and at weeks 7 to 8.

RESULTS

Overeating produced significantly less weight gain in the low protein diet group (3.16 kg; 95% CI, 1.88-4.44 kg) compared with the normal protein diet group (6.05 kg; 95% CI, 4.84-7.26 kg) or the high protein diet group (6.51 kg; 95% CI, 5.23-7.79 kg) (P = .002). Body fat increased similarly in all 3 protein diet groups and represented 50% to more than 90% of the excess stored calories. Resting energy expenditure, total energy expenditure, and body protein did not increase during overfeeding with the low protein diet. In contrast, resting energy expenditure (normal protein diet: 160 kcal/d [95% CI, 102-218 kcal/d]; high protein diet: 227 kcal/d [95% CI, 165-289 kcal/d]) and body protein (lean body mass) (normal protein diet: 2.87 kg [95% CI, 2.11-3.62 kg]; high protein diet: 3.18 kg [95% CI, 2.37-3.98 kg]) increased significantly with the normal and high protein diets.

CONCLUSIONS

Among persons living in a controlled setting, calories alone account for the increase in fat; protein affected energy expenditure and storage of lean body mass, but not body fat storage.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00565149.

Aerial ultra-low-volume application of naled: impact on nontarget imperiled butterfly larvae (Cyclargus thomasi bethunebakeri) and efficacy against adult mosquitoes (Aedes taeniorhynchus)

We assessed the exposure and acute toxicity of naled, applied aerially as an ultra-low-volume spray for mosquito control, on late instar larvae of the Miami blue (Cyclargus thomasi bethunebakeri) (Comstock and Huntington 1943) (Lepidoptera: Lycaenidae), an imperiled South Florida butterfly. We concurrently evaluated the control efficacy against caged adult female salt-marsh mosquitoes (Aedes taeniorhynchus) (Wiedemann 1821) (Diptera: Culicidae). This 3-yr study was conducted in north Key Largo (Monroe County, FL) beginning in 2006. The field trials incorporated 15 sampling stations: nine in the target spray zone, three in the spray drift zone at varying distances from the target zone, and three in the control zone not subjected to naled spray drift. A total of six field spray trials were completed, three at an altitude of 30.5 m (100 feet), and three at 45.7 m (150 feet). For all trials, the ultra-low-volume application of Trumpet EC insecticide (78% naled) at a rate of 54.8 ml/ha (0.75 fl. oz/acre) was effective in killing caged adult mosquitoes in the target zone. Butterfly larvae survival was significantly reduced in the spray zone compared with drift and control zones. Analysis of insecticide residue data revealed that the mortality of the late instar butterfly larvae was a result of exposure to excess residues of naled. Additional research is needed to determine mitigation strategies that can limit exposure of sensitive butterflies to naled while maintaining mosquito control efficacy.

Gastrointestinal sensations and pain: a review on basic, experimental and clinical findings

Painful sensations from the gastrointestinal (GI) tract are common symptoms in the clinic but the etiology is often not fully understood and underlying diseases can be difficult to diagnose and treat successfully. In clinical practice, GI pain is often diffuse and pain referral to somatic structures can be the presenting symptom. In addition, concomitant symptoms from the autonomic and enteric nervous system can be present and affect the pain experience. To examine patients suffering from GI pain, basic knowledge about the GI pain system is essential and assists to explain the often complex and diverse symptoms. Information about anatomical and physiological characteristics of the GI pain system come from basic, experimental and clinical research, which have also gained insight into pain mechanisms underlying chronic GI pain. Evidence for sensitisation at the peripheral and central level of the nervous system seems to be of importance. These findings have major implication for the evaluation and treatment of patients suffering from GI pain.

Education research: Bias and poor interrater reliability in evaluating the neurology clinical skills examination

OBJECTIVE

The American Board of Psychiatry and Neurology (ABPN) has recently replaced the traditional, centralized oral examination with the locally administered Neurology Clinical Skills Examination (NEX). The ABPN postulated the experience with the NEX would be similar to the Mini-Clinical Evaluation Exercise, a reliable and valid assessment tool. The reliability and validity of the NEX has not been established.

METHODS

NEX encounters were videotaped at 4 neurology programs. Local faculty and ABPN examiners graded the encounters using 2 different evaluation forms: an ABPN form and one with a contracted rating scale. Some NEX encounters were purposely failed by residents. Cohen's kappa and intraclass correlation coefficients (ICC) were calculated for local vs ABPN examiners.

RESULTS

Ninety-eight videotaped NEX encounters of 32 residents were evaluated by 20 local faculty evaluators and 18 ABPN examiners. The interrater reliability for a determination of pass vs fail for each encounter was poor (kappa 0.32; 95% confidence interval [CI] = 0.11, 0.53). ICC between local faculty and ABPN examiners for each performance rating on the ABPN NEX form was poor to moderate (ICC range 0.14-0.44), and did not improve with the contracted rating form (ICC range 0.09-0.36). ABPN examiners were more likely than local examiners to fail residents.

CONCLUSIONS

There is poor interrater reliability between local faculty and American Board of Psychiatry and Neurology examiners. A bias was detected for favorable assessment locally, which is concerning for the validity of the examination. Further study is needed to assess whether training can improve interrater reliability and offset bias.