Treatment of Severe Swallowing Dysfunction in Systemic Sclerosis with IVIG: Role of Antimuscarinic Antibodies.

Oropharyngeal and esophageal dysmotility can cause serious clinical complications such as aspiration pneumonia, cachexia, and sarcopenia, with a resulting increase in mortality and disability. The current standard of care for the treatment of SSc-associated swallowing dysfunction is mainly supportive, although severe cases are usually refractory to conventional management. Recent studies have shown that the abnormal production of functional autoantibodies such as anti-cholinergic muscarinic receptor III antibodies may participate in the pathogenesis of SSc-associated gastrointestinal dysmotility and may provide a novel target for therapeutic intervention. We describe two patients with severe and rapid onset of SSc-associated severe swallowing dysfunction and esophageal dysmotility who had failed standard of care therapy, requiring complete enteral and parenteral nutrition. Both patients were positive for the presence of circulating antimuscarinic III receptor antibodies. They were treated with IVIG at a dose of 2 g/Kg/month divided in two consecutive days, for six months. Following IVIG therapy, both patients markedly improved their symptoms as shown by a reduction in their UCLA2.0 score, and achieved an improvement of esophageal motility documented radiologically. Both patients resumed oral feeding and had their feeding tubes removed within the treatment period. None of the patients developed severe adverse events attributable to IVIG, except for low-grade fever during IVIG infusion in one of the cases. These results provide support for the role of functional autoantibodies in the development of SSc-associated gastrointestinal dysfunction.

A Rare Case of Mitochondrial Neurogastrointestinal Encephalomyopathy.

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare autosomal recessive disease due to mutations in the thymidine phosphorylase gene, leading to mitochondrial alterations and dysfunctions in oxidative phosphorylation. MNGIE is a multisystem disorder with gastrointestinal symptoms arising in large part from gut dysmotility and neurological manifestations including peripheral neuropathy. We discuss a patient with chronic vomiting, diarrhea, and weight loss with a prior unrevealing extensive workup who was hospitalized for severe protein-calorie malnutrition. The patient was found to have gastrointestinal dysmotility on a gastric emptying scan and persistently elevated lactate levels and was subsequently diagnosed with MNGIE after confirmatory testing.

A Review of Mathematics Determining Solute Uptake at the Blood-Brain Barrier in Normal and Pathological Conditions.

The blood-brain barrier (BBB) limits movement of solutes from the lumen of the brain microvascular capillary system into the parenchyma. The unidirectional transfer constant, Kin, is the rate at which transport across the BBB occurs for individual molecules. Single and multiple uptake experiments are available for the determination of Kin for new drug candidates using both intravenous and in situ protocols. Additionally, the single uptake method can be used to determine Kin in heterogeneous pathophysiological conditions such as stroke, brain cancers, and Alzheimer's disease. In this review, we briefly cover the anatomy and physiology of the BBB, discuss the impact of efflux transporters on solute uptake, and provide an overview of the single-timepoint method for determination of Kin values. Lastly, we compare preclinical Kin experimental results with human parallels.

Prevalence and Characteristics of Dysphagia Based on a Population-Based Survey.

BACKGROUND & AIMS: Although dysphagia is common, there is limited information about the prevalence and burden of illness of dysphagia in the United States. We performed a population-based survey of more than 31,000 adults to evaluate the epidemiology, clinical characteristics, and health care-seeking behavior of individuals with dysphagia. METHODS: We performed a cross-sectional analysis of adults in the United States who completed an online, self-administered health survey from April 4 through April 19, 2018. All respondents were asked which of the following symptoms they had ever experienced (presented in random order): dysphagia, abdominal pain, bloating, bowel incontinence, constipation, diarrhea, heartburn/reflux, nausea/vomiting, or none of the above. Only respondents who selected dysphagia continued the remaining survey, which included questions about dysphagia severity, use of compensatory maneuvers, health care seeking, and esophageal comorbidities. We used multivariable regression methods to adjust for confounding. RESULTS: Of 31,129 individuals who participated in the survey, 4998 respondents (16.1%) reported experiencing dysphagia; 92.3% of these had symptoms in the previous week. We found that 16.3% of respondents described their dysphagia over the previous 7 days as either quite a bit or very severe. Drinking liquids to help with dysphagia (86.0%) and taking longer to finish eating (76.5%) were the most common compensatory maneuvers. Overall, 51.1% of individuals sought care for their difficulty swallowing; older age, male sex, having a usual source of care and insurance, having comorbidities, and more severe dysphagia symptoms increased the odds for seeking care (P < .05). The most commonly reported esophageal comorbidities were gastroesophageal reflux disease (30.9%), eosinophilic esophagitis (8.0%), and esophageal stricture (4.5%). CONCLUSIONS: In a large population-based survey, we found that dysphagia is common; 1 of 6 adults reported experiencing difficulty swallowing. However, half of individuals have not discussed their symptoms with a clinician and many could have treatable disorders.

The Upper Esophageal Sphincter Assist Device Is Associated With Symptom Response in Reflux-Associated Laryngeal Symptoms.

Reflux-associated laryngeal symptoms (RALS) is the process in which chronic laryngeal symptoms are related to gastroesophagopharyngeal reflux.1 Impairment of upper esophageal sphincter (UES) reflexes may predispose to esophagopharyngeal reflux.1 The novel noninvasive nonpharmacologic UES assist device (UESAD) applies external cricoid pressure to augment intraluminal UES pressure by 20 to 30 mm Hg and reduce esophagopharyngeal reflux events.2 This study aimed to assess the therapeutic efficacy of the UESAD in a pragmatic clinical setting, and to identify factors associated with symptom response among patients with suspected RALS.

Oropharyngeal pH Testing Does Not Predict Response to Proton Pump Inhibitor Therapy in Patients with Laryngeal Symptoms.

OBJECTIVES: Predicting response to proton pump inhibitor (PPI) therapy in patients with laryngeal symptoms is challenging. The Restech Dx-pH probe is a transnasal catheter that measures oropharyngeal pH. In this study, we aimed to investigate the prognostic potential of oropharyngeal pH monitoring to predict responsiveness to PPI therapy in patients with laryngeal symptoms. METHODS: We conducted a physician-blinded prospective cohort study at a single academic institution between January 2013 and October 2014. Adult patients with Reflux Symptom Index scores (RSI) ≥13 off PPI therapy were recruited. Patients underwent video laryngoscopy and 24-h oropharyngeal pH monitoring, followed by an 8- to 12-week trial of omeprazole 40 mg daily. Prior to and following PPI therapy, patients completed various symptom questionnaires. The primary outcome was the association between PPI response and oropharyngeal pH metrics. PPI response was separated into three subgroups based on the post-treatment RSI score and % RSI response: non-response=RSI ≥13; partial response=post-treatment RSI <13 and change in RSI <50%; and complete response=post-treatment RSI <13 and change in RSI ≥50%. The primary analysis utilized a multinomial logistic regression controlling for the pre-treatment RSI score. A secondary analysis assessed the relationship between the change in RSI (post-pre) and oropharyngeal pH metrics via ordinary least square regression. RESULTS: Thirty-four patients completed the study and were included in final analysis. Symptom response to PPI therapy was as follows: 50% no response, 15% partial response, and 35% complete response. Non-responders had a higher pre-treatment RSI (P<0.01). There were no significant differences in oropharyngeal acid exposure (below pH of 4.0, 5.0, 5.5, 6.0, and RYAN scores) between responder types. The secondary analysis noted a trend between lower PPI response and a greater total percent time below pH of 5.0 (P=0.03), upright percent time below pH of 5.0 (P=0.07), and RYAN supine (corrected; P=0.03), as well as an association between PPI response and greater decreases in the Anxiety Sensitivity Inventory (P<0.01), Brief Symptom Inventory-18 (P<0.01), and Negative Affect Scale (P<0.01). CONCLUSIONS: Oropharyngeal pH testing did not predict laryngeal symptom response to PPI therapy. Contrary to hypothesis, our study signaled that the degree of oropharyngeal acid exposure is inversely related to PPI response. In addition, reduction in negative affect and psychological distress parallels PPI response.

Abilities of Oropharyngeal pH Tests and Salivary Pepsin Analysis to Discriminate Between Asymptomatic Volunteers and Subjects With Symptoms of Laryngeal Irritation.

BACKGROUND & AIMS: It has been a challenge to confirm the association between laryngeal symptoms and physiological reflux disease. We examined the ability of oropharyngeal pH tests (with the Restech Dx-pH system) and salivary pepsin tests (with Peptest) to discriminate between asymptomatic volunteers (controls) and subjects with a combination of laryngeal and reflux symptoms (laryngeal ± reflux). METHODS: We performed a physician-blinded prospective cohort study of 59 subjects at a single academic institution. Adult volunteers were recruited and separated into 3 groups on the basis of GerdQ and Reflux Symptom Index scores: controls (n = 20), laryngeal symptoms (n = 20), or laryngeal + reflux symptoms (n = 19). Subjects underwent laryngoscopy and oropharyngeal pH tests and submitted saliva samples for analysis of pepsin concentration. Primary outcomes included abnormal acid exposure and composite (RYAN) score for oropharyngeal pH tests and abnormal mean salivary pepsin concentration that was based on normative data. RESULTS: Complete oropharyngeal pH data were available from 53 subjects and complete salivary pepsin data from 35 subjects. We did not observe any significant differences between groups in percent of time spent below pH 4.0, 5.0, 5.5, 6.0, or RYAN scores or percent of subjects with positive results from tests for salivary pepsin (53% vs 40% vs 75%; P = .50, respectively). The laryngeal + reflux group had a significantly higher estimated mean concentration of salivary pepsin (117.9 ± 147.4 ng/mL) than the control group (32.4 ± 41.9 ng/mL) or laryngeal symptom group (7.5 ± 11.2 ng/mL) (P = .01 and P = .04, respectively). CONCLUSIONS: By using current normative thresholds, oropharyngeal pH testing and salivary pepsin analysis are not able to distinguish between healthy volunteers and subjects with a combination of laryngeal and reflux symptoms.

In vivo neuronal function of the fragile X mental retardation protein is regulated by phosphorylation.

Fragile X syndrome (FXS), caused by loss of the Fragile X Mental Retardation 1 (FMR1) gene product (FMRP), is the most common heritable cause of intellectual disability and autism spectrum disorders. It has been long hypothesized that the phosphorylation of serine 500 (S500) in human FMRP controls its function as an RNA-binding translational repressor. To test this hypothesis in vivo, we employed neuronally targeted expression of three human FMR1 transgenes, including wild-type (hFMR1), dephosphomimetic (S500A-hFMR1) and phosphomimetic (S500D-hFMR1), in the Drosophila FXS disease model to investigate phosphorylation requirements. At the molecular level, dfmr1 null mutants exhibit elevated brain protein levels due to loss of translational repressor activity. This defect is rescued for an individual target protein and across the population of brain proteins by the phosphomimetic, whereas the dephosphomimetic phenocopies the null condition. At the cellular level, dfmr1 null synapse architecture exhibits increased area, branching and bouton number. The phosphomimetic fully rescues these synaptogenesis defects, whereas the dephosphomimetic provides no rescue. The presence of Futsch-positive (microtubule-associated protein 1B) supernumerary microtubule loops is elevated in dfmr1 null synapses. The human phosphomimetic restores normal Futsch loops, whereas the dephosphomimetic provides no activity. At the behavioral level, dfmr1 null mutants exhibit strongly impaired olfactory associative learning. The human phosphomimetic targeted only to the brain-learning center restores normal learning ability, whereas the dephosphomimetic provides absolutely no rescue. We conclude that human FMRP S500 phosphorylation is necessary for its in vivo function as a neuronal translational repressor and regulator of synaptic architecture, and for the manifestation of FMRP-dependent learning behavior.

Yeast Est2p affects telomere length by influencing association of Rap1p with telomeric chromatin.

In Saccharomyces cerevisiae, the sequence-specific binding of the negative regulator Rap1p provides a mechanism to measure telomere length: as the telomere length increases, the binding of additional Rap1p inhibits telomerase activity in cis. We provide evidence that the association of Rap1p with telomeric DNA in vivo occurs in part by sequence-independent mechanisms. Specific mutations in EST2 (est2-LT) reduce the association of Rap1p with telomeric DNA in vivo. As a result, telomeres are abnormally long yet bind an amount of Rap1p equivalent to that observed at wild-type telomeres. This behavior contrasts with that of a second mutation in EST2 (est2-up34) that increases bound Rap1p as expected for a strain with long telomeres. Telomere sequences are subtly altered in est2-LT strains, but similar changes in est2-up34 telomeres suggest that sequence abnormalities are a consequence, not a cause, of overelongation. Indeed, est2-LT telomeres bind Rap1p indistinguishably from the wild type in vitro. Taken together, these results suggest that Est2p can directly or indirectly influence the binding of Rap1p to telomeric DNA, implicating telomerase in roles both upstream and downstream of Rap1p in telomere length homeostasis.