Pyridostigmine Research Articles

Epidemiology of myasthenia gravis in the province of Ourense (Galicia, Spain).

Myasthenia gravis (MG) is an autoimmune disease affecting nerve transmission at the level of the neuromuscular junction, and typically causes fluctuating muscle weakness. Epidemiological studies show an increase in MG prevalence, particularly among the older population. We performed a retrospective epidemiological study to determine the incidence and prevalence of MG in the province of Ourense (Galicia, Spain), characterised by population ageing. Patients were selected from our clinical neuromuscular diseases database by searching for patients with an active prescription for pyridostigmine bromide. Incidence was estimated for the period 2009-2018. We calculated prevalence at 31/12/2018. According to census data for the province of Ourense, the population on 1/1/2019 was 307 651, of whom 96 544 (31.4%) were aged ≥ 65 years. We identified 80 cases of MG, with a prevalence rate of 260 cases/1 000 000 population (95% CI, 202.7-316.4), rising to 517.9/1 000 000 population in those aged ≥ 65 (95% CI, 363.2-672.9). Cumulative incidence in the study period was 15.4 cases per 1 000 000 person-years. Early onset (≤ 50 years) was recorded in 29.1% of cases. The prevalence of MG in our health district is one of the highest published figures, and the disease is highly prevalent in the older population.

Acute Exposure to Pyridostigmine Bromide Disrupts Cholinergic Myenteric Neuroimmune Function in Mice.

Gulf War Illness (GWI) results from chemical exposure during the Gulf War, with notable impacts on gastrointestinal motility. Due to the limited demographic impacted by this ailment,an in-depth investigation of the GWI has yielded little regarding the underlying pathophysiological mechanisms. Here, the hypothesis that exposure to pyridostigmine bromide (PB) results in severe enteric neuro-inflammation, that cascades to disruptions in colonic motility, is tested. The analyses are performed on male C57BL/6 mice that are treated with physiologically similar doses of PB given to GW veterans. When colonic motility is assessed, GWI colons have significantly reduced forces in response to acetylcholine or electrical field stimulation. GWI is also accompanied by high levels of pro-inflammatory cytokines and chemokines, associated with increased numbers of CD40+ pro-inflammatory macrophages within the myenteric plexus. Enteric neurons responsible for mediating colonic motility reside within the myenteric plexus, and PB exposure reduced their numbers. Significant smooth muscle hypertrophy is also observed due to increased inflammation. Together, the results show that PB exposure caused functional and anatomical dysfunction, promoting impaired motility within the colon. Achieving a greater understanding of the mechanisms of GWI will allow more refinement in therapeutic options that improve veterans' quality of life.

Dysbiosis in gastrointestinal pathophysiology: Role of the gut microbiome in Gulf War Illness.

Gulf War Illness (GWI) has been reported in 25%-35% of veterans returned from the Gulf war. Symptoms of GWI are varied and include both neurological and gastrointestinal symptoms as well as chronic fatigue. Development of GWI has been associated with chemical exposure particularly with exposure to pyridostigmine bromide (PB) and permethrin. Recent studies have found that the pathology of GWI is connected to changes in the gut microbiota, that is the gut dysbiosis. In studies using animal models, the exposure to PB and permethrin resulted in similar changes in the gut microbiome as these found in GW veterans with GWI. Studies using animal models have also shown that phytochemicals like curcumin are beneficial in reducing the symptoms and that the extracellular vesicles (EV) released from gut bacteria and from the intestinal epithelium can both promote diseases and suppress diseases through the intercellular communication mechanisms. The intestinal epithelium cells produce EVs and these EVs of intestinal epithelium origin are found to suppress inflammatory bowel disease severity, suggesting the benefits of utilizing EV in treatments. On the contrary, EV from the plasma of septic mice enhanced the level of proinflammatory cytokines in vitro and neutrophils and macrophages in vivo, suggesting differences in the EV depending on the types of cells they were originated and/or influences of environmental changes. These studies suggest that targeting the EV that specifically have positive influences may become a new therapeutic strategy in the treatment of veterans with GWI.

Analysis of influencing factors of postoperative myasthenic crisis in 564 patients with myasthenia gravis in a single center.

To study the influencing factors of myasthenic crisis in patients with myasthenia gravis during perioperative period. A total of 564 myasthenia gravis (MG) patients who underwent standard expanded resection of thymoma/thymoma in the Department of Thoracic Surgery of Beijing Hospital from January 2011 to March 2022 were retrospectively included in the study. Clinical indicators such as gender, age, thymoma, American Society of Anesthesiologists (ASA) score, operation time, intraoperative blood loss, and some others were recorded. Osserman-stages IIB + III + IV (odds ratio [OR] 16.091, 95% confidence interval [CI] 5.170-50.076, p value < 0.001), the dosage of pyridostigmine bromide more than 240 mg (OR 6.462, 95% CI 3.110-13.427, p value < 0.001), ASA score 2 and 3 (OR 3.203, 95% CI 1.461-7.020, p value=0.004), low diffusion lung capacity for carbon monoxide (DLCO%) (OR 0.981, 95% CI 0.963-1.000 p value=0.049), and blood loss greater than 1000 ml (OR 16.590, 95% CI 1.911-144.011, p value=0.011) were independent risk factors for myasthenic crisis. Patients with poor Osserman stages, higher preoperative dosage of pyridostigmine bromide, higher ASA score, poor pulmonary function (low DLCO%), and more intraoperative bleeding should be highly vigilant for the occurrence of postoperative myasthenic crisis.

Novel slow-binding reversible acetylcholinesterase inhibitors based on uracil moieties for possible treatment of myasthenia gravis and protection from organophosphate poisoning

A series of new compounds in which uracil and 3,6-dimethyluracil moieties are bridged with different spacers were prepared and evaluated in vitro for the acetyl- and butyrylcholinesterase (AChE and BChE) inhibitory activities. These bisuracils are shown to be very effective inhibitors of AChE, inhibiting the enzyme at nano- and lower molar concentrations with extremely high selectivity for AChE vs. BChE. Kinetic analysis showed that the lead compound 2h acts as a slow-binding inhibitor of AChE and possess a long drug-target residence time (τ = 1/koff = 18.6 ± 7.5 min). Moreover, compound 2h ameliorated muscle weakness in myasthenia gravis rat model with a lower effective dose and longer lasting effect than pyridostigmine bromide. Besides, it was shown that compound 2h has an effect of increasing efficiency of antidotal therapy as a pretreatment for poisoning by organophosphates.

Kennedy’s disease presented with mastication fatigue combined with positive titin antibody: a case report

BackgroundSpinal and bulbar muscular atrophy (SBMA) is an X-linked recessive hereditary neuromuscular disorder caused by the expanded trinucleotide repeat in the androgen receptors gene. The major clinical manifestations of SBMA consist of weakness in the bulbar and limb muscles, fasciculations, tremors, cramps, sensory impairment, and gynecomastia. However, atypical SBMA cases may lead to misdiagnosis. Muscular fatigue and decremental responses to repetitive nerve stimulation (RNS), despite being observed in some SBMA patients, are usually occurred in MG patients, and patient with the symptom of mastication fatigue was rarely reported. In addition, cardiological investigations have been performed in SBMA patients and several ECG alterations were identified. Here we report an SBMA patient presenting with a rare onset symptom of mastication fatigue, who has been detected with a positive titin antibody in the serum and showed a WPW pattern electrocardiogram.Case presentationThe patient showed mildly progressive fatigue in the muscles of mastication over 3 years. Neurological examination showed facial muscle weakness and a wasting tongue with fasciculations, but the weakness, wasting, or fasciculations were not obvious in the limbs. 3-Hz RNS showed a decremental response in bilateral orbicularis oculi. The test of titin antibody was positive in the serum, and the electrocardiogram showed a WPW pattern ECG. Genetic analysis revealed an increased number (39 repeats) of tandem CAG repeats in the AR gene, which confirmed the diagnosis of SBMA. The fatigue symptom was significantly improved after oral pyridostigmine bromide treatment.ConclusionThis case calls for more attention to muscular fatigue as the onset symptoms of Kennedy’s disease. ECG screening is of importance in SBMA patients and further studies are needed to investigate the titin antibody in SBMA patients as well as other neurogenic disorders.

Evaluation of delayed LNFPIII treatment initiation protocol on improving long-term behavioral and neuroinflammatory pathology in a mouse model of Gulf War Illness

Chemical overexposures and war-related stress during the 1990–1991 Gulf War (GW) are implicated in the persisting pathological symptoms that many GW veterans continue to endure. These symptoms culminate into a disease known as Gulf War Illness (GWI) and affect about a third of the GW veteran population. Currently, comprehensive effective GWI treatment options are unavailable. Here, an established GWI mouse model was utilized to explore the (1) long-term behavioral and neuroinflammatory effects of deployment-related GWI chemicals exposure and (2) ability of the immunotherapeutic lacto-N-fucopentaose III (LNFPIII) to improve deficits when given months after the end of exposure. Male C57BL6/J mice (8–9 weeks old) were administered pyridostigmine bromide (PB) and DEET for 14 days along with corticosterone (CORT; latter 7 days) to emulate wartime stress. On day 15, a single injection of the nerve agent surrogate diisopropylfluorophosphate (DFP) was given. LNFPIII treatment began 7 months post GWI chemicals exposure and continued until study completion. A battery of behavioral tests for assessment of cognition/memory, mood, and motor function in rodents was performed beginning 8 months after exposure termination and was then followed by immunohistochemcal evaluation of neuroinflammation and neurogenesis. Within tests of motor function, prior GWI chemical exposure led to hyperactivity, impaired sensorimotor function, and altered gait. LNFPIII attenuated these motor-related deficits and improved overall grip strength. GWI mice also exhibited more anxiety-like behavior that was reduced by LNFPIII; this was test-specific. Short-term, but not long-term memory, was impaired by prior GWI exposure; LNFPIII improved this measure. In the brains of GWI mice, but not in mice treated with LNFPIII, glial activation was increased. Overall, it appears that months after exposure to GWI chemicals, behavioral deficits and neuroinflammation are present. Many of these deficits were attenuated by LNFPIII when treatment began long after GWI chemical exposure termination, highlighting its therapeutic potential for veterans with GWI.

Tailoring Two Chemometric Models for Determination of Three Neuromuscular Combined Medications and Application to Spiked Human Plasma.

Prednisolone, 6-mercaptopurine, and pyridostigmine bromide are co-administered together to treat a neuromuscular autoimmune disease called myasthenia gravis. Prednisolone and 6-mercaptopurine are immunosuppressant drugs. 6-Mercaptopurine is the active form of the pro-drug azathioprine. Pyridostigmine bromide is a cholinesterase enzyme inhibitor. Curently, green characteristics are taken into account by analysts when they develop new methods. The spectra of the three compounds and plasma are highly overlapped, so this study aims to remove this overlap and determine the three components quantitatively in raw powders and spiked human plasma using green methods. Two multivariate updated chemometric models called principle component analysis and partial least-squares were developed. Three greenness assessment tools: the eco-scale, the analytical greenness metric approach, and the green analytical method index, were used to evaluate the greenness behavior of the generated models. The two models were verified in accordance with Food and Drug Administration requirements, and the results were within acceptable limits. In addition they are relatively green in accordance with the abovementioned greenness evaluation tools. The developed models succeeded in determining the proposed drugs in their tertiary combinations and spiked human plasma with satisfactory precision, accuracy, and good greenness behavior. Two ecologically evaluated, multivariate spectrophotometric methods were developed for the determination of pyridostigmine bromide, 6-mercaptopurine, and prednisolone in spiked human plasma.

Impact of gulf war toxic exposures after mild traumatic brain injury

Chemical and pharmaceutical exposures have been associated with the development of Gulf War Illness (GWI), but how these factors interact with the pathophysiology of traumatic brain injury (TBI) remains an area of study that has received little attention thus far. We studied the effects of pyridostigmine bromide (an anti-nerve agent) and permethrin (a pesticide) exposure in a mouse model of repetitive mild TBI (r-mTBI), with 5 impacts over a 9-day period, followed by Gulf War (GW) toxicant exposure for 10 days beginning 30 days after the last head injury. We then assessed the chronic behavioral and pathological sequelae 5 months after GW agent exposure. We observed that r-mTBI and GWI cumulatively affect the spatial memory of mice in the Barnes maze and result in a shift of search strategies employed by r-mTBI/GW exposed mice. GW exposure also produced anxiety-like behavior in sham animals, but r-mTBI produced disinhibition in both the vehicle and GW treated mice. Pathologically, GW exposure worsened r-mTBI dependent axonal degeneration and neuroinflammation, increased oligodendrocyte cell counts, and increased r-mTBI dependent phosphorylated tau, which was found to colocalize with oligodendrocytes in the corpus callosum. These results suggest that GW exposures may worsen TBI-related deficits. Veterans with a history of both GW chemical exposures as well as TBI may be at higher risk for worse symptoms and outcomes. Subsequent exposure to various toxic substances can influence the chronic nature of mTBI and should be considered as an etiological factor influencing mTBI recovery.

Effect of treatment with Fufang Huangqi decoction on dose reductions and discontinuation of pyridostigmine bromide tablets, prednisone, and tacrolimus in patients with type I or II myasthenia gravis.

To investigate the clinical efficacy of Fufang Huangqi decoction in combination with pyridostigmine bromide tablets, prednisone, and tacrolimus in the treatment of type I and II myasthenia gravis (MG) through changes in the clinical symptom scores of 100 patients with type I and II MG. This study also aimed to examine dose reductions and dis-continuation of these 3 Western medicines after administration of Fufang Huangqi decoction. The clinical data on 100 patients with type I or II MG who were treated in the outpatient department of the Affiliated Hospital of Liaoning University of Traditional Chinese Medicine, China, between June 2017 and June 2020 were collected. The patients were divided into 4 groups based on whether they had taken pyridostigmine bromide tablets, prednisone, and/or tacrolimus at the time of their hospital visit: the Fufang Huangqi decoction group (group A), the pyridostigmine bromide tablets + Fufang Huangqi decoction group (group B), the pyridostigmine bromide tablets + prednisone + Fufang Huangqi decoction group (group C), and the pyridostigmine bromide tablets + tacrolimus + Fufang Huangqi decoction group (group D). The average treatment time was (15.6 ± 11.5) months (range: 0.5-55 months). Changes in the clinical symptom scores of the 4 groups of patients after medication administration and dose reductions and discontinuation of the 3 Western medicines were analyzed. An overall effectiveness rate of 86.00% was achieved in the 100 patients after treatment for (15.6 ± 11.5) months (range 0.5-55 months). The effectiveness rates were 85.71% in group A, 88.24% in group B, 76.92% in group C, and 80.00% in group D. The dosage of pyridostigmine bromide was reduced for 69.12% of the patients in group B for the first time after (4.2 ± 4.1) months, and 45.59% of the patients in group B discontinued pyridostigmine bromide after (8.8 ± 6.1) months. The dosage of pyridostigmine bromide was reduced for 46.15% of the patients in group C for the first time after (5.3 ± 3.4) months, and 23.08% of the patients in group C discontinued pyridostigmine bromide after (19.8 ± 11.0) months; 76.92% reduced hormone dosage after (2.8 ± 1.9) months, and 23.08% discontinued hormone treatment after (6.7 ± 2.9) months. The dosage of pyridostigmine bromide was reduced for 1 patient in group D after 1 month; this patient discontinued pyridostigmine bromide after 3 months and reduced tacrolimus dosage after 5 months. One patient in group D discontinued pyridostigmine bromide and tacrolimus on his own initiative at 0.5 months and took Fufang Huangqi decoction for 2 months without discontinuing Western medicine. Fufang Huangqi decoction is effective for the treatment of type I and II MG and improves the associated clinical symptoms. Moreover, this agent is conducive to dose reductions and discontinuation of basic Western medicines, thereby reducing the side effects experienced by patients.

A molecular docking-based comparative assessment of various anticholinergic drugs as antidotes to different nerve agent poisoning

Nerve agent poisoning is still a threat to civilization. Nerve agents function by binding with the enzyme acetylcholinesterase irreversibly. Accumulation of acetylcholine in the synapse causes over-stimulation of muscarinic and nicotinic acetylcholinergic receptors. Thus miosis, glandular hyper secretion, bronchoconstriction, vomiting, diarrhea and bradycardia occurs (by M1-M5 receptors stimulation); whereas convulsion and seizures occur due to the nicotinic receptors. Atropine is a non-selective muscarinic antagonists but no nicotinic antagonists are known. Seizures are controlled by diazepam. Enzyme aging occurs without treatment which causes the enzyme resistant to oxime therapy. Though numerous wet-lab based works has carried out, however, recent time there is an over-growing trend to make comparative assessment of drugs and toxicants. Here we made a molecular docking based comparative assessments between nerve agents toxicity and efficacy of different drugs to prevent this toxicity. Our results suggest that VX is the most harmful organophosphate nerve agents and HI-6 is the best drug followed by Obidoxime and Pralidoxime to free acetylcholinestarase. Docking results correspond the data trend of different in vivo experiments for the assessment of severity of different nerve agents and/or effectiveness of different antidote drugs. Our study reinforces the utility of pretreatment of the enzyme with a carbamic acid derivative like Pyridostigmine bromide which inhibits the enzyme reversibly to a smaller extent and thus, prevent the enzyme from aging and the nerve agent binding. Communicated by Ramaswamy H. Sarma

Acupuncture combined with western medication for ocular myasthenia gravis: a randomized controlled trial

To compare the clinical efficacy between acupuncture combined with western medication and simple western medication for ocular myasthenia gravis (OMG), and to explore its possible mechanism. A total of 60 patients of ocular myasthenia gravis were randomized into an acupuncture combined with western medication group (30 cases, 1 case dropped off) and a western medication group (30 cases, 2 cases dropped off). Oral pyridostigmine bromide tablet and prednisone acetate tablet were given in the western medication group. On the basis of the treatment in the western medication group, Tongdu Tiaoqi acupuncture (acupuncture for unblocking the governor vessel and regulating qi ) was applied at Baihui (GV 20), Fengfu (GV 16), Hegu (LI 4), Zusanli (ST 36), etc. in the acupuncture combined with western medication group, once a day, 6 days a week. The treatment was given 8 weeks in both groups. Before and after treatment, the OMG clinical absolute score was observed, electrophysiological indexes of orbicularis oculi (value of mean jitter, percentage of jitter >55 μs and percentage of blocks) were measured by single-fiber electromyography (SFEMG), serum levels of acetylcholine receptor antibody (AChR-Ab), interferon-gamma (IFN-γ) and interleukin-4 (IL-4) were detected by ELISA method. After treatment, the OMG clinical absolute scores, values of mean jitter, percentages of jitter >55 μs, percentages of blocks and serum levels of AChR-Ab, IFN-γ and IL-4 were decreased compared before treatment in both groups (P<0.05), and those in the acupuncture combined with western medication group were lower than the western medication group (P<0.05). Acupuncture combined with western medication can effectively improve ptosis, palpebra superior fatigability, eye movement disorder and neuromuscular junction dysfunction in patients with ocular myasthenia gravis, the therapeutic effect is superior to simple western medication. Its mechanism may be related to down-regulating serum levels of AChR-Ab, IFN-γ and IL-4 and promoting the recovery of orbicularis oculi function.

Self-double Emulsified Drug Delivery System of Pyridostigmine Bromide Augmented Permeation Across Caco-2 Cells

Aim: The study aims to enhance the permeability of pyridostigmine bromide by developing a self-double emulsifying drug delivery system (SDEDDS) and enteric-coated spheroids. Background: Pyridostigmine bromide is a reversible anticholinesterase used to treat Myasthenia Gravis, reverse neuromuscular blockade, and prevent nerve gas (i.e., soman) poisoning. It is readily soluble in water, but its poor and irregular intestinal absorption is responsible for its poor oral bioavailability (7.6±2.4%). Many approaches have been made to increase the bioavailability of this drug, but no significant improvement has been achieved to date. Presently pyridostigmine tablets are given orally, and a treatment schedule of multiple doses every day (3–6 times per day) is recommended for adult patients, while sustained-release pyridostigmine (Timespan®) tablets can be taken once or twice daily. An increase in permeability of pyridostigmine bromide may also result in reduced dosage frequency. Objective: In the present work, it is proposed to develop a self-double emulsifying drug delivery system (SDEDDS) of pyridostigmine bromide which will increase its intestinal permeability and hence its oral bioavailability. Methods: For the preparation of PB-SDEDDS, the primary water in oil emulsion was mixed with the optimized concentration of Tween 80 using a magnetic stirrer. PB-SDEDDS were converted into spheroids and were then characterized. Results: The pseudo ternary phase diagram was constructed, showing a double emulsion region. The viscosity of PB-SDEDDS at the different shear rates was found to be 125 mPas. The optimized PBSDEDDS formulation formed a bright white emulsion within 2 minutes, having droplet size around 20-25 μm. In vitro uptake studies of PB-SDEDDS on Caco2 cells demonstrated the increase in Papp value from (4.38±0.27) ×10-4 cm/s to (9.488±0.182) ×10-4 cm/s (2.166 folds) that was attributed to the PB-SDEDDS formulation. In vitro cytotoxicity studies on Caco2 cells revealed that the blank SDEDDS showed almost no toxicity after incubation for 2 hours at various dilutions tested. Among all formulations, F3 was optimized for the concentration of adsorbent and binder at a concentration of 10% each. SEM showed that the spheroids were spherical, and 73.92% of spheroids were in between 0.595-0.841 mm of size. The optimized formulation had 70.29% spheroids retained on sieve no. 30. The angle of repose showed good flow properties with 25.20 and stability with friability of 0.52 %. The disintegration time of the developed formulation was 3.30 minutes, and drug content was found to be 97.83%. The release studies showed that PB-SDEDDS improved the release significantly compared to the market formulation. Conclusion: The solid PB-SDEDDS resulted in favorable physical properties and did not affect its drug content and in vitro drug release profile. The self-double emulsifying drug delivery system of pyridostigmine bromide can be explored as a suitable alternative to its solid oral dosage form.

Regulatory Modulations and Dendritic Arborization in the Mouse Hippocampus Following Gulf War Toxicant Exposure

Gulf War illness (GWI) is a chronic multi‐symptom syndrome which affects approximately 30% of the nearly 700,000 Veterans who were deployed to the Persian Gulf from 1990 to 1991. These Veterans have reported experiencing a variety of symptoms including difficulties with learning and memory, depression and anxiety, and increased incidence of neurodegenerative diseases. Evidence suggests that combined exposure to both reversible and irreversible acetylcholinesterase (AChE) inhibitors is a likely risk factor. We modeled Gulf War exposure in male C57Bl/6J mice with three AChE inhibitors that have been implicated as causative agents for GWI: pyridostigmine bromide (PB), the anti‐sarin prophylactic; chlorpyrifos (CPF), an organophosphate insecticide; and N,N‐diethyl‐m‐toluamide (DEET), a common insect repellent. Previously, we reported acute hippocampal gene expression changes following 10 d of toxicant exposure, including significant downregulation of several neuronal immediate early genes (IEGs) such as Arc, Egr1, and Nr4a1, as well as hippocampal‐dependent memory impairment in a Y‐maze task. Arc is predominantly expressed in cortical and hippocampal neurons and is critical for long‐term potentiation (LTP) and stabilization of synaptic plasticity. IEGs such as Arc and Egr1 have also been suggested to play a role in determining the risk of developing major depressive disorder, which is often comorbid with GWI. Here, we quantified Arc protein expression in granule cells of the dentate gyrus with IHC at 2‐4 h post‐exposure and examined the effects of treatment with a neuroprotective Nrf2 activator, tert‐butylhydroquinone (tBHQ), at 14 weeks post‐exposure. Additionally, mice were either placed in a novel enriched environment for 5 min or kept in their home cage to evaluate induced Arc expression in granule cells at 4 h post‐exposure. We also assessed dendritic arborization, important in connectivity, in granule cells by measuring dendritic lengths and spine densities with Golgi staining at 12 weeks post‐exposure. We hypothesized that toxicant‐exposed mice would have fewer Arc+ granule cells in the dentate gyrus and show reductions in both basal and induced Arc expression at 4 h post‐exposure. We also hypothesized that exposed mice would display dendritic arbor reduction and loss of spines in granule cells at the chronic timepoint, and that this effect would be reversed by antioxidant treatment. Preliminary results indicate that Arc protein expression is decreased in granule cells of exposed mice at the acute but not chronic timepoint. Dendritic arbor complexity was significantly reduced at the chronic phase in exposed mice but improved when treated with 1% tBHQ formulated food pellets. Our results suggest that IEGs may only be dysregulated immediately following exposure but could contribute to long‐term detrimental effects on hippocampal neuroplasticity, which may be improved with antioxidant treatment.

Pyridostigmine bromide elicits progressive and chronic impairments in the cholinergic anti-inflammatory pathway in the prefrontal cortex and hippocampus of male rats

Gulf War Illness (GWI) is a multi-symptom illness that continues to affect over 250,000 American Gulf War veterans. The causes of GWI remain equivocal; however, prophylactic use of the acetylcholinesterase inhibitor pyridostigmine bromide (PB), and the stress of combat have been identified as two potential causative factors. Both PB and stress alter acetylcholine (ACh), which mediates both cognition and anti-inflammatory responses. As inflammation has been proposed to contribute to the cognitive deficits and immune dysregulation in GWI, the goal of this study was to determine the long-term effects of PB and stress on the cholinergic anti-inflammatory pathway in the central nervous system and periphery. We used our previously established rat model of GWI and in vivo microdialysis to assess cholinergic neurochemistry in the prefrontal cortex (PFC) and hippocampus following a mild immune challenge (lipopolysaccharide; LPS). We then examined LPS-induced changes in inflammatory markers in PFC and hippocampal homogenates. We found that PB treatment produces a long-lasting potentiation of the cholinergic response to LPS in both the PFC and hippocampus. Interestingly, this prolonged effect of PB treatment enhancing cholinergic responses to LPS was accompanied by paradoxical increases in the release of pro-inflammatory cytokines in these brain regions. Collectively, these findings provide evidence that neuroinflammation resulting from dysregulation of the cholinergic anti-inflammatory pathway is a mechanistic mediator in the progression of the neurochemical and neurocognitive deficits in GWI and more broadly suggest that dysregulation of this pathway may contribute to neuroinflammatory processes in stress-related neurological disorders.

Neurogenesis and chronic neurobehavioral outcomes are partially improved by vagus nerve stimulation in a mouse model of Gulf War illness

Gulf War illness (GWI) is a chronic, multi-symptom disorder that has impacted approximately one third of Gulf War veterans. GWI and its symptoms have been linked to the exposure to neurological chemicals, including the anti-nerve gas drug pyridostigmine bromide (PB) and the insecticide permethrin (PER), among others. Mouse models utilizing these chemicals have reported symptomology analogous to human GWI. These changes include behavioral and cognitive impairment, neuroinflammation and hippocampal pathogenesis. Disease modifying interventions that target these pathological components are desperately needed. Vagus nerve stimulation (VNS) is FDA approved for drug-resistant epilepsy and depression. VNS has also been used off-label to target a myriad of symptoms, some of which are encompassed within the Kansas and CDC definitions of clinical GWI symptomology. A GWI animal model in which mice are exposed to a daily injection of PB and PER for 10 consecutive days has been shown to exhibit cognitive impairment and hippocampal pathology. The purpose of this study was to determine if 2–4 weeks of continuous vagus nerve stimulation initiated at 32 weeks after exposure to PB and PER would improve cognitive performance and hippocampal pathology. The results of the study revealed that exposure to PB and PER produces long-term cognitive deficits and reduced hippocampal neurogenesis. The results also showed that the VNS treatment was anxiolytic, improved some aspects of pattern separation deficits, and mitigated the reduced hippocampal neurogenesis. Thus, VNS improves outcomes in a mouse model of GWI and should be examined as a potential therapeutic strategy for mitigating some symptomology associated with GWI.

Spotlight on MuSK positive myasthenia gravis: clinical characteristics, treatment and outcomes

BackgroundTo investigate the clinical characteristics, treatments and outcomes of patients with myasthenia gravis with antibodies to muscle-specific tyrosine kinase (MuSK-MG).MethodsWe retrospectively reviewed the cases of 21 patients with confirmed MuSK-MG between January 2012 and January 2020 in our centre. Detailed clinical data and long-term follow-up information were summarized.ResultsFemales (17/21, 81%) predominated among these MuSK-MG patients, and the mean age of onset in this group was 51.86 ± 16.16 years. MuSK-MG patients were divided into three subgroups according to the symptoms of muscle weakness at onset: ocular myasthenia gravis (OMG, 47.6%), bulbar myasthenia gravis (BMG, 42.9%), and generalized myasthenia gravis (GMG, 9.5%). The mean progression time from symptom onset to other muscle group involvement in OMG patients was 4.38 ± 2.54 months. Pyridostigmine bromide was adopted in 81.0% of patients, and 90.5% of patients received corticosteroids. Compared to usage in hospitals, the median daily dose of corticosteroids decreased significantly at the last follow-up. A total of 85.7% of patients received a long-term follow-up, with an average time of 1202.17 ± 976.73 days. At the end of the follow-up period, 4.8% of patients had achieved complete stable remission, 42.9% of patients had minimal manifestations, 19.0% had improved, the condition of 4.8% of patients remained unchanged, and 9.5% of patients died.ConclusionFemale patients were more prevalent in this study, and MuSK-MG patients rapidly progressed to a generalized state. Although approximately 50% of MuSK-MG patients can achieve a favourable outcome with conventional immunosuppressants, complete stable remission is rare, and approximately 15% respond poorly. More effective medications should be explored in these patients.

Association of Gulf War Illness-Related Symptoms with Military Exposures among 1990-1991 Gulf War Veterans Evaluated at the War-Related Illness and Injury Study Center (WRIISC).

Veterans with difficult-to-diagnose conditions who receive care in the Department of Veterans Affairs (VA) healthcare system can be referred for evaluation at one of three specialty VA War-Related Illness and Injury Study Centers (WRIISC). Veterans of the 1990–1991 Gulf War have long experienced excess rates of chronic symptoms associated with the condition known as Gulf War Illness (GWI), with hundreds evaluated at the WRIISC. Here we provide the first report from a cohort of 608 Gulf War Veterans seen at the WRIISC who completed questionnaires on chronic symptoms (>6 months) consistent with GWI as well as prominent exposures during Gulf War deployment. These included veterans’ reports of hearing chemical alarms/donning Military-Ordered Protective Posture Level 4 (MOPP4) gear, pesticide use, and use of pyridostigmine bromide (PB) pills as prophylaxis against the effects of nerve agents. Overall, veterans in the cohort were highly symptomatic and reported a high degree of exposures. In multivariable models, these exposures were significantly associated with moderate-to-severe chronic symptoms in neurocognitive/mood, fatigue/sleep, and pain domains. Specifically, exposure to pesticides was associated with problems with concentration and memory, problems sleeping, unrefreshing sleep, and joint pain. Use of MOPP4 was associated with light sensitivity and unrefreshing sleep and use of PB was associated with depression. We also evaluated the association of exposures with symptom summary scores based on veterans’ severity of symptoms in four domains and overall. In multivariable modeling, the pain symptom severity score was significantly associated with pesticide use (Odds ratio (OR): 4.13, 95% confidence intervals (CI): 1.78–9.57) and taking PB pills (OR: 2.28, 95% CI: 1.02–5.09), and overall symptom severity was significantly associated with use of PB pills (OR: 2.41, 95% CI: 1.01–5.75). Conclusion: Decades after deployment, Gulf War veterans referred to a VA tertiary evaluation center report a high burden of chronic symptoms, many of which were associated with reported neurotoxicant exposures during the war.

Health symptom trajectories and neurotoxicant exposures in Gulf War veterans: the Ft. Devens cohort

BackgroundThirty years ago, Gulf War (GW) veterans returned home with numerous health symptoms that have been associated with neurotoxicant exposures experienced during deployment. The health effects from these exposures have been termed toxic wounds. Most GW exposure-outcome studies utilize group analyses and thus individual fluctuations in symptoms may have been masked. This study investigates health symptom trajectories in the same veterans over 25 years.MethodsVeterans were categorized into 5 a priori trajectory groups for each health symptom and Chronic Multisymptom Illness (CMI) clinical case status. Multinomial logistic regression models were used to investigate associations between these trajectories and neurotoxicant exposures.ResultsResults indicate that more than 21 Pyridostigmine Bromide (PB) pill exposure was associated with consistent reporting of fatigue, pain, and cognitive/mood symptoms as well as the development of six additional symptoms over time. Chemical weapons exposure was associated with both consistent reporting and development of neurological symptoms over time. Reported exposure to tent heater exhaust was associated with later development of gastrointestinal and pulmonary symptoms. Veterans reporting exposure to more than 21 PB pills were more than 8 times as likely to consistently meet the criteria for CMI over time.ConclusionThis study highlights the importance of the continued documentation of the health impacts experienced by GW veterans’, their resulting chronic health symptoms, and the importance of exposure-outcome relationships in these veterans now 30 years post-deployment.

Myasthenia gravis-treatment and severity in nationwide cohort.

Myasthenia gravis (MG) is a rare autoimmune disorder of neuromuscular junction. MG healthcare burden has not been studied in Poland before. Data were drawn from the National Health Fund database; MG patient was defined as a person who received at least once medical service with ICD-10 code MG (G70) and at least two reimbursed prescriptions for pyridostigmine bromide or ambenonium chloride in two consecutive years. We have analyzed treatment: immunosuppression, intravenous immunoglobulins (IVIg), plasma exchange (PE), the number and length of hospitalizations (LOS), intensive care unit (ICU) care, and deaths between 2013 and 2018. In 2018, there were 9012 MG patients (F:M 1.62:1), and 30.6% had early -onset MG (<50years). 66.3% received symptomatic treatment only, 33.7%-glucocorticoids (CS) and/or other immunosuppressants (IS), 64.6%-CS only, 17.5%-azathioprine plus CS, 11%-azathioprine only, 4.6%-CS plus other IS (methotrexate, mycophenolate mofetil, cyclosporine, or tacrolimus), and 2%-other IS only. In 2018, 42.3% of patients were hospitalized at least once (mean 2.05/year), 13.7% due to MG (1.47/year). In 2018, 1.63% patients received PE, 2.33% IVIg. In 2013-2018, 2.7%-3.2% of MG patients required hospitalization in ICU. ICU mean LOS 2013-2018 was 11.5-15.0days/per patient/year. 2.1% of all MG patients had myasthenic crisis. Mean age at death was 75.7years for MG and 73.9 for general population (p=.006). All-cause mortality was higher for men (4.1%-5.1%) than for women (2.5%-3.1%), p<.01. Our findings confirm significant healthcare burden of MG, comprising a tool to plan resources needed for MG patients.