BACKGROUND: Deployment-related neurotoxicant exposures are implicated in the etiology of Gulf War illness (GWI), the multisymptom condition associated with military service in the 1990-1991 Gulf War (GW). A Q/R polymorphism at position 192 of the paraoxonase (PON)-1 enzyme produce PON1192 variants with different capacities for neutralizing specific chemicals, including certain acetylcholinesterase inhibitors.
METHODS: We evaluated PON1192 status and GW exposures in 295 GWI cases and 103 GW veteran controls. Multivariable logistic regression determined independent associations of GWI with GW exposures overall and in PON1192 subgroups. Exact logistic regression explored effects of exposure combinations in PON1192 subgroups.
RESULTS: Hearing chemical alarms (proxy for possible nerve agent exposure) was associated with GWI only among RR status veterans (OR = 8.60, p = 0.014). Deployment-related skin pesticide use was associated with GWI only among QQ (OR = 3.30, p = 0.010) and QR (OR = 4.22, p < 0.001) status veterans. Exploratory assessments indicated that chemical alarms were associated with GWI in the subgroup of RR status veterans who took pyridostigmine bromide (PB) (exact OR = 19.02, p = 0.009) but not RR veterans who did not take PB (exact OR = 0.97, p = 1.00). Similarly, skin pesticide use was associated with GWI among QQ status veterans who took PB (exact OR = 6.34, p = 0.001) but not QQ veterans who did not take PB (exact OR = 0.59, p = 0.782).
CONCLUSIONS: Study results suggest a complex pattern of PON1192 exposures and exposure-exposure interactions in the development of GWI.

CONCLUSIONS: In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.
OBJECTIVE: Elevated serum bromide levels can cause dermatological, gastrointestinal, and neurological abnormalities. As bromide and chloride are both halogens, bromide may interfere with chloride assays, causing a falsely high serum chloride concentration and a low or negative anion gap. There is a paucity of data describing bromide toxicity from high doses of pyridostigmine bromide (PB). This case report describes a patient with an elevated bromide level with neurological symptoms from a therapeutic dose of PB.
CONCLUSIONS: A 37-year-old male with myasthenia gravis secondary to type B2 thymoma status following thymectomy presented in myasthenic crisis. He required mechanical ventilation and was managed with steroids, intravenous immune globulin, plasmapheresis, and PB. On day 9, the patient experienced acute agitation. He had an anion gap of 2 mEq/L and a chloride concentration of 109 mEq/L. The plasma creatinine concentration was 0.63 to 1.15 mg/dL and urine output was 0.76 to 1.79 mL/kg/h throughout his admission. All other laboratory values were normal. The daily dose of PB was 660 mg on day 9, but the patient received 76 mg of intravenous PB over the first few days of his admission with the largest dose in 24 hours equal to 48 mg. On day 10, the patient\'s bromide level was 37 μg/mL. His agitation was initially managed with quetiapine, followed by PB dose reduction. To our knowledge, there are 2 cases in the literature of bromide toxicity secondary to PB. These patients experienced neurological symptoms with bromide levels of 88 to 90 μg/mL. Bromide concentrations of more than 12 μg/mL are associated with a higher risk of neuronal dysfunction demonstrated as disturbances on an electroencephalogram, and levels greater than 50 μg/mL are considered toxic. While our patient\'s bromide level was not as high as those previously reported, no other causes for his agitation were identified.
CONCLUSIONS: Elevated bromide levels from therapeutic PB can occur, and monitoring of these levels should be considered.

BACKGROUND: Chronic Gulf War Illness (GWI) is characterized by cognitive and mood impairments, as well as persistent neuroinflammation and oxidative stress. This study aimed to investigate the efficacy of Epidiolex®, a Food and Drug Administration (FDA)-approved cannabidiol (CBD), in improving brain function in a rat model of chronic GWI.
METHODS: Six months after exposure to low doses of GWI-related chemicals [pyridostigmine bromide, N,N-diethyl-meta-toluamide (DEET), and permethrin (PER)] along with moderate stress, rats with chronic GWI were administered either vehicle (VEH) or CBD (20 mg/kg, oral) for 16 weeks. Neurobehavioral tests were conducted on 11 weeks after treatment initiation to evaluate the performance of rats in tasks related to associative recognition memory, object location memory, pattern separation, and sucrose preference. The effect of CBD on hyperalgesia was also examined. The brain tissues were processed for immunohistochemical and molecular studies following behavioral tests.
RESULTS: GWI rats treated with VEH exhibited impairments in all cognitive tasks and anhedonia, whereas CBD-treated GWI rats showed improvements in all cognitive tasks and no anhedonia. Additionally, CBD treatment alleviated hyperalgesia in GWI rats. Analysis of hippocampal tissues from VEH-treated rats revealed astrocyte hypertrophy and increased percentages of activated microglia presenting NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) complexes as well as elevated levels of proteins involved in NLRP3 inflammasome activation and Janus kinase/signal transducers and activators of the transcription (JAK/STAT) signaling. Furthermore, there were increased concentrations of proinflammatory and oxidative stress markers along with decreased neurogenesis. In contrast, the hippocampus from CBD-treated GWI rats displayed reduced levels of proteins mediating the activation of NLRP3 inflammasomes and JAK/STAT signaling, normalized concentrations of proinflammatory cytokines and oxidative stress markers, and improved neurogenesis. Notably, CBD treatment did not alter the concentration of endogenous cannabinoid anandamide in the hippocampus.
CONCLUSIONS: The use of an FDA-approved CBD (Epidiolex®) has been shown to effectively alleviate cognitive and mood impairments as well as hyperalgesia associated with chronic GWI. Importantly, the improvements observed in rats with chronic GWI in this study were attributed to the ability of CBD to significantly suppress signaling pathways that perpetuate chronic neuroinflammation.

Myasthenia gravis (MG) is a multifaceted autoimmune disorder affecting the postsynaptic neuromuscular junction. In this study, we examined CD4+ and CD8+ T lymphocyte levels and ratios within peripheral blood mononuclear cells (PBMCs) in MG patients. Additionally, we assessed lymphocytes for the expression of CD71, which functions as a transferrin receptor mediating the uptake of iron into the cells. Building on recent discussions regarding CD20 depletion treatments in MG, we also scrutinized lymphocytes for CD20 expression. Comparative analyses were conducted among healthy controls, newly diagnosed MG patients, those undergoing pyridostigmine treatment alone, and MG patients receiving combination therapies. In the patients, the ratio of CD3+CD4+ T lymphocytes to CD3+ T lymphocytes was found to be decreased compared to the healthy controls, while the ratio of CD3+CD8+ cells to CD3+CD4+ cells increased. An increase in the percentage of CD71-expressing lymphocytes was observed in MG patients compared to the healthy control group, while CD20+ lymphocytes exhibited no statistical changes. Moreover, heightened serum lipid peroxidation levels were found in MG patients. These results suggest a possible relationship between iron metabolism, levels of CD71-expressing cells, and lipid peroxidation in MG. Conversely, pyridostigmine treatment reduced the levels of CD71-expressing cells and lipid peroxidation, suggesting potential immunomodulatory and antioxidant impacts of pyridostigmine in MG, either directly or indirectly.

BACKGROUND: Pyridostigmine is hypothesized to improve neurogenic orthostatic hypotension (nOH) symptoms without causing or exacerbating supine hypertension. The objective of this review was to evaluate the safety and efficacy of pyridostigmine for management of nOH.
METHODS: A literature search of PubMed, Embase, and CENTRAL was performed in December 2023 for prospective trials with a placebo or active comparator.
RESULTS: Four randomized and two non-randomized studies were reviewed. Three studies utilizing a single dose, crossover design found significant differences of orthostatics using adjunctive pyridostigmine. Two studies assessing longer-term endpoints demonstrated conflicting efficacy of pyridostigmine with one trial finding significant improvement in orthostatics and symptoms after three months of therapy. Use of pyridostigmine did not lead to supine hypertension with most adverse effects being cholinergic.
CONCLUSIONS: Pyridostigmine may be considered as an adjunctive medication in individuals with nOH refractory to standard treatment options as it carries a favorable safety profile with low risk for supine hypertension.

Gulf War Illness (GWI) describes a series of symptoms suffered by veterans of the Gulf war, consisting of cognitive, neurological and gastrointestinal dysfunctions. Two chemicals associated with GWI are the insecticide permethrin (PER) and the nerve gas prophylactic pyridostigmine-bromide (PB). In this study we assessed the effects of PER and PB exposure on the pathology and subsequent alcohol (EtOH)-induced liver injury, and the influence of a macrophage depletor, PLX3397, on EtOH-induced liver damage in PER/PB-treated mice. Male C57BL/6 mice were injected daily with vehicle or PER/PB for 10 days, followed by 4 months recovery, then treatment with PLX3397 and a chronic-plus-single-binge EtOH challenge for 10 days. PER/PB exposure resulted in the protracted increase in liver transaminases in the serum and induced chronic low-level microvesicular steatosis and inflammation in GWI vs Naïve mice up to 4 months after cessation of exposure. Furthermore, prior exposure to PER/PB also resulted in exacerbated response to EtOH-induced liver injury, with enhanced steatosis, ductular reaction and fibrosis. The enhanced EtOH-induced liver damage in GWI-mice was attenuated by strategies designed to deplete macrophages in the liver. Taken together, these data suggest that exposure to GWI-related chemicals may alter the liver\'s response to subsequent ethanol exposure.

Though it has been over 30 years since the 1990-1991 Gulf War (GW), the pathophysiology of Gulf War Illness (GWI), the complex, progressive illness affecting approximately 30% of GW Veterans, has not been fully characterized. While the symptomology of GWI is broad, many symptoms can be attributed to immune and endocrine dysfunction as these critical responses appear to be dysregulated in many GWI patients. Since such dysregulation emerges in response to immune threats or stressful situations, it is unsurprising that clinical studies suggest that GWI may present with a latent phenotype. This is most often observed in studies that include an exercise challenge during which many GWI patients experience an exacerbation of symptoms. Unfortunately, very few preclinical studies include such physiological stressors when assessing their experimental models of GWI, which creates variable results that hinder the elucidation of the mechanisms mediating GWI. Thus, the purpose of this review is to highlight the clinical and preclinical findings that investigate the inflammatory component of GWI and support the concept that GWI may be characterized as having a latent phenotype. We will mainly focus on studies assessing the progressive cognitive impairments associated with GWI and emphasize the need for physiological stressors in future work to create a more unified hypothesis that can identify potential therapeutics for this patient population.

BACKGROUND: In this investigation, we explored the effects of pharmacological cholinergic stimulation on cardiac function and renal inflammation following acute myocardial infarction (AMI) in spontaneously hypertensive rats (SHRs).
METHODS: Adult male SHRs were randomized into three experimental groups: sham-operated; AMI + Veh (infarcted, treated with vehicle); and AMI + PY (infarcted, treated with the cholinesterase inhibitor, pyridostigmine bromide (PY)-40 mg/kg, once daily for seven days). Rats were euthanized 7 or 30 days post-surgery. The clinical parameters were assessed on the day before euthanasia. Subsequent to euthanasia, blood samples were collected and renal tissues were harvested for histological and gene expression analyses aimed to evaluate inflammation and injury.
RESULTS: Seven days post-surgery, the AMI + PY group demonstrated improvements in left ventricular diastolic function and autonomic regulation, and a reduction in renal macrophage infiltration compared to the AMI + Veh group. Furthermore, there was a notable downregulation in pro-inflammatory gene expression and an upregulation in anti-inflammatory gene expression. Analysis 30 days post-surgery showed that PY treatment had a sustained positive effect on renal gene expression, correlated with a decrease in biomarkers, indicative of subclinical kidney injury.
CONCLUSIONS: Short-term cholinergic stimulation with PY provides both cardiac and renal protection by mitigating the inflammatory response after AMI.

BACKGROUND: Postoperative ileus, driven by the cholinergic anti-inflammatory pathway, is the most common complication in patients undergoing colorectal surgery. By inhibiting acetylcholinesterase, pyridostigmine can potentially modulate the cholinergic anti-inflammatory pathway and accelerate gastrointestinal recovery. This study aimed to assess the efficacy of pyridostigmine in improving gastrointestinal recovery after colorectal surgery.
METHODS: This double-blinded RCT enrolled adult patients undergoing elective colorectal surgery at two hospitals in South Australia. Patients were randomized to 60 mg oral pyridostigmine or placebo twice daily starting 6 h after surgery until the first passage of stool. The primary outcome was GI-2, a validated composite measure of time to first stool and tolerance of oral diet. Secondary outcomes included incidence of postoperative ileus (defined as GI-2 greater than 4 days), duration of hospital stay, and 30-day complications, evaluated by intention-to-treat univariate analysis.
RESULTS: Of 130 patients recruited (mean(s.d.) age 58.4(16.4) years; 73 men, 56%), 65 were allocated to each arm. The median GI-2 was 1 day shorter with pyridostigmine compared with placebo (2 (i.q.r. 1-3) versus 3 (2-4) days; P = 0.015). However, there were no significant differences in postoperative ileus (17.2 versus 21.5%; P = 0.532) or duration of hospital stay (median 5 (i.q.r. 4-8.75) versus 5 (4-7.5) days; P = 0.921). Similarly, there were no significant differences in overall complications, anastomotic leak, cardiac complications, or patient-reported side effects.
CONCLUSIONS: Pyridostigmine resulted in a quicker return of GI-2 and was well tolerated. Larger multicentre studies are required to determine the optimal dosing and evaluate the impact of pyridostigmine in different surgical settings. Registration number: ACTRN12621000530820 (https://anzctr.org.au).

We report 2 cases of pediatric ocular myasthenia gravis. The first case was a 7-year-old girl who presented with bilateral ophthalmoplegia and ptosis that correlated with the onset of upper respiratory symptoms. Neuroimaging and acetylcholine receptor antibody testing were unremarkable. The ice pack test was positive. Symptoms greatly improved with pyridostigmine, with full resolution of ophthalmoplegia achieved by 8-month follow-up. The second case was a 4-year-old girl who presented emergently with ptosis and bilateral ophthalmoplegia. Acetylcholine receptor antibodies testing was positive. The patient was started on pyridostigmine and intravenous immunoglobulin and is scheduled to follow-up with pediatric ophthalmology in the outpatient setting.