Sicca syndrome during ipilimumab and nivolumab therapy for metastatic renal cell carcinoma

Introduction

Dry mouth is the main symptom of sicca syndrome, which rarely occurs as an immune-related adverse event. Here we report a case of sicca syndrome caused by immune checkpoint inhibitor treatment.

Case presentation

A 70-year-old man was diagnosed with left renal cell carcinoma after radical left nephrectomy. Nine years later, computed tomography revealed a metastatic nodule in the upper left lung lobe. Subsequently, ipilimumab and nivolumab were administered for recurrent disease. After 13 weeks of treatment, xerostomia and dysgeusia were noted. Salivary gland biopsy revealed lymphocyte and plasma cell infiltration in the salivary glands. Sicca syndrome was diagnosed and pilocarpine hydrochloride was prescribed without corticosteroids, with continuation of immune checkpoint inhibitor therapy. The symptoms alleviated after 36 weeks of treatment, with shrinkage of the metastatic lesions.

Conclusion

We experienced sicca syndrome caused by immune checkpoint inhibitors. Sicca syndrome improved without steroids and the immunotherapy could be continued.

Attenuation of initial pilocarpine-induced electrographic seizures by methionine sulfoximine pretreatment tightly correlates with the reduction of extracellular taurine in the hippocampus

OBJECTIVE

Initiation and development of early seizures by chemical stimuli is associated with brain cell swelling resulting in edema of seizure-vulnerable brain regions. We previously reported that pretreatment with a nonconvulsive dose of glutamine (Gln) synthetase inhibitor methionine sulfoximine (MSO) mitigates the intensity of initial pilocarpine (Pilo)-induced seizures in juvenile rats. We hypothesized that MSO exerts its protective effect by preventing the seizure-initiating and seizure-propagating increase of cell volume. Taurine (Tau) is an osmosensitive amino acid, whose release reflects increased cell volume. Therefore, we tested whether the poststimulus rise of amplitude of Pilo-induced electrographic seizures and their attenuation by MSO are correlated with the release of Tau from seizure-affected hippocampus.

METHODS

Lithium-pretreated animals were administered MSO (75 mg/kg ip) 2.5 h before the induction of convulsions by Pilo (40 mg/kg ip). Electroencephalographic (EEG) power was analyzed during 60 min post-Pilo, at 5-min intervals. Extracellular accumulation of Tau (eTau) served as a marker of cell swelling. eTau, extracellular Gln (eGln), and extracellular glutamate (eGlu) were assayed in the microdialysates of the ventral hippocampal CA1 region collected at 15-min intervals during the whole 3.5-h observation period.

RESULTS

The first EEG signal became apparent at ~10 min post-Pilo. The EEG amplitude across most frequency bands peaked at ~40 min post-Pilo, and showed strong (r ~ .72-.96) temporal correlation with eTau, but no correlation with eGln or eGlu. MSO pretreatment delayed the first EEG signal in Pilo-treated rats by ~10 min, and depressed the EEG amplitude across most frequency bands, to values that remained strongly correlated with eTau (r > .92) and moderately correlated (r ~ -.59) with eGln, but not with eGlu.

SIGNIFICANCE

Strong correlation between attenuation of Pilo-induced seizures and Tau release indicates that the beneficial effect of MSO is due to the prevention of cell volume increase concurrent with the onset of seizures.

Beneficial Effects of Rosmarinic Acid In Vitro and In Vivo Models of Epileptiform Activity Induced by Pilocarpine

Epilepsy is characterized by a predisposition to generate recurrent and spontaneous seizures; it affects millions of people worldwide. Status epilepticus (SE) is a severe type of seizure. In this context, screening potential treatments is very important. In the present study, we evaluated the beneficial effects of rosmarinic acid (RA) in pilocarpine-induced in vitro and in vivo models of epileptiform activity. Using an in vitro model in combined entorhinal cortex-hippocampal from Wistar rats we evaluated the effects of RA (10 µg/mL) on the lactate release and a glucose fluorescent analogue, 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NDBG), after incubation in high potassium aCSF supplemented or not with pilocarpine. In the in vivo model, SE was induced in male C57BL/6 mice by pilocarpine. At 1, 24, and 48 h after the end of SE mice were treated with RA (30 mg/kg/v.o.). We evaluated the neuromotor impairment by neuroscore tests and protein carbonyl levels in the cerebral cortex. In both in vitro models, RA was able to decrease the stimulated lactate release, while no effect on 2-NBDG uptake was found. RA has beneficial effects in models of epileptiform activity in vivo and in vitro. We found that RA treatment attenuated SE-induced neuromotor impairment at the 48 h timepoint. Moreover, post-SE treatment with RA decreased levels of protein carbonyls in the cerebral cortex of mice when compared to their vehicle-treated counterparts. Importantly, RA was effective in a model of SE which is relevant for the human condition. The present data add to the literature on the biological effects of RA, which could be a good candidate for add-on therapy in epilepsy.

Effect of Topical Pilocarpine Instilled Before Laser Peripheral Iridotomy on Regional Iris Thickness in Primary Angle Closure Disease: A Swept-Source Anterior Segment Optical Coherence Tomography Pilot Study

PURPOSE

To determine whether the temporal-superior or the nasal-superior iris area becomes thinner (more optimal) for laser peripheral iridotomy (LPI) after pilocarpine instillation in primary angle closure disease (PACD); and to identify an angle for optimal penetration of the laser beam.

PATIENTS AND METHODS

Iris thickness at 2 mm from the iris root in the preset scanning axes was measured using swept-source anterior segment optical coherence tomography before and 60 minutes after the instillation of pilocarpine 2% in one eye of 30 consecutive Japanese PACD patients with thick, dark brown iris. Iris thickness at 1:30 and 10:30 clock hour positions were evaluated in sagittal and oblique directions, resulting sagittal iris thickness (SIT) and minimum iris thickness (MIT) parameters, respectively.

RESULTS

Compared to the baseline values, iris thickness decreased significantly (P < .001) in both locations after pilocarpine instillation. Both before and after pilocarpine instillation the temporal-superior iris thickness was significantly smaller than the nasal-superior thickness (P ≤ .001). After pilocarpine instillation, the temporal-superior iris was significantly thinner in an approximately 13° angle direction temporal to the sagittal direction than in the sagittal direction (MIT: 0.322 mm; SIT: 0.346 mm, P < .001).

CONCLUSIONS

After pilocarpine instillation, the temporal-superior iris and an approximately 13° angle temporal to the sagittal direction may provide an optimal location and laser beam angle for LPI in PACD eyes.

Anticonvulsant and antioxidant effects of lamotrigine on pilocarpine-induced status epilepticus in mice

OBJECTIVES

The anticonvulsant and antioxidant effects of lamotrigine on status epilepticus (SE) are incompletely understood. We assessed these effects of lamotrigine on pilocarpine (Pilo)-induced SE in mice.

METHODS

Male C57BL/J6 mice were assigned to three groups: the control group, Pilo (400 mg/kg, s.c.)-induced SE (Pilo group) and lamotrigine (20 mg/kg, i.p.) treated (Pilo/lamotrigine group). The latency to SE of Racine's stage 3 or higher, the mortality rate within 2 h of Pilo administration, and the duration of SE until sacrifice were examined. Nitric oxide (NO), malondialdehyde and glutathione of oxidative stress biomarkers were detected in the hippocampus of the sacrificed animals in the above groups. NO was also detected in the cultured rat hippocampal neurons treated with 4 μM Pilo, Pilo+100 μM lamotrigine (Pilo/lamotrigine) and Pilo/lamotrigine+ N-methyl-D-aspartic acid (NMDA) receptor antagonist (10 μM MK-801, 3 μM ifenprodil) to examine the antioxidant effects of lamotrigine via non-NMDA-related pathways.

RESULTS

lamotrigine prolonged the latency to SE, the SE duration until sacrifice, and decreased the mortality rate in mice with Pilo-induced SE. Lamotrigine also decreased hippocampal concentrations of NO and malondialdehyde and increased the concentrations of glutathione in the SE model. Furthermore, there were significant differences in NO concentrations between groups of cultured rat hippocampal neurons treated with Pilo and Pilo/lamotrigine, and with Pilo/lamotrigine and Pilo/lamotrigine+MK-801.

CONCLUSION

Our findings suggest that lamotrigine exerts anticonvulsant and antioxidant effects on SE, but its antioxidant activity may not be fully exerted via NMDA-related pathways.

Dysautonomia in two littermate kittens

Case summary

Two 6-month-old littermate Russian Blue cross kittens presented for megaesophagus, intermittent vomiting and regurgitation. The male kitten was diagnosed with aspiration pneumonia and was suspected to have a hiatal hernia on thoracic radiographs. It presented 1 month later in acute respiratory distress and was euthanized. Post-mortem examination revealed a severe gastroesophageal intussusception with approximately 90% of the stomach inverted into the distal esophagus. Histologic examination confirmed dysautonomia with marked neuronal dropout and degeneration with necrosis, satellitosis of the celiac ganglion and the myenteric and submucosal plexuses throughout the gastrointestinal tract. The less-affected littermate showed improvement on cisapride and was doing well at home at the time of writing.

Relevance and novel information

Dysautonomia is rare in cats, with only a few reports of affected littermates. Both kittens are significantly younger than the median age previously reported. Detailed descriptions of diagnostic and histopathology findings are included. Gastroesophageal intussusception is a novel complication to consider when managing feline dysautonomia.

Oxygenated Water Increases Seizure Threshold in Various Rodent Seizure Models

Oxygenated water (OW) contains more oxygen than normal drinking water. It may induce oxygen enrichment in the blood and reduce oxidative stress. Hypoxia and oxidative stress could be involved in epilepsy. We aimed to examine the effects of OW-treated vs. control on four rodent models of epilepsy: (1) prenatal betamethasone priming with postnatal N-methyl-D-aspartate (NMDA)-triggered spasm, (2) no prenatal betamethasone, (3) repetitive kainate injection, and (4) intraperitoneal pilocarpine. We evaluated, in (1) and (2), the latency to onset and the total number of spasms; (3) the number of kainate injections required to induce epileptic seizures; (4) spontaneous recurrent seizures (SRS) (numbers and duration). In model (1), the OW-treated group showed significantly increased latency to onset and a decreased total number of spasms; in (2), OW completely inhibited spasms; in (3), the OW-treated group showed a significantly decreased number of injections required to induce epileptic seizures; and in (4), in the OW-treated group, the duration of a single SRS was significantly reduced. In summary, OW may increase the seizure threshold. Although the underlying mechanism remains unclear, OW may provide an adjunctive alternative for patients with refractory epilepsy.

Combined Treatment of Dichloroacetic Acid and Pyruvate Increased Neuronal Survival after Seizure

During seizure activity, glucose and Adenosine triphosphate (ATP) levels are significantly decreased in the brain, which is a contributing factor to seizure-induced neuronal death. Dichloroacetic acid (DCA) has been shown to prevent cell death. DCA is also known to be involved in adenosine triphosphate (ATP) production by activating pyruvate dehydrogenase (PDH), a gatekeeper of glucose oxidation, as a pyruvate dehydrogenase kinase (PDK) inhibitor. To confirm these findings, in this study, rats were given a per oral (P.O.) injection of DCA (100 mg/kg) with pyruvate (50 mg/kg) once per day for 1 week starting 2 h after the onset of seizures induced by pilocarpine administration. Neuronal death and oxidative stress were assessed 1 week after seizure to determine if the combined treatment of pyruvate and DCA increased neuronal survival and reduced oxidative damage in the hippocampus. We found that the combined treatment of pyruvate and DCA showed protective effects against seizure-associated hippocampal neuronal cell death compared to the vehicle-treated group. Treatment with combined pyruvate and DCA after seizure may have a therapeutic effect by increasing the proportion of pyruvate converted to ATP. Thus, the current research demonstrates that the combined treatment of pyruvate and DCA may have therapeutic potential in seizure-induced neuronal death.

Role of pilocarpine use following laser peripheral iridotomy in eyes with refractory acute angle closure glaucoma: A case report and literature review

RATIONALE

Angle closure glaucoma (ACG) is one of the most emergent types of glaucoma in clinical practice. Laser peripheral iridotomy (LPI) could minimize pupillary block and prevent ACG from an acute attack. However, recurrent increase in intraocular pressure (IOP) may still occur despite successful LPI. The aim of this study is to highlight the importance of postLPI pilocarpine use and larger LPI size as well as to share some experiences of cataract surgery in patients with ACG.

PATIENT CONCERNS

A 63-year-old female was referred to our hospital for headache, and poor control of IOP in the right eye for 3 hours.

DIAGNOSES

The patient was diagnosed ACG in the right eye. Recurrence of ACG in the right eye and new-onset and recurrent ACG in the left eye were noted during follow-up, despite successful LPI. The diagnosis was confirmed through slit lamp and gonioscope examination.

INTERVENTIONS

The LPI size was enlarged and pilocarpine use was maintained at 2% (1 drop 4 times a day) in both the eyes. Finally, cataract surgery was performed in both the eyes.

OUTCOMES

No recurrence of ACG was noted during postLPI pilocarpine use in both the eyes. The postoperative IOP was stable for >6 months after cataract surgery without any surgical intervention or antiglaucoma medication use. No discomfort or major complication was observed.

CONCLUSION

This report highlights the importance of postLPI pilocarpine use and larger LPI size in patients with refractory ACG.

A Review on the Role of Pilocarpine on the Management of Xerostomia and the Importance of the Topical Administration Systems Development

Xerostomia is linked to an increased risk of dental caries, oral fungal infections, and speaking/swallowing difficulties, factors that may significantly degrade patients’ life, socially- or emotionally-wise. Consequently, there is an increasing interest in developing management approaches for confronting this oral condition, at which pilocarpine, a parasympathomimetic agent, plays a vital role. Although the therapeutic effects of orally administrated pilocarpine on the salivary gland flow and the symptoms of xerostomia have been proved by numerous studies, the systemic administration of this drug is affiliated with various adverse effects. Some of the typical adverse effects include sweating, nausea, vomiting, diarrhea, rhinitis, dizziness and increased urinary frequency. In this vein, new strategies to develop novel and effective dosage forms for topical (i.e., in the oral cavity) pilocarpine administration, in order for the salivary flow to be enhanced with minimal systemic manifestations, have emerged. Therefore, the purpose of the current review is to survey the literature concerning the performance of topical pilocarpine delivery systems. According to the findings, the topical delivery of pilocarpine can be regarded as the equivalent to systemic delivery of the drug, efficacy-wise, but with improved patient tolerance and less adverse effects.

Anti-Epileptic Effect of Crocin on Experimental Temporal Lobe Epilepsy in Mice

Temporal lobe epilepsy (TLE) is a common kind of refractory epilepsy. More than 30% TLE patients were multi-drug resistant. Some patients may even develop into status epilepticus (SE) because of failing to control seizures. Thus, one of the avid goals for anti-epileptic drug development is to discover novel potential compounds to treat TLE or even SE. Crocin, an effective component of Crocus sativus L., has been applied in several epileptogenic models to test its anti-epileptic effect. However, it is still controversial and its effect on TLE remains unclear. Therefore, we investigated the effects of crocin on epileptogenesis, generalized seizures (GS) in hippocampal rapid electrical kindling model as well as SE and spotaneous recurrent seizure (SRS) in pilocarpine-induced TLE model in ICR mice in this study. The results showed that seizure stages and cumulative afterdischarge duration were significantly depressed by crocin (20 and 50 mg/kg) during hippocampal rapid kindling acquisition. And crocin (100 mg/kg) significantly reduced the incidence of GS and average seizure stages in fully kindled animals. In pilocarpine-induced TLE model, the latency of SE was significantly prolonged and the mortality of SE was significantly decreased by crocin (100 mg/kg), which can also significantly suppress the number of SRS. The underlying mechanism of crocin may be involved in the protection of neurons, the decrease of tumor necrosis factor-α in the hippocampus and the increase of brain derived neurotrophic factor in the cortex. In conclusion, crocin may be a potential and promising anti-epileptic compound for treatment of TLE.

Network Architecture Producing Swing to Stance Transitions in an Insect Walking System

The walking system of the stick insect is one of the most thoroughly described invertebrate systems. We know a lot about the role of sensory input in the control of stepping of a single leg. However, the neuronal organization and connectivity of the central neural networks underlying the rhythmic activation and coordination of leg muscles still remain elusive. It is assumed that these networks can couple in the absence of phasic sensory input due to the observation of spontaneous recurrent patterns (SRPs) of coordinated motor activity equivalent to fictive stepping-phase transitions. Here we sought to quantify the phase of motor activity within SRPs in the isolated and interconnected meso- and meta-thoracic ganglia. We show that SRPs occur not only in the meso-, but also in the metathoracic ganglia of the stick insect, discovering a qualitative difference between them. We construct a network based on neurophysiological data capable of reproducing the measured SRP phases to investigate this difference. By comparing network output to the biological measurements we confirm the plausibility of the architecture and provide a hypothesis to account for these qualitative differences. The neural architecture we present couples individual central pattern generators to reproduce the fictive stepping-phase transitions observed in deafferented stick insect preparations after pharmacological activation, providing insights into the neural architecture underlying coordinated locomotion.

Inhibition of TRPC3 channels by a novel pyrazole compound confers antiseizure effects

OBJECTIVE

As a key member of the transient receptor potential (TRP) superfamily, TRP canonical 3 (TRPC3) regulates calcium homeostasis and contributes to neuronal excitability. Ablation of TRPC3 lessens pilocarpine-induced seizures in mice, suggesting that TRPC3 inhibition might represent a novel antiseizure strategy. Among current TRPC3 inhibitors, pyrazole 3 (Pyr3) is most selective and potent. However, Pyr3 only provides limited benefits in pilocarpine-treated mice, likely due to its low metabolic stability and potential toxicity. We recently reported a modified pyrazole compound 20 (or JW-65) that has improved stability and safety. The objective of this study was to explore the effects of TRPC3 inhibition by our current lead compound JW-65 on seizure susceptibility.

METHODS

We first examined the pharmacokinetic properties including plasma half-life and brain to plasma ratio of JW-65 after systemic administration in mice. We then investigated the effects of TRPC3 inhibition by JW-65 on behavioral and electrographic seizures in mice treated with pilocarpine. To ensure our findings are not model specific, we assessed the susceptibility of JW-65-treated mice to pentylenetetrazole (PTZ)-induced seizures with phenytoin as a comparator.

RESULTS

JW-65 showed adequate half-life and brain penetration in mice, justifying its use for central nervous system conditions. Systemic treatment with JW-65 before pilocarpine injection in mice markedly impaired the initiation of behavioral seizures. This antiseizure action was recapitulated when JW-65 was administered after pilocarpine-induced behavioral seizures were well established and was confirmed by time-locked electroencephalographic monitoring and synchronized video. Moreover, JW-65-treated mice showed substantially decreased susceptibility to PTZ-induced seizures in a dose-dependent manner.

SIGNIFICANCE

These results suggest that pharmacological inhibition of the TRPC3 channels by our novel compound JW-65 might represent a new antiseizure strategy engaging a previously undrugged mechanism of action. Hence, this proof-of-concept study establishes TRPC3 as a novel feasible therapeutic target for the treatment of some forms of epilepsy.

The cholinergic system modulates negative BOLD responses in the prefrontal cortex once electrical perforant pathway stimulation triggers neuronal afterdischarges in the hippocampus

Repeated high-frequency pulse-burst stimulations of the rat perforant pathway elicited positive BOLD responses in the right hippocampus, septum and prefrontal cortex. However, when the first stimulation period also triggered neuronal afterdischarges in the hippocampus, then a delayed negative BOLD response in the prefrontal cortex was generated. While neuronal activity and cerebral blood volume (CBV) increased in the hippocampus during the period of hippocampal neuronal afterdischarges (h-nAD), CBV decreased in the prefrontal cortex, although neuronal activity did not decrease. Only after termination of h-nAD did CBV in the prefrontal cortex increase again. Thus, h-nAD triggered neuronal activity in the prefrontal cortex that counteracted the usual neuronal activity-related functional hyperemia. This process was significantly enhanced by pilocarpine, a mACh receptor agonist, and completely blocked when pilocarpine was co-administered with scopolamine, a mACh receptor antagonist. Scopolamine did not prevent the formation of the negative BOLD response, thus mACh receptors modulate the strength of the negative BOLD response.

Hippocampal Sclerosis in Pilocarpine Epilepsy: Survival of Peptide-Containing Neurons and Learning and Memory Disturbances in the Adult NMRI Strain Mouse

The present experiments reveal the alterations of the hippocampal neuronal populations in chronic epilepsy. The mice were injected with a single dose of pilocarpine. They had status epilepticus and spontaneously recurrent motor seizures. Three months after pilocarpine treatment, the animals were investigated with the Barnes maze to determine their learning and memory capabilities. Their hippocampi were analyzed 2 weeks later (at 3.5 months) with standard immunohistochemical methods and cell counting. Every animal displayed hippocampal sclerosis. The neuronal loss was evaluated with neuronal-N immunostaining, and the activation of the microglia was measured with Iba1 immunohistochemistry. The neuropeptide Y, parvalbumin, and calretinin immunoreactive structures were qualitatively and quantitatively analyzed in the hippocampal formation. The results were compared statistically to the results of the control mice. We detected neuronal loss and strongly activated microglia populations. Neuropeptide Y was significantly upregulated in the sprouting axons. The number of parvalbumin- and calretinin-containing interneurons decreased significantly in the Ammon’s horn and dentate gyrus. The epileptic animals displayed significantly worse learning and memory functions. We concluded that degeneration of the principal neurons, a numerical decrease of PV-containing GABAergic neurons, and strong peptidergic axonal sprouting were responsible for the loss of the hippocampal learning and memory functions.

A Novel Hydrogen Sulfide Donor Reduces Pilocarpine-Induced Status Epilepticus and Regulates Microglial Inflammatory Profile

Although epilepsy is one of the most common neurologic disorders, there is still a lack of effective therapeutic drugs for it. Recently, we synthesized a novel hydrogen sulfide (H₂S) donor, which is found to reduce seizures in animal models effectively. But it remains to be determined for its mechanism. In the present study, we found that the novel H₂S donor could reduce pilocarpine-induced seizures in mice. It alleviated the epileptic behavior, the hippocampal electroencephalography (EEG) activity of seizures, and the damage of hippocampal neurons in status epilepticus mice. In addition, the novel H₂S donor could reduce microglial inflammatory response. It not only reduced the upregulation of pro-inflammatory markers [inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX2)] in status epilepticus mice, but also increased the levels of microglial anti-inflammatory marker arginase-1 (Arg-1). In lipopolysaccharide-treated microglia BV2 cells, administration of the H₂S donor also significantly reduced the lipopolysaccharide-induced upregulation of the expression of the pro-inflammatory markers and increased the expression of the anti-inflammatory markers. Thus, the novel H₂S donor regulates microglial inflammatory profile in status epilepticus mice and in vitro. These results suggested that the novel H₂S donor can reduce seizures and regulate microglial inflammatory profile, which may be a novel mechanism and potential therapeutic strategy of the H₂S donor anti-seizures.

Dual Targeting by Inhibition of Phosphoinositide-3-Kinase and Mammalian Target of Rapamycin Attenuates the Neuroinflammatory Responses in Murine Hippocampal Cells and Seizures in C57BL/6 Mice

Emerging evidence suggests the association of seizures and inflammation; however, underlying cell signaling mechanisms are still not fully understood. Overactivation of phosphoinositide-3-kinases is associated with both neuroinflammation and seizures. Herein, we speculate the PI3K/Akt/mTOR pathway as a promising therapeutic target for neuroinflammation-mediated seizures and associated neurodegeneration. Firstly, we cultured HT22 cells for detection of the downstream cell signaling events activated in a lipopolysaccharide (LPS)-primed pilocarpine (PILO) model. We then evaluated the effects of 7-day treatment of buparlisib (PI3K inhibitor, 25 mg/kg p.o.), dactolisib (PI3K/mTOR inhibitor, 25 mg/kg p.o.), and rapamycin (mTORC1 inhibitor, 10 mg/kg p.o.) in an LPS-primed PILO model of seizures in C57BL/6 mice. LPS priming resulted in enhanced seizure severity and reduced latency. Buparlisib and dactolisib, but not rapamycin, prolonged latency to seizures and reduced neuronal loss, while all drugs attenuated seizure severity. Buparlisib and dactolisib further reduced cellular redox, mitochondrial membrane potential, cleaved caspase-3 and p53, nuclear integrity, and attenuated NF-κB, IL-1β, IL-6, TNF-α, and TGF-β1 and TGF-β2 signaling both in vitro and in vivo post-PILO and LPS+PILO inductions; however, rapamycin mitigated the same only in the PILO model. Both drugs protected against neuronal cell death demonstrating the contribution of this pathway in the seizure-induced neuronal pyknosis; however, rapamycin showed resistance in a combination model. Furthermore, LPS and PILO exposure enhanced pAkt/Akt and phospho-p70S6/total-p70S6 kinase activity, while buparlisib and dactolisib, but not rapamycin, could reduce it in a combination model. Partial rapamycin resistance was observed possibly due to the reactivation of the pathway by a functionally different complex of mTOR, i.e., mTORC2. Our study substantiated the plausible involvement of PI3K-mediated apoptotic and inflammatory pathways in LPS-primed PILO-induced seizures and provides evidence that its modulation constitutes an anti-inflammatory mechanism by which seizure inhibitory effects are observed. We showed dual inhibition by dactolisib as a promising approach. Targeting this pathway at two nodes at a time may provide new avenues for antiseizure therapies.

Pilocarpine-Induced Effects on Salivary Secretion as a Pharmacological Biomarker for Cholinergic Parasympathetic Activation

Pilocarpine-induced salivary secretion could serve as a nontherapeutic target engagement biomarker in a clinical setting to test the activity of an M3 positive allosteric modulator (PAM). The potentiating effect on the reactivity of the M3 receptor to the agonistic effect of pilocarpine would support the mechanism of action of an M3 PAM in a variety of therapeutic areas. The aim of this study was to determine the optimal pilocarpine dose needed for evaluation of this potentiating effect. Therefore, the effects of pilocarpine on salivary secretion rate and its pharmacokinetics were explored at single doses of 2.5, 5, and 10 mg of pilocarpine or placebo. The study also explored the test-retest variability of the pilocarpine-induced effects on salivary secretion. Pilocarpine caused a reproducible, dose-related increase in overall and maximum salivary secretion rate, in line with pilocarpine exposure. Oral doses of pilocarpine from 2.5 to 10 mg were safe and well tolerated, consistent with the published safety profile. These results support the use of pilocarpine in single-dose pharmacological challenge studies. The recommended dose for evaluating M3 PAM activity would be between 2.5 and 5 mg, showing a small increase in salivary secretion rate with room for further increase due to PAM activation.

The Discordance between Network Excitability and Cognitive Performance Following Vigabatrin Treatment during Epileptogenesis

Vigabatrin (VGB), a potent selective γ-aminobutyric acid transaminase (GABA-T) inhibitor, is an approved non-traditional anti-seizure drug for patients with intractable epilepsy. Nevertheless, its effect on epileptogenesis, and whether this effect is correlated with post-epileptogenic cognitive function remain unclear. Based on lithium-pilocarpine-induced seizure modeling, we evaluated the effect of VGB on epileptogenesis and neuronal damage following status epilepticus in Sprague-Dawley rats. Cognitive evaluations were performed with the aid of inhibitory avoidance testing. We found that VGB could interrupt epileptogenesis by reducing spontaneous recurrent seizures, hippocampal neuronal damage, and chronic mossy fiber sprouting. Nevertheless, VGB did not help with the retention of cognitive performance. Our findings suggest that further research into the role of VGB in epileptogenesis and the treatment of epilepsy in clinical practice is warranted.

Early Intervention via Stimulation of the Medial Septal Nucleus Improves Cognition and Alters Markers of Epileptogenesis in Pilocarpine-Induced Epilepsy

Over one-third of patients with temporal lobe epilepsy are refractory to medication. In addition, anti-epileptic drugs often exacerbate cognitive comorbidities. Neuromodulation is an FDA treatment for refractory epilepsy, but patients often wait >20 years for a surgical referral for resection or neuromodulation. Using a rodent model, we test the hypothesis that 2 weeks of theta stimulation of the medial septum acutely following exposure to pilocarpine will alter the course of epileptogenesis resulting in persistent behavioral improvements. Electrodes were implanted in the medial septum, dorsal and ventral hippocampus, and the pre-frontal cortex of pilocarpine-treated rats. Rats received 30 min/day of 7.7 Hz or theta burst frequency on days 4-16 post-pilocarpine, prior to the development of spontaneous seizures. Seizure threshold, spikes, and oscillatory activity, as well as spatial and object-based learning, were assessed in the weeks following stimulation. Non-stimulated pilocarpine animals exhibited significantly decreased seizure threshold, increased spikes, and cognitive impairments as compared to vehicle controls. Furthermore, decreased ventral hippocampal power (6-10 Hz) correlated with both the development of spikes and impaired cognition. Measures of spikes, seizure threshold, and cognitive performance in both acute 7.7 Hz and theta burst stimulated animals were statistically similar to vehicle controls when tested during the chronic phase of epilepsy, weeks after stimulation was terminated. These data indicate that modulation of the septohippocampal circuit early after pilocarpine treatment alters the progression of epileptic activity, resulting in elevated seizure thresholds, fewer spikes, and improved cognitive outcome. Results from this study support that septal theta stimulation has the potential to serve in combination or as an alternative to high frequency thalamic stimulation in refractory cases and that further research into early intervention is critical.

Administration of pilocarpine by microneedle patch as a novel method for cystic fibrosis sweat testing

The sweat test is the gold standard for the diagnosis of cystic fibrosis (CF). The test utilizes iontophoresis to administer pilocarpine to the skin to induce sweating for measurement of chloride concentration in sweat. However, the sweat test procedure needs to be conducted in an accredited lab with dedicated instrumentation, and it can lead to inadequate sweat samples being collected in newborn babies and young children due to variable sweat production with pilocarpine iontophoresis. We tested the feasibility of using microneedle (MN) patches as an alternative to iontophoresis to administer pilocarpine to induce sweating. Pilocarpine-loaded MN patches were developed. Both MN patches and iontophoresis were applied on horses to induce sweating. The sweat was collected to compare the sweat volume and chloride concentration. The patches contained an array of 100 MNs measuring 600 μm long that were made of water-soluble materials encapsulating pilocarpine nitrate. When manually pressed to the skin, the MN patches delivered >0.5 mg/cm2 pilocarpine, which was double that administered by iontophoresis. When administered to horses, MN patches generated the same volume of sweat when normalized to drug dose and more sweat when normalized to skin area compared to iontophoresis using a commercial device. Moreover, both MN patches and iontophoresis generated sweat with comparable chloride concentration. These results suggest that administration of pilocarpine by MN patches may provide a simpler and more-accessible alternative to iontophoresis for performing a sweat test for the diagnosis of CF.

Effect of Lacosamide and Ethosuximide Chronic Treatment on Neural Precursor Cells and Cognitive Functions after Pilocarpine Induced Status Epilepticus in Mice

Seizures in about 40% of patients with epilepsy fail to respond to anti-seizure medication (ASM) and may lead to uncontrolled and prolonged seizures often inducing status epilepticus (SE). The aim of the study was to evaluate the impact of a long-term treatment with two different generation ASMs: ethosuximide (ETS, a classic ASM) and lacosamide (LCM, a 3rd generation ASM) on neural stem cells’ (NSCs’) proliferation and learning and memory functions after pilocarpine (PILO)-induced SE in mice. The following drugs were used: LCM (10 mg/kg), ETS (20 mg/kg), and PILO (300 mg/kg). Cell counting was done using confocal microscope and ImageJ software. Cognitive functions were evaluated with the Morris water maze (MWM) test. The level of several selected neurometabolites was measured with magnetic resonance spectroscopy (MRS). Obtained results indicated no significant impact of ETS treatment on the neurogenesis process in PILO mice. Interestingly, LCM significantly decreased the total amount of newborn neurons. The MWM test indicated no significant changes in the time and distance traveled by the ETS and LCM groups compared to PILO control mice, although all measured parameters were more favorable for the PILO mice treated with ASM. Conclusions: The presented results show that long term treatment with LCM and ETS seems to be safe for the cognitive functions and the proper course of neurogenesis in the mouse PILO-induced SE model, although one should remember that LCM administered chronically may act to reduce new neurons’ formation.

Evaluation of a mucoadhesive pilocarpine tablet for the treatment of xerostomia: a randomized, double-blind, crossover clinical trial

The objectives of this study were to determine the effectiveness of a mucoadhesive tablet of pilocarpine, 5 mg, for the treatment of xerostomia and verify its pharmacokinetic profile. The randomized, double-blind, crossover clinical trial involved 25 older adults (60 to 80 years) with xerostomia and hyposalivation who were randomly divided into groups A and B. Once daily, for 7 days, group A used a mucoadhesive tablet containing pilocarpine, while group B used a mucoadhesive tablet without the active ingredient (first intervention). After 7 days of washout (no treatment), use of the medications resumed for 7 days, with a crossover between groups (second intervention). Xerostomia was evaluated through a shortened version of the Summated Xerostomia Inventory-Dutch Version, and the unstimulated salivary flow (USF) and stimulated salivary flow (SSF) of the patients were measured. The patients were evaluated at baseline and 7, 14, and 21 days. Then, the pharmacokinetic profiles of mucoadhesive and conventional oral pilocarpine tablets were compared using saliva obtained from 8 patients. Both of the interventions resulted in a significant reduction in Summated Xerostomia Inventory scores and a significant increase in the mean USF (P < 0.05). A statistically significant increase in the mean SSF only occurred when pilocarpine was administered (P < 0.05). No significant adverse effects were found. The mucoadhesive tablet resulted in much higher salivary concentrations of pilocarpine than did the conventional oral tablet. Both formulations of the mucoadhesive tablet, with or without pilocarpine, relieved patients' dry mouth symptoms. Trial registration: Registro Brasileiro de Ensaios Clinicos (ReBEC) No. RBR-9qdnws.

Concise Synthesis of Both Enantiomers of Pilocarpine

Furan-2-carboxylic acid was used as a starting material for the synthesis of dehydro-homopilopic acid. Esterification, hydrogenation and enzymatic hydrolysis followed by the reduction of Weinreb amides and a single-step attachment of a 1-methyl-imidazole residue allowed for the concise synthesis of both enantiomers of pilocarpine.