Deschloroclozapine exhibits an exquisite agonistic effect at lower concentration compared to clozapine-N-oxide in hM3Dq expressing chemogenetically modified rats.

Introduction: Within the realm of chemogenetics, a particular form of agonists targeting designer receptors exclusively activated by designer drugs (DREADDs) has emerged. Deschloroclozapine (DCZ), a recently introduced DREADDs agonist, demonstrates remarkable potency in activating targeted neurons at a lower dosage compared to clozapine-N-oxide (CNO). Methods: We conducted a comparative analysis of the effects of subcutaneously administered CNO (1 mg/kg) and DCZ (0.1 mg/kg) in our transgenic rats expressing hM3Dq and mCherry exclusively in oxytocin (OXT) neurons. Results and Discussion: Notably, DCZ exhibited a swift and robust elevation of serum OXT, surpassing the effects of CNO, with a significant increase in the area under the curve (AUC) up to 3 hours post-administration. Comprehensive assessment of brain neuronal activity, using Fos as an indicator, revealed comparable effects between CNO and DCZ. Additionally, in a neuropathic pain model, both CNO and DCZ increased the mechanical nociceptive and thermal thresholds; however, the DCZ-treated group exhibited a significantly accelerated onset of the effects, aligning harmoniously with the observed alterations in serum OXT concentration following DCZ administration. These findings emphasize the remarkable efficacy of DCZ in rats, suggesting its equivalent or potentially superior performance to CNO at considerably lower dosages, thus positioning it as a promising contender among DREADDs agonists.

Nitric oxide synthase contributes to the maintenance of LTP in the oxytocin-mRFP1 neuron of the rat hypothalamus.

Oxytocin (OXT) is a neuropeptide hormone that plays a critical role in nociception. Long-term potentiation (LTP) is a major form of synaptic plasticity in the central nervous system. Recently, LTP has been reported in the hypothalamus; however, data on LTP in hypothalamic OXT-ergic neurons are unclear. Furthermore, the signaling pathways for hypothalamic OXT-ergic neuronal LTP and its physiological significance remain unknown. Herein, we aimed to investigate the induction of hypothalamic OXT-ergic neuronal LTP and its synaptic mechanism using OXT-monomeric red fluorescent protein 1 transgenic rats to visualize and record from OXT-ergic neurons. The hypothalamic paraventricular nucleus (PVN) OXT-ergic neuronal LTP induced by the pairing protocol was dependent on N-methyl-D-aspartate receptor (NMDAR). Furthermore, nitric oxide synthase (NOS) is required to maintain the LTP regardless of the NMDARs. In addition, hypothalamic OXT-ergic neuronal LTP was not induced in the adjuvant arthritis rat model but increased excitatory postsynaptic currents were detected. LTP in hypothalamic OXT-ergic neurons in the PVN in the presence of NOS may be involved in neuronal changes during OXT synthesis in chronic inflammation.

Chemogenetic Activation of Oxytocin Neurons Improves Pain in a Reserpine-induced Fibromyalgia Rat Model.

Fibromyalgia (FM) is a syndrome characterized by chronic pain with depression as a frequent comorbidity. However, efficient management of the pain and depressive symptoms of FM is lacking. Given that endogenous oxytocin (OXT) contributes to the regulation of pain and depressive disorders, herein, we investigated the role of OXT in an experimental reserpine-induced FM model. In FM model, OXT-monomeric red fluorescent protein 1 (OXT-mRFP1) transgenic rats exhibited increased depressive behavior and sensitivity in a mechanical nociceptive test, suggesting reduced pain tolerance. Additionally, the development of the FM-like phenotype in OXT-mRFP1 FM model rats was accompanied by a significant reduction in OXT mRNA expression in the magnocellular neurons of the paraventricular nucleus. OXT-mRFP1 FM model rats also had significantly fewer tryptophan hydroxylase (TPH)- and tyrosine hydroxylase (TH)-immunoreactive (ir) neurons as well as reduced serotonin and norepinephrine levels in the dorsal raphe and locus coeruleus. To investigate the effects of stimulating the endogenous OXT pathway, rats expressing OXT-human muscarinic acetylcholine receptor (hM3Dq)-mCherry designer receptors exclusively activated by designer drugs (DREADDs) were also assessed in the FM model. Treatment of these rats with clozapine-N-oxide (CNO), an hM3Dq-activating drug, significantly improved characteristic FM model-induced pathophysiological pain, but did not alter depressive-like behavior. The chemogenetically induced effects were reversed by pre-treatment with an OXT receptor antagonist, confirming the specificity of action via the OXT pathway. These results indicate that endogenous OXT may have analgesic effects in FM, and could be a potential target for effective pain management strategies for this disorder.

ANCA-Associated Vasculitis after Moderna COVID-19 Vaccination.

We experienced a case of myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA)-associated vasculitis after Moderna COVID-19 vaccination. An 82-year-old woman developed pyrexia and general malaise one month after her third booster vaccine, and the symptoms persisted. Blood testing revealed inflammation, a high level of MPO-ANCA, and microscopic hematuria. MPO-ANCA-associated vasculitis was diagnosed by renal biopsy. The symptoms improved with steroid therapy. Common adverse reactions to mRNA vaccines against COVID-19 include pyrexia and general malaise, but MPO-ANCA-associated vasculitis can also occur. If pyrexia, prolonged general malaise, urinary occult blood, or renal impairment is observed, the onset of MPO-ANCA-associated vasculitis should be considered.

Endogenous oxytocin exerts anti-nociceptive and anti-inflammatory effects in rats.

Oxytocin is involved in pain transmission, although the detailed mechanism is not fully understood. Here, we generate a transgenic rat line that expresses human muscarinic acetylcholine receptors (hM3Dq) and mCherry in oxytocin neurons. We report that clozapine-N-oxide (CNO) treatment of our oxytocin-hM3Dq-mCherry rats exclusively activates oxytocin neurons within the supraoptic and paraventricular nuclei, leading to activation of neurons in the locus coeruleus (LC) and dorsal raphe nucleus (DR), and differential gene expression in GABA-ergic neurons in the L5 spinal dorsal horn. Hyperalgesia, which is robustly exacerbated in experimental pain models, is significantly attenuated after CNO injection. The analgesic effects of CNO are ablated by co-treatment with oxytocin receptor antagonist. Endogenous oxytocin also exerts anti-inflammatory effects via activation of the hypothalamus-pituitary-adrenal axis. Moreover, inhibition of mast cell degranulation is found to be involved in the response. Taken together, our results suggest that oxytocin may exert anti-nociceptive and anti-inflammatory effects via both neuronal and humoral pathways.

Oestrogen-dependent hypothalamic oxytocin expression with changes in feeding and body weight in female rats.

Oxytocin (OXT) is produced in the hypothalamic nuclei and secreted into systemic circulation from the posterior pituitary gland. In the central nervous system, OXT regulates behaviours including maternal and feeding behaviours. Our aim is to evaluate whether oestrogen regulates hypothalamic OXT dynamics. Herein, we provide the first evidence that OXT dynamics in the hypothalamus vary with sex and that oestrogen may modulate dynamic changes in OXT levels, using OXT-mRFP1 transgenic rats. The fluorescence intensity of OXT-mRFP1 and expression of the OXT and mRFP1 genes in the hypothalamic nuclei is highest during the oestrus stage in female rats and decreased significantly in ovariectomised rats. Oestrogen replacement caused significant increases in fluorescence intensity and gene expression in a dose-related manner. This is also demonstrated in the rats' feeding behaviour and hypothalamic Fos neurons using cholecystokinin-8 and immunohistochemistry. Hypothalamic OXT expression is oestrogen-dependent and can be enhanced centrally by the administration of oestrogen.

Expression of oxytocin in hypothalamus and reduction of nociceptive stress following administration of Kamikihi-to in female rats.

Hypothalamo-neurohypophysial oxytocin (OXT) plays an essential role in reproduction and in several socio-physiological functions, including stress reduction, anxiety relief, feeding suppression, social recognition, and trust building. Recent studies suggest that the central OXT system is also involved in antinociceptive and anti-inflammatory functions. Kamikihi-to (KKT), a Japanese traditional herbal (Kampo) medicine composed of 14 herbal ingredients, is clinically prescribed for patients with psychological symptoms, including anxiety, depression, and insomnia, and it has been associated with OXT expression. We investigated the antinociceptive response and OXT expression according to sex and the effects of KKT pre administration in a rat model. We found that nociceptive responses measured via the hot plate and formalin tests were attenuated following the administration of KKT-enriched feed for 4 weeks. The observation of mRFP1 fluorescence in OXT-mRFP1 transgenic rats revealed that KKT-administered rats showed increased expression of OXT in the magnocellular and parvocellular paraventricular nucleus of the hypothalamus. Food intake in the KKT-pre-administered group significantly decreased after cholecystokinin (CCK)-8 administration. Our results suggest that KKT is involved in the attenuation of nociceptive stress in female rats by enhancing the expression of OXT in the hypothalamus.

Upregulation of the hypothalamo-neurohypophysial system and activation of vasopressin neurones attenuates hyperalgesia in a neuropathic pain model rat.

Arginine vasopressin (AVP) is a hypothalamic neurosecretory hormone well known as an antidiuretic, and recently reported to be involved in pain modulation. The expression kinetics of AVP and its potential involvement in the descending pain modulation system (DPMS) in neuropathic pain (NP) remains unclear. We investigated AVP expression and its effects on mechanical and thermal nociceptive thresholds using a unilateral spinal nerve ligation (SNL) model. All rats with SNL developed NP. Intensities of enhanced green fluorescent protein (eGFP) in the supraoptic and paraventricular nuclei, median eminence, and posterior pituitary were significantly increased at 7 and 14 days post-SNL in AVP-eGFP rats. In situ hybridisation histochemistry revealed significantly increased AVP mRNA expression at 14 days post-SNL compared with the sham control group. The chemogenetic activation of AVP neurones significantly attenuated mechanical and thermal hyperalgesia with elevated plasma AVP concentration. These analgesic effects were suppressed by pre-administration with V1a receptor antagonist. AVP neurones increased the neuronal activity of serotonergic dorsal raphe, noradrenergic locus coeruleus, and inhibitory interneurones in the spinal dorsal horn. These results suggest that the hypothalamo-neurohypophysial system of AVP is upregulated in NP and activated endogenous AVP exerts analgesic effects via the V1a receptors. AVP neurones may activate the DPMS.

Coronary artery lesion distribution in patients with chronic kidney disease undergoing percutaneous coronary intervention.

PURPOSE: To determine the location of coronary atherosclerosis distribution observed in patients with chronic kidney disease (CKD). METHODS: A cross-sectional study was conducted using the database of cardiovascular medicine data from Saitama Sekishinkai Hospital to clarify the association between renal function and angiographic characteristics of coronary atherosclerosis. In total, 3268 patients who underwent percutaneous coronary intervention were included. Propensity score matching revised the total to 1772. The association of renal function with the location and/or distribution of coronary atherosclerosis lesions was then examined. RESULTS: Overall, coronary lesion was observed in the left anterior descending coronary artery (LAD) in 56% patients, whereas 28% and 22% were in the right coronary artery (RCA) and left circumflex coronary artery (LCX), respectively. LAD was most affected and observed in 57% patients with stage 1 CKD. RCA was second-most affected, at 26% CKD stage 1, but it increased to 31%, 38%, and 59% in CKD 3, 4, and 5, respectively. In CKD 5 patients, the RCA was the most affected artery (59%), with 41% LAD lesions. Logistic regression analysis after propensity score matching showed that the odds ratios for an RCA lesion was 3.658 in CKD 5 (p = .025) compared with CKD 1 after adjusting for traditional risk factors. CONCLUSION: The prevalence of RCA lesions, but not LAD or LCX lesions, increased with increasing CKD stage. The pathophysiology of coronary atherosclerosis may differ by lesion location. Deterioration of renal function may affect progression of atherosclerosis more in the RCA than in the LAD or LCX.

Chemogenetic activation of endogenous arginine vasopressin exerts anorexigenic effects via central nesfatin-1/NucB2 pathway.

We examined whether the chemogenetic activation of endogenous arginine vasopressin (AVP) affects central nesfatin-1/NucB2 neurons, using a transgenic rat line that was previously generated. Saline (1 mL/kg) or clozapine-N-oxide (CNO, 1 mg/mL/kg), an agonist for hM3Dq, was subcutaneously administered in adult male AVP-hM3Dq-mCherry transgenic rats (300-370 g). Food and water intake were significantly suppressed after subcutaneous (s.c.) injection of CNO, with aberrant circadian rhythmicity. The percentages of Fos expression in nesfatin-1/NucB2-immunoreactive neurons were significantly increased in the hypothalamus and brainstem at 120 min after s.c. injection of CNO. Suppressed food intake that was induced by chemogenetic activation of endogenous AVP was ablated after intracerebroventricularly administered nesfatin-1/NucB2-neutralizing antibody in comparison with vehicle, without any alteration of water intake nor circadian rhythmicity. These results suggest that chemogenetic activation of endogenous AVP affects, at least in part, central nesfatin-1/NucB2 neurons and may exert anorexigenic effects in the transgenic rats.

A Case of Neurosarcoidosis-Induced Syndrome of Inappropriate Secretion of Antidiuretic Hormone Diagnosed with Neuroendoscopy.

We treated a patient with neurosarcoidosis, which caused the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), in whom diagnosis was performed using neuroendoscopy. The patient was a 56-year-old female who was hospitalized for hyponatremia and diagnosed with SIADH based on a detailed examination. During the course, she developed impaired consciousness due to acute hydrocephalus, which improved after ventricular drainage. Head magnetic resonance imaging (MRI) confirmed nodular lesions at the floor of the third ventricle and the cerebral aqueduct. Neuroendoscopic biopsy led to the diagnosis of neurosarcoidosis. Her hyponatremia improved after steroid therapy. Neurosarcoidosis can cause SIADH, and complication of hydrocephalus may lead to a poor prognosis. Neuroendoscopy appears to be effective for the diagnosis of neurosarcoidosis with hydrocephalus and helps in deciding the treatment modality.

Infected Aneurysm after Endoscopic Submucosal Dissection.

A 79-year-old man on hemodialysis was hospitalized for further investigation. Early gastric cancer was diagnosed by gastrointestinal endoscopy and endoscopic submucosal dissection (ESD) was performed. Fever and abdominal pain thereafter developed, and a severe inflammatory response was observed on a blood test. Contrast computed tomography (CT) showed ulcer-like projections and soft tissue surrounding the aorta, from the celiac to left renal artery. An infected aneurysm was diagnosed. Although infected aneurysms developing after laparoscopic cholecystectomy or biopsy of contiguous esophageal duplication cyst have been reported, those developing after ESD have not. When fever and abdominal pain develop after ESD, an infected aneurysm should be considered and contrast CT performed.

A case of histopathologically confirmed infective endocarditis with no vegetations observed during preoperative diagnosis.

An 81-year-old woman on maintenance hemodialysis (HD) was admitted to the hospital with fever and repeated positive blood cultures for coagulase-negative staphylococci. The patient had a history of aortic valve replacement for aortic valve stenosis (AS). Although one major criterion and two minor criteria from the Duke criteria were met and therefore infective endocarditis (IE) was suspected for this case, no definitive diagnosis was made. Vegetations were not observed on the transesophageal echocardiography, but AS was prominent. The patient was refractory to antibiotic therapy using vancomycin, and blood cultures did not convert to negative. To treat the suspected IE and AS, aortic valve replacement was performed. Although vegetations were not observed in the resected valve, gram-positive cocci were found in clusters, and a histopathological diagnosis of IE was made. The postoperative blood culture converted from positive to negative, and the patient was subsequently discharged from the hospital. While relative risk of IE is high in HD patients, a definitive diagnosis of IE may be difficult due to calcification of the valve and valve replacement. In HD patients with bacteremia, suspicion of IE should be aggressively pursued if other sources of infections are negative, and if the patient is refractory to medical treatment, surgical treatment may be necessary.

Clinical effects of the new phosphorus binder, bixalomer in hemodialysis patients switched from sevelamer hydrochloride.

It has been reported that sevelamer hydrochloride, which is often used as a polymer phosphorus (P) binder for managing serum P concentration in dialysis patients, causes gastrointestinal adverse effects such as constipation, etc. The reason for this is thought to be that sevelamer hydrochloride has high water absorption, causing it to absorb water and swell in the gastrointestinal tract. In June 2012, the new polymer P binder bixalomer was launched in Japan. Since bixalomer has low swelling due to water absorption, it can be expected to alleviate adverse effects in the gastrointestinal system. In our study, for 21 cases of maintenance hemodialysis patients undergoing treatment with sevelamer hydrochloride at our hospital, the P binder was switched from sevelamer hydrochloride to the same dosage of bixalomer, and the concentrations of serum P, corrected calcium (Ca) and whole parathyroid hormone (PTH) before and one month after the switch were compared. In addition, gastrointestinal symptoms (acid reflux, abdominal pain, indigestion, diarrhea and constipation) were evaluated before and after the switch using a questionnaire based on the Japanese version of the Gastrointestinal Symptom Rating Scale (GSRS). By switching to bixalomer, serum P concentration was significantly reduced (P=0.024), but there were no significant changes observed for serum corrected Ca and whole PTH. Furthermore, there were no significant changes observed for all five of the evaluation items of the GSRS, before and after the switch. These results suggest that although bixalomer can more potently reduce the serum P concentration than sevelamer hydrochloride, there were no significant differences in the effects of both P binders on the gastrointestinal symptoms.

Telmisartan lowers home blood pressure and improves insulin resistance without correlation between their changes.

Telmisartan is an angiotensin type 1 receptor blocker (ARB), which also partially activates liganding peroxisome proliferator-activated receptor gamma. However, the relationship between the effects of telmisartan on hemodynamics and metabolism has not sufficiently been elucidated in clinical settings. We examined the long-term effects of telmisartan on hemodynamics including home blood pressure (BP) and on insulin resistance representing as homeostasis model assessment (HOMA-R). Twenty-seven hypertensive patients were consecutively enrolled at our outpatient department. At entry, all of the participants were previously prescribed another ARB for more than 3 months and then the former ARB were replaced by telmisartan. Hemodynamic and metabolic parameters were measured before treatment and at points 1 and 3 months after treatment with telmisartan. Telmisartan significantly lowered home systolic blood pressure (SBP) and diastolic blood pressure (DBP) (DBP) and improved HOMA-R during the treatment period. However, the changes in home SBP and DBP were not correlated with that of HOMA-R. In conclusion, telmisartan lowers home BP and improves insulin resistance without correlation between their changes.

Close association of vascular and valvular calcification and prognosis of patients on continuous ambulatory peritoneal dialysis.

In the present study, we examined the association between vascular and valvular calcification and the prognosis of patients on continuous ambulatory peritoneal dialysis (CAPD). Data were collected from the records of patients introduced onto CAPD therapy during 1999 - 2006 at the Department of Nephrology, Saitama Medical University. At the start of CAPD, cardiac and vascular echography were used to examine 162 patients (average age: 56 +/- 5 years; 58 men, 104 women; 43 with and 119 without diabetes) for evaluation of vascular and valvular calcification. Both vascular and valvular calcification were found in 32 patients. Vascular calcification was found in 16, and valvular calcification in 11. Over 5 years, 11 patients suffered from cardiovascular disease (7 with stroke, 4 with myocardial infarction). All of these patients had vascular or valvular calcification at the start of CAPD therapy. We also used Cox hazard analysis to examine values for Ca, P, Ca x P, intact parathyroid hormone (iPTH), and lipids. None of these values were independent contributory factors for incidence of cardiovascular disease in patients on CAPD. These data suggest the importance of vascular and valvular echography to evaluate patients on CAPD, especially at the start of CAPD therapy. Vascular and valvular calcification are important factors for determining the prognosis of patients on CAPD.

Risk factors and cause of removal of peritoneal dialysis catheter in patients on continuous ambulatory peritoneal dialysis.

In the present study, we examined the risk factors and causes for removal of the peritoneal dialysis (PD) catheter in patients on continuous ambulatory PD (CAPD). Data were collected from the records of patients who received CAPD therapy from 1995 to 2007 in the Department of Nephrology, Saitama Medical University. During that time, 473 patients were introduced onto CAPD therapy and the PD catheter was removed from 63 patients. Catheters were removed in 30 patients (47%) because of peritoneal infection, in 11 (17%) because of dialysis failure, in 8 (13%) because of neoplasm of the gastrointestinal tract, in 6 (10%) because of perforation of the gastrointestinal tract, in 2 (3%) because of laceration of PD catheter, and in 3 each (5%) because of transplantation and home hemodialysis therapy. Duration of CAPD was 5.6 +/- 1.2 years. In patients who experienced peritoneal infection, causative organisms were Staphylococcus (mainly methicillin-resistant S. aureus), Candida, Pseudomonas, and non tuberculous Mycobacterium. Failure to continue PD therapy related to dialysis deficiency. All patients were examined for encapsulating peritoneal sclerosis (EPS) by computed tomography (CT) enhanced using contrast material. In 9 cases in which the CT findings indicated EPS, treatment with oral prednisolone (20 mg daily) was started; the dose was then gradually reduced over 1 year. After removal of the PD catheter, no patient developed EPS. All removed catheters were examined using electron microscopy. The catheters from patients who experienced PD peritonitis revealed biofilm formation; however, no biofilm formation was found in PD catheters removed from patients without infection. Despite appropriate antibiotic therapy, peritoneal infection remains the major cause of PD catheter removal. Biofilm formation might be an obstacle to PD continuation.

Effect of angiotensin receptor blockers on cardiovascular events in patients undergoing hemodialysis: an open-label randomized controlled trial.

BACKGROUND: Cardiovascular disease is the leading cause of mortality in patients with kidney failure treated with hemodialysis (HD). Although angiotensin receptor blockers (ARBs) reduce cardiovascular disease (CVD) events in patients with diabetes and chronic kidney disease, their effect in patients with kidney failure on HD therapy is not known. STUDY DESIGN: Open-labeled randomized trial. SETTING & PARTICIPANTS: Patients aged 30 to 80 years receiving HD 2 to 3 times weekly for 1 to 5 years at 5 university-affiliated dialysis centers. INTERVENTIONS: Treatment with ARBs (valsartan, candesartan, and losartan) versus without ARBs after stratification by sex, age, systolic blood pressure, and diabetes. OUTCOMES: The primary end point is the development of fatal and nonfatal CVD events, defined as the composite of CVD death, myocardial infarction, stroke, congestive heart failure, coronary artery bypass grafting, or percutaneous coronary intervention. The secondary end point is all-cause death. RESULTS: 366 subjects initially were randomly assigned to an ARB or no ARB (control), but after a run-in phase, 180 were retained in each group. Mean age was 60 years, 59% were men, 51% had diabetes, and mean predialysis systolic blood pressure was 154 mm Hg. There were 93 fatal or nonfatal CVD events (52%); 34 (19%) in the ARB group and 59 (33%) in the non-ARB group. After adjustment for age, sex, diabetes, systolic blood pressure, and center, treatment with an ARB was independently associated with reduced fatal and nonfatal CVD events (hazard ratio, 0.51; 95% confidence interval, 0.33 to 0.79; P = 0.002). There were 63 deaths (35%); 25 (14%) in the ARB group and 38 (21%) in the non-ARB group. After adjustment, all-cause mortality differed between the 2 groups (hazard ratio, 0.64; 95% confidence interval, 0.39 to 1.06; P = 0.1). LIMITATIONS: Because of the small sample size of this trial, the large effect may be a spurious finding. Use of an open-label design and 3 different agents in the ARB group might have influenced results. CONCLUSION: Use of an ARB may be effective in reducing nonfatal CVD events in patients undergoing long-term HD. A larger study is required to confirm these results.