Intracerebroventricular Infusion Research Articles

Reduction in Hippocampal Amyloid-β Peptide (Aβ) Content during Glycine-Proline-Glutamate (Gly-Pro-Glu) Co-Administration Is Associated with Changes in Inflammation and Insulin-like Growth Factor (IGF)-I Signaling

Alzheimer’s disease (AD) is characterized by the deposition in the brain of senile plaques composed of amyloid-β peptides (Aβs) that increase inflammation. An endogenous peptide derived from the insulin-like growth factor (IGF)-I, glycine-proline-glutamate (GPE), has IGF-I-sensitizing and neuroprotective actions. Here, we examined the effects of GPE on Aβ levels and hippocampal inflammation generated by the intracerebroventricular infusion of Aβ25-35 for 2 weeks (300 pmol/day) in ovariectomized rats and the signaling-related pathways and levels of Aβ-degrading enzymes associated with these GPE-related effects. GPE prevented the Aβ-induced increase in the phosphorylation of p38 mitogen-activated protein kinase and the reduction in activation of signal transducer and activator of transcription 3, insulin receptor substrate-1, and Akt, as well as on interleukin (IL)-2 and IL-13 levels in the hippocampus. The functionality of somatostatin, measured as the percentage of inhibition of adenylate cyclase activity and the levels of insulin-degrading enzyme, was also preserved by GPE co-treatment. These findings indicate that GPE co-administration may protect from Aβ insult by changing hippocampal cytokine content and somatostatin functionality through regulation of leptin- and IGF-I-signaling pathways that could influence the reduction in Aβ levels through modulation of levels and/or activity of Aβ proteases.

S-Nitrosoglutathione Attenuates Oxidative Stress and Improves Retention Memory Dysfunctions in Intra-Cerebroventricular-Streptozotocin Rat Model of Sporadic Alzheimer's Disease via Activation of BDNF and Nuclear Factor Erythroid 2-Related Factor-2 Antioxidant Signaling Pathway.

The brain-derived neurotrophic factor (BDNF) and transcription nuclear factor erythroid 2-related factor-2 (NRF-2) play an important role in Alzheimer's disease (AD). However, the interactive involvement of BDNF and NRF-2 in respect to antioxidant mechanisms in different parts of the AD brain is still unclear. Considering the above condition, used S-nitrosoglutathione (GSNO) to examine whether it modulates the BDNF and NRF-2 levels to activate signaling pathway to promote antioxidant levels in AD brains. AD was induced by intracerebroventricular infusion of streptozotocin (ICV-STZ, 3 mg/kg) in Wistar rats. The effect of GSNO was analyzed by evaluating the retention of memory in months 1, 2, and 3. After the behavior study, rats were sacrificed and accessed the amyloid beta (Aβ)-40, Aβ42, glutathione (GSH), BDNF, and NRF-2 levels in the hippocampus, cortex, and amygdala tissue. Pretreatment with GSNO (50 µg/kg/intraperitoneal/day) restored the BDNF, and NRF-2 levels toward normalcy as compared with ICV-STZ + saline-treated animals. Also, GSNO treatment reversed the oxidative stress and increased the GSH levels toward normal levels. Further, reduced Aβ levels and neuronal loss in different brain regions. As a result, GSNO treatment improved the cognitive deficits in ICV-STZ-treated rats. The results showed that endogenous nitric oxide donor GSNO improved the cognitive deficits and ICV-STZ-induced AD pathological conditions, possibly via attenuating the oxidative stress. Hence, the above finding supported that GSNO treatment may activate BDNF and NRF-2 antioxidant signaling pathways in the AD brain to normalize oxidative stress, which is the main causative factor for ICV-STZ-induced AD pathogenesis.

Intracerebroventricular PROK2 infusion could increase the secretion of male reproductive hormones by stimulating the HPG axis.

Prokineticin 2 (PROK2), an important neuropeptide that plays a key role in the neuronal migration of gonadotropin-releasing hormone (GnRH) in the hypothalamus, is known to have regulatory effects on the gonads. In the present study, the impact of intracerebroventricular (icv) PROK2 infusion on hypothalamic-pituitary-gonadal axis (HPG) hormones, testicular tissues, and sperm concentration was investigated. Rats were randomly divided into four groups: control, sham, PROK2 1.5 and PROK2 4.5. Rats in the PROK2 1.5 and PROK2 4.5 groups were administered 1.5nmol and 4.5nmol PROK2 intracerebroventricularly for 7days via an osmotic mini pump (1µl/h), respectively. Rat blood serum follicle stimulating hormone (FSH), luteinizing hormone (LH) and testosterone hormone levels were determined with the ELISA method in the blood samples after 7days of infusion. GnRH mRNA expression was determined with the RT-PCR in hypothalamus tissues. analyze Sperm concentration was determined, and testicular tissue was examined histologically with the hematoxylin-eosin staining method. It was observed that GnRH mRNA expression increased in both PROK2 infusion groups. Serum FSH, LH and testosterone hormone levels also increased in these groups. Although sperm concentration increased in PROK2 infusion groups when compared to the control and sham, the differences were not statistically significant. Testicular tissue seminiferous epithelial thickness was higher in the PROK2 groups when compared to the control and sham groups. The present study findings demonstrated that icv PROK2 infusion induced the HPG axis. It could be suggested that PROK2 could be a potential agent in the treatment of male infertility induced by endocrinological defects.

Inhibition of NF-κB with an Analog of Withaferin-A Restores TDP-43 Homeostasis and Proteome Profiles in a Model of Sporadic ALS.

The current knowledge on pathogenic mechanisms in amyotrophic lateral sclerosis (ALS) has widely been derived from studies with cell and animal models bearing ALS-linked genetic mutations. However, it remains unclear to what extent these disease models are of relevance to sporadic ALS. Few years ago, we reported that the cerebrospinal fluid (CSF) from sporadic ALS patients contains toxic factors for disease transmission in mice via chronic intracerebroventricular (i.c.v.) infusion. Thus a 14-day i.c.v. infusion of pooled CSF samples from ALS cases in mice provoked motor impairment as well as ALS-like pathological features. This offers a unique paradigm to test therapeutics in the context of sporadic ALS disease. Here, we tested a new Withaferin-A analog (IMS-088) inhibitor of NF-κB that was found recently to mitigate disease phenotypes in mouse models of familial disease expressing TDP-43 mutant. Our results show that oral intake of IMS-088 ameliorated motor performance of mice infused with ALS-CSF and it alleviated pathological changes including TDP-43 proteinopathy, neurofilament disorganization, and neuroinflammation. Moreover, CSF infusion experiments were carried out with transgenic mice having neuronal expression of tagged ribosomal protein (hNfL-RFP mice), which allowed immunoprecipitation of neuronal ribosomes for analysis by mass spectrometry of the translational peptide signatures. The results indicate that treatment with IMS-088 prevented many proteomic alterations associated with exposure to ALS-CSF involving pathways related to cytoskeletal changes, inflammation, metabolic dysfunction, mitochondria, UPS, and autophagy dysfunction. The effective disease-modifying effects of this drug in a mouse model based on i.c.v. infusion of ALS-CSF suggest that the NF-κB signaling pathway represents a compelling therapeutic target for sporadic ALS.

The Contribution of Na+ or Cl− to Central NaCl−induced Cardiovascular Responses in Rodents

A high salt diet elevates plasma and cerebrospinal fluid NaCl concentrations in salt-sensitive hypertensive humans and animals. Acute or chronic intracerebroventricular (ICV) infusion of hypertonic NaCl elevates sympathetic nerve activity and blood pressure. However, it is unclear which ion, Na+ or Cl−, contributes to this response. The purpose of the present study was to investigate the extent to which acute increases in cerebrospinal fluid Na+ and Cl− increase ABP and HR in rodents. Male Sprague Dawley rats (n=6; body weight: 270-350 g) were anesthetized with isoflurane (2-3% in 100% O2) and instrumented with a lateral ventricle cannula for ICV infusions. Additionally, arterial and venous catheters were implanted to record BP and administer drugs, respectively. At least 4 days after recovery, ABP and HR were measured in response to ICV infusion (10uL over 10 min) of the following solutions: artificial cerebrospinal fluid (aCSF); 0.3 M and 0.6 M NaCl; 0.15 M and 0.3 M Na2SO4, and 0.3 M and 0.6 M NH4Cl. Each animal received one ICV infusion of each solution every other day. Data are presented as mean ± SE. Baseline ABP and HR did not differ across each ICV infusion (ABP: from 98 ± 6 mmHg to 106 ± 6 mmHg; and HR: from 337 ± 17 bpm to 363 ± 12 bpm). As expected, ICV infusion of 0.3 M and 0.6 M NaCl produced concentration-dependent increases in ABP (Δpeak ABP 0.3 M NaCl: 17 ± 2 mmHg; 0.6 M NaCl: 26 ± 3 mmHg). While ICV infusions of Na2SO4 at both concentrations also increased ABP, the magnitudes were reduced compared to NaCl (Δpeak ABP 0.15 M Na2SO4: 11 ± 2 mmHg; 0.3 M Na2SO4: 17 ± 3 mmHg). On the other hand, infusion of NH4Cl produced a modest increase in ABP (Δpeak ABP 0.3 M NH4Cl: 8 ± 2 mmHg and 0.6 M NH4Cl: 9 ± 3 mmHg). However, it did not differ from aCSF (Δpeak ABP aCSF: 6 ± 2 mmHg). HR responses induced by NaCl varied greatly (Δpeak HR 0.3 M NaCl: 15 ± 22 bpm; 0.6 M NaCl: 19 ± 17 bpm). In contrast, both concentrations of Na2SO4 consistently increased HR (Δpeak HR 0.15 M Na2SO4: 64±10 bpm; 0.3 M Na2SO4: 60±10 bpm). Additionally, ICV infusions of NH4Cl also tended to enhance HR (Δpeak HR 0.3 M NH4Cl: 38 ± 13 bpm and 0.6 M NH4Cl: 41 ± 23 bpm). To end, ICV infusion of aCSF increased HR by 18 ± 3 bpm. These results suggest that the NaCl−induced pressor response is largely attributed to Na+. However, Na+ alone cannot fully account for the NaCl−induced pressor response. NIH R01 HL163906, HL152680, HL145875. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The additive effect between citalopram and muscimol upon induction of antinociceptive effect in male mice

Previous investigations have revealed the role of GABAergic and serotonergic systems in the modulation of pain behavior. This research aimed to examine the effects of intracerebroventricular (i.c.v.) infusion of GABAA receptor agonist and antagonist as well as citalopram on pain behavior in male mice. For i.c.v. microinjection, a guide cannula was surgically implanted in the left lateral ventricle of male mice. Pain behavior was evaluated using a tail-flick test. Tail flick latency was measured in each experimental group of mice every 15min (for 60min). I.c.v. microinjection of muscimol (0.5 and 1µg/mouse; GABAA receptor agonist) into the left lateral ventricle dose-dependently induced an antinociceptive effect. On the other hand, i.c.v. infusion of bicuculline (1µg/mouse; GABAA receptor antagonist) induced a hyperalgesia response. Moreover, intraperitoneally (i.p.) administration of citalopram (8mg/kg) produced an antinociceptive effect. Co-treatment of citalopram (8mg/kg) along with muscimol (0.25µg/mouse) or bicuculline (0.25µg/mouse) potentiated the antinociceptive effect produced by citalopram. We found an additive antinociceptive effect of citalopram and muscimol in male mice. In conclusion, our results suggested an interaction between citalopram and GABAergic agents on the modulation of pain behavior in male mice.

Setmelanotide Administration Improves Cardiac Systolic Function in Sirtuin-3 Deficient Mice

We previously showed that activation of the brain leptin-melanocortin system, particularly melanocortin-4 receptors (MC4R), markedly improves cardiac function in experimental models of heart failure (HF) via mechanisms that are still poorly understood. Sirtuin 3 (Sirt3) is an important regulator of mitochondrial oxidative phosphorylation and deficiency of Sirt3 has been implicated in cardiovascular diseases. We recently found increased Sirt3 expression as well as increased levels of NAD+, the main Sirt3 activator, in cardiomyocytes of rats treated with chronic intracerebroventricular infusion of leptin at a dose that does not spill over into the systemic circulation. Therefore, we hypothesized that stimulation of Sirt3 activity is required for the improvement of cardiac function during activation of the brain leptin-MC4R axis. To test this hypothesis, we first examined if chronic MC4R activation, using an MC4R agonist, setmelanotide, improves cardiac function in naïve Sirt3-deficient (Sirt3-KO) mice. Baseline cardiac function was assessed by echocardiography (VisualSonics-VEVO3100®) in male and female Sirt3-KO and wild-type (WT) control mice (n=5/group) at 20 weeks of age, and then weekly during setmelanotide treatment (2 mg/kg/day — i.p. via osmotic minipump model 1002) for 3 weeks. Chronic MC4R activation with setmelanotide transiently reduced food intake in both groups and promoted weight loss in Sirt3-KO mice. Setmelanotide treatment improved systolic function in WT mice as evidenced by increases in ejection fraction and fractional shortening (EF: 52.8±4.4 vs. 72.4±4.4%; FS: 26.9±2.7 vs. 42.8±6.4%, for baseline vs. week 3, respectively) and other measures of systolic function including circumferential and longitudinal strains. Despite showing a tendency for reduced systolic function compared to WT controls at baseline, Sirt3-KO mice also exhibited improvement in systolic function with setmelanotide administration (EF: 44.1±1.8 vs. 65.3±2.9% and FS: 21.4±1.0 vs. 35.1±2.1%). No major changes were observed in measures of diastolic function. These results suggest that in a non-HF model, MC4R activation does not require stimulation of Sirt3 to improve indices of systolic function. (1R01HL163076, 1R01DK121411, P20GM104357, P30GM149404, U54GM115428, and AHA-835218). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Adenosine A2A Receptor Blockade Provides More Effective Benefits at the Onset Rather than after Overt Neurodegeneration in a Rat Model of Parkinson's Disease.

Adenosine A2A receptor (A2AR) antagonists are the leading nondopaminergic therapy to manage Parkinson's disease (PD) since they afford both motor benefits and neuroprotection. PD begins with a synaptic dysfunction and damage in the striatum evolving to an overt neuronal damage of dopaminergic neurons in the substantia nigra. We tested if A2AR antagonists are equally effective in controlling these two degenerative processes. We used a slow intracerebroventricular infusion of the toxin MPP+ in male rats for 15 days, which caused an initial loss of synaptic markers in the striatum within 10 days, followed by a neuronal loss in the substantia nigra within 30 days. Interestingly, the initial loss of striatal nerve terminals involved a loss of both dopaminergic and glutamatergic synaptic markers, while GABAergic markers were preserved. The daily administration of the A2AR antagonist SCH58261 (0.1 mg/kg, i.p.) in the first 10 days after MPP+ infusion markedly attenuated both the initial loss of striatal synaptic markers and the subsequent loss of nigra dopaminergic neurons. Strikingly, the administration of SCH58261 (0.1 mg/kg, i.p. for 10 days) starting 20 days after MPP+ infusion was less efficacious to attenuate the loss of nigra dopaminergic neurons. This prominent A2AR-mediated control of synaptotoxicity was directly confirmed by showing that the MPTP-induced dysfunction (MTT assay) and damage (lactate dehydrogenase release assay) of striatal synaptosomes were prevented by 50 nM SCH58261. This suggests that A2AR antagonists may be more effective to counteract the onset rather than the evolution of PD pathology.

Anxiolytic effect of alamandine in male transgenic rats with low brain angiotensinogen is dependent on activation of MrgD receptors

Alamandine is a peptide hormone belonging to the renin–angiotensin system (RAS). It acts through the Mas-related G-protein coupled receptor type D, MrgD, which is expressed in different tissues, including the brain. In the present study, we hypothesize that a lack of alamandine, through MrgD, could cause the anxiety-like behavior in transgenic rats with low brain angiotensinogen [TGR(ASrAOGEN)680]. Adult male transgenic rats exhibited a significant increase in the latency to feeding time in the novelty suppressed feeding test and a decrease in the percentage of time and entries in the open arms in the elevated plus maze. These effects were reversed by intracerebroventricular infusion of alamandine. Pretreatment with D-Pro7-Ang-(1–7), a Mas and MrgD receptor antagonist, prevented the anxiolytic effects induced by this peptide. However, its effects were not altered by the selective Mas receptor antagonist, A779. In conclusion, our data indicates that alamandine, through MrgD, attenuates anxiety-like behavior in male TGR(ASrAOGEN)680, which reinforces the importance of the counter-regulatory RAS axis as promising target for the treatment of neuropsychiatric disorders.

Additive anxiolytic-like effect of citicoline and ACPA in the non-acute restraint stress (NARS) and acute restraint stress (ARS) mice

The cannabinoid system plays a key role in stress-related emotional symptoms such as anxiety. Citicoline is a supplemental substance with neuroprotective properties that alleviates anxiety-related behaviors. There is a relation between the actions of cannabinoids and cholinergic systems. So, we decided to evaluate the effects of intracerebroventricular (i.c.v.) infusion of cannabinoid CB1 receptor agents on citicoline-produced response to anxiety-like behaviors in the non-acute restraint stress (NARS) and acute restraint stress (ARS) mice. For i.c.v. microinjection of drugs, a guide cannula was inserted in the left lateral ventricle. ARS was induced by movement restraint for 4 h. Anxiety-related behaviors were assessed using an elevated plus maze (EPM). The results showed that induction of ARS for 4 h decreased the percentage of time spent in the open arms (%OAT) and the percentage of entries to the open arms (%OAE) without affecting locomotor activity, showing anxiogenic-like behaviors. i.c.v. infusion of ACPA (1 µg/mouse) induced an anxiolytic-like effect due to the enhancement of %OAT in the NARS and ARS mice. Nonetheless, i.c.v. microinjection of AM251 (1 µg/mouse) decreased %OAT in the NARS and ARS mice which suggested an anxiogenic-like response. Intraperitoneal (i.p.) administration of citicoline (80 mg/kg) induced an anxiolytic-like effect by the augmentation of %OAT in the ARS mice. Furthermore, when ACPA and citicoline were co-administrated, ACPA potentiated the anxiolytic-like effect induced by citicoline in the NARS and ARS mice. On the other hand, when AM251 and the citicoline were co-injected, AM251 reversed the anxiolytic-like response induced by the citicoline in the NARS and ARS mice. The results of this research exhibited an additive effect between citicoline and ACPA on the induction of anxiolytic-like response in the NARS and ARS mice. Our results indicated an interaction between citicoline and cannabinoid CB1 receptor drugs on the control of anxiety-like behaviors in the NARS and ARS mice.

Pretreatment with Liposome-Encapsulated Shrimp Shell Extract Attenuated Neuronal Damage and Death in Aβ1-42-Induced Memory Deficits in Rats.

The accumulation of amyloid-beta (Aβ) peptides is a crucial factor in the neuronal degeneration of Alzheimer's disease (AD). The current study investigated the underlying neuroprotective mechanisms of shrimp shell extract (SSE) and liposome-encapsulated SSE (SSE/L) against Aβ1-42-induced neuronal damage and death in rats. Intracerebroventricular infusion of Aβ1-42 effectively induced memory decline, as observed in a reduction of the rat's discriminating ability in the novel object recognition and novel object location tasks. Oral pretreatment with 100mg/kg of SSE demonstrated no preventive effect on the memory decline induced by Aβ1-42 infusion. However, treatment with SSE/L 100mg/kg BW effectively attenuated memory deficits in both behavioral assessments following two and four weeks after Aβ1-42 infusion. Moreover, SSE/L exerted neuroprotective effects by reducing lipid peroxidation and increasing Nrf2/HO-1 expression. There was a significant decrease in Iba1 and GFAP (biomarkers of microglia and astrocyte activity, respectively), as well as a decrease in the levels of NF-κB expression and the inflammatory cytokines TNF-α and IL-6 in the cortical and hippocampal tissues. Treatment with SSE/L also reduced the pro-apoptotic proteins Bax and cleaved caspase-3 while raising the anti-apoptotic protein Bcl2. In addition, the beneficial effects of SSE/L were along with the effects of a positive control commercial astaxanthin (AST). The findings of this study indicated that SSE/L provided neuroprotective effects on Aβ1-42-induced AD rats by ameliorating oxidative stress, neuroinflammation and apoptotic cell death. Therefore, SSE/L might be employed to prevent and mitigate Aβ accumulation-induced neurotoxicity in AD.

Fibroblast growth factor 21 alleviates diabetes-induced cognitive decline.

Diabetes mellitus (DM) causes damage to the central nervous system, resulting in cognitive impairment. Fibroblast growth factor 21 (FGF21) exhibits the potential to alleviate neurodegeneration. However, the therapeutic effect of intracerebroventricular (i.c.v) FGF21 infusion on diabetes-induced cognitive decline (DICD) and its potential mechanisms remain unclear. In this study, the impact of FGF21 on DICD was explored, and 1H nuclear magnetic resonance (NMR)-based metabolomics plus 13C NMR spectroscopy in combine with intravenous [1-13C]-glucose infusion were used to investigate the underlying metabolic mechanism. Results revealed that i.c.v FGF21 infusion effectively improved learning and memory performance of DICD mice; neuron loss and apoptosis in hippocampus and cortex were significantly blocked, suggesting a potential neuroprotective role of FGF21 in DICD. Metabolomics results revealed that FGF21 modulated DICD metabolic alterations related to glucose and neurotransmitter metabolism, which are characterized by distinct recovered enrichment of [3-13C]-lactate, [3-13C]-aspartate, [4-13C]-glutamine, [3-13C]-glutamine, [4-13C]-glutamate, and [4-13C]- γ-aminobutyric acid (GABA) from [1-13C]-glucose. Moreover, diabetes-induced neuron injury and metabolic dysfunctions might be mediated by PI3K/AKT/GSK-3β signaling pathway inactivation in the hippocampus and cortex, which were activated by i.c.v injection of FGF21. These findings indicate that i.c.v FGF21 infusion exerts its neuroprotective effect on DICD by remodeling cerebral glucose and neurotransmitter metabolism by activating the PI3K/AKT/GSK-3β signaling pathway.

Deoxycholic Acid, a Secondary Bile Acid, Increases Cardiac Output and Blood Pressure in Rats.

Deoxycholic acid (DCA) is a secondary bile acid produced by gut bacteria. Elevated serum concentrations of DCA are observed in cardiovascular disease (CVD). We hypothesized that DCA might influence hemodynamic parameters in rats. The concentration of DCA in systemic blood was measured with liquid chromatography coupled with mass spectrometry. Arterial blood pressure (BP), heart rate (HR) and echocardiographic parameters were evaluated in anesthetized, male, 3-4-month-old Sprague-Dawley rats administered intravenously (IV) or intracerebroventricularly (ICV) with investigated compounds. Mesenteric artery (MA) reactivity was tested ex vivo. The baseline plasma concentration of DCA was 0.24 ± 0.03 mg/L. The oral antibiotic treatment produced a large decrease in the concentration. Administered IV, the compound increased BP and HR in a dose-dependent manner. DCA also increased heart contractility and cardiac output. None of the tested compounds-prazosin (an alpha-blocker), propranolol (beta-adrenolytic), atropine (muscarinic receptor antagonist), glibenclamide (K-ATP inhibitor) or DY 268 (FXR antagonist), glycyrrhetinic acid (11HSD2 inhibitor)-significantly diminished the DCA-induced pressor effect. ICV infusion did not exert significant HR or BP changes. DCA relaxed MAs. Systemic vascular resistance did not change significantly. DCA elevates BP primarily by augmenting cardiac output. As a metabolite derived from gut bacteria, DCA potentially serves as a mediator in the interaction between the gut microbiota and the host's circulatory system.

First in man study of intravitreal tripeptidyl peptidase 1 for CLN2 retinopathy

Background/ObjectivesCLN2 Batten Disease is a fatal neurodegenerative condition of childhood associated with retinal dystrophy and blindness. Intracerebroventricular infusion of rhTPP1 greatly slows the rate of neurodegenerative decline but not retinopathy. Intravitreal rhTPP1 is known to slow retinal degeneration in a canine model of CLN2. We report a first-in-man controlled clinical trial of intravitreal rhTPP1 for CLN2 associated retinal dystrophy.Subjects/methods8 children aged 5–9 with CLN2 Batten Disease were prospectively enroled. Severely affected patients were preferentially selected, provided that vision was better than no perception of light. Children underwent 8 weekly intravitreal injections of rhTPP1 (0.2 mg in 0.05 ml) into the right eye for 12–18 months. The left eye was untreated and acts as a paired control. The primary outcome was safety based on the clinical detection of complications. A secondary outcome was paracentral macular volume (PMV) measured by spectral domain OCT. Linear regression/paired t tests were used to compare rates of decline.ResultsNo severe adverse reactions (uveitis, raised IOP, media opacity) occurred. The mean baseline PMV was 1.28 mm3(right), 1.27 mm3(left). 3 of the youngest patients exhibited bilateral progressive retinal thinning (p < 0.05), whereas retinal volume was stable in the remaining 5 patients. In the 3 patients undergoing retinal degeneration, the rate of PMV loss was slower in the treated vs. untreated eye (p = 0.000042, p = 0.0011, p = 0.00022).ConclusionsIntravitreal rhTPP1 appears to be a safe and effective treatment for CLN2 related retinopathy however commencement of treatment early in the course of disease is more likely to be efficacious.

DDEL-01. UTILIZING SENSOR ARRAYS FOR INTRACRANIAL PRESSURE (ICP) RESPONSE TO CEREBROSPINAL FLUID (CSF) DRUG ADMINISTRATION, AND POTENTIAL IMPLICATIONS FOR PERSONALIZED CARE IN CNS METASTASES PATIENTS

Abstract BACKGROUND Patients with leptomeningeal carcinomatosis (LC) may have elevated intracranial pressure (ICP) due to LC cancer cells having the potential to obstruct the arachnoid granulations.,Given that LC treatment may involve intrathecal (IT) drug delivery, monitoring ICP may be important for safe IT drug delivery. The EnClear device is a novel CNS drug delivery device with both intracranial and intralumbar CSF access and single-use sensing arrays that measure ICP in these dual locations. METHODS This is a non-human primate (NHP) study on three healthy NHP subjects undergoing IT gene therapy via intracerebroventricular (ICV). The sensor arrays measured ICP before, during, and after ICV infusion in both intracranial and lumbar locations. Our goal was to compare individual subject pressure response to drug administration as well as to compare lumbar and cranial pressure waveforms for concordance. Pressure response was quantified as change in pressure (ΔP) following volume (ΔV) administration, known as intracranial elastance (ΔP/ΔV). RESULTS Significant correlations were observed between ventricular and lumbar ICP waveforms with an average of 0.88 correlation coefficient. Pressure measurements between subjects demonstrated variable response to identical infusion volumes, with maximum pressures ranging from 20 mmHg to 40 mmHg. Intracranial elastance was calculated for each subject during infusions and resulted in a range of 12 to 36 mmHg/mL, a 3-fold difference in elastance between subjects. CONCLUSION In healthy NHPs, changes to cranial volume and pressure response can be measured in the lumbar space with good correlation between the two measurement locations. Despite this consistency between these two locations on the same subject, intersubject variability was seen despite identical drug administration. Pressure waveform sensing systems can be incorporated in the future to enable clinicians to understand individual patient brain compliance and leverage this knowledge for personalized drug delivery, particularly in patients with LC.

K252a Prevents Microglial Activation Induced by Anoxic Stimulation of Carotid Bodies in Rats.

Inducing carotid body anoxia through the administration of cyanide can result in oxygen deprivation. The lack of oxygen activates cellular responses in specific regions of the central nervous system, including the Nucleus Tractus Solitarius, hypothalamus, hippocampus, and amygdala, which are regulated by afferent pathways from chemosensitive receptors. These receptors are modulated by the brain-derived neurotrophic factor receptor TrkB. Oxygen deprivation can cause neuroinflammation in the brain regions that are activated by the afferent pathways from the chemosensitive carotid body. To investigate how microglia, a type of immune cell in the brain, respond to an anoxic environment resulting from the administration of NaCN, we studied the effects of blocking the TrkB receptor on this cell-type response. Male Wistar rats were anesthetized, and a dose of NaCN was injected into their carotid sinus to induce anoxia. Prior to the anoxic stimulus, the rats were given an intracerebroventricular (icv) infusion of either K252a, a TrkB receptor inhibitor, BDNF, or an artificial cerebrospinal fluid (aCSF). After the anoxic stimulus, the rats were perfused with paraformaldehyde, and their brains were processed for microglia immunohistochemistry. The results indicated that the anoxic stimulation caused an increase in the number of reactive microglial cells in the hypothalamic arcuate, basolateral amygdala, and dentate gyrus of the hippocampus. However, the infusion of the K252a TrkB receptor inhibitor prevented microglial activation in these regions.

The effects of neuropeptide W on food consumption and feeding behavior in neonatal meat-type chicks: Role of CRF1/CRF2 and NPY1 receptors

In several studies, the regulatory role of the neuropeptide W (NPW) system in food intake has been demonstrated. Considering the lack of avian studies in this field, the current research was conducted to evaluate the effects of intracerebroventricular (ICV) infusion of NPW and its interferences with corticotropin, melanocortin, and neuropeptide Y (NPY) receptors on meal consumption and feeding behaviors of broilers. In the first experiment, birds were injected with NPW (0.75, 1.5, and 3 nmol) in addition to saline. In the second experiment, saline, CRF1 receptor antagonist (NBI35965, 30 μg), NPW (3 nmol), and simultaneous injections of NBI35965 and NPW were performed. Experiments 3–8 were identical to experiment 2, except that CRF2 receptor antagonist (K41498, 30 μg), MC3/MC4 receptor antagonist (SHU9119, 0.5 nmol), MC4 receptor antagonist (HS024, 0.5 nmol), NPY1 receptor antagonist (BMS193885, 1.25 nmol), NPY2 receptor antagonist (CYM9484, 1.25 nmol), and NPY5 receptor (antagonist L-152,804, 1.25 nmol) were administrated instead of NBI35965. After that, cumulative feed intake and feeding behavior were monitored for 2 h and 30 min after injections, respectively. Following the infusion of NPW (1.5 and 3 nmol), there was a significant stimulation of meal consumption in chickens (P < 0.05). Concomitant injection of NBI35965 and K41498 with NPW enhanced the appetite-increasing effect of NPW (P < 0.05); while BMS193885 suppressed this effect of NPW (P < 0.05). Injection of SHU9119, HS024, CYM9484, and L-152804 with NPW at the same time, had no significant effect on NPW-induced hyperphagia (P > 0.05). NPW also significantly decreased the standing period and the number of jumps, steps, and exploratory pecks, and led to an increase in sitting period and feeding pecks (P < 0.05). Based on the observations, it seems that NPW-induced hyperphagia could be mediated through CRF1, CRF2, and NPY1 receptors in neonatal broilers.

Persistent brain exposure to high sodium induces stroke onset by upregulation of cerebral microbleeds and oxidative stress in hypertensive rats.

High salt intake induces hypertension and enhances stroke onset. However, whether an increase in brain sodium exposure itself is harmful and has poor prognosis remains unknown. Therefore, we employed hypertensive rats that underwent intracerebroventricular (ICV) infusion of sodium for 28 days and evaluated stroke onset and related cytotoxic brain injuries. Forty-seven spontaneously hypertensive stroke-prone (SHRSP) and 39 normotensive rats (Wistar Kyoto rats [WKY]) underwent persistent ICV infusion of the following four solutions: artificial cerebrospinal fluid, 0.9%, 2.7%, and 9% saline for 28 days. We evaluated stroke onset and all-cause mortality between SHRSP and WKY at each ICV sodium concentration as the primary endpoints. Our secondary objective was to explore histological brain injuries associated with SHRSP induced by high sodium ICV. The results indicated that ICV infusion of 2.7% and 9% sodium showed a significant increase in stroke onset, decrease in body weight, and increase rate of brain water content in SHRSP compared to WKY. Increased blood pressure was not observed for ICV infusion of high sodium, while serum sodium concentration was significantly increased in SHRSP compared to WKY. Histological evaluations revealed that higher sodium infusion significantly increased the number of activated microglia, superoxide, neuronal cell loss, and microbleeds compared to WKY and SHRSP with 0.9% sodium. We conclude that persistent exposure to high sodium in the brain is one of the risk factors for stroke onset upregulating cerebral microbleeds and oxidative stress in hypertensive rats.

MiR135a administration ameliorates brain ischemic damage by preventing TRPM7 activation during brain ischemia.

miRNA-based strategies have recently emerged as a promising therapeutic approach in several neurodegenerative diseases. Unregulated cation influx is implicated in several cellular mechanisms underlying neural cell death during ischemia. The brain constitutively active isoform of transient receptor potential melastatin 7 (TRPM7) represents a glutamate excitotoxicity-independent pathway that significantly contributes to the pathological Ca2+ overload during ischemia. In the light of these premises, inhibition of TRPM7 may be a reasonable strategy to reduce ischemic injury. Since TRPM7 is a putative target of miRNA135a, the aim of the present paper was to evaluate the role played by miRNA135a in cerebral ischemia. Therefore, the specific objectives of the present paper were: (1) to evaluate miR135a expression in temporoparietal cortex of ischemic rats; (2) to investigate the effect of the intracerebroventricular (icv) infusion of miR135a on ischemic damage and neurological functions; and (3) to verify whether miR135a effects may be mediated by an alteration of TRPM7 expression. miR135a expression was evaluated by RT- PCR and FISH assay in temporoparietal cortex of ischemic rats. Ischemic volume and neurological functions were determined in rats subjected to transient middle cerebral artery occlusion (tMCAo) after miR135a intracerebroventricular perfusion. Target analysis was performed by Western blot. Our results demonstrated that, in brain cortex, 72 h after ischemia, miR135a expression increased, while TRPM7 expression was parallelly downregulated. Interestingly, miR135a icv perfusion strongly ameliorated the ischemic damage and improved neurological functions, and downregulated TRPM7 protein levels. The early prevention of TRPM7 activation is protective during brain ischemia.

Abstract P218: Ubr1 And Nedd4-2 Synergistically Modulate Ace2 Ubiquitination In Hypertensive Male Mice

Angiotensin-converting enzyme 2 (ACE2) is a counter-regulatory player in the renin-angiotensin system (RAS). Downregulation of ACE2 in hypertension results in vasoconstriction, sympathetic over-activation, and hypertension. Recently, we identified UBR1, an E3 ubiquitin-protein ligase, as a potential ubiquitinase modulating ACE2 expression, notably in hypertensive male mice where UBR1 is upregulated in the hypothalamus and peripheral organs. Here, we aim to understand the role of UBR1 in hypertension and its crosstalk with Nedd4-2, another E3 ligase regulating ACE2. C57BI/6J male mice (3 month-old, n=18) were implanted with telemetry probes for weekly 24 h BP recording. One week following baseline BP recording, mice were implanted with subcutaneous osmotic pumps containing Ang-II (600 ng/kg/min). After confirming hypertension, mice were divided into 4 treatment groups (n=6/group); 1) peripheral UBR1 siRNA via osmotic pump (50 μg/day/2 weeks), 2) central UBR1 siRNA via intracerebroventricular infusion (ICV) (50 μg/day/2 weeks) 3) scrambled shRNA + Ang-II, and 4) no treatment. After 6 weeks of BP recording, mice were euthanized, and hypothalami were harvested for protein analysis (Capillary Western). BP was transiently reduced during the resting phase after 3 weeks of ICV UBR1 siRNA infusion compared to the Ang-II group (MAP: 114±7 vs . 135±3 mmHg). Ang-II infusion enhanced UBR1 protein levels versus no treatment (Fold Change:1.6±0.1 vs . 1.0±0.04; p&lt;0.05) which was prevented by peripheral and central UBR1 siRNA infusion, respectively (0.7±0.08, 1.3±0.08 vs. 1.6±0.1, p&lt;0.05). Interestingly, while UBR1 siRNA infusion increased ACE2 expression (1.7±0.1, 2±0.2, p&lt;0.01, respectively), it was also associated with increased Nedd4-2 levels ( 2.9±0.1, 3.5±0.2, p&lt;0.0001, respectively), and pNedd4-2 (4.1±0.4, 3.8±0.5, p&lt;0.001, respectively). Together, these data suggest that while prevention of UBR1 upregulation in hypertension is associated with an increase in ACE2 expression, it is not sufficient to permanently reduce BP as other E3 ligases, like Nedd4-2, appear to compensate for the knockdown.