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Gáll Z, Boros B, Kelemen K, Urkon M, Zolcseak I, Márton K, Kolcsar M. Melatonin improves cognitive dysfunction and decreases gliosis in the streptozotocin-induced rat model of sporadic Alzheimer's disease. Front Pharmacol 2024; 15:1447757. [PMID: 39135795 PMCID: PMC11317391 DOI: 10.3389/fphar.2024.1447757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2024] [Accepted: 07/15/2024] [Indexed: 08/15/2024] Open
Abstract
Introduction Alzheimer's disease (AD) and other forms of dementia have a devastating effect on the community and healthcare system, as neurodegenerative diseases are causing disability and dependency in older population. Pharmacological treatment options are limited to symptomatic alleviation of cholinergic deficit and accelerated clearance of β-amyloid aggregates, but accessible disease-modifying interventions are needed especially in the early phase of AD. Melatonin was previously demonstrated to improve cognitive function in clinical setting and experimental studies also. Methods In this study, the influence of melatonin supplementation was studied on behavioral parameters and morphological aspects of the hippocampus and amygdala of rats. Streptozotocin (STZ) was injected intracerebroventricularly to induce AD-like symptoms in male adult Wistar rats (n = 18) which were compared to age-matched, sham-operated animals (n = 16). Melatonin was administered once daily in a dose of 20 mg/kg body weight by oral route. Behavioral analysis included open-field, novel object recognition, and radial-arm maze tests. TNF-α and MMP-9 levels were determined from blood samples to assess the anti-inflammatory and neuroprotective effects of melatonin. Immunohistological staining of brain sections was performed using anti-NeuN, anti-IBA-1, and anti-GFAP primary antibodies to evaluate the cellular reorganization of hippocampus. Results and Discussion The results show that after 40 days of treatment, melatonin improved the cognitive performance of STZ-induced rats and reduced the activation of microglia in both CA1 and CA3 regions of the hippocampus. STZ-injected animals had higher levels of GFAP-labeled astrocytes in the CA1 region, but melatonin treatment reduced this to that of the control group. In conclusion, melatonin may be a potential therapeutic option for treating AD-like cognitive decline and neuroinflammation.
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Affiliation(s)
- Zsolt Gáll
- Department of Pharmacology and Clinical Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, Târgu Mures, Romania
| | - Bernadett Boros
- Faculty of Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, Târgu Mures, Romania
| | - Krisztina Kelemen
- Department of Physiology, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, Târgu Mures, Romania
| | - Melinda Urkon
- Department of Pharmacology and Clinical Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, Târgu Mures, Romania
| | - István Zolcseak
- Faculty of Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, Târgu Mures, Romania
| | - Kincső Márton
- Faculty of Medicine, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, Târgu Mures, Romania
| | - Melinda Kolcsar
- Department of Pharmacology and Clinical Pharmacy, George Emil Palade University of Medicine, Pharmacy, Science, and Technology of Targu Mures, Târgu Mures, Romania
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Homolak J, Varvaras K, Sciacca V, Babic Perhoc A, Virag D, Knezovic A, Osmanovic Barilar J, Salkovic-Petrisic M. Insights into Gastrointestinal Redox Dysregulation in a Rat Model of Alzheimer's Disease and the Assessment of the Protective Potential of D-Galactose. ACS OMEGA 2024; 9:11288-11304. [PMID: 38496956 PMCID: PMC10938400 DOI: 10.1021/acsomega.3c07152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/14/2023] [Accepted: 01/04/2024] [Indexed: 03/19/2024]
Abstract
Recent evidence suggests that the gut plays a vital role in the development and progression of Alzheimer's disease (AD) by triggering systemic inflammation and oxidative stress. The well-established rat model of AD, induced by intracerebroventricular administration of streptozotocin (STZ-icv), provides valuable insights into the GI implications of neurodegeneration. Notably, this model leads to pathophysiological changes in the gut, including redox dyshomeostasis, resulting from central neuropathology. Our study aimed to investigate the mechanisms underlying gut redox dyshomeostasis and assess the effects of D-galactose, which is known to benefit gut redox homeostasis and alleviate cognitive deficits in this model. Duodenal rings isolated from STZ-icv animals and control groups were subjected to a prooxidative environment using 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) or H2O2 with or without D-galactose in oxygenated Krebs buffer ex vivo. Redox homeostasis was analyzed through protein microarrays and functional biochemical assays alongside cell survival assessment. Structural equation modeling and univariate and multivariate models were employed to evaluate the differential response of STZ-icv and control samples to the controlled prooxidative challenge. STZ-icv samples showed suppressed expression of catalase and glutathione peroxidase 4 (GPX4) and increased baseline activity of enzymes involved in H2O2 and superoxide homeostasis. The altered redox homeostasis status was associated with an inability to respond to oxidative challenges and D-galactose. Conversely, the presence of D-galactose increased the antioxidant capacity, enhanced catalase and peroxidase activity, and upregulated superoxide dismutases in the control samples. STZ-icv-induced gut dysfunction is characterized by a diminished ability of the redox regulatory system to maintain long-term protection through the transcription of antioxidant response genes as well as compromised activation of enzymes responsible for immediate antioxidant defense. D-galactose can exert beneficial effects on gut redox homeostasis under physiological conditions.
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Affiliation(s)
- Jan Homolak
- Department
of Pharmacology & Croatian Institute for Brain Research, University of Zagreb School of Medicine, 10000 Zagreb, Croatia
- Interfaculty
Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, 72074 Tübingen, Germany
| | - Konstantinos Varvaras
- Department
of Medicine, School of Health Sciences, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
| | - Vittorio Sciacca
- Faculty
of Medicine, University of Catania, 95131 Catania, Italy
| | - Ana Babic Perhoc
- Department
of Pharmacology & Croatian Institute for Brain Research, University of Zagreb School of Medicine, 10000 Zagreb, Croatia
| | - Davor Virag
- Department
of Pharmacology & Croatian Institute for Brain Research, University of Zagreb School of Medicine, 10000 Zagreb, Croatia
| | - Ana Knezovic
- Department
of Pharmacology & Croatian Institute for Brain Research, University of Zagreb School of Medicine, 10000 Zagreb, Croatia
| | - Jelena Osmanovic Barilar
- Department
of Pharmacology & Croatian Institute for Brain Research, University of Zagreb School of Medicine, 10000 Zagreb, Croatia
| | - Melita Salkovic-Petrisic
- Department
of Pharmacology & Croatian Institute for Brain Research, University of Zagreb School of Medicine, 10000 Zagreb, Croatia
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3
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Homolak J, De Busscher J, Zambrano-Lucio M, Joja M, Virag D, Babic Perhoc A, Knezovic A, Osmanovic Barilar J, Salkovic-Petrisic M. Altered Secretion, Constitution, and Functional Properties of the Gastrointestinal Mucus in a Rat Model of Sporadic Alzheimer's Disease. ACS Chem Neurosci 2023; 14:2667-2682. [PMID: 37477640 PMCID: PMC10401635 DOI: 10.1021/acschemneuro.3c00223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 07/07/2023] [Indexed: 07/22/2023] Open
Abstract
The gastrointestinal (GI) system is affected in Alzheimer's disease (AD); however, it is currently unknown whether GI alterations arise as a consequence of central nervous system (CNS) pathology or play a causal role in the pathogenesis. GI mucus is a possible mediator of GI dyshomeostasis in neurological disorders as the CNS controls mucus production and secretion via the efferent arm of the brain-gut axis. The aim was to use a brain-first model of sporadic AD induced by intracerebroventricular streptozotocin (STZ-icv; 3 mg/kg) to dissect the efferent (i.e., brain-to-gut) effects of isolated central neuropathology on the GI mucus. Morphometric analysis of goblet cell mucigen granules revealed altered GI mucus secretion in the AD model, possibly mediated by the insensitivity of AD goblet cells to neurally evoked mucosal secretion confirmed by ex vivo cholinergic stimulation of isolated duodenal rings. The dysfunctional efferent control of the GI mucus secretion results in altered biochemical composition of the mucus associated with reduced mucin glycoprotein content, aggregation, and binding capacity in vitro. Finally, functional consequences of the reduced barrier-forming capacity of the mucin-deficient AD mucus are demonstrated using the in vitro two-compartment caffeine diffusion interference model. Isolated central AD-like neuropathology results in the loss of efferent control of GI homeostasis via the brain-gut axis and is characterized by the insensitivity to neurally evoked mucosal secretion, altered mucus constitution with reduced mucin content, and reduced barrier-forming capacity, potentially increasing the susceptibility of the STZ-icv rat model of AD to GI and systemic inflammation induced by intraluminal toxins, microorganisms, and drugs.
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Affiliation(s)
- Jan Homolak
- Department
of Pharmacology, University of Zagreb School
of Medicine, 10 000 Zagreb, Croatia
- Croatian
Institute for Brain Research, University
of Zagreb School of Medicine, 10 000 Zagreb, Croatia
| | | | - Miguel Zambrano-Lucio
- School
of Medicine, Autonomous University of Nuevo
Leon, Monterrey, Nuevo Leon 66455, Mexico
| | - Mihovil Joja
- Department
of Pharmacology, University of Zagreb School
of Medicine, 10 000 Zagreb, Croatia
- Department
of Infection and Immunity, Luxembourg Institute
of Health, L-4354 Esch-sur-Alzette, Luxembourg
- Faculty
of
Science, Technology and Medicine, University
of Luxembourg, L-4365 Esch-sur-Alzette, Luxembourg
| | - Davor Virag
- Department
of Pharmacology, University of Zagreb School
of Medicine, 10 000 Zagreb, Croatia
- Croatian
Institute for Brain Research, University
of Zagreb School of Medicine, 10 000 Zagreb, Croatia
| | - Ana Babic Perhoc
- Department
of Pharmacology, University of Zagreb School
of Medicine, 10 000 Zagreb, Croatia
- Croatian
Institute for Brain Research, University
of Zagreb School of Medicine, 10 000 Zagreb, Croatia
| | - Ana Knezovic
- Department
of Pharmacology, University of Zagreb School
of Medicine, 10 000 Zagreb, Croatia
- Croatian
Institute for Brain Research, University
of Zagreb School of Medicine, 10 000 Zagreb, Croatia
| | - Jelena Osmanovic Barilar
- Department
of Pharmacology, University of Zagreb School
of Medicine, 10 000 Zagreb, Croatia
- Croatian
Institute for Brain Research, University
of Zagreb School of Medicine, 10 000 Zagreb, Croatia
| | - Melita Salkovic-Petrisic
- Department
of Pharmacology, University of Zagreb School
of Medicine, 10 000 Zagreb, Croatia
- Croatian
Institute for Brain Research, University
of Zagreb School of Medicine, 10 000 Zagreb, Croatia
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4
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Andrade MK, Souza LC, Azevedo EM, Bail EL, Zanata SM, Andreatini R, Vital MABF. Melatonin reduces β-amyloid accumulation and improves short-term memory in streptozotocin-induced sporadic Alzheimer's disease model. IBRO Neurosci Rep 2023; 14:264-272. [PMID: 36926592 PMCID: PMC10011440 DOI: 10.1016/j.ibneur.2023.01.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 01/24/2023] [Indexed: 01/27/2023] Open
Abstract
Melatonin is a hormone secreted by the pineal gland, it can be associated with circadian rhythms, aging and neuroprotection. Melatonin levels are decreased in sporadic Alzheimer's disease (sAD) patients, which suggests a relationship between the melatonergic system and sAD. Melatonin may reduce inflammation, oxidative stress, TAU protein hyperphosphorylation, and the formation of β-amyloid (Aβ) aggregates. Therefore, the objective of this work was to investigate the impact of treatment with 10 mg/kg of melatonin (i.p) in the animal model of sAD induced by the intracerebroventricular (ICV) infusion of 3 mg/kg of streptozotocin (STZ). ICV-STZ causes changes in the brain of rats similar to those found in patients with sAD. These changes include; progressive memory decline, the formation of neurofibrillary tangles, senile plaques, disturbances in glucose metabolism, insulin resistance and even reactive astrogliosis characterized by the upregulation of glucose levels and glial fibrillary acidic protein (GFAP). The results show that ICV-STZ caused short-term spatial memory impairment in rats after 30 days of STZ infusion without locomotor impairment which was evaluated on day 27 post-injury. Furthermore, we observed that a prolonged 30-day treatment with melatonin can improve the cognitive impairment of animals in the Y-maze test, but not in the object location test. Finally, we demonstrated that animals receiving ICV-STZ have high levels of Aβ and GFAP in the hippocampus and that treatment with melatonin reduces Aβ levels but does not reduce GFAP levels, concluding that melatonin may be useful to control the progression of amyloid pathology in the brain.
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Key Words
- AD, Alzheimer Disease
- APP, Amyloid precursor protein
- Alzheimer's disease
- Aβ, β-amyloid
- GFAP
- GFAP, Glial fibrillary acidic protein
- ICV-STZ, Intracerebroventricular injection of streptozotocin
- MEL, Melatonin
- MT1, Melatonin Receptor 1
- MT2, Melatonin Receptor 2
- Melatonin
- OLT, Object location test
- STZ, Streptozotocin
- Short-term memory
- Streptozotocin
- TNF-α, Tumor Necrosis factor alpha
- Y maze
- sAD, Sporadic Alzheimer disease
- β-amyloid
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Affiliation(s)
- Marcos K Andrade
- Department of Pharmacology, Federal University of Paraná, PR, Brazil
| | - Leonardo C Souza
- Department of Pharmacology, Federal University of Paraná, PR, Brazil
| | - Evellyn M Azevedo
- Department of Physiology, Federal University of Paraná, PR, Brazil.,Department of Basic Pathology, Federal University of Paraná, PR, Brazil
| | - Ellen L Bail
- Department of Physiology, Federal University of Paraná, PR, Brazil.,Department of Basic Pathology, Federal University of Paraná, PR, Brazil
| | - Silvio M Zanata
- Department of Basic Pathology, Federal University of Paraná, PR, Brazil
| | | | - Maria A B F Vital
- Department of Pharmacology, Federal University of Paraná, PR, Brazil
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Grünblatt E, Homolak J, Babic Perhoc A, Davor V, Knezovic A, Osmanovic Barilar J, Riederer P, Walitza S, Tackenberg C, Salkovic-Petrisic M. From attention-deficit hyperactivity disorder to sporadic Alzheimer's disease-Wnt/mTOR pathways hypothesis. Front Neurosci 2023; 17:1104985. [PMID: 36875654 PMCID: PMC9978448 DOI: 10.3389/fnins.2023.1104985] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 01/31/2023] [Indexed: 02/18/2023] Open
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disorder with the majority of patients classified as sporadic AD (sAD), in which etiopathogenesis remains unresolved. Though sAD is argued to be a polygenic disorder, apolipoprotein E (APOE) ε4, was found three decades ago to pose the strongest genetic risk for sAD. Currently, the only clinically approved disease-modifying drugs for AD are aducanumab (Aduhelm) and lecanemab (Leqembi). All other AD treatment options are purely symptomatic with modest benefits. Similarly, attention-deficit hyperactivity disorder (ADHD), is one of the most common neurodevelopmental mental disorders in children and adolescents, acknowledged to persist in adulthood in over 60% of the patients. Moreover, for ADHD whose etiopathogenesis is not completely understood, a large proportion of patients respond well to treatment (first-line psychostimulants, e.g., methylphenidate/MPH), however, no disease-modifying therapy exists. Interestingly, cognitive impairments, executive, and memory deficits seem to be common in ADHD, but also in early stages of mild cognitive impairment (MCI), and dementia, including sAD. Therefore, one of many hypotheses is that ADHD and sAD might have similar origins or that they intercalate with one another, as shown recently that ADHD may be considered a risk factor for sAD. Intriguingly, several overlaps have been shown between the two disorders, e.g., inflammatory activation, oxidative stress, glucose and insulin pathways, wingless-INT/mammalian target of rapamycin (Wnt/mTOR) signaling, and altered lipid metabolism. Indeed, Wnt/mTOR activities were found to be modified by MPH in several ADHD studies. Wnt/mTOR was also found to play a role in sAD and in animal models of the disorder. Moreover, MPH treatment in the MCI phase was shown to be successful for apathy including some improvement in cognition, according to a recent meta-analysis. In several AD animal models, ADHD-like behavioral phenotypes have been observed indicating a possible interconnection between ADHD and AD. In this concept paper, we will discuss the various evidence in human and animal models supporting the hypothesis in which ADHD might increase the risk for sAD, with common involvement of the Wnt/mTOR-pathway leading to lifespan alteration at the neuronal levels.
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Affiliation(s)
- Edna Grünblatt
- Department of Child and Adolescent Psychiatry and Psychotherapy, Psychiatric University Hospital Zurich (PUK), University of Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich and the Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Jan Homolak
- Department of Pharmacology and Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Ana Babic Perhoc
- Department of Pharmacology and Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Virag Davor
- Department of Pharmacology and Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Ana Knezovic
- Department of Pharmacology and Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Jelena Osmanovic Barilar
- Department of Pharmacology and Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Peter Riederer
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University Hospital Würzburg, Würzburg, Germany.,Department and Research Unit of Psychiatry, Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Susanne Walitza
- Department of Child and Adolescent Psychiatry and Psychotherapy, Psychiatric University Hospital Zurich (PUK), University of Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich and the Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Christian Tackenberg
- Neuroscience Center Zurich, University of Zurich and the Swiss Federal Institute of Technology (ETH) Zurich, Zurich, Switzerland.,Institute for Regenerative Medicine (IREM), University of Zurich, Schlieren, Switzerland
| | - Melita Salkovic-Petrisic
- Department of Pharmacology and Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
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Homolak J, Babic Perhoc A, Knezovic A, Osmanovic Barilar J, Koc F, Stanton C, Ross RP, Salkovic-Petrisic M. Disbalance of the Duodenal Epithelial Cell Turnover and Apoptosis Accompanies Insensitivity of Intestinal Redox Homeostasis to Inhibition of the Brain Glucose-Dependent Insulinotropic Polypeptide Receptors in a Rat Model of Sporadic Alzheimer's Disease. Neuroendocrinology 2022; 112:744-762. [PMID: 34607331 DOI: 10.1159/000519988] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 09/29/2021] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Gastrointestinal dyshomeostasis is investigated in the context of metabolic dysfunction, systemic, and neuroinflammation in Alzheimer's disease. Dysfunctional gastrointestinal redox homeostasis and the brain-gut incretin axis have been reported in the rat model of insulin-resistant brain state-driven neurodegeneration induced by intracerebroventricular streptozotocin (STZ-icv). We aimed to assess whether (i) the structural epithelial changes accompany duodenal oxidative stress; (ii) the brain glucose-dependent insulinotropic polypeptide receptor (GIP-R) regulates redox homeostasis of the duodenum; and (iii) the STZ-icv brain-gut axis is resistant to pharmacological inhibition of the brain GIP-R. METHODS GIP-R inhibitor [Pro3]-GIP (85 μg/kg) was administered intracerebroventricularly to the control and the STZ-icv rats 1 month after model induction. Thiobarbituric acid reactive substances (TBARSs) were measured in the plasma and duodenum, and the sections were analyzed morphometrically. Caspase-3 expression and activation were assessed by Western blot and multiplex fluorescent signal amplification. RESULTS Intracerebroventricular [Pro3]-GIP decreased plasma TBARSs in the control and STZ-icv animals and increased duodenal TBARSs in the controls. In the controls, inhibition of brain GIP-R affected duodenal epithelial cells, but not villus structure, while all morphometric parameters were altered in the STZ-icv-treated animals. Morphometric changes in the STZ-icv animals were accompanied by reduced levels of caspase-3. Suppression of brain GIP-R inhibited duodenal caspase-3 activation. CONCLUSION Brain GIP-R seems to be involved in the regulation of duodenal redox homeostasis and epithelial cell turnover. Resistance of the brain-gut GIP axis and morphological changes indicative of abnormal epithelial cell turnover accompany duodenal oxidative stress in the STZ-icv rats.
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Affiliation(s)
- Jan Homolak
- Department of Pharmacology, University of Zagreb School of Medicine, Zagreb, Croatia
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Ana Babic Perhoc
- Department of Pharmacology, University of Zagreb School of Medicine, Zagreb, Croatia
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Ana Knezovic
- Department of Pharmacology, University of Zagreb School of Medicine, Zagreb, Croatia
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Jelena Osmanovic Barilar
- Department of Pharmacology, University of Zagreb School of Medicine, Zagreb, Croatia
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Fatma Koc
- APC Microbiome Ireland, Cork, Ireland
- Teagasc Food Research Centre, Cork, Ireland
| | - Catherine Stanton
- APC Microbiome Ireland, Cork, Ireland
- Teagasc Food Research Centre, Cork, Ireland
| | | | - Melita Salkovic-Petrisic
- Department of Pharmacology, University of Zagreb School of Medicine, Zagreb, Croatia
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
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7
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Homolak J, Babic Perhoc A, Knezovic A, Kodvanj I, Virag D, Osmanovic Barilar J, Riederer P, Salkovic-Petrisic M. Is Galactose a Hormetic Sugar? An Exploratory Study of the Rat Hippocampal Redox Regulatory Network. Mol Nutr Food Res 2021; 65:e2100400. [PMID: 34453395 DOI: 10.1002/mnfr.202100400] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 07/24/2021] [Indexed: 01/22/2023]
Abstract
SCOPE Galactose, a ubiquitous monosaccharide with incompletely understood physiology is often exploited for inducing oxidative-stress mediated aging in animals. Recent research demonstrates that galactose can conserve cellular function during periods of starvation and prevent/alleviate cognitive deficits in a rat model of sporadic Alzheimer's disease. The present aim is to examine the acute effects of oral galactose on the redox regulatory network (RRN). METHODS AND RESULTS Rat plasma and hippocampal RRNs are analyzed upon acute orogastric gavage of galactose (200 mg kg-1 ). No systemic RRN disbalance is observed; however, a mild pro-oxidative shift accompanied by a paradoxical increment in tissue reductive capacity suggesting overcompensation of endogenous antioxidant systems is observed in the hippocampus. Galactose-induced increment of reductive capacity is accompanied by inflation of the hippocampal pool of nicotinamide adenine dinucleotide phosphates indicating ROS detoxification through disinhibition of the oxidative pentose phosphate pathway flux, reduced neuronal activity, and upregulation of Leloir pathway gatekeeper enzyme galactokinase-1. CONCLUSION Based on the observed findings, and in the context of previous work on galactose, a hormetic hypothesis of galactose is proposed suggesting that the protective effects may be inseparable from its pro-oxidative action at the biochemical level.
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Affiliation(s)
- Jan Homolak
- Department of Pharmacology, University of Zagreb School of Medicine, Zagreb, Croatia.,Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Ana Babic Perhoc
- Department of Pharmacology, University of Zagreb School of Medicine, Zagreb, Croatia.,Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Ana Knezovic
- Department of Pharmacology, University of Zagreb School of Medicine, Zagreb, Croatia.,Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Ivan Kodvanj
- Department of Pharmacology, University of Zagreb School of Medicine, Zagreb, Croatia.,Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Davor Virag
- Department of Pharmacology, University of Zagreb School of Medicine, Zagreb, Croatia.,Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Jelena Osmanovic Barilar
- Department of Pharmacology, University of Zagreb School of Medicine, Zagreb, Croatia.,Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Peter Riederer
- Clinic and Polyclinic for Psychiatry, Psychosomatics and Psychotherapy, University Hospital Wuerzburg, Wuerzburg, Germany.,University of Southern Denmark Odense, Odense, Denmark
| | - Melita Salkovic-Petrisic
- Department of Pharmacology, University of Zagreb School of Medicine, Zagreb, Croatia.,Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
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8
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Homolak J, Babic Perhoc A, Knezovic A, Osmanovic Barilar J, Salkovic-Petrisic M. Failure of the Brain Glucagon-Like Peptide-1-Mediated Control of Intestinal Redox Homeostasis in a Rat Model of Sporadic Alzheimer's Disease. Antioxidants (Basel) 2021; 10:1118. [PMID: 34356351 PMCID: PMC8301063 DOI: 10.3390/antiox10071118] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 07/07/2021] [Accepted: 07/09/2021] [Indexed: 02/06/2023] Open
Abstract
The gastrointestinal system may be involved in the etiopathogenesis of the insulin-resistant brain state (IRBS) and Alzheimer's disease (AD). Gastrointestinal hormone glucagon-like peptide-1 (GLP-1) is being explored as a potential therapy as activation of brain GLP-1 receptors (GLP-1R) exerts neuroprotection and controls peripheral metabolism. Intracerebroventricular administration of streptozotocin (STZ-icv) is used to model IRBS and GLP-1 dyshomeostasis seems to be involved in the development of neuropathological changes. The aim was to explore (i) gastrointestinal homeostasis in the STZ-icv model (ii) assess whether the brain GLP-1 is involved in the regulation of gastrointestinal redox homeostasis and (iii) analyze whether brain-gut GLP-1 axis is functional in the STZ-icv animals. Acute intracerebroventricular treatment with exendin-3(9-39)amide was used for pharmacological inhibition of brain GLP-1R in the control and STZ-icv rats, and oxidative stress was assessed in plasma, duodenum and ileum. Acute inhibition of brain GLP-1R increased plasma oxidative stress. TBARS were increased, and low molecular weight thiols (LMWT), protein sulfhydryls (SH), and superoxide dismutase (SOD) were decreased in the duodenum, but not in the ileum of the controls. In the STZ-icv, TBARS and CAT were increased, LMWT and SH were decreased at baseline, and no further increment of oxidative stress was observed upon central GLP-1R inhibition. The presented results indicate that (i) oxidative stress is increased in the duodenum of the STZ-icv rat model of AD, (ii) brain GLP-1R signaling is involved in systemic redox regulation, (iii) brain-gut GLP-1 axis regulates duodenal, but not ileal redox homeostasis, and iv) brain-gut GLP-1 axis is dysfunctional in the STZ-icv model.
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Affiliation(s)
- Jan Homolak
- Department of Pharmacology, University of Zagreb School of Medicine, 10 000 Zagreb, Croatia; (A.B.P.); (A.K.); (J.O.B.); (M.S.-P.)
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, 10 000 Zagreb, Croatia
| | - Ana Babic Perhoc
- Department of Pharmacology, University of Zagreb School of Medicine, 10 000 Zagreb, Croatia; (A.B.P.); (A.K.); (J.O.B.); (M.S.-P.)
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, 10 000 Zagreb, Croatia
| | - Ana Knezovic
- Department of Pharmacology, University of Zagreb School of Medicine, 10 000 Zagreb, Croatia; (A.B.P.); (A.K.); (J.O.B.); (M.S.-P.)
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, 10 000 Zagreb, Croatia
| | - Jelena Osmanovic Barilar
- Department of Pharmacology, University of Zagreb School of Medicine, 10 000 Zagreb, Croatia; (A.B.P.); (A.K.); (J.O.B.); (M.S.-P.)
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, 10 000 Zagreb, Croatia
| | - Melita Salkovic-Petrisic
- Department of Pharmacology, University of Zagreb School of Medicine, 10 000 Zagreb, Croatia; (A.B.P.); (A.K.); (J.O.B.); (M.S.-P.)
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, 10 000 Zagreb, Croatia
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