Alzheimer's disease (AD) is the most common form of dementia. Characterized by progressive neurodegeneration, AD typically begins with mild cognitive decline escalating to severe impairment in communication and responsiveness. It primarily affects cerebral regions responsible for cognition, memory, and language processing, significantly impeding the functional independence of patients. With nearly 50 million dementia cases worldwide, a number expected to triple by 2050, the need for effective treatments is more urgent than ever. Recent insights into the association between obesity, type 2 diabetes mellitus, and neurodegenerative disorders have led to the development of promising treatments involving antidiabetic and anti-obesity agents. One such novel promising candidate for addressing AD pathology is a lipidized analogue of anorexigenic peptide called prolactin-releasing peptide (palm11-PrRP31). Interestingly, anorexigenic and orexigenic peptides have opposite effects on food intake regulation, however, both types exhibit neuroprotective properties. Recent studies have also identified ghrelin, an orexigenic peptide, as a potential neuroprotective agent. Hence, we employed both anorexigenic and orexigenic compounds to investigate the common mechanisms underpinning their neuroprotective effects in a triple transgenic mouse model of AD (3xTg-AD mouse model) combining amyloid-beta (Aβ) pathology and Tau pathology, two hallmarks of AD. We treated 3xTg-AD mice for 4 months with two stable lipidized anorexigenic peptide analogues - palm11-PrRP31, and liraglutide, a glucagon-like peptide 1 (GLP-1) analogue - as well as Dpr3-ghrelin, a stable analogue of the orexigenic peptide ghrelin, and using the method of immunohistochemistry and western blot demonstrate the effects of these compounds on the development of AD-like pathology in the brain. Palm11-PrRP31, Dpr3-ghrelin, and liraglutide reduced intraneuronal deposits of Aβ plaque load in the hippocampi and amygdalae of 3xTg-AD mice. Palm11-PrRP31 and Dpr3-ghrelin reduced microgliosis in the hippocampi, amygdalae, and cortices of 3xTg-AD mice. Palm11-PrRP31 and liraglutide reduced astrocytosis in the amygdalae of 3xTg-AD mice. We propose that these peptides are involved in reducing inflammation, a common mechanism underlying their therapeutic effects. This is the first study to demonstrate improvements in AD pathology following the administration of both orexigenic and anorexigenic compounds, highlighting the therapeutic potential of food intake-regulating peptides in neurodegenerative disorders.

• Keywords
• 3xTg-AD mice, Alzheimer’s disease, Anorexigenic peptide analogues, Neuroinflammation, Orexigenic peptide analogues,
• MeSH
• Alzheimer Disease * drug therapy   pathology   genetics   metabolism   MeSH
• Ghrelin * pharmacology   therapeutic use   MeSH
• Prolactin-Releasing Hormone * pharmacology   therapeutic use   analogs & derivatives   MeSH
• Humans MeSH
• Disease Models, Animal MeSH
• Mice, Inbred C57BL MeSH
• Mice, Transgenic MeSH
• Mice MeSH
• Neuroinflammatory Diseases * drug therapy   pathology   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Male MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Ghrelin * MeSH
• Prolactin-Releasing Hormone * MeSH

Since 1975, the incidence of obesity has increased to epidemic proportions, and the number of patients with obesity has quadrupled. Obesity is a major risk factor for developing other serious diseases, such as type 2 diabetes mellitus, hypertension, and cardiovascular diseases. Recent epidemiologic studies have defined obesity as a risk factor for the development of neurodegenerative diseases, such as Alzheimer's disease (AD) and other types of dementia. Despite all these serious comorbidities associated with obesity, there is still a lack of effective antiobesity treatment. Promising candidates for the treatment of obesity are anorexigenic neuropeptides, which are peptides produced by neurons in brain areas implicated in food intake regulation, such as the hypothalamus or the brainstem. These peptides efficiently reduce food intake and body weight. Moreover, because of the proven interconnection between obesity and the risk of developing AD, the potential neuroprotective effects of these two agents in animal models of neurodegeneration have been examined. The objective of this review was to explore anorexigenic neuropeptides produced and acting within the brain, emphasizing their potential not only for the treatment of obesity but also for the treatment of neurodegenerative disorders.

• Keywords
• Alzheimer´s-like pathology, anorexigenic neuropeptides, antiobesity treatment, neuroprotection,
• MeSH
• Alzheimer Disease drug therapy   metabolism   pathology   prevention & control   MeSH
• Hypothalamus drug effects   metabolism   pathology   MeSH
• Anti-Obesity Agents * pharmacology   therapeutic use   MeSH
• Humans MeSH
• Brain drug effects   metabolism   pathology   MeSH
• Neurodegenerative Diseases drug therapy   metabolism   prevention & control   MeSH
• Neuropeptides * metabolism   pharmacology   therapeutic use   MeSH
• Neuroprotective Agents * pharmacology   therapeutic use   MeSH
• Obesity * drug therapy   metabolism   MeSH
• Eating drug effects   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Names of Substances
• Anti-Obesity Agents * MeSH
• Neuropeptides * MeSH
• Neuroprotective Agents * MeSH

The worldwide increase in the incidence of obesity and cardiovascular and neurodegenerative diseases, e.g. Alzheimer's disease, is related to many factors, including an unhealthy lifestyle and aging populations. However, the interconnection between these diseases is not entirely clear, and it is unknown whether common mechanisms underlie these conditions. Moreover, there are currently no fully effective therapies for obesity and neurodegeneration. While there has been extensive research in preclinical models addressing these issues, the experimental findings have not been translated to the clinic. Another challenge relates to the time of onset of individual diseases, which may not be easily identified, since there are no specific indicators or biomarkers that define disease onset. Hence knowing when to commence preventive treatment is unclear. This is especially pertinent in neurodegenerative diseases, where the onset of the disease may be subtle and occur decades before the signs and symptoms manifest. In metabolic and cardiovascular disorders, the risk may occur in-utero, in line with the concept of fetal programming. This review provides a brief overview of the link between obesity, cardiovascular and neurodegenerative diseases and discusses potential common mechanisms including the role of the gut microbiome.

• MeSH
• Alzheimer Disease * metabolism   MeSH
• Humans MeSH
• Neurodegenerative Diseases * metabolism   MeSH
• Obesity complications   diagnosis   epidemiology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Review MeSH

The most important risk factor for the development of sporadic Alzheimer's disease (AD) is ageing. Senescence accelerated mouse prone 8 (SAMP8) is a model of sporadic AD, with senescence accelerated resistant mouse (SAMR1) as a control. In this study, we aimed to determine the onset of senescence-induced neurodegeneration and the related potential therapeutic window using behavioral experiments, immunohistochemistry and western blotting in SAMP8 and SAMR1 mice at 3, 6 and 9 months of age. The Y-maze revealed significantly impaired working spatial memory of SAMP8 mice from the 6th month. With ageing, increasing plasma concentrations of proinflammatory cytokines in SAMP8 mice were detected as well as significantly increased astrocytosis in the cortex and microgliosis in the brainstem. Moreover, from the 3rd month, SAMP8 mice displayed a decreased number of neurons and neurogenesis in the hippocampus. From the 6th month, increased pathological phosphorylation of tau protein at Thr231 and Ser214 was observed in the hippocampi of SAMP8 mice. In conclusion, changes specific for neurodegenerative processes were observed between the 3rd and 6th month of age in SAMP8 mice; thus, potential neuroprotective interventions could be applied between these ages.

• Keywords
• Alzheimer’s disease, insulin resistance, neuroinflammation, senescence accelerated mouse prone 8, tau pathology,
• MeSH
• Cytokines metabolism   MeSH
• Hippocampus * metabolism   MeSH
• Disease Models, Animal MeSH
• Mice MeSH
• tau Proteins * genetics   metabolism   MeSH
• Aging physiology   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Cytokines MeSH
• tau Proteins * MeSH

BACKGROUND/OBJECTIVE: Anorexigenic palmitoylated prolactin-releasing peptide (palm11-PrRP) is able to act centrally after peripheral administration in rat and mouse models of obesity, type 2 diabetes mellitus and/or neurodegeneration. Functional leptin and intact leptin signaling pathways are necessary for the body weight reducing and glucose tolerance improving effect of palm11-PrRP. We have previously shown that palm11-PrRP31 had glucose-lowering properties but not anti-obesity effect in Koletsky rats with leptin signaling disturbances, so improvements in glucose metabolism appear to be completely independent of leptin signaling. The purpose of this study was to describe relationship between metabolic and neurodegenerative pathologies and explore if palm11-PrRP31 could ameliorate them in obese fa/fa rat model with leptin signaling disruption. SUBJECT/METHODS: The fa/fa rats and their age-matched lean controls at the age 32 weeks were used for this study. The rats were infused for 2 months with saline or palm11-PrRP31 (n = 7-8 per group) at a dose of 5 mg/kg per day using Alzet osmotic pumps. During the dosing period food intake and body weight were monitored. At the end of experiment the oral glucose tolerance test was performed; plasma and tissue samples were collected and arterial blood pressure was measured. Then, markers of leptin and insulin signaling, Tau phosphorylation, neuroinflammation, and synaptogenesis were measured by western blotting and immunohistochemistry. RESULTS: Fa/fa rats developed obesity, mild glucose intolerance, and peripheral insulin resistance but not hypertension while palm11-PrRP31 treatment neither lowered body weight nor attenuated glucose tolerance but ameliorated leptin and insulin signaling and synaptogenesis in hippocampus. CONCLUSION: We demonstrated that palm11-PrRP31 had neuroprotective features without anti-obesity and glucose lowering effects in fa/fa rats. This data suggest that this analog has the potential to exert neuroprotective effect despite of leptin signaling disturbances in this rat model.

• MeSH
• Diabetes Mellitus, Type 2 * drug therapy   MeSH
• Glucose MeSH
• Prolactin-Releasing Hormone pharmacology   therapeutic use   MeSH
• Insulin therapeutic use   MeSH
• Rats MeSH
• Leptin * MeSH
• Mice MeSH
• Obesity metabolism   MeSH
• Body Weight MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Glucose MeSH
• Prolactin-Releasing Hormone MeSH
• Insulin MeSH
• Leptin * MeSH

BACKGROUND: Obesity leads to low-grade inflammation in the adipose tissue and liver and neuroinflammation in the brain. Obesity-induced insulin resistance (IR) and neuroinflammation seem to intensify neurodegeneration including Alzheimer's disease. In this study, the impact of high-fat (HF) diet-induced obesity on potential neuroinflammation and peripheral IR was tested separately in males and females of THY-Tau22 mice, a model of tau pathology expressing mutated human tau protein. METHODS: Three-, 7-, and 11-month-old THY-Tau22 and wild-type males and females were tested for mobility, anxiety-like behavior, and short-term spatial memory in open-field and Y-maze tests. Plasma insulin, free fatty acid, cholesterol, and leptin were evaluated with commercial assays. Liver was stained with hematoxylin and eosin for histology. Brain sections were 3',3'-diaminobenzidine (DAB) and/or fluorescently detected for ionized calcium-binding adapter molecule 1 (Iba1), glial fibrillary acidic protein (GFAP), and tau phosphorylated at T231 (pTau (T231)), and analyzed. Insulin signaling cascade, pTau, extracellular signal-regulated kinase 1/2 (ERK1/2), and protein phosphatase 2A (PP2A) were quantified by western blotting of hippocampi of 11-month-old mice. Data are mean ± SEM and were subjected to Mann-Whitney t test within age and sex and mixed-effects analysis and Bonferroni's post hoc test for age comparison. RESULTS: Increased age most potently decreased mobility and increased anxiety in all mice. THY-Tau22 males showed impaired short-term spatial memory. HF diet increased body, fat, and liver weights and peripheral IR. HF diet-fed THY-Tau22 males showed massive Iba1+ microgliosis and GFAP+ astrocytosis in the hippocampus and amygdala. Activated astrocytes colocalized with pTau (T231) in THY-Tau22, although no significant difference in hippocampal tau phosphorylation was observed between 11-month-old HF and standard diet-fed THY-Tau22 mice. Eleven-month-old THY-Tau22 females, but not males, on both diets showed decreased synaptic and postsynaptic plasticity. CONCLUSIONS: Significant sex differences in neurodegenerative signs were found in THY-Tau22. Impaired short-term spatial memory was observed in 11-month-old THY-tau22 males but not females, which corresponded to increased neuroinflammation colocalized with pTau(T231) in the hippocampi and amygdalae of THY-Tau22 males. A robust decrease in synaptic and postsynaptic plasticity was observed in 11-month-old females but not males. HF diet caused peripheral but not central IR in mice of both sexes.

• Keywords
• Alzheimer’s disease, Neuroinflammation, Obesity, Peripheral insulin resistance, Sex differences, THY-Tau22 mouse,
• MeSH
• Diet, High-Fat adverse effects   MeSH
• Phosphorylation MeSH
• Hippocampus metabolism   MeSH
• Insulin Resistance * MeSH
• Memory, Short-Term MeSH
• Disease Models, Animal MeSH
• Brain metabolism   physiopathology   MeSH
• Mice, Inbred C57BL MeSH
• Mice, Transgenic MeSH
• Mice MeSH
• Obesity complications   etiology   MeSH
• Mobility Limitation MeSH
• tau Proteins MeSH
• Sex Factors MeSH
• Aging metabolism   MeSH
• Tauopathies complications   genetics   MeSH
• Inflammation MeSH
• Fatty Liver metabolism   pathology   MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Mice MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• MAPT protein, human MeSH Browser
• tau Proteins MeSH