Alzheimer's disease: Is this a brain specific diabetic condition?

[Alzheimer's disease, amyloid-b peptides and ubiquitin-proteasome system: Therapeutic perspectives]

The Alzheimer's disease - an age-related neurodegenerative disorder leading to a progressive cognitive impairment - is characterized by an intracerebral accumulation of soluble β-amyloid (Aβ) oligomers, followed by the appearance of abnormally ubiquitinylated neurofibrillary tangles - a process associated with a chronic inflammation. The systematic presence of ubiquitinylated inclusions reflects a decrease in the proteasome activity due to (and contributing to) the presence of Aβ oligomers - a central dysfunction in the etiology of the disease. The involvement of the ubiquitin-proteasome system opens new therapeutic perspectives for both prevention and treatment.

Diabetic Encephalopathy in a Preclinical Experimental Model of Type 1 Diabetes Mellitus: Observations in Adult Female Rat

Patients affected by diabetes mellitus (DM) show diabetic encephalopathy with an increased risk of cognitive deficits, dementia and Alzheimer's disease, but the mechanisms are not fully explored. In the male animal models of DM, the development of cognitive impairment seems to be the result of the concomitance of different processes such as neuroinflammation, oxidative stress, mitochondrial dysfunction, and aberrant synaptogenesis. However, even if diabetic encephalopathy shows some sex-dimorphic features, no observations in female rats have been so far reported on these aspects. Therefore, in an experimental model of type 1 DM (T1DM), we explored the impact of one month of pathology on memory abilities by the novel object recognition test and on neuroinflammation, synaptogenesis and mitochondrial functionality. Moreover, given that steroids are involved in memory and learning, we also analysed their levels and receptors. We reported that memory dysfunction can be associated with different features in the female hippocampus and cerebral cortex. Indeed, in the hippocampus, we observed aberrant synaptogenesis and neuroinflammation but not mitochondrial dysfunction and oxidative stress, possibly due to the results of locally increased levels of progesterone metabolites (i.e., dihydroprogesterone and allopregnanolone). These observations suggest specific brain-area effects of T1DM since different alterations are observed in the cerebral cortex.

Synergistic effects of hIAPP and Aβ1-42 impaired the olfactory function associated with the decline of adult neurogenesis in SVZ

According to many in the field，the prevalence of Alzheimer's disease (AD) in type II diabetes (T2DM) populations is considerably higher than that in the normal population. Human islet amyloid polypeptide (hIAPP) is considered to be a common risk factor for T2DM and AD. Preliminary observations around T2DM animal model show that the decrease of adult neural stem cells (NSCs) in the subventricular zone (SVZ) is accompanied by olfactory dysfunction. Furthermore, impaired olfactory function could serve as to an early predictor of neurodegeneration，which is associated with cognitive impairment. However, the synergistic effects between hIAPP and amyloid-beta (Aβ) _1-42 in the brain and the neurodegeneration remains to be further clarified. In this study, olfactory capacity, synaptic density, status of NSC in SVZ, and status of newborn neurons in olfactory bulb (OB) were assessed 6 months after stereotactic injection of oligomer Aβ_1-42 into the dens gyrus (DG) of hIAPP-/+ mice or wild-type homogenous mice. Our results set out that Aβ₄₂ and amylin co-localized into OB and raised Aβ₄₂ deposition in hIAPP^-/+ mice compared with wild-type brood mice. In addition, 6 months after injection of Aβ_1-42 in hIAPP^-/+ mice, these mice showed increased olfactory dysfunction, significant loss of synapses, depletion of NSC in SVZ, and impaired cell renewal in OB. Our present study suggested that the synergistic effects between hIAPP and Aβ_1-42 impairs olfactory function and was associated with decreased neurogenesis in adults with SVZ.

The role of LRP1 in Aβ efflux transport across the blood-brain barrier and cognitive dysfunction in diabetes mellitus

BACKGROUND

The incidence of cognitive dysfunction in diabetes is increasing yearly, which severely affects the quality of life of patients and places a heavy burden on families and society. It has been demonstrated that impaired clearance of cerebral amyloid β-protein (Aβ) is a central event in the initiation and progression of Aβ deposition and cognitive impairment in diabetic patients. However, until now, the molecular mechanism by which diabetes mellitus induces impaired clearance of Aβ has remained unclear.

OBJECTIVE

To investigate the role and mechanism of lipoprotein receptor-related protein 1 (LRP1) in Aβ clearance impairment and cognitive function damage caused by diabetes.

METHODS

SPF male C57BL/6 mice were bred, and streptozotocin (STZ) (60 mg/kg/d) was intraperitoneally injected for 5 days to establish a diabetes model. The novel object recognition test and fear conditioning test were used to assess the cognitive function of mice in each group. Western blotting, qRT-PCR, ELISAs, and immunofluorescence staining were used to detect the expression levels of Aβ and Aβ clearance-related proteins in mouse brains. HBMECs were cultured in vitro to establish the blood-brain barrier model. The clearance rate of Aβ and the expression levels of LRP1 were measured under different glucose concentration culture conditions. HBMECs were transfected with lentivirus to overexpress or knock down the LRP1, and then, the changes in Aβ clearance were detected again. We injected adeno-associated virus AAV9-SP-A-LRP1 shRNA into the tail vein of DM mice to selectively knock down LRP1 gene expression in cerebral vascular endothelial cells. Then, the cognitive function and the expression levels of Aβ and Aβ clearance-related proteins in the brains of normal, DM and LRP1 knockdown mice were detected.

RESULTS

Compared with the controls, diabetic mice showed impaired cognitive performance, increased deposition of Aβ in the brain and decreased expression of LRP1 in the brain microvasculature. In vitro experiments showed that high glucose can downregulate the expression of LRP1 in HBMECs and damage the Aβ clearance across the blood-brain barrier (BBB). The reduction in the clearance rate of Aβ induced by high glucose was reversed by LRP1 overexpression but further substantially decreased when LRP1 was knocked down.

CONCLUSION

Hyperglycemia can impair Aβ efflux in the brain by downregulating the expression of LRP1 in the brain microvasculature, eventually resulting in cognitive impairment.

Cognitive disorder and dementia in type 2 diabetes mellitus

Insulin, a key pleiotropic hormone, regulates metabolism through several signaling pathways in target tissues including skeletal muscle, liver, and brain. In the brain, insulin modulates learning and memory, and impaired insulin signaling is associated with metabolic dysregulation and neurodegenerative diseases. At the receptor level, in aging and Alzheimer’s disease (AD) models, the amount of insulin receptors and their functions are decreased. Clinical and animal model studies suggest that memory improvements are due to changes in insulin levels. Furthermore, diabetes mellitus (DM) and insulin resistance are associated with age-related cognitive decline, increased levels of β-amyloid peptide, phosphorylation of tau protein; oxidative stress, pro-inflammatory cytokine production, and dyslipidemia. Recent evidence shows that deleting brain insulin receptors leads to mild obesity and insulin resistance without influencing brain size and apoptosis development. Conversely, deleting insulin-like growth factor 1 receptor (IGF-1R) affects brain size and development, and contributes to behavior changes. Insulin is synthesized locally in the brain and is released from the neurons. Here, we reviewed proposed pathophysiological hypotheses to explain increased risk of dementia in the presence of DM. Regardless of the exact sequence of events leading to neurodegeneration, there is strong evidence that mitochondrial dysfunction plays a key role in AD and DM. A triple transgenic mouse model of AD showed mitochondrial dysfunction, oxidative stress, and loss of synaptic integrity. These alterations are comparable to those induced in wild-type mice treated with sucrose, which is consistent with the proposal that mitochondrial alterations are associated with DM and contribute to AD development. Alterations in insulin/IGF-1 signaling in DM could lead to mitochondrial dysfunction and low antioxidant capacity of the cell. Thus, insulin/IGF-1 signaling is important for increased neural processing and systemic metabolism, and could be a specific target for therapeutic strategies to decrease alterations associated with age-related cognitive decline.

Effect of a purine derivative containing selenium to improve memory decline and anxiety through modulation of the cholinergic system and Na+/K+-ATPase in an Alzheimer's disease model

Alzheimer's disease (AD) is a worldwide problem, and there are currently no treatments that can stop this disease. To investigate the binding affinity of 6-((4-fluorophenyl) selanyl)-9H-purine (FSP) with acetylcholinesterase (AChE), to verify the effects of FSP in an AD model in mice and to evaluate the toxicological potential of this compound in mice. The binding affinity of FSP with AChE was investigated by molecular docking analyses. The AD model was induced by streptozotocin (STZ) in Swiss mice after FSP treatment (1 mg/kg, intragastrically (i.g.)), 1st-10th day of the experimental protocol. Anxiety was evaluated in an elevated plus maze test, and memory impairment was evaluated in the Y-maze, object recognition and step-down inhibitory avoidance tasks. The cholinergic system was investigated based on by looking at expression and activity of AChE and expression of choline acetyltransferase (ChAT). We evaluated expression and activity of Na⁺/K⁺-ATPase. For toxicological analysis, animals received FSP (300 mg/kg, i.g.) and aspartate aminotransferase, alanine aminotransferase activities were determined in plasma and δ-aminolevulinate dehydratase activity in brain and liver. FSP interacts with residues of the AChE active site. FSP mitigated the induction of anxiety and memory impairment caused by STZ. FSP protected cholinergic system dysfunction and reduction of activity and expression of Na⁺/K⁺-ATPase. FSP did not modify toxicological parameters evaluated and did not cause the death of mice. FSP protected against anxiety, learning and memory impairment with involvement of the cholinergic system and Na⁺/K⁺-ATPase in these actions.

Association of impaired fasting glucose and Type 2 Diabetes Mellitus with brain volume changes in Alzheimer's Disease patients analyzed by MRI: a retrospective study

Objectives

Alzheimer’s disease (AD), impaired fasting glucose (IFG), and Type 2 diabetes mellitus (T2DM) were reported associated with smaller brain volumes. Nevertheless, the association of hyperglycemia with brain volume changes in AD patients remains unclear. To investigate this issue, structural magnetic resonance imaging was used to compare brain volumes among AD patients with different fasting glucose levels.

Methods

Eighty-five AD patients were divided into three groups based on their fasting glucose level as suggested by the American Diabetes Association: normal fasting glucose group (AD_NFG, n = 45), AD_IFG group (n = 15), and AD_T2DM group (n = 25). Sagittal 3D T1-weighted images were obtained to calculate the brain volume. Brain parenchyma and 33 brain structures were automatically segmented. Each regional volume was analyzed among groups. For regions with statistical significance, partial correlation analysis was used to evaluate their relationships with fasting glucose level, corrected for Mini-Mental State Examination score, age, education level, cholesterol, triglyceride, and blood pressure.

Results

Compared with the AD_IFG and AD_NFG groups, the volume of pons in AD_T2DM group was significantly smaller. Fasting glucose was negatively correlated with pontine volume.

Conclusions

T2DM may exacerbate pontine atrophy in AD patients, and fasting glucose level is associated with pontine volume.

Pathways of Prevention: A Scoping Review of Dietary and Exercise Interventions for Neurocognition

Alzheimer's disease and related dementias (ADRD) represent an increasingly urgent public health concern, with an increasing number of baby boomers now at risk. Due to a lack of efficacious therapies among symptomatic older adults, an increasing emphasis has been placed on preventive measures that can curb or even prevent ADRD development among middle-aged adults. Lifestyle modification using aerobic exercise and dietary modification represents one of the primary treatment modalities used to mitigate ADRD risk, with an increasing number of trials demonstrating that exercise and dietary change, individually and together, improve neurocognitive performance among middle-aged and older adults. Despite several optimistic findings, examination of treatment changes across lifestyle interventions reveals a variable pattern of improvements, with large individual differences across trials. The present review attempts to synthesize available literature linking lifestyle modification to neurocognitive changes, outline putative mechanisms of treatment improvement, and discuss discrepant trial findings. In addition, previous mechanistic assumptions linking lifestyle to neurocognition are discussed, with a focus on potential solutions to improve our understanding of individual neurocognitive differences in response to lifestyle modification. Specific recommendations include integration of contemporary causal inference approaches for analyzing parallel mechanistic pathways and treatment-exposure interactions. Methodological recommendations include trial multiphase optimization strategy (MOST) design approaches that leverage individual differences for improved treatment outcomes.

A combined miRNA-piRNA signature to detect Alzheimer's disease

Alzheimer's disease (AD) is the most common neurodegenerative disorder causing huge emotional and economic burden to our societies. An effective therapy has not been implicated yet, which is in part also due to the fact that pathological changes occur years before clinical symptoms manifest. Thus, there is a great need for the development of a translatable biomarker. Recent evidence highlights microRNAs as candidate biomarkers. In this study, we use next-generation sequencing to study the small noncoding RNAome (sncRNAome) in exosomes derived from human cerebrospinal fluid (CSF). We show that the sncRNAome from CSF-derived exosomes is dominated not only by microRNAs (miRNAs) but also by PIWI-interacting RNAs (piRNAs). We define a combined signature consisting of three miRNAs and three piRNAs that are suitable to detect AD with an AUC of 0.83 in a replication cohort and furthermore predict the conversion of mild-cognitive impaired (MCI) patients to AD dementia with an AUC of 0.86 for the piRNA signature. When combining the smallRNA signature with pTau and Aβ 42/40 ratio the AUC reaches 0.98. Our study reports a novel exosomal small noncoding RNA signature to detect AD pathology and provides the first evidence that in addition to miRNAs, piRNAs should also be considered as a candidate biomarker for AD.

Piperine attenuates cognitive impairment in an experimental mouse model of sporadic Alzheimer's disease

Piperine, the major alkaloid constituent of black pepper, has been reported to possess a wide range of pharmacological effects on the central nervous system, including antidepressant, anticonvulsant and anti-ischemic activities. In the present study, we aimed to investigate the therapeutic potential and neuroprotective mechanisms of piperine in an experimental mouse model of sporadic Alzheimer's disease (sAD) induced by intracerebroventricular (ICV) infusion of streptozotocin (STZ). STZ was infused bilaterally at a dose of 1.5 mg/kg/day on day 1 and day 3. From day 8, piperine (2.5-10 mg/kg body weight) was administered intraperitoneally once daily for 15 consecutive days. The locomotor activity and cognitive performance of mice were evaluated using open field test and Morris water maze test, respectively. On day 23, all animals were sacrificed, and the hippocampus was used for biochemical, neurochemical and neuroinflammatory determinations. Our data revealed that the ICV-STZ-infused sAD mouse showed an increased oxidative-nitrosative stress, an altered neurotransmission and an elevated neuroinflammation in hippocampus, as well as significant cognitive deficits. All these alterations can be ameliorated by piperine in a dose-dependent manner. In summary, our findings predict a therapeutic potential of piperine against cognitive deficits in sAD mouse. This effect might be due to its abilities to ameliorate oxidative-nitrosative stress, restore neurotransmission and reduce neuroinflammation.

The Role of Insulin-Like Growth Factors and Insulin-Like Growth Factor-Binding Proteins in the Nervous System

The insulin-like growth factors (IGF-I and IGF-II) and their receptors are widely expressed in nervous tissue from early embryonic life. They also cross the blood brain barriers by active transport, and their regulation as endocrine factors therefore differs from other tissues. In brain, IGFs have paracrine and autocrine actions that are modulated by IGF-binding proteins and interact with other growth factor signalling pathways. The IGF system has roles in nervous system development and maintenance. There is substantial evidence for a specific role for this system in some neurodegenerative diseases, and neuroprotective actions make this system an attractive target for new therapeutic approaches. In developing new therapies, interaction with IGF-binding proteins and other growth factor signalling pathways should be considered. This evidence is reviewed, gaps in knowledge are highlighted, and recommendations are made for future research.

Iron Metabolism of the Skeletal Muscle and Neurodegeneration

Recent studies clearly indicate that the endocrine function of the skeletal muscle is essential for a long and healthy life. Regular exercise, which has been shown to stimulate the release of myokines, lowers the risk of many diseases, including Alzheimer’s and Parkinson’s disease, emphasizing the role of skeletal muscle in proper functioning of other tissues. In addition, exercise increases insulin sensitivity, which may also impact iron metabolism. Even though the role of iron in neurodegeneration is well established, the exact mechanisms of iron toxicity are not known. Interestingly, exercise has been shown to modulate iron metabolism, mainly by reducing body iron stores. Insulin signaling and iron metabolism are interconnected, as high tissue iron stores are associated with insulin resistance, and conversely, impaired insulin signaling may lead to iron accumulation in an affected tissue. Excess iron accumulation in tissue triggers iron-dependent oxidative stress. Further, iron overload in the skeletal muscle not only negatively affects muscle contractility but also might impact its endocrine function, thus possibly affecting the clinical outcome of diseases, including neurodegenerative diseases. In this review, we discuss possible mechanisms of iron dependent oxidative stress in skeletal muscle, its impact on muscle mass and endocrine function, as well as on neurodegeneration processes.

Birth weight and catch up growth are associated with childhood impulsivity in two independent cohorts

Individuals born after intrauterine growth restriction (IUGR) are more impulsive towards palatable foods, but it is not clear 1) if IUGR-related impulsivity is specific for foods and solely based on response inhibition and 2) if the development of impulsivity is due to being born IUGR per se or to growing up fast in the first few years of life (catch up growth). Children were classified in the IUGR group if the birth weight ratio was below 0.85. Delta z score for BMI was used as a measure of catch up growth. In MAVAN (N = 274), impulsivity was measured by the Information Sampling Task from the Cambridge Neuropsychological Test Automated Battery (IST - CANTAB), and in GUSTO using the Sticker Delay Task (N = 327). There is a significant effect of interaction between being born IUGR and the magnitude of catch up growth on the reflection impulsivity from IST-CANTAB at 60 months, in which greater catch up growth associates with greater impulsivity in the IST fixed condition in IUGR children. The finding was reproduced in children from the GUSTO cohort using the Sticker Delay Task. We confirmed that catch up growth interacts with IUGR, having a major role in the development of impulsivity in the first years of life and influencing inhibitory control and decision making processes.

Targeting central β2 receptors ameliorates streptozotocin-induced neuroinflammation via inhibition of glycogen synthase kinase3 pathway in mice

Alzheimer's disease (AD) is portrayed by progressive cognitive decline and pathological deposition of amyloid plaques as well as neurofibrillary tangles. Most of AD cases are sporadic, resulting from overlap of various environmental and genetic factors. Intra-cerebroventricular injection of streptozotocin (STZ) leads to insulin resistance brain state accompanied by memory decline, oxidative stress, and neuro-degeneration which mimic the pathologies associated with sporadic Alzheimer's disease (SAD). In the current study, protective effects of formoterol in STZ-induced SAD were studied. Formoterol-induced improvement in cognition was confirmed using Morris water maze and Y maze together with histopathological evidences. Moreover, prominent declines in oxidative stress, neuro-inflammation, and apoptotic parameters were recorded upon its injection in STZ-induced SAD mouse model. This was manifested by the decrement of malondialdehyde, hydrogen peroxide, interleukin-1β, interleukin-6, tumor necrosis factor-α, and caspase-3levels contrary to reduced glutathione and interleukin-10 increments. Formoterol also reversed STZ-induced alteration in acetylcholine and glutamate levels. Furthermore, it could be concluded that formoterol was capable of combating STZ-induced neuro-inflammation and retarding the development of the main pathological hallmarks of AD through glycogen synthase kinase-3 deactivation.

Neuroactive Steroids and Sex-Dimorphic Nervous Damage Induced by Diabetes Mellitus

Diabetes mellitus is a metabolic disease where improper glycaemic control may induce severe complications in different organs. In this review, we will discuss alterations occurring in peripheral and central nervous system of patients with type 1 (i.e., insulin dependent diabetes mellitus,) or type 2 diabetes (i.e., non-insulin dependent diabetes mellitus), as well as related experimental models. A particular focus will be on the role exerted by neuroactive steroids (i.e., important regulators of nervous functions) in the nervous damage induced by diabetes. Indeed, the nervous levels of these molecules are affected by the pathology and, in agreement, their neuroprotective effects have been reported. Interestingly, the sex is another important variable. As discussed, nervous diabetic complications show sex dimorphic features in term of incidence, functional outcomes and neuroactive steroid levels. Therefore, these features represent an interesting background for possible sex-oriented therapies with neuroactive steroids aimed to counteract nervous damage observed in diabetic pathology.

Evaluation of Animal Models by Comparison with Human Late-Onset Alzheimer's Disease

Despite many efforts to alleviate the pathological conditions of Alzheimer's disease (AD), effective therapeutic drugs have not been developed, mainly because of the lack of molecular information about AD and animal models. We observed the reciprocal regulation of AD-associated genes (AD genes) and their related functions. Upregulated AD genes were positioned in central regions in the protein-protein interaction network and were involved in inflammation and DNA repair pathways. Downregulated AD genes positioned in the periphery of the network were associated with metabolic pathways. Using these features of AD genes, we found that 5×FAD, amyloid β-injected mice, and rats in the initial phases after bilateral common carotid artery occlusion (BCCAO) exhibited patterns that were most similar to those of AD. In contrast, using differentially expressed genes from animal models, we observed that 3×Tg and animals in late phases of BCCAO were positioned close to AD genes.

Endoplasmic reticulum stress/autophagy pathway is involved in diabetes-induced neuronal apoptosis and cognitive decline in mice

Diabetes mellitus is a significant global public health problem depicting a rising prevalence worldwide. As a serious complication of diabetes, diabetes-associated cognitive decline is attracting increasing attention. However, the underlying mechanisms are yet to be fully determined. Both endoplasmic reticulum (ER) stress and autophagy have been reported to modulate neuronal survival and death and be associated with several neurodegenerative diseases. Here, a streptozotocin-induced diabetic mouse model and primary cultured mouse hippocampal neurons were employed to investigate the possible role of ER stress and autophagy in diabetes-induced neuronal apoptosis and cognitive impairments, and further explore the potential molecular mechanisms. ER stress markers GRP78 and CHOP were both enhanced in diabetic mice, as was phosphorylation of PERK, IRE1α, and JNK. In addition, the results indicated an elevated level of autophagy in diabetic mice, as demonstrated by up-regulated expressions of autophagy markers LC3-II, beclin 1 and down-regulated level of p62, and increased formation of autophagic vacuoles and LC3-II aggregates. Meanwhile, we found that these effects could be abolished by ER stress inhibitor 4-phenylbutyrate or JNK inhibitor SP600125 in vitro. Furthermore, neuronal apoptosis of diabetic mice was attenuated by pretreatment with 4-phenylbutyrate, while aggravated by application of inhibitor of autophagy bafilomycin A1 in vitro. These results suggest that ER stress pathway may be involved in diabetes-mediated neurotoxicity and promote the following cognitive impairments. More important, autophagy was induced by diabetes possibly through ER stress-mediated JNK pathway, which may protect neurons against ER stress-associated cell damages.

Suppression of adiponectin receptor 1 promotes memory dysfunction and Alzheimer's disease-like pathologies

Recent studies on neurodegeneration have focused on dysfunction of CNS energy metabolism as well as proteinopathies. Adiponectin (ADPN), an adipocyte-derived hormone, plays a major role in the regulation of insulin sensitivity and glucose homeostasis in peripheral organs via adiponectin receptors. In spite of accumulating evidence that adiponectin has neuroprotective properties, the underlying role of adiponectin receptors has not been illuminated. Here, using gene therapy-mediated suppression with shRNA, we found that adiponectin receptor 1 (AdipoR1) suppression induces neurodegeneration as well as metabolic dysfunction. AdipoR1 knockdown mice exhibited increased body weight and abnormal plasma chemistry and also showed spatial learning and memory impairment in behavioural studies. Moreover, AdipoR1 suppression resulted in neurodegenerative phenotypes, diminished expression of the neuronal marker NeuN, and increased expression and activity of caspase 3. Furthermore, AD-like pathologies including insulin signalling dysfunction, abnormal protein aggregation and neuroinflammatory responses were highly exhibited in AdipoR1 knockdown groups, consistent with brain pathologies in ADPN knockout mice. Together, these results suggest that ADPN-AdipoR1 signalling has the potential to alleviate neurodegenerative diseases such as Alzheimer’s diseases.

Metabolic and neuroprotective effects of dapagliflozin and liraglutide in diabetic mice

This study assessed the metabolic and neuroprotective actions of the sodium glucose cotransporter-2 inhibitor dapagliflozin in combination with the GLP-1 agonist liraglutide in dietary-induced diabetic mice. Mice administered low-dose streptozotocin (STZ) on a high-fat diet received dapagliflozin, liraglutide, dapagliflozin-plus-liraglutide (DAPA-Lira) or vehicle once-daily over 28 days. Energy intake, body weight, glucose and insulin concentrations were measured at regular intervals. Glucose tolerance, insulin sensitivity, hormone and biochemical analysis, dual-energy X-ray absorptiometry densitometry, novel object recognition, islet and brain histology were examined. Once-daily administration of DAPA-Lira resulted in significant decreases in body weight, fat mass, glucose and insulin concentrations, despite no change in energy intake. Similar beneficial metabolic improvements were observed regarding glucose tolerance, insulin sensitivity, HOMA-IR, HOMA-β, HbA1c and triglycerides. Plasma glucagon, GLP-1 and IL-6 levels were increased and corticosterone concentrations decreased. DAPA-Lira treatment decreased alpha cell area and increased insulin content compared to dapagliflozin monotherapy. Recognition memory was significantly improved in all treatment groups. Brain histology demonstrated increased staining for doublecortin (number of immature neurons) in dentate gyrus and synaptophysin (synaptic density) in stratum oriens and stratum pyramidale. These data demonstrate that combination therapy of dapagliflozin and liraglutide exerts beneficial metabolic and neuroprotective effects in diet-induced diabetic mice. Our results highlight important personalised approach in utilising liraglutide in combination with dapagliflozin, instead of either agent alone, for further clinical evaluation in treatment of diabetes and associated neurodegenerative disorders.

Profile of 6 microRNA in blood plasma distinguish early stage Alzheimer's disease patients from non-demented subjects

Alzheimer's disease (AD) is the most common age-related dementia. Among its major challenges is identifying molecular signatures characteristic for the early AD stage in patients with Mild Cognitive Impairment (MCI-AD), which could serve for deciphering the AD pathomechanism and also as non-invasive, easy-to-access biomarkers. Using qRT-PCR we compared the microRNA (miRNA) profiles in blood plasma of 15 MCI-AD patients, whose diagnoses were confirmed by cerebrospinal fluid (CSF) biomarkers, with 20 AD patients and 15 non-demented, age-matched individuals (CTR).To minimize methodological variability, we adhered to standardization of blood and CSF assays recommended by the international Joint Programming for Neurodegenerative Diseases (JPND) BIOMARKAPD consortium, and we employed commercially available Exiqon qRT-PCR-assays. In the first screening, we assessed 179 miRNAs of plasma. We confirmed 23 miRNAs reported earlier as AD biomarker candidates in blood and found 26 novel differential miRNAs between AD and control subjects. For representative 15 differential miRNAs, the TargetScan, MirTarBase and KEGG database analysis indicated putative protein targets among such AD hallmarks as MAPT (Tau), proteins involved in amyloidogenic proteolysis, and in apoptosis. These 15 miRNAs were verified in separate, subsequent subject groups. Finally, 6 miRNAs (3 not yet reported in AD context and 3 reported in AD blood) were selected as the most promising biomarker candidates differentiating early AD from controls with the highest fold changes (from 1.32 to 14.72), consistent significance, specificities from 0.78 to 1 and sensitivities from 0.75 to 1. (patent pending, PCT/IB2016/052440).

Suspected non-Alzheimer's pathology - Is it non-Alzheimer's or non-amyloid?

Neurodegeneration, the progressive loss of neurons, is a major process involved in dementia and age-related cognitive impairment. It can be detected clinically using currently available biomarker tests. Suspected Non-Alzheimer Pathology (SNAP) is a biomarker-based concept that encompasses a group of individuals with neurodegeneration, but no evidence of amyloid deposition (thereby distinguishing it from Alzheimer's disease (AD)). These individuals may often have a clinical diagnosis of AD, but their clinical features, genetic susceptibility and progression can differ significantly, carrying crucial implications for precise diagnostics, clinical management, and efficacy of clinical drug trials. SNAP has caused wide interest in the dementia research community, because it is still unclear whether it represents distinct pathology separate from AD, or whether in some individuals, it could represent the earliest stage of AD. This debate has raised pertinent questions about the pathways to AD, the need for biomarkers, and the sensitivity of current biomarker tests. In this review, we discuss the biomarker and imaging trials that first recognized SNAP. We describe the pathological correlates of SNAP and comment on the different causes of neurodegeneration. Finally, we discuss the debate around the concept of SNAP, and further unanswered questions that are emerging.

Type 2 diabetes and quality of life

It is true that a primary goal of diabetes early diagnosis and treatment is quality of life (QoL). The term QoL is still confusing but it is agreed that it composes of four components: The physical component, mental, cogitative component, psychological and social component. Many articles have been written addressing those four components. During the last five years 15500 articles and reviews have been written addressing diabetes and coronary arterial disease, 16100 addressing diabetes and renal function, 28900 addressing diabetes and retinopathy, 16800 addressing diabetic foot ulcers and other 26300 addressing diabetic neuropathy. Moreover 17200 articles are dealing with diabetic sexual dysfunction, 24500 with the correlation of diabetes and depression 17500 about diabetes and dementia, only 1 about diabetes and family functioning and 1950000 about diabetes and QoL, indicating the worldwide interest. In order to confront this metabolic anomaly and its consequences, researchers developed numerous generic and disease specific psychometric tools. With the aid of those psychometric tools the scientific community has started to realize the gruesome effect of diabetes on patients’ lives. Diabetic’s QoL becomes worse when complications start to develop or comorbidities coexist. Dominant amongst complications, in health-related quality of life (HRQoL) lowering, but not related to risk factors (genetic, the weight of birth, or others) is coronary arterial disease followed by renal failure, blindness, and the combination of micro- and macro-vascular complications and in some studies by sexual dysfunction. Moreover many are the comorbidities which deteriorate further the effect of diabetes in a patient life. Among them obesity, hypertension, dyslipidemia, depression, arthritis are the most common. Most intriguing field for research is the interaction of diabetes and depression and in some cases the progression to dementia. Many aspects and combinations of actions are under researchers’ microscope regarding the improvement of HRQoL scores. Until now, the studies performed, have demonstrated little to moderate benefit. More of them are needed to draw safe conclusions on the topic of the best combination of actions to optimize the HRQoL scores.

Hormone therapy for prostate cancer increases the risk of Alzheimer's disease: a nationwide 4-year longitudinal cohort study

INTRODUCTION

Androgen-deprivation therapy (ADT) is recognized to be the preferred first-line treatment for advanced prostate cancer. However, the risk-benefit ratio of ADT remains poorly defined and the relationship between androgen depletion and dementia is not clear.

AIM

To investigate the risk of developing Alzheimer's disease (AD) in patients undergoing ADT for prostate cancer.

METHODS

Data from 24 360 prostate cancer patients were collected from the Longitudinal Health Insurance Database of Taiwan. In total, 15 959 patients who underwent ADT were included in the study cohort, and another 8401 patients who did not receive ADT were included as a non-ADT cohort.

RESULTS

During the average 4-year follow-up period, the incidence of AD was 2.78 per 1000 person-years in the non-ADT cohort and 5.66 per 1000 person-years in the ADT cohort. After adjusting for age and all comorbidities, the combined ADT cohort was found to be 1.84 times more likely to develop AD than the non-ADT control group (95%CI 1.33-2.55, p < 0.001).

CONCLUSIONS

The present results suggest that ADT use is associated with an increased risk of developing AD.

Human gut microbiota: the links with dementia development

Dementia is a comprehensive category of brain diseases that is great enough to affect a person's daily functioning. The most common type of dementia is Alzheimer's disease, which makes most of cases. New researches indicate that gastrointestinal tract microbiota are directly linked to dementia pathogenesis through triggering metabolic diseases and low-grade inflammation progress. A novel strategy is proposed for the management of these disorders and as an adjuvant for psychiatric treatment of dementia and other related diseases through modulation of the microbiota (e.g. with the use of probiotics).

Human gut microbiota: the links with dementia development

Dementia is a comprehensive category of brain diseases that is great enough to affect a person's daily functioning. The most common type of dementia is Alzheimer's disease, which makes most of cases. New researches indicate that gastrointestinal tract microbiota are directly linked to dementia pathogenesis through triggering metabolic diseases and low-grade inflammation progress. A novel strategy is proposed for the management of these disorders and as an adjuvant for psychiatric treatment of dementia and other related diseases through modulation of the microbiota (e.g. with the use of probiotics).