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Intranasal Insulin for Cognition / New study in HIV+
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Download the PDF here
Download the PDF here
Intranasal Insulin for the Treatment of HAND.....Johns Hopkins University study.....https://clinicaltrials.gov/ct2/show/NCT03081117
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"Our findings demonstrate that intranasal insulin treatment reverses cognitive impairment in conventional EcoHIV-infected mice."
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Intranasal insulin in Alzheimer's dementia or mild cognitive impairment: a systematic review jml of neurology July 2018
Background and aims
Due to common pathophysiological findings of Alzheimer's disease (AD) with diabetes mellitus (DM), insulin has been suggested as a possible treatment of AD or mild cognitive impairment (MCI). A safe alternative of IV insulin is intranasal (IN) insulin. The aim of this systematic review is to investigate the effects of IN insulin on cognitive function of patients with either AD or MCI.
Methods
A literature search of the electronic databases Medline, Scopus and CENTRAL was performed to identify RCTs investigating the effect of IN insulin administration on cognitive tasks, in patients with AD or MCI.
Results
Seven studies (293 patients) met our inclusion criteria. Most studies showed that verbal memory and especially story recall was improved after IN insulin administration. Sometimes the effect was restricted for apoe4 (-) patients. Intranasal insulin did not affect other cognitive functions. However, there were some positive results in functional status and daily activity. Data suggested that different insulin types and doses may have different effects on different apoe4 groups. In addition, the effects of treatment on Αβ levels differed from study to study. Finally, IN insulin resulted in minor adverse effects.
Conclusions
Intranasal insulin improved story recall performance of apoe4 (-) patients with AD or MCI. Other cognitive functions were not affected, but there were some positive results in functional status and daily activity. Since IN insulin is a safe intervention, future studies should be conducted with larger doses and after proper selection of patients and insulin types.
The present systematic review examined the effects of IN insulin administration on cognitive function of patients with AD or MCI. Collective evidence shows improvement in verbal memory and especially story recall, while IN insulin effects on other aspects of cognition was neutral. The data suggest that the treatment effect is modified by the apoe4 gene carriage status of patients: Apoe4 (-) patients showed more consistent cognitive gains in comparison to apoe4 (+) patients, whose performance either remained stable or declined after IN insulin treatment. However, there is evidence hinting that even these patients may benefit from IN insulin if a long-acting form of insulin rather than a rapid or short-acting form is used. Current data are not definite on whether IN insulin can be used as treatment for dementia of AD or MCI but provide strong evidence for its safety as the systemic side effects and especially hypoglycemia were essentially negligible. Proper selection of patients, stratification by disease stage, apoe4 carrier status and different types of insulin and doses will be needed in future studies for clearer results.
Attention, executive function and response inhibition
Attention, executive function and response inhibition were tested in five studies [30, 32, 33, 34, 35]. In four of them, the assessment of attention and response inhibition was done with SCWT (Stroop Color Word Test) [30, 32, 33, 34]. In general, no significant effects were observed in SCWT after administration of different types and doses of intranasal insulin [30, 32, 33, 34, 35]. Significant improvement was noticed only in one study, but the effect was restricted to discordant items [34]. There was no effect on concordant items or the number of errors [34].
Another study assessed attention/executive function with the use of "Trails B test", "RBANS digit span forward" and "RBANS digit span backward" [35]. Significantly improved performance was observed only for the first task [35] (Table 4).
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Intranasal insulin in Alzheimer's dementia or mild cognitive impairment: a systematic review......https://www.ncbi.nlm.nih.gov/pubmed/29392460
Intranasal insulin improves memory in
humans.....https://www.ncbi.nlm.nih.gov/pubmed/15288712/
Trials of Diabetes-Related
Therapies......https://www.alzforum.org/news/conference-coverage/trials-diabetes-related-therapies-mainly-bust
Adverse Side Effects of Intranasal Detemir Insulin in the SNIFF Trial.....https://www.j-alz.com/content/adverse-side-effects-intranasal-detemir-insulin-sniff-trial
Latest intranasal insulin results for Alzheimer's muddied by malfunctioning inhaler.....https://www.mdedge.com/clinicalneurologynews/article/190235/alzheimers-cognition/latest-intranasal-insulin-results
Intranasal Insulin for the Treatment of HAND.....Johns Hopkins University study.....https://clinicaltrials.gov/ct2/show/NCT03081117
Brief Summary:
Infection with HIV (the virus that causes AIDS) can lead to problems with brain function, such as memory, concentration, judgment, and the speed or control of hands and legs. Neurologists have called this condition HIV-associated neurocognitive disorder (HAND). This research is being done to see if insulin taken through the nose as a spray (intranasal insulin) can help people with HIV who are having problems with memory and brain function, or HAND.
Participants will be given either insulin or placebo. A placebo is an inactive substance that looks like the study drug, but does not contain study drug. For this research study, the placebo will be a clear, saline-based liquid spray that looks like the insulin spray but has no insulin. Participants will not be told whether they receive insulin or placebo during the study.
All participants will take the intranasal spray twice a day, about 30 minutes after a meal. Participants will use a specialized intranasal drug administration device. The total daily dose of insulin is 40 IU split between 20 IU in the morning and 20 IU in the evening. Participants will take the intranasal spray for 24 weeks.
The researchers will record symptoms and side effects during the study. Procedures include neurocognitive testing of memory and brain function, two optional lumbar punctures ("spinal taps"), two MRI brain scans, monthly blood draws, and clinical assessments.
Actual Study Start Date :
August 1, 2017
Estimated Primary Completion Date :
July 2021
Estimated Study Completion Date :
July 2021
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Intranasal insulin therapy reverses hippocampal dendritic injury and cognitive impairment in a model of HIV-associated neurocognitive disorders in EcoHIV-infected mice
Kim, Boe-Hyuna; Kelschenbach, Jennifera; Borjabad, Alejandraa; Hadas, Erana; He, Hongxiaa; Potash, Mary Janea; Nedelcovych, Michael T.b,c; Rais, Ranab,c; Haughey, Norman J.c; McArthur, Justin C.c; Slusher, Barbara S.b,c; Volsky, David J.a
AIDS: may 1 2019
Objective: Almost half of HIV-positive people on antiretroviral therapy have demonstrable mild neurocognitive impairment (HIV-NCI), even when virologically suppressed. Intranasal insulin therapy improves cognition in Alzheimer's disease and diabetes. Here we tested intranasal insulin therapy in a model of HIV-NCI in EcoHIV-infected conventional mice.
Design and methods: Insulin pharmacokinetics following intranasal administration to mice was determined by ELISA. Mice were inoculated with EcoHIV to cause NCI; 23 days or 3 months after infection they were treated daily for 9 days with intranasal insulin (2.4 IU/mouse) and examined for NCI in behavioral tests and HIV burdens by quantitative PCR. Some animals were tested for hippocampal neuronal integrity by immunostaining and expression of neuronal function-related genes by real time-quantitative PCR. The effect of insulin treatment discontinuation on cognition and neuropathology was also examined.
Results: Intranasal insulin administration to mice resulted in μIU/ml levels of insulin in cerebrospinal fluid with a half-life of about 2 h, resembling pharmacokinetic parameters of patients receiving 40 IU. Intranasal insulin treatment starting 23 days or 3 months after infection completely reversed NCI in mice. Murine NCI correlated with reductions in hippocampal dendritic arbors and downregulation of neuronal function genes; intranasal insulin reversed these changes coincident with restoration of cognitive acuity, but they returned within 24 h of treatment cessation. Intranasal insulin treatment reduced brain HIV DNA when started 23 but not 90 days after infection.
Conclusion: Our preclinical studies support the use of intranasal insulin administration for treatment of HIV-NCI and suggest that some dendritic injury in this condition is reversible.
Introduction
Neurocognitive impairments (NCI) in HIV-infected people are collectively known as HIV-associated neurocognitive disorders (HAND) of increasing severity from asymptomatic neurocognitive impairment (ANI), mild neurocognitive disorder (MND), to HIV-associated dementia (HAD) [1]. Chronically HIV-infected people who are virologically suppressed on long-term antiretroviral therapy (ART) rarely progress to HAD but about 50% of them will develop ANI or MND (here referred to as HIV-NCI) [2–4]. Some HIV-NCI patients report difficulties performing daily tasks, but the growing majority have 'silent' deficits only apparent in cognitive tests [5,6]. This largely asymptomatic NCI increases a patient's risk of progression to symptomatic disease [7,8] and the severity of NCI manifestations increases with age [3,9,10] suggesting substantial long-term health concerns associated with NCI. There are currently no therapies to prevent NCI progression in virologically suppressed individuals, nor any to address the effects of NCI on long-term management of chronic HIV infection.
HIV-NCI is diagnosed primarily in neuropsychological tests [1,11]. In contrast to HAD, HIV-NCI under ART shows minimal overt neuropathology and the disease is thought to arise from neuronal dysfunction rather than frank neuronal loss [6,12,13]. HIV-NCI includes mild dysfunctions in attention, learning/memory, working memory, executive function, and fine motor skills, in one or multiple domains [1,14], resembling the mild cognitive impairment accompanying aging, type 2 diabetes mellitus (T2DM), and the early prodromal stages of Alzheimer's disease [15–17]. One common determinant in all these conditions is a metabolic dysregulation in the brain, which for aging, obesity, and Alzheimer's disease was at least in part linked in animal models to deficient insulin signaling (reviewed in [6,18]). Intranasal insulin treatment may improve cognitive function in both T2DM and early Alzheimer's disease patients [19–22]. The efficacy of this treatment in HIV-NCI is unknown, but intranasal insulin administration was recently shown to inhibit HIV infection in culture and mitigate feline immunodeficiency virus (FIV)-induced encephalitis in cats [23]. The goal of the present work was to evaluate intranasal insulin therapy in a model of HIV-NCI in conventional mice infected with chimeric HIV, EcoHIV [24,25]. Short-term intranasal insulin therapy reverses hippocampal dendritic injury, gene dysregulation in the brain, and NCI in EcoHIV-infected mice, but these benefits diminish within 24 h of insulin treatment cessation.
Discussion
Our findings demonstrate that intranasal insulin treatment reverses cognitive impairment in conventional EcoHIV-infected mice. The behavioral defects and physiological changes in brains of these mice may form a useful model of HIV-NCI in HIV-positive people on ART. Chronically EcoHIV-infected mice have low lymphoid and brain HIV burdens and remain immunocompetent, in part due to control of HIV replication by the host immune system [24,31,36,37]. Like chronically HIV-infected patients on ART [38], despite virus control, infected mice develop mild abnormalities in gut, lung, and nervous system including chronic, ART-independent HIV-NCI [24,25,31,36,39–42]. Human HIV-NCI is a life-long condition that cannot be prevented even when ART is initiated several months after primary HIV infection [43]. Although animal models cannot fully replicate human disease, our results in EcoHIV-infected mice suggest that intranasal insulin delivery could be an effective treatment for HIV-NCI. This conclusion is based on several findings in the present work.
Starting with intranasal insulin administration, both peak central nervous system (CNS) concentrations and half-life of 2.4 IU intranasal-delivered insulin in mice resembled the intranasal-insulin pharmacokinetics profile in humans receiving 40 IU [44]. Separately, we have shown that intranasal insulin at this dose increases energy metabolism in mouse brain but not plasma glucose levels [26], affirming the reported safety profile of short-term intranasal insulin administration in people [45]. Because 40 IU insulin shows reproducible therapeutic efficacy in clinical trials of Alzheimer's disease and T2DM patients [19–22], we have achieved therapeutic doses of insulin in mouse CNS. As in animal models of nonviral cognitive diseases [46–48], short-term intranasal insulin treatment here was effective in reversing murine HIV-NCI. However, as in the SAMP8 mouse model of aging/Alzheimer's disease [48], the beneficial effect of a single intranasal insulin administration on cognition in infected mice lasted only about 24 h, possibly due to combined limitations of short half-life of intranasal-delivered insulin (Fig. 1 and [44]) and transient nature of insulin signaling [49]. This suggests that long-term intranasal insulin administration will be essential for the preservation of cognitive function [50] and implies prospect of life-long adjunct intranasal insulin therapy to mitigate progression of NCI with aging [3,10]. Importantly, this is feasible, however, further studies are imperative to determine potential side effects of such therapy [45,51] and complications that may arise from patient noncompliance and other treatments.
Second, we show that intranasal insulin treatment reversed impairment in all three cognitive abilities tested in EcoHIV-infected mice, visuospatial learning, working memory, and contextual (explicit) memory. Working memory is a prefrontal cortex (PFC) executive function [52,53] required for spatial learning in RAWM [17,29], whereas both visuospatial and explicit memory require functional integrity of the hippocampus and entorhinal cortex in the medial temporal lobe [54,55]. Thus, mouse HIV-NCI resembles human HIV-NCI in the putative diffuse injury to the anatomical structures and neuronal networks spanning the PFC, striatum, and medial temporal lobe, a feature distinguishing mild NCI from the characteristic severe white matter injury and motor dysfunction of HIV dementia [3,12,56]. The cognitive abilities measured in EcoHIV-infected mice are among seven cognitive domains evaluated in standardized neuropsychological tests for NCI diagnosis [1] and they are frequently abnormal in clinically asymptomatic NCI individuals (reviewed in [14,57,58]). Declines in working and explicit memory also serve as indicators of HIV-NCI progression, particularly with aging [3,9,10]. The beneficial effects of intranasal insulin on these functions in EcoHIV-infected mice, including in older animals (Fig. 2e), indicate that this treatment could mitigate some of the major cognitive deficits in patients with HIV-NCI and potentially lessen the effect of aging on NCI severity.
Third, our results link memory impairment in EcoHIV-infected mice to downregulation of selected neuronal function genes and hippocampal dendritic dearborization without apparent neuronal loss in the region. The joint onset of these changes, their joint reversal by intranasal insulin, and their joint reappearance with insulin withdrawal indicate a strong causal relationship between the hippocampal injury and memory defects in this model. Synaptic but not dendritic injury and impaired memory were observed in transgenic mice expressing Tat in astrocytes [59] suggesting that Tat produced by EcoHIV-infected cells [36] contributes to murine NCI observed here. Synaptodendritic injury, rather than neurodegeneration, is considered the primary defect responsible for NCI in HIV infection [12,60], but it was first documented in brain tissues from AIDS patients with active HIV replication [61,62]. Neuropathological studies in successfully HIV-suppressed individuals with NCI are rare [63]. However, a consensus is building that these individuals have limited HIV-specific brain abnormalities including minimal HIV-related neuroinflammation [6,13,63] and that their NCI correlates with synaptodendritic injury, best represented by reduced combined scores of MAP2 and synaptic marker synaptophysin [64]. Considering our findings here and elsewhere on immunocompetence and unremarkable brain histopathology in chronically EcoHIV-infected mice [24,36,65], we propose that this model mimics neuronal injury aspects of NCI in HIV suppressed people, particularly patients with visuospatial and verbal memory deficits and nonnecrotic functional changes in the hippocampus [66,67].
The mechanisms responsible for the neuronal injury observed here are unknown. The restoration of dendritic arbors and memory after insulin treatment indicates that relevant neurons survive and can return to full functionality, similar to reversal of memory and synaptic deficits in amyloid beta precursor protein (APP) transgenic mice treated with insulin-like growth factor-2 (IGF-2) [68] and transient loss of MAP2 dendritic staining after moderate traumatic brain injury [69]. Common to the three systems are instability of hippocampal dendritic arbors and synaptic termini in response to pathogenic stimuli and dendritic regrowth by surviving neurons either after cessation of the stimulus [69] or upon empirical restorative treatment ([68] and this work). The speed of dendritic changes is illustrated in the brain trauma study, where hippocampal MAP2 staining declined 4 h after brain impact and recovered partially by 24 h [69]. The proposed mechanism of dendritic structural stability includes reversible MAP2-microtubule association under the control of mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK-ERK) and CaMKII pathways [70]. Notably, CaMKII and its regulator NRGN [71] are transcriptionally downregulated in EcoHIV infection here, as is the neurotrophin BDNF that enhances dendrite formation [72], and they are restored to normal expression with insulin treatment. Although further similarities between EcoHIV model and HIV-NCI in patients on ART must be established, mechanistic studies on the reversible destabilization of hippocampal dendritic arbors by HIV in this model may lead to long-acting treatment of human HIV-NCI.
Finally, our results open avenues for better understanding of beneficial effects of insulin on HIV-NCI in clinically asymptomatic people. The brain is an insulin-sensitive organ [51] and multiple studies in animals and humans suggest a role for insulin and IGF in maintaining neuronal plasticity and cognitive function (reviewed in [18,51,73]). We have recently shown that murine NCI caused by EcoHIV (but not virus replication) can be prevented by treatment with the glutaminase antagonist 6-diazo-5-oxo-L-norleucine [25]. This finding, and downmodulation of the PPAT and TMG5 metabolism-related genes here, suggest that EcoHIV-infected mice demonstrate some of the metabolic dysregulation characterizing human HAND [6,74], possibly explaining some benefits of insulin treatment. The question of potential development of insulin resistance [74] upon long-term intranasal insulin treatment can also be experimentally addressed. Finally, the recent FIV study [23] and the present work indicate that insulin can affect FIV and HIV infection in the brain of their respective hosts. Reduction in HIV brain burdens or expression would mitigate the pathogenic stimulus for cognitive impairment. Exploration of these insulin effects may lead to new antiviral strategies that will also mitigate NCI.
Intranasal insulin treatment reverses murine HIV-neurocognitive impairment independent of HIV brain burdens
EcoHIV-infected mice manifested cognitive impairment (murine HIV-NCI) 1 month after infection as shown by their failure to learn the hidden platform location in RAWM compared with uninfected mice (Fig. 2a). When treated daily with intranasal insulin for 9 days, infected mice performed similarly in RAWM to untreated or insulin-treated-uninfected mice (Fig. 2a), suggesting that their NCI was reversed. All mouse groups performed equally well in finding the visible platform (right panel in Fig. 2a), indicating that neither EcoHIV infection nor intranasal insulin-affected animal mobility, vision, or motivation. Intranasal insulin treatment had no effect on HIV levels in spleen but significantly reduced HIV brain burdens (Fig. 2b). EcoHIV infection of mice had no effect on brain insulin concentrations compared with mock-infected mice (Fig. 2c). Pharmacokinetics assessment of intranasal insulin delivery after RAWM evaluation indicated preferential peptide accumulation in the brain in both EcoHIV and mock-infected mice (Fig. 2c).
To confirm insulin effects on cognition, groups of mice were subjected to intranasal insulin treatment and evaluated for a contextual associative fear responses [30] by fold change (Fig. 2d). Infected conditioned mice spent less time exhibiting the threat-induced freezing response compared with control mice when placed in the fear conditioning chamber the next day (context panel in Fig. 2d), indicating impairment in recall of the conditioned response. Intranasal insulin treatment returned the freezing response time of infected mice to that of uninfected animals (Fig. 2d). Finally, we inquired whether EcoHIV-infected mice remain sensitive to the beneficial effects of insulin 3 months after infection (Fig. 2e). The RAWM measures of murine NCI were similar 1 and 3 months after HIV infection, confirming the chronic nature of HIV-NCI in mice [24]. This chronic NCI was also fully reversible with 9 days of intranasal insulin treatment (Fig. 2a and e). However, in contrast to early HIV-NCI in mice, HIV DNA brain levels were not significantly affected by insulin treatment 3 months after infection (Fig. 2f). Direct evaluation of insulin effects on EcoHIV replication in primary mouse macrophages in culture (see Figure in Supplemental Digital Content, http://links.lww.com/QAD/B435) indicated that insulin can inhibit HIV replication but only at IU/ml concentrations, which were about 100-fold higher than those attained in the brain after intranasal insulin (Fig. 1). These results suggest that intranasal insulin therapy is equally effective in reversing early and chronic HIV-NCI in EcoHIV-infected mice but that the effect of insulin on cognition in long-term-infected animals is independent of HIV DNA levels in brain.
The benefits of intranasal insulin treatment in murine HIV-neurocognitive impairment diminish rapidly upon treatment discontinuation
The contrast between the short half-life of intranasal-delivered insulin in mouse brain (Fig. 1) and the effectiveness of intranasal insulin in ameliorating HIV-NCI (Figs. 2 and 3), prompted us to investigate the durability of insulin effects on cognition. To this end, we discontinued intranasal insulin treatment in parallel groups of uninfected and EcoHIV-infected mice on the third day of cognitive evaluation in RAWM (Fig. 4a and b and blue columns in Fig. 4c). RAWM evaluation proceeded until completion, mice were tested for virus burden (Fig. 4c) and hippocampal dendrite integrity (Fig. 4d and e). The standard last 3-day average representation of RAWM results (Fig. 4a) shows that treatment cessation in infected animals dramatically worsened their performance in the maze compared with infected, continually treated animals. A plot of daily retention trial (working memory) data for all animal groups (Fig. 4b) revealed that intranasal insulin began to restore working memory in infected mice on the first day of testing, reached statistical significance on the second day, and maximum effect by day 5.
However, discontinuation of insulin treatment in infected mice resulted in a complete return of working memory impairment within 24 h (Fig. 4b, blue columns). Reproducing data shown in Fig. 2, untreated infected mice tested 1 month after infection had detectable HIV DNA in the brain that was reduced following intranasal insulin by more than 90%; insulin had no effect on levels of splenic virus (Fig. 4c). Discontinuation of insulin treatment restored HIV brain burdens to close to pretreatment levels and significantly increased peripheral virus burdens compared with untreated mice (Fig. 4c). Analysis of hippocampal dendrite integrity revealed a similar pattern of efficacy (Fig. 4d and e), with insulin restoring dendrite MAP2 integrity in the CA1 and CA3 regions of the hippocampus to levels similar to uninfected mice. Cessation of insulin treatment resulted in a return of dendritic damage with MAP2 staining at levels seen in infected untreated mice. These results confirm the beneficial effects of intranasal insulin on cognition and hippocampal dendrite integrity in EcoHIV-infected mice (Figs. 2 and 3) and show that treatment discontinuation rapidly reverses these benefits.
Intranasal insulin treatment reverses hippocampal dendritic injury and normalizes expression of selected brain function genes in murine HIV-neurocognitive impairment
The spatial memory deficit in EcoHIV-infected mice (Fig. 2a) points to the hippocampus as the primary anatomical substrate of this dysfunction [17,29]. We tested hippocampal neuronal integrity in HIV-NCI mice by staining brain sections for the neuronal dendrite marker MAP2 [32,33] and neuronal cell body marker NeuN (Fig. 3a). We found a significant reduction in MAP2 staining in the CA1 and CA3 regions of the hippocampus of infected mice compared with controls (Fig. 3a and b), coinciding in real time with NCI in these animals shown in Fig. 2a. Insulin treatment of infected mice restored MAP2 stained dendrites to control levels (Fig. 3a and b), coinciding with restoration of spatial memory (Fig. 2a). In contrast, neuronal cell bodies visualized by NeuN costaining remained unaltered under all conditions tested, suggesting that EcoHIV infection does not cause hippocampal neuronal loss (Fig. 3a and b), similar to the normal HIV neuropathology in HIV-infected patients on ART [13]. These results suggest that EcoHIV infection disrupts neuronal dendritic integrity in the hippocampus and that this process is reversible by intranasal insulin treatment.
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