Gut Microbiome Changes in Patients With Idiopathic Normal Pressure Hydrocephalus

BACKGROUND

The gut microbiome is a complex system within the human gastrointestinal tract. The bacteria play a significant role in human health, and some can promote inflammation and pathologic processes through chemical interactions or metabolites. Gut microbiome dysbiosis has been linked to some neurological and other diseases. Here we aimed to examine microbiome differences between patients with a progressive neurological disorder, idiopathic normal pressure hydrocephalus (iNPH), compared with healthy controls (CO).

METHODS

We recruited 37 neurologically healthy CO and 10 patients with shunted iNPH. We evaluated these participants' cognition using the CERAD-NB test battery and CDR test, and collected a variety of information, including about dietary habits and health. We also collected fecal samples, which were subjected to 16S amplicon sequencing to analyze differences in gut microbiome composition.

RESULTS

We found that the iNPH group exhibited significantly different abundances of 10 bacterial genera compared with the CO group. The Escherichia/Shigella and Anaeromassilibacillus genera were most remarkably increased. Other increased genera were Butyrivibrio , Duncaniella , and an unidentified genus. The decreased genera were Agathobaculum , Paramuribaculum , Catenibacterium , and 2 unidentified genera.

CONCLUSIONS

Here we report the first identified microbiome differences in iNPH patients compared with healthy controls.

Incidence and Risk Factors of Transient Global Amnesia

INTRODUCTION

Transient global amnesia (TGA) is a spontaneously resolving, anterograde amnesia that lasts mostly <24 h and often occurs with retrograde amnesia. The etiology of TGA remains unclear, although in recent decades, many risk factors and preceding events have been identified. There are few up-to-date reports on the TGA incidence in Northern Europe. In this study, we report the incidence and risk factors associated with TGA in Finland.

MATERIALS AND METHODS

The study included all patients with suspected TGA that were referred to Kuopio University Hospital (KUH) in 2017. The hospital catchment area included 246,653 individuals. Risk factors and demographic data were collected from medical records. The TGA incidence rates were calculated as the number of patients with TGA divided by the number of individuals at risk in different age groups.

RESULTS

In 2017, 56 patients were treated for TGA at KUH. Of these, 46 had a first-ever TGA. The most common event preceding TGA was physical effort (n = 28, 50%), followed by emotional stress (n = 11, 19.6%) and water contact or a temperature change (n = 11, 19.6%). The most common comorbidities were hypercholesterolemia (n = 22, 39.3%), hypertensive disease (n = 21, 37.5%), hypothyroidism (n = 11, 19.6%), coronary artery disease (n = 8, 14.3%), and migraine (n = 7, 12.5%). TGA occurred most often in December (n = 9, 16.0%), March (n = 8, 14.3%), or October (n = 8, 14.3%), and least often in November and May (n = 2, 3.6% in both months). The crude incidence of a first TGA in Eastern Finland was 18.6/100,000 inhabitants, and when standardized to the European population in 2010, it was 14.3/100,000 inhabitants. Therefore, the TGA incidence was higher than previously reported in European countries.

DISCUSSION

The most common precipitating factors for TGA were physical effort, emotional stress, and water contact/temperature change. The incidence of TGA was high in the Eastern Finnish population.

Traumatic Brain Injury Associates with an Earlier Onset in Sporadic Frontotemporal Dementia

BACKGROUND

Currently, there are few studies considering possible modifiable risk factors of frontotemporal dementia (FTD).

OBJECTIVE

In this retrospective case-control study, we evaluated whether a history of traumatic brain injury (TBI) associates with a diagnosis of FTD or modulates the clinical phenotype or onset age in FTD patients.

METHODS

We compared the prevalence of prior TBI between individuals with FTD (N = 218) and age and sex-matched AD patients (N = 214) or healthy controls (HC; N = 100). Based on the patient records, an individual was categorized to the TBI+ group if they were reported to have suffered from TBI during lifetime. The possible associations of TBI with age of onset and disease duration were also evaluated in the whole FTD patient group or separately in the sporadic and genetic FTD groups.

RESULTS

The prevalence of previous TBI was the highest in the FTD group (19.3%) when compared to the AD group (13.1%, p = 0.050) or HC group (12%, p = 0.108, not significant). Preceding TBI was more often associated with the sporadic FTD cases than the C9orf72 repeat expansion-carrying FTD cases (p = 0.003). Furthermore, comparison of the TBI+ and TBI- FTD groups indicated that previous TBI was associated with an earlier onset age in the FTD patients (B = 3.066, p = 0.010).

CONCLUSION

A preceding TBI associates especially with sporadic FTD and with earlier onset of symptoms. The results of this study suggest that TBI may be a triggering factor for the neurodegenerative processes in FTD. However, understanding the precise underlying mechanisms still needs further studies.

Incidence of first-ever transient ischemic attack in Eastern Finland

OBJECTIVES

The incidence of stroke has been declining in Finland, as well as in Europe. However, it is unclear whether the incidence of transient ischemic attack (TIA) is also decreasing. In fact, the TIA incidence in the Finnish population has never been reported. Therefore, here we investigated the incidence of TIA in the Eastern Finnish population in 2017.

MATERIALS AND METHODS

All patients with suspected TIA, from a defined catchment area, were referred to a neurological emergency unit at Kuopio University Hospital (KUH) in the Northern Savonia region of Eastern Finland, which had a population of 246,653 in 2017. The original study population comprised TIA patients diagnosed based on the WHO TIA criteria in 2017. Incidence rates were calculated by dividing the number of TIA cases by the number of people in different age groups.

RESULTS

Among 432 patients with a suspected TIA referred to the neurological emergency unit at Kuopio University Hospital in 2017, 293 were living in Northern Savonia and were ultimately diagnosed with TIA after neurological examinations. The number of first-ever TIAs was 211. The crude incidence of all TIA was 122/100,000 inhabitants, and of first-ever TIA was 86/100,000. The age-standardized incidence (European population 2010) of the first-ever TIA was calculated to be 64/100,000. The mean age of first-ever TIA patients was 70 years: 72 years for women versus 68 years for men.

CONCLUSIONS

We found a high incidence of TIA in Eastern Finland.

Modifiable potential risk factors in familial and sporadic frontotemporal dementia

Objective

Only a few studies have evaluated modifiable risk factors for frontotemporal dementia (FTD). Here, we evaluated several modifiable factors and their association with disease phenotype, genotype, and prognosis in a large study population including Finnish and Italian patients with FTD and control groups.

Methods

In this case–control study, we compared the presence of several cardiovascular and other lifestyle‐related diseases and education between Finnish and Italian patients with familial (n = 376) and sporadic (n = 654) FTD, between different phenotypes of FTD, and between a subgroup of Finnish FTD patients (n = 221) and matched Finnish patients with Alzheimer's disease (AD) (n = 214) and cognitively healthy controls (HC) (n = 100).

Results

Patients with sporadic FTD were less educated (p = 0.042, B = ‐0.560, 95% CI −1.101 to −0.019) and had more heart diseases (p < 0.001, OR = 2.265, 95% CI 1.502–3.417) compared to patients with familial FTD. Finnish FTD patients were less educated (p = 0.032, B = 0.755, 95% CI 0.064–1.466) compared with AD patients. The Finnish FTD group showed lower prevalence of hypertension than the HC group (p = 0.003, OR = 2.162, 95% CI 1.304–3.583) and lower prevalence of hypercholesterolemia than in the HC group (p < 0.001, OR = 2.648, 95%CI 1.548–4.531) or in the AD group (p < 0.001, OR = 1.995, 95% CI 1.333–2.986). Within the FTD group, clinical phenotypes also differed regarding education and lifestyle‐related factors.

Interpretation

Our study suggests distinct profiles of several modifiable factors in the FTD group depending on the phenotype and familial inheritance history and that especially sporadic FTD may be associated with modifiable risk factors.

New insights into the genetic etiology of Alzheimer's disease and related dementias

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele.

Pet ownership supports quality of life in home-dwelling people with Alzheimer's disease

OBJECTIVES

Human-animal interactions have beneficial psychosocial and psychophysiological effects on individuals in both the presence and absence of medical health conditions. No previous prospective studies with long follow-up have investigated the effects of domestic pets on individuals with Alzheimer's disease (AD) who live at home. We examined the effects of pets on quality of life (QoL) and general well-being during a 5-year follow-up of home-dwelling persons with AD.

METHODS

In a prospective study including 223 patients with very mild (Clinical Dementia Rating Scale [CDR] 0.5) or mild (CDR 1) AD at baseline who participated in the ALSOVA study, 40 (18%) had a pet. Self- and proxy-rated QoL in AD quality of life-AD (QoL-AD), 15D, and self-rated visual analogic scale (VAS) were assessed annually for 3 years and after 5 years. The Mini-Mental State Examination, Neuropsychiatric Inventory, and CDR sum of boxes (CDR sum of boxes) were measured at the same visits.

RESULTS

A significant positive effect of pet ownership (p = 0.003, proxy-rated QoL-AD) on QoL was found over the entire follow-up. However, self-rated QoL-AD, 15D, and VAS did not significantly differ between pet owners and non-pet owners.

CONCLUSIONS

The findings suggest that having a pet may support QoL in home-dwelling persons with AD. Self-rated or general QoL or well-being measurements are not an accurate method for studying QoL in individuals with dementia over time due to a lack of insight. Adding proxy-rated evaluations to this kind of study is recommended.

The Positive Effects of Pet Ownership on Alzheimer's Disease

BACKGROUND

Human-animal interactions are known to have many beneficial psychosocial and psychophysiological effects on persons with and without medical health conditions. There are no previous prospective studies with long follow-up times on the effects of domestic pets on the persons with Alzheimer's disease (AD) living at home.

OBJECTIVE

To investigate the effects of pets on the activities of daily living (ADL), disease progression, and neuropsychiatric symptoms (NPS) during a five-year follow-up on the persons with AD.

METHODS

Altogether 223 home-dwelling persons (mean age 75.2 years) with very mild (CDR 0.5) or mild (CDR 1) AD at baseline were included for this study. ADCS-ADL, NPI, MMSE, and CDR-SOB were measured at baseline, annually for three years and after five years.

RESULTS

Totally 40 (17.9%) participants had a pet. At the baseline, pet owners and non-pet owners had no significant differences in age, gender, or the ADCS-ADL, NPS, and CDR-SOB scores, while MMSE was lower in pet owners than non-pet owners (20.2 versus 21.7; p = 0.009). Over the follow-up, pet owners had significantly better mean ADCS-ADL (57.5 versus 54.0; p = 0.031), NPI (9.3 versus 13.0; p = 0.038), and CDR-SOB scores (5.7 versus 6.6; p = 0.004) compared to non-pet owners. The differences in the MMSE scores between the groups detected at baseline attenuated over time.

CONCLUSION

Significant positive effects of the pets on ADL functions, NPS, and disease progression were detected over the whole follow-up suggesting that having a pet may support daily activity and slow the disease progression in AD.

The CERAD Neuropsychological Battery in Patients with Idiopathic Normal Pressure Hydrocephalus Compared with Normal Population and Patients with Mild Alzheimer's Disease

BACKGROUND

The usefulness of CERAD Neuropsychological Battery for describing the cognitive impairment in idiopathic normal pressure hydrocephalus (iNPH) is unknown.

OBJECTIVE

To compare the cognitive profile of patients with iNPH to patients with mild Alzheimer's disease (AD) and age-matched cognitively healthy individuals by using the CERAD-NB.

METHODS

We studied CERAD-NB subtest results, including the Mini-Mental State Examination (MMSE), between 199 patients with probable iNPH, 236 patients with mild AD, and 309 people with normal cognition, using age, education, and gender adjusted multivariate linear regression model. In addition, the effects of AD-related brain pathology detected in frontal cortical brain biopsies in iNPH patients' cognitive profiles were examined.

RESULTS

The iNPH patients performed worse than cognitively healthy people in all CERAD-NB subtests. Despite similar performances in the MMSE, AD patients outperformed iNPH patients in Verbal Fluency (p = 0.016) and Clock Drawing (p < 0.001) tests. However, iNPH patients outperformed AD patients in the Boston Naming Test and Word List Recall and Recognition (p < 0.001). AD-related pathology in brain biopsies did not correlate with the CERAD-NB results.

CONCLUSION

At the time of the iNPH diagnosis, cognitive performances differed from cognitively healthy people in all CERAD-NB subtests. When the iNPH and AD patients' results were compared, the iNPH patients performed worse in Verbal Fluency and Clock Drawing tests while the AD group had more pronounced episodic memory dysfunctions. This study demonstrates significant differences in the CERAD-NB subtests between cognitive profiles of iNPH and AD patients. These differences are not captured by the MMSE alone.

Biomarker counseling, disclosure of diagnosis and follow-up in patients with mild cognitive impairment: A European Alzheimer's disease consortium survey

OBJECTIVES

Mild cognitive impairment (MCI) is associated with an increased risk of further cognitive decline, partly depending on demographics and biomarker status. The aim of the present study was to survey the clinical practices of physicians in terms of biomarker counseling, management, and follow-up in European expert centers diagnosing patients with MCI.

METHODS

An online email survey was distributed to physicians affiliated with European Alzheimer's disease Consortium centers (Northern Europe: 10 centers; Eastern and Central Europe: 9 centers; and Southern Europe: 15 centers) with questions on attitudes toward biomarkers and biomarker counseling in MCI and dementia. This included postbiomarker counseling and the process of diagnostic disclosure of MCI, as well as treatment and follow-up in MCI.

RESULTS

The response rate for the survey was 80.9% (34 of 42 centers) across 20 countries. A large majority of physicians had access to biomarkers and found them useful. Pre- and postbiomarker counseling varied across centers, as did practices for referral to support groups and advice on preventive strategies. Less than half reported discussing driving and advance care planning with patients with MCI.

CONCLUSIONS

The variability in clinical practices across centers calls for better biomarker counseling and better training to improve communication skills. Future initiatives should address the importance of communicating preventive strategies and advance planning.

Low Serum High-Density Lipoprotein Cholesterol Levels Associate with the C9orf72 Repeat Expansion in Frontotemporal Lobar Degeneration Patients

 Decreased levels of serum high-density lipoprotein (HDL) cholesterol have previously been linked to systemic inflammation and neurodegenerative diseases, such as Alzheimer’s disease. Here, we aimed to analyze the lipoprotein profile and inflammatory indicators, the high-sensitivity C-reactive peptide (hs-CRP) and glycoprotein acetyls (GlycA), in sporadic and C9orf72 repeat expansion-associated frontotemporal lobar degeneration (FTLD) patients. The C9orf72 hexanucleotide repeat expansion is the most frequent genetic etiology underlying FTLD. The concentrations of different lipid measures in the sera of 67 FTLD patients (15 C9orf72 repeat expansion carriers), including GlycA, were analyzed by nuclear magnetic resonance spectroscopy. To verify the state of systemic inflammation, hs-CRP was also quantified from patient sera. We found that the total serum HDL concentration was decreased in C9orf72 repeat expansion carriers when compared to non-carriers. Moreover, decreased concentrations of HDL particles of different sizes and subclass were consistently observed. No differences were detected in the very low- and low-density lipoprotein subclasses between the C9orf72 repeat expansion carriers and non-carriers. Furthermore, hs-CRP and GlycA levels did not differ between the C9orf72 repeat expansion carriers and non-carriers. In conclusion, the HDL-related changes were linked with C9orf72 repeat expansion associated FTLD but were not seen to associate with systemic inflammation. The underlying reason for the HDL changes remains unclear.

Psychometric Properties of the Neuropsychiatric Inventory: A Review

Neuropsychiatric symptoms cause a significant burden to individuals with neurocognitive disorders and their families. Insights into the clinical associations, neurobiology, and treatment of these symptoms depend on informant questionnaires, such as the commonly used Neuropsychiatric Inventory (NPI). As with any scale, the utility of the NPI relies on its psychometric properties, but the NPI faces unique challenges related to its skip-question and scoring formats. In this narrative review, we examined the psychometric properties of the NPI in a framework including properties pertinent to construct validation, and health-related outcome measurement in general. We found that aspects such as test-retest and inter-rater reliability are major strengths of the NPI in addition to its flexible and relatively quick administration. These properties are desired in clinical trials. However, the reported properties appear to cover only some of the generally examined psychometric properties, representing perhaps necessary but insufficient reliability and validity evidence for the NPI. The psychometric data seem to have significant gaps, in part because small sample sizes in the relevant studies have precluded more comprehensive analyses. Regarding construct validity, only one study has examined structural validity with the NPI subquestions. Measurement error was not assessed in the reviewed studies. For future validation, we recommend using data from all subquestions, collecting larger samples, paying specific attention to construct validity and formulating hypotheses a priori. Because the NPI is an outcome measure of interest in clinical trials, examining measurement error could be of practical importance.

Ongoing pain in streptozotocin model of diabetes in the rat: correlation with cutaneous cheminociception

Streptozotocin (STZ) is commonly used to induce diabetes mellitus in experimental animal studies on peripheral diabetic neuropathy (PDN). Animals with STZ model of diabetes commonly develop changes in test stimulus-evoked pain behavior. However, it is still unclear whether rats with STZ model of diabetes have ongoing pain. Here we assessed whether STZ-induced diabetes induces ongoing pain-like behavior in male rats using conditioned place-preference (CPP) paradigm. CPP was tested in the fourth week of diabetes by pairing one chamber of the CPP device with vehicle and another chamber with either pregabalin (an established analgesic; 30 mg/kg i.p.; n = 9) or Chembridge-5861528 (a TRPA1 channel antagonist; 30 mg/kg i.p.; n = 9). After drug-pairings, the animals were allowed to choose which chamber they preferred. Mechanical sensitivity was assessed with monofilaments and chemonociception in the skin by determining mustard oil-induced pain behavior. Diabetic animals developed in two weeks mechanical hypersensitivity that changed into hyposensitivity by the fourth week. Mustard oil-induced sustained pain was reduced by the 4^th week. After 4 weeks of diabetes, neither pregabalin nor the TRPA1 antagonist induced a significant overall change in the median CPP, although both drugs significantly reduced median withdrawal responses evoked by noxious mechanical stimulation. Pregabalin-induced CPP, however, had a significant positive correlation with the sustained pain behaviour induced by topical mustard oil. In conclusion, the present results suggest that the response to topical mustard oil may predict ongoing pain-like behavior in the STZ model of diabetes.

Metabolic Profiles Help Discriminate Mild Cognitive Impairment from Dementia Stage in Alzheimer's Disease

Accurate differentiation between neurodegenerative diseases is developing quickly and has reached an effective level in disease recognition. However, there has been less focus on effectively distinguishing the prodromal state from later dementia stages due to a lack of suitable biomarkers. We utilized the Disease State Index (DSI) machine learning classifier to see how well quantified metabolomics data compares to clinically used cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease (AD). The metabolic profiles were quantified for 498 serum and CSF samples using proton nuclear magnetic resonance spectroscopy. The patient cohorts in this study were dementia (with a clinical AD diagnosis) (N = 359), mild cognitive impairment (MCI) (N = 96), and control patients with subjective memory complaints (N = 43). DSI classification was conducted for MCI (N = 51) and dementia (N = 214) patients with low CSF amyloid-β levels indicating AD pathology and controls without such amyloid pathology (N = 36). We saw that the conventional CSF markers of AD were better at classifying controls from both dementia and MCI patients. However, quantified metabolic subclasses were more effective in classifying MCI from dementia. Our results show the consistent effectiveness of traditional CSF biomarkers in AD diagnostics. However, these markers are relatively ineffective in differentiating between MCI and the dementia stage, where the quantified metabolomics data provided significant benefit.

Relationships between Cognition and Activities of Daily Living in Alzheimer's Disease During a 5-Year Follow-Up: ALSOVA Study

BACKGROUND

Impaired cognition and activities of daily living (ADL) are core symptoms of Alzheimer's disease (AD), but their relationship is unclear.

OBJECTIVES

To explore relationships between cognitive domains and functional ability during 5-year follow-up in persons with AD.

METHODS

We analyzed ALSOVA study data from 236 individuals with very mild or mild AD at baseline. The CERAD Neuropsychological Battery (CERAD-NB) was used as a cognitive measure and Alzheimer's Disease Cooperative Study ADL (ADCS-ADL) as a functional measure, analyzing the IADL and BADL sub-scores separately. Annual regression models and linear mixed-effect models (LMMs) covering a 5-year follow-up period were used.

RESULTS

Annually, the CERAD-NB total and especially Verbal Fluency, Clock Drawing, and Constructional Praxis were associated with the total ADCS-ADL and IADL scores increasingly yet modestly, and to a lesser extent the BADL score. In the LMMs, the same measures and MMSE were associated with ADL.

CONCLUSION

Measures of executive function and visuoconstructive skills appear to be associated with caregiver-interview based ADL measure during the progression of AD.

Subtle Cognitive Impairment and Alzheimer's Disease-Type Pathological Changes in Cerebrospinal Fluid are Common Among Neurologically Healthy Subjects

BACKGROUND

The neuropathology of Alzheimer's disease (AD) has previously been shown to be rather common among the elderly.

OBJECTIVE

The aim of this study was to inspect the associations between cerebrospinal fluid (CSF) AD biomarker concentrations, age, the APOEɛ4 allele, cardiovascular diseases, diabetes, and cognitive performance in a cohort of a neurologically healthy population.

METHODS

This study included 93 subjects (42 men, mean age 67 years) without previous neurological symptoms or subjective cognitive complaints. Their cognition was assessed, and CSF biomarkers and APOEɛ4 status were analyzed.

RESULTS

Of the studied subjects, 8.6% (n = 8) had a pathological CSF AD biomarker profile. An increase in age correlated positively with CSF tau pathology and negatively with global cognitive performance.

CONCLUSION

AD-type pathological changes in CSF and subtle cognitive impairment are common within a population with no previous memory complaints. Age was the main risk factor for the changes.

Low Prevalence of Cancer in Patients with Frontotemporal Lobar Degeneration

Several studies have reported reduced risk of cancer in patients with Alzheimer's disease (AD) or Parkinson's disease. The relationship between cancer and frontotemporal lobar degeneration (FTLD) has not been previously reported. Here, our aim was to evaluate the occurrence of cancer in Finnish FTLD patients with a high proportion of C9ORF72 repeat expansion carriers in comparison to age- and sex-matched group of AD patients and control subjects classified as not cognitively impaired (NCI). The prevalence of cancer was 9.7% in FTLD, 18.7% in AD, and 17.4% in NCI (FTLD versus AD p = 0.012, FTLD versus NCI p = 0.029) groups. No differences were observed between C9ORF72 repeat expansion carriers and non-carriers inside the FTLD group. To our knowledge, this is the first study showing significantly lower prevalence of cancer in FTLD patients compared to patients with AD or NCI subjects. Our data suggest an inverse association between neurodegeneration and cancer and that FTLD-specific mechanisms may underlie the especially strong inverse association observed in this study.

Pronociceptive effects induced by cutaneous application of a transient receptor potential ankyrin 1 (TRPA1) channel agonist methylglyoxal in diabetic animals: comparison with tunicamycin-induced endoplastic reticulum stress

Methylglyoxal (MG) is a reactive carbonyl compound generated in diabetes mellitus. MG is an established transient receptor potential ankyrin 1 (TRPA1) channel agonist that contributes to TRPA1-mediated diabetic pain hypersensitivity. Here we studied whether exposure to diabetes and thereby to elevated endogenous MG modulates hypersensitivity induced by intradermal MG. Moreover, since diabetes induces endoplasmic reticulum (ER) stress, we compared the role of TRPA1 in diabetes and ER stress by assessing whether tunicamycin-induced ER stress, without diabetes, produces TRPA1-mediated pain hypersensitivity and by assessing whether ER stress and diabetes have similar modulatory effects on MG-induced hypersensitivity. In vitro patch clamp recording was performed to assess whether tunicamycin is a TRPA1 agonist. Behavioral tests showed that mechanical hypersensitivity induced by MG is reduced in diabetes and ER stress. In healthy controls, hypersensitivity induced by MG was reduced when MG was administered for the second time in the same but not adjacent plantar sites. Hypersensitivity induced by ER stress was reversed by pharmacological blocking of TRPA1. In vitro patch clamp recording indicated that tunicamycin itself (30 μM) is not a TRPA1 agonist. The results indicate that pain hypersensitivity induced by non-diabetic ER stress as well as that induced by diabetes is mediated TRPA1. Reduction of MG-induced hypersensitivity in diabetes or ER stress may, at least partly, be explained by peripheral mechanisms.

Contact sensitizer 2,4-dinitrochlorobenzene is a highly potent human TRPA1 agonist

2,4-Dinitrochlorobenzene (DNCB) is widely used in human clinical studies and in experimental animal studies to evoke allergic contact dermatitis. 2,4-Dinitrochlorobenzene is a potent immunogen capable of inducing contact sensitization in all humans exposed. However, the mechanism by which DNCB evokes such symptoms is presently unknown. TRPA1 is a nonselective cation channel that is expressed in peptidergic sensory neurons and fibroblasts. TRPA1 activation was recently implicated in the pathophysiology of atopic dermatitis especially in transducing cutaneous itch signals. Here, we test the hypothesis that DNCB acts as a TRPA1 agonist and thereby evokes allergic symptoms. We found that DNCB activates human TRPA1 dose dependently in FLIPR experiments with an EC50 of 167 nM, an effect that was fully blocked by selective TRPA1 antagonists Chembridge-5861528 and A-967079. Similarly, DNCB activated nonselective TRPA1 current in patch clamp studies. Neutralization of 3 critical cysteines in TRPA1 resulted in a loss of DNCB agonism.

Prospective flutemetamol positron emission tomography and histopathology in normal pressure hydrocephalus

BACKGOUND/OBJECTIVE: To determine the level of association between uptake of the amyloid positron emission tomography (PET) imaging agent [(18)F]flutemetamol and the level of amyloid-β measured by immunohistochemical and histochemical staining in a frontal cortical region biopsy site.

METHODS

Seventeen patients with probable normal pressure hydrocephalus (NPH) underwent prospective [(18)F]flutemetamol PET and subsequent frontal cortical brain biopsy during ventriculoperitoneal shunting. Tissue amyloid-β was evaluated using the monoclonal antibody 4G8, thioflavin S and Bielschowsky silver stain.

RESULTS

Four of the 17 patients (23.5%) had amyloid-β pathology based on the overall pathology read and also showed increased [(18)F]flutemetamol uptake. [(18)F]Flutemetamol standardized uptake values from the biopsy site were significantly associated with biopsy specimen amyloid-β levels (Pearson's r = 0.67; p = 0.006). There was also good correlation between the biopsy specimen amyloid-β level and uptake of [(18)F]flutemetamol in the region contralateral to the biopsy site (r = 0.67; p = 0.006), as well as with composite cortical [(18)F]flutemetamol uptake (r = 0.65; p = 0.008). The blinded visual read showed a high level of agreement between all readers (κ = 0.88). Two of 3 readers were in full agreement on all images; 1 reader disagreed on 1 of the 17 NPH cases. Blinded visual assessments of PET images by 1 reader were associated with 100% sensitivity to the overall pathology read, and assessments by the 2 others were associated with 75% sensitivity (overall sensitivity by majority read was 75%); specificity of all readers was 100%.

CONCLUSIONS

[(18)F]Flutemetamol detects brain amyloid-β in vivo and shows promise as a valuable tool to study and possibly facilitate diagnosis of Alzheimer's disease both in patients with suspected NPH and among the wider population.

Human inducible pluripotent stem cell-derived sensory neurons express multiple functional ion channels and GPCRs

Aims

Aim of the study was to characterize functional ion channel and GPCR responses by using selective pharmacological tools and intracellular calcium imaging from human inducible pluripotent stem cell-derived sensory neurons.

Methods

Sensory neurons were generated from human keratinocytes that were reprogrammed to inducible pluripotent stem cells by using standard Yamanaka factors. Inducible pluripotent stem cells were differentiated into sensory neurons by using 2 differentiation protocols (small molecule and PA6 co-culture). Sensory neurons were loaded with intracellular calcium dye Fluo-4. Single-cell calcium imaging was performed with Photometrics Evolve EM-CCD camera at physiological temperature. Cells were perfused with a Ringer solution at 2–3 ml/min into which pharmacological compounds were dissolved. Data was analyzed with Till Photonics Offline Analysis program.

Results

Most of the results were obtained from PA6 differentiated neurons. 50 s application of 50 mM KCl solution was used as diagnostic tool to activate voltage-gated calcium channels and thereby evoke intracellular calcium elevation. Functional ASIC, NMDA, kainate and TRPA1 ion channels were present in a subset of sensory neurons. Majority of sensory neurons showed robust responses to purinergic stimulation with ATP and histaminergic stimulation with histamine, but not to subtype selective histamine H1, H2 or H4 stimulation suggesting the presence of H3 receptor subtype All cells responded strongly to protease-activated receptor stimulation with a low dose of trypsin. Interestingly, at single-cell level notable heterogeneity of ion channel and GPCR responses was observed.

Conclusions

Our results suggest that iPS-derived sensory neurons will be valuable in further pharmacological studies as well as sensory neuropathy disease modeling.

Spinal transient receptor potential ankyrin 1 channel induces mechanical hypersensitivity, increases cutaneous blood flow, and mediates the pronociceptive action of dynorphin A

We characterized pain behavior and cutaneous blood flow response induced by activation of the spinal transient receptor potential ankyrin 1 (TRPA1) channel using intrathecal drug administrations in the rat. Additionally, we assessed whether the pronociceptive actions induced by intrathecally administered dynorphin A, cholecystokinin or prostaglandin F(2α) are mediated by the spinal TRPA1 channel. Cinnamaldehyde, a TRPA1 agonist, produced a dose-related (3-10 μg) cutaneous blood flow increase and mechanical hypersensitivity effect. These effects at the currently used doses were of short duration and attenuated, although not completely, by pretreatment with A-967079, a TRPA1 antagonist. The cinnamaldehyde-induced hypersensitivity was also reduced by pretreatment with minocycline (an inhibitor of microglial activation), but not by carbenoxolone (a gap junction decoupler). In vitro study, however, indicated that minocycline only poorly blocks the TRPA1 channel. The mechanical hypersensitivity effect induced by dynorphin A, but not that by cholecystokinin or prostaglandin F(2α), was attenuated by a TRPA1 antagonist Chembridge-5861528 as well as A-967079. The cinnamaldehyde-induced cutaneous blood flow increase was not suppressed by MK-801, an NMDA receptor antagonist, or bicuculline, a GABA(A) receptor antagonist. The results indicate that spinal TRPA1 channels promote mechanical pain hypersensitivity and due to antidromic activation of nociceptive nerve fibers increase cutaneous blood flow. The attenuation of the cinnamaldehyde-induced hypersensitivity effect by minocycline may be explained by action other than block of the TRPA1 channel. Moreover, the spinal TRPA1 channel is involved in mediating the pronociceptive action of dynorphin A, but not that of the spinal cholecystokinin or prostaglandin F(2α).

Sustained TRPA1 activation in vivo

Transient receptor potential A1 (TRPA1) is a calcium permeable non-selective cation channel that is selectively localized to peptidergic C-fibres in the pain pathway. TRPA1 is highly conserved across the animal kingdom and it is able to detect a wide range of potentially toxic environmental chemicals. An unusual mechanism of TRPA1 activation was recently elucidated in which reactive agonists bind covalently to cysteines and lysine in the intracellular N-terminus. Despite a covalent activation mechanism, only transient TRPA1 activation is seen in the maintained presence of reactive agonists in whole-cell patch clamp experiments. I suggest that previous patch clamp studies are performed under conditions that do not fully mimic all aspects of TRPA1 activation. Here, I argue that compelling evidence exists for sustained TRPA1 activation in several chronic (neuropathic) pain-related pathophysiological conditions in vivo. I discuss briefly putative mechanisms that are likely to contribute to and maintain sustained TRPA1 agonist levels through increased production and/or decreased metabolism and inactivation. Chronic pain can be understood as a false alarm evoked by sustained and increased levels of endogenous TRPA1 agonists in various pathophysiological conditions.

Decreased brain creatine levels in elderly apolipoprotein E epsilon 4 carriers

Apolipoprotein E (ApoE) genotype has been shown to influence results in neuroimaging studies using a number of various imaging modalities. No in vivo data exists on whether or not there are ApoE-related changes observable by proton magnetic resonance spectroscopy (MRS). In this study we measured absolute peak areas of proton MR spectra obtained from the occipital cortex in 22 non-demented elderly with (n = 8) or without (n = 14) the ApoE epsilon4 allele. No statistically significant differences were found in levels of N-acetyl aspartate, myo-inositol, or choline containing compounds between the groups. Instead, compared with the non-carriers, the levels of creatine were significantly lower in the epsilon4 carriers, suggesting increased metabolic demands in the brain of the epsilon4 carriers. The levels of creatine also correlated significantly with age and performance on the Mini-Mental State Examination test in the epsilon4 carriers, but not in the non-carriers. These findings may be of significant clinical interest as potential indicator of incipient AD, and also from therapeutical point of view given the potential neuroprotective effects of creatine.

Norepinephrine-induced sustained inward current in brown fat cells: alpha(1)-mediated by nonselective cation channels

The nature of the sustained norepinephrine-induced depolarization in brown fat cells was examined by patch-clamp techniques. Norepinephrine (NE) stimulation led to a whole cell current response consisting of two phases: a first inward current, lasting for only 1 min, and a sustained inward current, lasting as long as the adrenergic stimulation was maintained. The nature of the sustained current was here investigated. It could be induced by the alpha(1)-agonist cirazoline but not by the beta(3)-agonist CGP-12177A. Reduction of extracellular Cl(-) concentration had no effect, but omission of extracellular Ca(2+) or Na(+) totally eliminated it. When unstimulated cells were studied in the cell-attached mode, some activity of approximately 30 pS nonselective cation channels was observed. NE perfusion led to a 10-fold increase in their open probability (from approximately 0.002 to approximately 0.017), which persisted as long as the perfusion was maintained. The activation was much stronger with the alpha(1)-agonist phenylephrine than with the beta(3)-agonist CGP-12177A, and with the Ca(2+) ionophore A-23187 than with the adenylyl cyclase activator forskolin. We conclude that the sustained inward current was due to activation of approximately 30 pS nonselective cation channels via alpha(1)-adrenergic receptors and that the effect may be mediated via an increase in intracellular free Ca(2+) concentration.

Attitudes towards neuroleptic treatment: reliability and validity of the attitudes towards neuroleptic treatment (ANT) questionnaire

Non-compliance problems may rise to 50% among patients undergoing neuroleptic treatment. There are no direct measures available to predict compliance, if previous non-compliance is not taken into account. Attitudes towards neuroleptic treatment and insight into psychotic symptoms may vary during the course of the treatment process. It would be relevant to evaluate these items before taking any clinical action and later reassess the degree of change. The instrument thus far available has been the Drug Attitude Inventory. It has limitations for use with first-episode-patients and their follow-up. Its statements are dichotomous, which makes it difficult to determine the variation of attitudes e.g. during maintenance treatment, and most of the items concentrate on the subjective state of the patient, leaving attitudes as a minority in the scale. In this study, we report the new Attitudes towards Neuroleptic Treatment (ANT) questionnaire for the quantitative assessment of attitudes. We developed 10 statements for attitudes and two items for insight in the Visual Analogue Scale form (0-100 points). These were compared with the Drug Attitude Inventory 10 Questionnaire (DAI-10) (Hogan, T. P., Awad, A.G., Eastwood, R., 1983. A self-report scale predictive of drug compliance in schizophrenics: reliability and discriminative validity. Psychol. Med. 13, 177-183.) among 106 subjects receiving neuroleptic medication. The 12 Visual Analogue Scales showed a high inter-item consistency and fair test-retest validity. The results were in accordance with the DAI-10. The scales comprised three factors: general attitudes, subjective feeling and expectations and insight. Attitudes towards neuroleptic treatment and insight into psychotic symptoms are different dimensions and can be measured quantitatively. The Attitudes towards Neuroleptic Treatment scale is useful in assessing the state of attitudes before starting medication and for follow-up among patients receiving neuroleptic medication.

Regulation of the activity of 27 pS nonselective cation channels in excised membrane patches from rat brown-fat cells

The regulation of the activity of the approximately 30 pS nonselective cation channel (NSC channel) was studied by the patch-clamp technique in inside-out patches obtained from rat brown-fat cells. NSC channel activity was induced by excision; reduced redox state induced by dithiothreitol accelerated the kinetics in the excised state. The NSC channels were inhibited by the fenamates flufenamic acid and mefenamic acid but not by NS-1619 or SKF-96365. The channels were inhibited by purine nucleotides but not by polyamines. No evidence for protein kinase C, CaM kinase or protein kinase A activation of the NSC channel was obtained. NSC-channel activity was stimulated in a concentration-dependent manner by Ca2+ but the EC50 was very high (0.81 mM), in comparison to expected cytosolic Ca2+ levels. In the presence of ATP, even higher Ca2+ levels were necessary for comparable NSC-channel activation. The increase in Po was not associated with an increase in open-time constants. We conclude that although high Ca2+ levels can experimentally activate the NSC channel, a further mediatory step must probably be postulated in order to link alpha1-adrenergic stimulation to NSC-channel activation.

Stereospecific modulation of GABA(A) receptor function by urocanic acid isomers

A deamination product of histidine, urocanic acid, accumulates in the skin of mammals as trans-urocanic acid. Ultraviolet (UV) irradition converts it to the cis-isomer that is an important mediator in UV-induced immunosuppression. We have recently shown that urocanic acid interferes with the agonist binding to GABA(A) receptors. We now report that the effects of urocanic acid on binding of a convulsant ligand (t-butylbicyclo[35S]phosphorothionate) to GABA(A) receptors in brain membrane homogenates are dependent on pH of the incubation medium, the agonistic actions being enhanced at the normal pH of the skin (5.5). Using Xenopus laevis oocytes expressing recombinant rat alpha1beta1gamma2S GABA(A) receptors, the low pH potentiated the direct agonistic action of trans-urocanic acid under two-electrode voltage-clamp, whereas cis-urocanic acid retained its low efficacy both at pH 5.5 and 7.4. The results thus indicate clear differences between urocanic acid isomers in functional activity at one putative receptor site of immunosuppression, the GABA(A) receptor, the presence of which in the skin remains to be demonstrated.

Mass spectrometric (HPLC/ESI--MS/MS) quantification of pyrimido[1,3-a]purin-10(3H)-one, a guanine adduct formed by reaction of malondialdehyde with DNA

A high performance liquid chromatography/electrospray ionization tandem mass spectrometric (HPLC/ESI MS/MS) method has been developed for quantification of pyrimido[1,2-a]purin-10(3H)-one adducts from DNA. The method is based on acid-catalyzed cleavage of the adducts from DNA and the use of [2,3a,10-13C3]pyrimido[1,2-a]purin-10(3H)-one as an internal standard in the analysis. For this purpose the latter compound was prepared. Rate constants for the acid-catalyzed cleavage of pyrimido[1,2-a]purin-10(3H)-one from the corresponding 2'-deoxyribonucleoside were determined, and its hydrolytic stability and possible formation by a cross reaction between guanine and [2,3a,10]pyrimido[1,2-a]purin-10(3H)-one were studied.

Oxygen-dependent inhibition of respiration in isolated renal tubules by nitric oxide

BACKGROUND

The partial pressure (tension) of oxygen (PO2) in the kidney medulla has been established to be lower than that of the cortex. The kidney medulla has been shown to be particularly sensitive to hypoxia. However, the measured PO2 in the kidney medulla is sufficient to support maximal respiration. It has been recently shown that endogenously produced nitric oxide (NO) may inhibit oxygen consumption in the kidney. We studied whether NO plays a role in hypersensitivity of the kidney medulla to hypoxia.

METHODS

We studied the effect of added NO on isolated cortical and outer medullary renal tubules in simultaneous oxygen consumption and NO measurements at different oxygen concentrations.

RESULTS

We found that NO could potently and reversibly inhibit respiration at nanomolar concentrations. The inhibitory effect of NO was markedly increased at low physiological oxygen concentrations. The effect of NO was cGMP independent because the selective guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) at a 10 microM concentration had no effect on basal or NO-inhibited respiration. The value for half-maximal NO-mediated inhibition of respiration was virtually identical to that found in isolated mitochondria, and therefore, NO was most likely directly acting on mitochondria. Interestingly, we found no differences in sensitivity to NO-mediated inhibition between outer medullary and cortical tubules.

CONCLUSIONS

We suggest that because of its low PO2, the renal outer medulla is more sensitive to hypoxia, not because of the low PO2 as such, but probably because of the competition between NO and oxygen to control respiration.

Butyrylcholinesterase K variant and apolipoprotein E4 genes do not act in synergy in Finnish late-onset Alzheimer's disease patients

Examination of the allelic frequency of the butyrylcholinesterase K (BChE-K) variant gene revealed no increase among Finnish late-onset Alzheimer's disease (AD) patients either as a whole or among a subset of AD patients carrying the epsilon4 allele of apolipoprotein E (ApoE4). In contrast, BChE-K allele frequency was significantly reduced in the Finnish AD patient group under 75 years of age carrying the ApoE4 allele when compared to the non-demented controls (chi2, P < 0.05). The proportion of subjects with both BChE-K and ApoE4 alleles was 14% and 41% in AD and control groups, respectively (chi2, P < 0.01; odds-ratio 0.22, 95% CI 0.07-0.71). These results are in contrast to a previous study on English AD patients, in which the genes for BChE-K and ApoE4 were suggested to act in synergy.

Kinetics of the inhibition of mitochondrial respiration by NO

The kinetics of the inhibition of mitochondrial respiration by NO was examined in isolated mitochondria (here obtained from rat brown adipose tissue). The Ki of NO for the inhibition was approximately 27 nM; the IC50 of NO increased in proportion to the square of an increase in O2 tension. The Km of O2 for respiration was approximately 16 microM; in the presence of NO, the dependence of respiration on O2 tension had a Hill coefficient of approximately 2. The unusual kinetics is probably related to the ability of cytochrome c oxidase to use 2 NO or 1 O2 as electron acceptor. The interaction between NO and O2 in the control of respiration could be described by the formula VO2(O2, NO) = VO2max x ([O2]2/((16 microM x (1 + [NO]/27 nM))2 + [O2]2)). Thus, the kinetics is such that respiration in the presence of physiological levels of NO is very sensitive to decreasing O2 tension.

Modulation of calcium-activated non-selective cation channel activity by nitric oxide in rat brown adipose tissue

1. Single-channel calcium-activated non-selective cation currents from isolated rat brown fat cells were measured using the inside-out patch configuration of the patch-clamp technique. The existence of a possible modulatory effect of nitric oxide on the putative redox-modulatory site located on the intracellular side of the non-selective cation channel was investigated. 2. The nitric oxide-releasing substances nitroglycerin, sodium nitroprusside, S-nitrosocysteine and S-nitroso-N-acetyl-D,L-penicillamine (all at 100 microM) were able to block channel activity almost completely. 3. In each case the blockade was persistent and could not be washed away. Dithiothreitol (DTT, 2 mM) was able to reverse the blockade to a large extent, whereas oxidized DTT (2 mM) was without effect. 4. It was concluded that nitric oxide can modulate non-selective cation channel activity by oxidizing sulfhydryl groups and that this effect can be reversed by reduction.

Reversible blockade of the calcium-activated nonselective cation channel in brown fat cells by the sulfhydryl reagents mercury and thimerosal

We have used patch-clamp techniques to study the effect of the sulfhydryl group oxidizing agents mercury and thimerosal on calcium-activated nonselective cation channels from brown adipose tissue. 100 nmol/l mercury and 50 mumol/l thimerosal induced a complete block. Blockade could be reversed by reduction of the mercaptide by dithiotreitol (DTT). Mercury was found to be the most potent blocker (IC50-value 21 x 10(-9) mol/l), whereas thimerosal (IC50-value 1.5 x 10(-6) mol/l) was as effective as 3',5-dichlorodiphenylamine-2-carboxylic acid (DCDPC). The DCDPC effect, however, could not be reversed by DTT, indicating different blocking mechanisms. It is concluded that SH-groups are involved in gating of the calcium-activated nonselective channel.