Plasma proteome profiling identifies changes associated to AD but not to FTD.

BACKGROUND: Frontotemporal dementia (FTD) is caused by frontotemporal lobar degeneration (FTLD), characterized mainly by inclusions of Tau (FTLD-Tau) or TAR DNA binding43 (FTLD-TDP) proteins. Plasma biomarkers are strongly needed for specific diagnosis and potential treatment monitoring of FTD. We aimed to identify specific FTD plasma biomarker profiles discriminating FTD from AD and controls, and between FTD pathological subtypes. In addition, we compared plasma results with results in post-mortem frontal cortex of FTD cases to understand the underlying process. METHODS: Plasma proteins (n = 1303) from pathologically and/or genetically confirmed FTD patients (n = 56; FTLD-Tau n = 16; age = 58.2 ± 6.2; 44% female, FTLD-TDP n = 40; age = 59.8 ± 7.9; 45% female), AD patients (n = 57; age = 65.5 ± 8.0; 39% female), and non-demented controls (n = 148; 61.3 ± 7.9; 41% female) were measured using an aptamer-based proteomic technology (SomaScan). In addition, exploratory analysis in post-mortem frontal brain cortex of FTD (n = 10; FTLD-Tau n = 5; age = 56.2 ± 6.9, 60% female, and FTLD-TDP n = 5; age = 64.0 ± 7.7, 60% female) and non-demented controls (n = 4; age = 61.3 ± 8.1; 75% female) were also performed. Differentially regulated plasma and tissue proteins were identified by global testing adjusting for demographic variables and multiple testing. Logistic lasso regression was used to identify plasma protein panels discriminating FTD from non-demented controls and AD, or FTLD-Tau from FTLD-TDP. Performance of the discriminatory plasma protein panels was based on predictions obtained from bootstrapping with 1000 resampled analysis. RESULTS: Overall plasma protein expression profiles differed between FTD, AD and controls (6 proteins; p = 0.005), but none of the plasma proteins was specifically associated to FTD. The overall tissue protein expression profile differed between FTD and controls (7-proteins; p = 0.003). There was no difference in overall plasma or tissue expression profile between FTD subtypes. Regression analysis revealed a panel of 12-plasma proteins discriminating FTD from AD with high accuracy (AUC: 0.99). No plasma protein panels discriminating FTD from controls or FTD pathological subtypes were identified. CONCLUSIONS: We identified a promising plasma protein panel as a minimally-invasive tool to aid in the differential diagnosis of FTD from AD, which was primarily associated to AD pathophysiology. The lack of plasma profiles specifically associated to FTD or its pathological subtypes might be explained by FTD heterogeneity, calling for FTD studies using large and well-characterize cohorts.

Influence of Induced Blood Pressure Variability on the Assessment of Cerebral Autoregulation in Patients after Cardiac Arrest.

OBJECTIVE: To determine if increasing variability of blood pressure influences determination of cerebral autoregulation. METHODS: A prospective observational study was performed at the ICU of a university hospital in the Netherlands. 13 comatose patients after cardiac arrest underwent baseline and intervention (tilting of bed) measurements. Mean flow velocity (MFV) in the middle cerebral artery and mean arterial pressure (MAP) were measured. Coefficient of variation (CV) was used as a standardized measure of dispersion in the time domain. In the frequency domain, coherence, gain, and phase were calculated in the very low and low frequency bands. RESULTS: The CV of MAP was significantly higher during intervention compared to baseline. On individual level, coherence in the VLF band changed in 5 of 21 measurements from unreliable to reliable and in 6 of 21 measurements from reliable to unreliable. In the LF band 1 of 21 measurements changed from unreliable to reliable and 3 of 21 measurements from reliable to unreliable. Gain in the VLF and LF band was lower during intervention compared to baseline. CONCLUSIONS: For the ICU setting, more attention should be paid to the exact experimental protocol, since changes in experimental settings strongly influence results of estimation of cerebral autoregulation.

[Orthostatic hypotension in elderly patients]. / Orthostatische hypotensie bij de oudere patiënt.

- Orthostatic hypotension is a condition in which there is insufficient recovery of the blood pressure drop which occurs after getting up, which causes a temporary reduction of cerebral perfusion. This increases the risk of falls resulting in injuries.- Orthostatic hypotension is most common in the elderly. The cause is usually multifactorial (including reduced circulating volume, reduced peripheral resistance and limited heart rate increase). Orthostatic hypotension caused by autonomic dysfunction is called neurogenic orthostatic hypotension.- The most important groups of drugs that may elicit orthostatic hypotension are: diuretics (but only if they lead to hypovolaemia), antidepressants (mainly tricyclic antidepressants), sympatholytics (alpha-blockers as well as beta-blockers) and vasodilators (for example, nitrates).- Treatment of the elderly with orthostatic hypotension starts with lifestyle advice (getting up slowly) and possible medication adjustments.

[Treatment of dementia]. / Behandeling van dementie.

- Treatment options for patients with dementia are limited. This article provides an overview of possible interventions, both pharmaceutical and non-pharmaceutical, for Alzheimer's disease, vascular dementia and mixed dementia.- Pharmaceutical treatment options include cholinesterase inhibitors, memantine and experimental medication. Cholinesterase inhibitors are only recommended for Alzheimer's disease and mixed dementia, not for vascular dementia or mild cognitive impairment. There is no proof of effectiveness for the other pharmaceutical options.- Interventions towards cardiovascular risk factors do not slow down cognitive decline.- Evidence is still lacking for other non-pharmaceutical interventions such as memory training and dietary supplements. Physical exercise may have a positive effect on dementia, but research is still ongoing.- Many patients with dementia exhibit behavioural changes such as agitation and depression. We recommend non-pharmaceutical interventions as a first step to lower the burden of this behaviour for both patients and caregivers.

[Dementia: growing disaster or declining epidemic?] / Dementie: groeiende ramp of afnemende epidemie?

- There is currently a lot of uncertainty about the future prevalence of dementia. Not only increasing age, but also educational level and lifestyle of the population appear to play a role.- There is little scientific and societal attention for the great uncertainty around average incidence and prevalence estimates for dementia.- When estimating the prognosis of people with dementia, the average disease course is often used as a basis, while this is not at all representative of the individual course of most patients.- The beneficial findings of recent lifestyle intervention studies ask for more targeted prevention strategies for risk groups. There is no standard preventative strategy which works equally well for everyone.- Given the large influence of dementia-related publications on the expectations of people regarding their ageing, it is important to present measures of dispersion alongside all study results.

Diffusion tensor imaging of the hippocampus predicts the risk of dementia; the RUN DMC study.

INTRODUCTION: Cerebral small vessel disease is one of the most important risk factors for dementia, and has been related to hippocampal atrophy, which is among the first observed changes on conventional MRI in patients with dementia. However, these volumetric changes might be preceded by loss of microstructural integrity of the hippocampus for which conventional MRI is not sensitive enough. Therefore, we investigated the relation between the hippocampal diffusion parameters and the risk of incident dementia, using diffusion tensor imaging, independent of hippocampal volume. METHODS: The RUNDMC study is a prospective study among 503 elderly with small vessel disease, without dementia, with 5 years follow-up in 2012 (99.6% response-rate). Cox regression analysis was performed to calculate hazard ratios for dementia, of fractional anisotropy and mean diffusivity within the hippocampus, adjusted for demographics, hippocampal volume, and white matter. This was repeated in participants without evident hippocampal volume loss, because in these participants the visible damage might not yet have already started, whereas damage might have started on a microstructural level. RESULTS: 43 participants developed dementia (8.6%), resulting in a 5.5-year cumulative risk of 11.1% (95%CI 7.7-14.6). Higher mean diffusivity was associated with an increased 5-year risk of dementia. In the subgroup of participants with the upper half hippocampal volume, higher hippocampal mean diffusivity, more than doubled the 5-year risk of dementia. CONCLUSION: This is the first prospective study showing a relation between a higher baseline hippocampal mean diffusivity and the risk of incident dementia in elderly with small vessel disease at 5-year follow-up, independent of hippocampal volume and white matter volume.

[Desmopressin for nocturia in the old: an inappropriate treatment due to the high risk of side-effects?]. / Desmopressine voor de behandeling van nycturie bij ouderen: ongewenst door hoog risico op bijwerkingen?

Desmopressin, a synthetic analog of the antidiuretic hormone, is used in the treatment of enuresis nocturna in children and increasingly also in adults. Nocturia in the elderly causes sleeping disorders and is associated with a higher risk of falling and increased mortality. Desmopressin leads to a significant decrement of nocturia and consequently, a better sleep quality and is for this reason increasingly prescribed in the old. Desmopressin causes borderline hyponatremia (130-135 mmol/l) in 15% and severe hyponatremia in 5% of all adult users. Factors that predispose to hyponatremia are a higher dose, age > 65 years, a low-normal serum sodium, a high 24-hour urine volume and co-medication (thiazide diuretics, tricyclic antidepressants, serotonin-reuptake-inhibitors, chlorpromazine, carbamazipine, loperamide, Non-Steroidal-Anti-Inflammatory-Drugs). Hyponatremia is associated with headache, nausea, vomiting, dizziness, and can cause somnolence, loss of consciousness and death. We present two cases where initiation of desmopressin led to hyponatremia, requiring hospitalization. In view of the high risk of desmopressin-associated hyponatremia in the older population, alternative treatment strategies for nocturia must be considered first. If desmopressin is prescribed, strict follow-up of serum sodium levels is necessary.

[Life-threatening serotonin syndrome following a single dose of a serotonin reuptake inhibitor during maintenance therapy with a monoamine oxidase inhibitor]. / Levensbedreigend serotoninesyndroom na eenmalige toevoeging van een serotonineheropnameremmer aan een onderhoudsbehandeling met een monoamineoxidaseremmer.

A 72-year-old man presented to the emergency clinic with motor restlessness and diminished consciousness 24 hours after he had mistakenly been given venlafaxine. He was referred from the psychiatric clinic where he was treated with tranylcypromine. Shortly after arrival, a severe serotonin syndrome developed with generalised myoclonic seizures, hyperreflexia, hypertonia, a rapid increase in temperature to 40.9 degrees C, hypertension, tachycardia, respiratory insufficiency, hyperkalaemia and metabolic acidosis. The patient was treated with the sedative propofol and the muscle relaxant rocuronium, followed by intubation and artificial respiration. He was cooled on a cooling mattress. Twenty-four hours later the airway tube could be removed and after 48 hours he was returned to the psychiatric ward in good condition. Tranylcypromine is a monoamine oxidase inhibitor and venlafaxine is a serotonin and noradrenaline reuptake inhibitor. When two serotoninergic agents are combined, the serotonin syndrome may develop, and this may be life-threatening. The treatment of this syndrome with propofol and rocuronium can be given quickly and safely in practically every hospital.

Reproducibility of cerebral blood volume measurements by near infrared spectroscopy in 16 healthy elderly subjects.

Near infrared spectroscopy (NIRS) is a non-invasive method to monitor cerebral haemodynamics. Used either alone or in combination with other non-invasive methods such as transcranial Doppler sonography, this technique is well suited for use in cerebrovascular research in ageing. Reproducibility of NIRS, however, has only been determined in neonates and adults. We applied controlled desaturation (the O(2)-method) to measure the cerebral blood volume (CBV) with NIRS in 16 healthy subjects aged 65 to 88. This method uses deoxygenated haemoglobin (the concentration of which is manipulated by desaturation) as an intravascular tracer for NIRS. We determined repeatability (between tests interval: 2 min), short-term reproducibility (intervals of 20 and 40 min) and long-term reproducibility (interval > 2 weeks). We found a coefficient of variation (CV) of 12.5% for repeatability and a CV of 11.7% for short-term reproducibility. The CV for long-term reproducibility was 15%. We conclude that NIRS can reproducibly measure CBV in subjects aged 65 and older, using the O(2)-method. In this group of healthy subjects, this method was well tolerated.

['Gold standard', not 'golden standard']. / Liever 'goudstandaard' dan 'gouden standaard'.

In medical literature, both 'gold standard' and 'golden standard' are employed to describe a reference test used for comparison with a novel method. The term 'gold standard' in its current sense in medical research was coined by Rudd in 1979, in reference to the monetary gold standard. In the same way that the monetary gold standard allowed for the comparison of different currencies, the medical gold standard allowed for the comparison of different diagnostic tests. Whereas the gold standard was never regarded as infallible, the incorrect term 'golden standard' implies a level of perfection that is unattainable in medical science. Consequently, the correct term should be 'gold standard'.

[Immunodeficiency in adult patients as the first sign of a primary underlying condition]. / Immuundeficiëntie bij een volwassen patiënt als eerste manifestatie van een primaire onderliggende ziekte.

Three male patients, aged 56, 40 and 52 years, presented with recurrent infections and clinically suspected immunodeficiency, which was confirmed by the presence of hypogammaglobulinaemia. In one patient, no obvious underlying disease was identifiable, and primary immunodeficiency syndromes were considered in the differential diagnosis. A thorough diagnostic work-up revealed the presence of non-Hodgkin lymphoma in an iliac crest biopsy specimen. The second patient was found to have a thymoma. In the third patient, the immunodeficiency was the key to the ultimate diagnosis of multiple myeloma, which was still asymptomatic at that stage. Establishing the underlying condition had important therapeutic and prognostic consequences in these patients.