Hyperuricemia and dementia – a case-control study

BACKGROUND There is evidence that uric acid may have antioxidant and neuroprotective effects and might therefore alter the risk for neurodegenerative diseases such as dementia. So far, the relation between serum uric acid (SUA) levels or hyperuricemia and dementia remains elusive. Most studies focused on the disease or SUA levels. Effects of anti-hyperuricemic treatment have not been considered yet. This study investigated the association between hyperuricemia and dementia taking into account anti-hyperuricemic treatment. METHODS We used longitudinal German public health insurance data and analyzed the association between hyperuricemia with and without different treatment options and dementia in a case-control design. Applying logistic regression the analysis was adjusted for several potential confounders including various comorbidities and polypharmacy. RESULTS We identified 27,528 cases and 110,112 matched controls of which 22% had a diagnosis of hyperuricemia or gout and 17% received anti-hyperuricemic drugs. For patients with a diagnosis of hyperuricemia we found a slightly reduced risk for dementia (adjusted odds ratio [OR] 0.94, 95% confidence interval [CI] 0.89 to 0.98). The risk reduction was more pronounced for patients treated with anti-hyperuricemic drugs (adjusted OR 0.89, 95% CI 0.85 to 0.94, for regular treatment). CONCLUSIONS Our results showed a slight reduction for dementia risk in patients with hyperuricemia, both with and without anti-hyperuricemic treatment

Interaction of antidepressant and antipsychotic drugs with the human organic cation transporters hOCT1, hOCT2 and hOCT3

International audienceBesides the three antidepressant-sensitive, Na+- and Cl―dependent monoamine transporters, Na+-independent organic cation transporters (OCTs) are known to transport monoamines. However, little is known about the interactions of psychotropic drugs with human (h) OCTs. In the present study, a series of diverse antidepressant and antipsychotic drugs were examined for their inhibitory potency at hOCT1, hOCT2 and hOCT3 by measuring inhibition of [H-3]-MPP+ uptake into HEK293 cells stably expressing one of the three hOCTs. The inhibitory potencies (IC(50)s) ranged from 1 to 900 mu M. Most of the examined drugs showed highest inhibitory potency at hOCT1 which is very sparsely expressed in the brain and mainly involved in renal and hepatic clearance of cationic drugs. At their upper therapeutic plasma concentrations, several drugs are expected to inhibit by more than 20 % hOCT1 and could thus interfere with the pharmacokinetics of hOCT1-transported drugs in the kidney and liver, namely trimipramine, desipramine and fluoxetine (by about 37 %), levomepromazine and nefazodone (by about 32 %), and clozapine and amitriptyline (by about 22 %). At hOCT2 and hOCT3, which are involved in monoamine homeostasis in the brain, IC(50)s of most psychoactive drugs were in the high micromolar range. At their upper plasma concentrations, only three compounds, bupropion, nefazodone and clozapine, showed potential for inhibition, of about 18 % at hOCT2 (bupropion), about 22 % at hOCT3 (nefazodone) and of approximately 10 % at hOCT2 and hOCT3 (clozapine). Thus, under the assumption of a tenfold accumulation in the brain, bupropion, nefazodone and clozapine may notably inhibit the corresponding hOCTs. It remains to be shown whether such a direct inhibition plays a role in the clinical effects of these three drugs

The Janus-like Association between Proton Pump Inhibitors and Dementia

Early pharmacoepidemiological studies suggested that Proton Pump Inhibitors (PPIs) might increase the risk of Alzheimer’s Disease (AD) and non-AD related dementias. These findings were supported by preclinical studies, specifically stressing the proamyloidogenic and indirect anticholinergic effects of PPIs. However, further large-scale pharmacoepidemiological studies showed inconsistent results on the association between PPIs and dementia. Pharmacodynamically, these findings might be related to the LXR/RXR-mediated amyloid clearance effect and anti-inflammatory action of PPIs. Further aspects that influence PPI effects on AD are related to patient- specific pharmacokinetic and pharmacogenomic characteristics. In conclusion, a personalized (individualized) medicinal approach is necessary to model and predict the potential harmful or beneficial effects of PPIs in AD and non-AD-related dementias in the future

Mutational profiling in the peripheral blood leukocytes of patients with systemic mast cell activation syndrome using next-generation sequencing

Mast cell activation syndrome (MCAS) and systemic mastocytosis (SM) are two clinical systemic mast cell activation disease variants. Few studies to date have investigated the genetic basis of MCAS. The present study had two aims. First, to investigate whether peripheral blood leukocytes from MCAS patients also harbor somatic mutations in genes implicated in SM using next-generation sequencing (NGS) technology and a relatively large MCAS cohort. We also addressed the question, whether some of the previously as somatic reported mutations are indeed germline mutations. Second, to identify germline mutations of relevance to MCAS pathogenesis. Here, mutation frequency in the present MCAS cohort was compared to that in public- and in-house databases in the case of frequent variants, and co-segregation was investigated in multiply affected families in the case of rare variants (allele frequency < 1%). MCAS diagnoses were assigned according to current criteria. Twenty five candidate genes were selected on the basis of published findings for SM. NGS was performed using a 76kbp custom designed Agilent SureSelect Target Enrichment and an Illumina Hiseq2000 2x100bp sequencing run. NGS revealed 67 germline mutations. No somatic mutations were detected. None of the germline mutations showed unequivocal association with MCAS. Failure to detect somatic mutations was probably attributable to the dilution of mutated mast cell DNA in normal leukocyte DNA. The present exploratory association findings suggest that some of the detected germline mutations may be functionally relevant and explain familial aggregation. Independent replication studies are therefore warranted

Familial Occurrence of Systemic Mast Cell Activation Disease

<div><p>Systemic <i>mast cell activation disease</i> (MCAD) comprises disorders characterized by an enhanced release of mast cell mediators accompanied by accumulation of dysfunctional mast cells. Demonstration of familial clustering would be an important step towards defining the genetic contribution to the risk of systemic MCAD. The present study aimed to quantify familial aggregation for MCAD and to investigate the variability of clinical and molecular findings (e.g. somatic mutations in KIT) among affected family members in three selected pedigrees. Our data suggest that systemic MCAD pedigrees include more systemic MCAD cases than would be expected by chance, i.e., compared with the prevalence of MCAD in the general population. The prevalence of MCAD suspected by symptom self-report in first-degree relatives of patients with MCAD amounted to approximately 46%, compared to prevalence in the general German population of about 17% (p<0.0001). In three families with a high familial loading of MCAD, the subtype of MCAD and the severity of mediator-related symptoms varied between family members. In addition, genetic alterations detected in <i>KIT</i> were variable, and included mutations at position 816 of the amino acid sequence. In conclusion, our data provide evidence for common familial occurrence of MCAD. Our findings observed in the three pedigrees together with recent reports in the literature suggest that, in familial cases (i.e., in the majority of MCAD), mutated disease-related operator and/or regulator genes could be responsible for the development of somatic mutations in KIT and other proteins important for the regulation of mast cell activity. Accordingly, the immunohistochemically different subtypes of MCAD (i.e. mast cell activation syndrome and systemic mastocytosis) should be more accurately regarded as varying presentations of a common generic root process of mast cell dysfunction, than as distinct diseases.</p></div

Pedigree of a family with a high familial loading of mast cell activation disease.

<p>Filled symbols indicate family members with either <i>systemic mastocytosis</i> (<i>SM</i>), according to WHO criteria, or <i>mast cell activation syndrome</i> (<i>MCAS</i>); open symbols denote clinically healthy family members. Squares, males; circles, females; symbols with a diagonal line through, deceased. <i>Mild</i>, <i>moderate</i> and <i>severe</i> indicate the clinical intensity of the mast cell activation disease. The arrow indicates the index patient. Bold type: genetic alterations detected in the tyrosine kinase, <i>KIT</i>. GNNK(–/+): ratio of the GNNK(–) over the GNNK(+) isoform (i.e., the amount of PCR amplification product without and with the tetrapeptide sequence glycine-asparagine-asparagine-lysine [GNNK]).</p

Characteristics of index patients, their first-degree relatives, and healthy controls.

<p>Characteristics of index patients, their first-degree relatives, and healthy controls.</p

Cav3 T-Type Voltage-Gated Ca2+ Channels and the Amyloidogenic Environment: Pathophysiology and Implications on Pharmacotherapy and Pharmacovigilance

Voltage-gated Ca2+ channels (VGCCs) were reported to play a crucial role in neurotransmitter release, dendritic resonance phenomena and integration, and the regulation of gene expression. In the septohippocampal system, high- and low-voltage-activated (HVA, LVA) Ca2+ channels were shown to be involved in theta genesis, learning, and memory processes. In particular, HVA Cav2.3 R-type and LVA Cav3 T-type Ca2+ channels are expressed in the medial septum-diagonal band of Broca (MS-DBB), hippocampal interneurons, and pyramidal cells, and ablation of both channels was proven to severely modulate theta activity. Importantly, Cav3 Ca2+ channels contribute to rebound burst firing in septal interneurons. Consequently, functional impairment of T-type Ca2+ channels, e.g., in null mutant mouse models, caused tonic disinhibition of the septohippocampal pathway and subsequent enhancement of hippocampal theta activity. In addition, impairment of GABA A/B receptor transcription, trafficking, and membrane translocation was observed within the septohippocampal system. Given the recent findings that amyloid precursor protein (APP) forms complexes with GABA B receptors (GBRs), it is hypothesized that T-type Ca2+ current reduction, decrease in GABA receptors, and APP destabilization generate complex functional interdependence that can constitute a sophisticated proamyloidogenic environment, which could be of potential relevance in the etiopathogenesis of Alzheimer’s disease (AD). The age-related downregulation of T-type Ca2+ channels in humans goes together with increased Aβ levels that could further inhibit T-type channels and aggravate the proamyloidogenic environment. The mechanistic model presented here sheds new light on recent reports about the potential risks of T-type Ca2+ channel blockers (CCBs) in dementia, as observed upon antiepileptic drug application in the elderly

Odds ratios for the symptoms and findings collected in the questionnaire (independent variables) occurring in first-degree relatives, compared with the healthy control group.

<p>Odds ratios for the symptoms and findings collected in the questionnaire (independent variables) occurring in first-degree relatives, compared with the healthy control group.</p