Type 1 hyperlipoproteinemia due to a novel deletion of exons 3 and 4 in the GPIHBP1 gene

Objectives

Type 1 hyperlipoproteinemia is an autosomal recessive disorder characterized by severely elevated plasma triglyceride levels, which may lead to abdominal pain and pancreatitis, eruptive xanthomas and failure to thrive. Mutations in the genes encoding lipoprotein lipase (LPL), apolipoprotein CII (APOC2), apolipoprotein AV (APOA5), lipase maturing factor 1 (LMF1) or glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1 (GPIHBP1) have been found to cause Type 1 hyperlipoproteinemia.

Methods

Two sibpairs belonging to two different branches of an extended pedigree were referred for molecular elucidation for their increased plasma triglyceride levels, which untreated were >27 mmol/L. The genes LPL, APOC2, APOA5, LMF1 and GPIHBP1 were analyzed by DNA sequencing.

Results

No mutations were found in LPL, APOC2, APOA5 or LMF1. No PCR products were obtained for exons 3 and 4 of GPIHBP1 from DNA of the 4 affected subjects. Subsequent long-range PCR revealed that the four affected were homozygous for a deletion comprising exons 3 and 4 of GPIHBP1. No increase in LPL activity was found in post-heparin plasma from the subjects.

Conclusion

Homozygosity for a deletion of exons 3 and 4 of GPIHBP1 results in Type 1 hyperlipoproteinemia.     

Increasing use of anticoagulants in Germany and its impact on hospitalization rates for genitourinary bleeding

Journal of Thrombosis and Thrombolysis - The aim of the study was to compare nationwide time trends of prescribed oral anticoagulants (OAC) with the time trend of genitourinary bleedings (GUB) in...     

What is microglia neurotoxicity (Not)?

Microglia most likely appeared early in evolution as they are not only present in vertebrates, but are also found in nervous systems of various nonvertebrate organisms. Mammalian microglia are derived from a specific embryonic, self‐renewable myeloid cell population that is throughout lifetime not replaced by peripheral myeloid cells. These phylogenic and ontogenic features suggest that microglia serve vital functions. Yet, microglia often are described as neurotoxic cells, that actively kill (healthy) neurons. Since it is from an evolutionary point of view difficult to understand why an important and vulnerable organ like the brain should host numerous potential killers, we here review the concept of microglia neurotoxicity. On one hand it is discussed that most of our understanding about how microglia kill neurons is based on in vitro experiments or correlative staining studies that suffer from the difficulty to discriminate microglia and peripheral myeloid cells in the diseased brain. On the other hand it is described that a more functional approach by mutating, inactivating or deleting microglia is seldom associated with a beneficial outcome in an acute injury situation, suggesting that microglia are normally important protective elements in the brain. This might change in chronic disease or the aged brain, where; however, it remains to be established whether microglia simply lose their protective capacities or whether microglia become truly neurotoxic cells. GLIA 2014;62:841–854     

Prevalence of depression among memory clinic patients as measured by the Cornell Scale of Depression in Dementia

Objectives: Depression in dementia is common, but the prevalence rates differ according to the populations studied and which diagnostic tools are being used. The aim of this study is to explore the prevalence of depression among patients referred to a memory clinic or an outpatient clinic as measured by the Cornell Scale of Depression in dementia (CSDD) and to investigate which factors are associated with depression.

Method: The CSDD was completed for 1470 patients on their first visit to a memory clinic or an outpatient clinic. The prevalence of depression using three different cut-off points was calculated. Logistic regression and correlation analyses were performed.

Results: Half of the patients had dementia. The mean CSDD was 6.7 (SD: 5.3) for the whole group, and 50.2% had a score above 5, whereas 37.5% had depression defined as a CSDD score above 7, and 14.1% had a score above 12. The mean scores were higher among those with dementia other than Alzheimer's disease, those with previous depression, and those with greater impairment in the activities of daily living (ADL). In the logistic regression analyses, younger age, ADL dysfunction, and previous depression were significantly associated with higher CSDD scores.

Conclusion: We found that depressive symptoms are common among patients referred for a dementia assessment in specialist health care. The strongest factors associated with depressive symptoms were younger age, ADL impairment, and previous depression.     

Migration of murine intestinal dendritic cell subsets upon intrinsic and extrinsic TLR3 stimulation

Initiation of adaptive immunity to particulate antigens in lymph nodes largely depends on their presentation by migratory dendritic cells (DCs). DC subsets differ in their capacity to induce specific types of immunity, allowing subset-specific DC-targeting to influence vaccination and therapy outcomes. Faithful drug design, however, requires exact understanding of subset-specific versus global activation mechanisms. cDC1, the subset of DCs that excel in supporting immunity toward viruses, intracellular bacteria, and tumors, express uniquely high levels of the pattern recognition receptor TLR3. Using various murine genetic models, we show here that both, the cDC1 and cDC2 subsets of cDCs are activated and migrate equally well in response to TLR3 stimulation in a cell extrinsic and TNF-α dependent manner, but that cDC1 show a unique requirement for type I interferon signaling. Our findings reveal common and differing pathways regulating DC subset migration, offering important insights for the design of DC-based vaccination and therapy approaches.     

The neuroprotective role of microglial cells against amyloid beta‐mediated toxicity in organotypic hippocampal slice cultures

During Alzheimer’s disease (AD) progression, microglial cells play complex roles and have potentially detrimental as well as beneficial effects. The use of appropriate model systems is essential for characterizing and understanding the roles of microglia in AD pathology. Here, we used organotypic hippocampal slice cultures (OHSCs) to investigate the impact of microglia on amyloid beta (Aβ)‐mediated toxicity. Neurons in OHSCs containing microglia were not vulnerable to cell death after 7 days of repeated treatment with Aβ_1‐42 oligomer‐enriched preparations. However, when clodronate was used to remove microglia, treatment with Aβ_1‐42 resulted in significant neuronal death. Further investigations indicated signs of endoplasmic reticulum stress and caspase activation after Aβ_1‐42 challenge only when microglia were absent. Interestingly, microglia provided protection without displaying any classic signs of activation, such as an amoeboid morphology or the release of pro‐inflammatory mediators (e.g., IL‐6, TNF‐α, NO). Furthermore, depleting microglia or inhibiting microglial uptake mechanisms resulted in significant more Aβ deposition compared to that observed in OHSCs containing functional microglia, suggesting that microglia efficiently cleared Aβ. Because inhibiting microglial uptake increased neuronal cell death, the ability of microglia to engulf Aβ is thought to contribute to its protective properties. Our study argues for a beneficial role of functional ramified microglia whereby they act against the accumulation of neurotoxic forms of Aβ and support neuronal resilience in an in situ model of AD pathology.