Aberrant agouti-related protein system in the hypothalamus of the anx/anx mouse is associated with activation of microglia

Agouti-related protein (AgRP) is a key orexigenic neuropeptide expressed in the hypothalamic arcuate nucleus and a marker for neurons conveying hormonal signals of hunger to the brain. Mice homozygous for the anorexia (anx) mutation are characterized by decreased food intake, starvation, and death by 3-5 weeks of age. At this stage immunoreactivity for AgRP is increased in cell bodies but decreased in the nerve terminals. We studied when during early postnatal development the aberrant phenotype of the AgRP system becomes apparent in anx/anx mice and possible underlying mechanisms. AgRP and ionized calcium binding adapter molecule (Iba1), a marker for activated microglia, as well as Toll-like receptor 2 (TLR-2), were studied by immunohistochemistry at postnatal days P1, P5, P10, P12, P15 and P21 in anx/anx and wild-type mice. We found that the AgRP system in the anx/anx mouse develops similarly to the wild type until P12, when AgRP fibers in anx/anx mice cease to increase in density in the main projection areas. At P21, AgRP fiber density in anx/anx mice was significantly reduced vs. P15, in certain regions. At P21, many strongly AgRP-positive cell bodies were observed in the anx/anx arcuate nucleus vs. only few and weakly fluorescent ones in the wild type. The decrease in AgRP fiber density in anx/anx mice overlapped with an increase in Iba1 and TLR-2 immunoreactivities. Thus, the aberrant appearance of the AgRP system in the anx/anx mouse in the early postnatal development could involve a microglia-associated process and the innate immune system.     

Plasma YKL-40: a BMI-independent marker of type 2 diabetes

OBJECTIVE—YKL-40 is produced by macrophages, and plasma YKL-40 is elevated in patients with diseases characterized by inflammation. In the present study, YKL-40 was examined in relation to obesity, inflammation, and type 2 diabetes.RESEARCH DESIGN AND METHODS—Plasma YKL-40 and adipose tissue YKL-40 mRNA levels were investigated in 199 subjects who were divided into four groups depending on the presence or absence of type 2 diabetes and obesity. In addition, plasma YKL-40 was examined in healthy subjects during a hyperglycemic clamp, in which the plasma glucose level was kept at 15 mmol/l for 3 h, and during a hyperinsulinemic-euglycemic clamp.RESULTS—Patients with type 2 diabetes had higher plasma YKL-40 (76.7 vs. 45.1 ng/ml, P = 0.0001) but not higher expression in adipose tissue YKL-40 mRNA (1.20 vs. 0.98, P = 0.2) compared with subjects with a normal glucose tolerance. Within the groups with normal glucose tolerance and type 2 diabetes, obesity subgroups showed no difference with respect to either plasma YKL-40 or adipose tissue YKL-40 mRNA levels. Multivariate regression analysis showed that plasma YKL-40 was associated with fasting plasma glucose (β = 0.5, P = 0.0014) and plasma interleukin (IL)-6 (β = 0.2, P = 0.0303). Plasma YKL-40 was not related to parameters of obesity. There were no changes in plasma YKL-40 in healthy subjects during either hyperglycemic or hyperinsulinemic-euglycemic clamps.CONCLUSIONS—Plasma YKL-40 was identified as an obesity-independent marker of type 2 diabetes related to fasting plasma glucose and plasma IL-6 levels.YKL-40 (chitinase-3-like-1 [CHI3L1], human cartilage glycoprotein-39), is a heparin-, chitin-, and collagen-binding lectin produced by immunologically active cells such as macrophages (1) and neutrophils (2). YKL-40 is a member of the mammalian chitinase-like proteins and is a phylogenetically highly conserved serum protein (1,3–5). Other cells shown to produce YKL-40 are vascular smooth muscle and endothelia cells (6–8), arthritic chondrocytes (3), cancer cells (9), and embryonic and fetal cells (10). The exact functions of YKL-40 are unknown. Currently, YKL-40 is known to stimulate growth of fibroblast cells (11), activate the AKT and phosphoinositide-3 kinase signaling pathway, exert antiapoptosis (12), and function in angiogenesis (7) and may take part in the innate immune response (13). High plasma concentrations of YKL-40 are found in patients with diseases characterized by inflammation or increased tissue remodeling or with cancer (1,9).Adipose tissue is recognized as a source of inflammation (14–16). A high BMI is associated with increased levels of proinflammatory cytokines, and obesity is characterized as a state of chronic systemic low-grade inflammation (17). Studies demonstrate an accumulation of activated macrophages and other immune active cells in adipose tissue from obese subjects (17,18) as possible sources of inflammatory cytokines, determining a link between obesity, low-grade inflammation, and insulin resistance, and both obesity and low-grade inflammation have been linked with the development of insulin resistance and type 2 diabetes (19).One previous study (20) has shown an elevation of serum YKL-40 in type 2 diabetes. In the present study, using plasma and adipose tissue biopsy material from 103 healthy control subjects and 96 patients with type 2 diabetes with a wide range of BMI, we studied the possible relationship between plasma YKL-40 and adipose tissue expression of YKL-40 on the one hand and obesity, insulin resistance, and inflammation on the other.We further measured the macrophage marker CD68 in adipose tissue. We hypothesized that macrophages in the adipose tissue might secrete YKL-40 and that plasma YKL-40 would represent macrophage infiltration in adipose tissue and serve as a marker of insulin resistance. In order to obtain further information about the regulation of systemic YKL-40, we examined plasma YKL-40 during hyperglycemic and hyperinsulinemic-euglycemic conditions.     

Clopidogrel therapy--implications for hip fracture surgery

It remains unclear whether it is justifiable to delay hip fracture surgery in patients who are taking clopidogrel therapy-to allow the drug's anti-platelet effect to wear off. In a follow-up of 740 consecutive admissions with hip fracture we describe the extent of blood loss and complications in 17 (2.3%) who were taking clopidogrel. The peri-operative fall in haemoglobin was 1.3g/dl (95% CI: 0.4-2.3g/dl) less in the 10 patients in whom the surgeon's policy was for surgery to be delayed for at least 5 days. However, this group also experienced thromboembolic complications that were potentially attributable to this approach. Clopidogrel therapy does have implications for peri-operative blood loss, but hip fracture is a complex and multifactorial condition. We propose an individualised approach to patients taking this increasingly common drug.     

A new RNA branching activity: the GIR1 ribozyme

The formation of lariat intermediates during the first step of splicing of group II introns and spliceosomal introns is a well-studied fundamental reaction in molecular biology. Apart from this prominent example, there are surprisingly few occurrences of branched nucleotides or even 2',5'-phosphodiester bonds in biology. We recently described a new ribozyme, the GIR1 branching ribozyme, which catalyzes the formation of a tiny lariat that caps an mRNA. This new example together with work on artificial branching ribozymes and deoxyribozymes shows that branching is facile and points to the possibility that branching reactions could be more prevalent than previously recognized.     

Anti-apoptotic signaling and failure of apoptosis in the ischemic rat hippocampus

Several anti-apoptotic proteins are induced in CA1 neurons after transient forebrain ischemia (TFI), but fail to protect the majority of these cells from demise. Correlating cell death morphologies (apoptosis-like and necrosis-like death) with immunohistochemistry (IHC), we investigated whether anti-apoptosis contributes to survival, compromises apoptosis effector functions and/or delays death in CA1 neurons 1-7 days after TFI. As surrogate markers for bioenergetic failure, the IHC of respiratory chain complex (RCC) subunits was investigated. Dentate granule cell (DGC) apoptosis following colchicine injection severed as a reference for classical apoptosis. Heat shock protein 70 (Hsp70), neuronal apoptosis inhibitory protein (NAIP) and manganese superoxide dismutase (MnSOD) were upregulated in the majority of intact CA1 neurons paralleling the occurrence of CA1 neuronal death (days 3-7) as well as in a proportion of apoptosis-(<50%) and necrosis-like (<30%) CA1 neurons. Colchicine did not provoke an anti-apoptotic response in DGC at all. In addition, more than 70% of apoptosis- and necrosis-like CA1 neurons had completely lost their RCC subunits suggesting bioenergetic failure; by contrast, following colchicine injection, 88% of all apoptotic DGC presented RCC subunits. Thus, anti-apoptotic proteins may, in a subset of ischemic CA1 neurons, prevent cell death, while in others, affected by pronounced energy failure, they may cause secondary necrosis.     

Are cancer survivors at an increased risk for divorce? A Danish cohort study

The purpose of this study was to determine the risk for divorce among cancer survivors. We conducted a nationwide, population-based study of 46,303 persons aged 30-60 years in whom selected cancers were diagnosed in 1981-2000 and 221,028 randomly sampled, cancer-free controls. Information on socioeconomic status, demographics and comorbidity was obtained from Danish administrative registries. We analysed the risk for divorce, adjusted for known risk factors, during follow-up and whether the socioeconomic and health status at the time of diagnosis had an impact on the risk for divorce. Except for survivors of cervix cancer, who had an increased risk for divorce, we found that cancer survivors were not at greater risk for divorce than the general population (rate ratios (RR), 1.06; 95% confidence interval (CI), 1.0;1.1 and RR, 0.98; 95% CI, 0.9;1.0 for women and men, respectively). This finding shows that cancer survivors need not have unnecessary fears for their marriage.     

Genes harbouring susceptibility SNPs are differentially expressed in the breast cancer subtypes

Recently, genome-wide association studies of breast cancer revealed single nucleotide polymorphisms (SNPs) in five genes with novel association to susceptibility. While there is little doubt that the novel susceptibility markers produced from such highly powered studies are true, the mechanisms by which they cause the susceptibility remain undetermined. We have looked at the expression levels of the identified genes in tumours and found that they are highly significantly differentially expressed between the five established breast cancer subtypes. Also, a significant association between SNPs in these genes and their expression in tumours was seen as well as a significantly different frequency of the SNPs between the subtypes. This suggests that the observed genes are associated with different breast cancer subtypes, and may exert their effect through their expression in the tumours. Thus, future studies stratifying patients by their molecular subtypes may give much more power to classic case control studies, and genes of no or borderline significance may appear to be high-penetrant for certain subtypes and, therefore, be identifiable.     

Acute psychological reactions in assault victims of non-domestic violence: peritraumatic dissociation, post-traumatic stress disorder, anxiety and depression

The aims of this study were to investigate acute and subacute post-traumatic reactions in victims of physical non-domestic violence. A Norwegian sample of 138 physically assaulted victims was interviewed and a questionnaire was completed. The following areas were examined: the frequency and intensity of acute and subacute psychological reactions such as peritraumatic dissociation (PD), post-traumatic stress disorder (PTSD) and anxiety and depression; the relationship between several psychological reactions; the relationship between psychological reactions and level of physical injury, perceived life threat, and potential of severe physical injury, and the relationship between psychological reactions and socio-demographic variables. The following distress reactions were measured retrospectively: PD, PTSD, and anxiety and depression. Thirty-three per cent of the victims scored as probable PTSD cases according to the Post Traumatic Symptoms Scale 10 (PTSS-10); the corresponding Impact of Event Scale-15 (IES-15) score identified prevalence of 34% respectively. Forty-four per cent scored as cases with probable anxiety and depression, according to the Hopkins Symptom Check List 25 (HSCL-25). Severity of perceived threat predicted higher scores on all measures of psychological reactions. There were no statistically significant differences between acute and subacute groups on PD, PTSS-10, IES-15, IES-22 and HSCL-25 according to measured means (and standard deviations) and occurrence of probable cases and risk level cases. The results showed no connection between severity of physical injury and caseness. The acute psychological impairment that results from assault violence may have a deleterious effect on the mental health of victims.