Blood Glucose Measurement by Infrared Spectroscopy

For the development of an implantable artificial endocrine pancreas, a sensor for blood glucose measurement is needed providing a long-term stability. This goal can be achieved by the application of infrared spectroscopy which, unlike electrochemical sensors, responds directly to the glucose molecule.

An investigation under physiological conditions revealed five glucose absorption bands in the near and middle infrared range. These are 1040, 1085, 1109, 1160 and 1365 cm–1. Only the 1040 cm–1 frequency coincides with none of the other infrared-active blood substances like proteins, lipids and urea. Nevertheless, the other absorption bands too, especially the 1109 cm–1 frequency, can be used for blood glucose measurement, if the superimposed absorptions are compensated. Methods for the compensation have been found. Technically feasible embodiments of an infrared glucose sensor are described.

Bidirectional rescue of extreme genetic predispositions to anxiety: impact of CRH receptor 1 as epigenetic plasticity gene in the amygdala

The continuum of physiological anxiety up to psychopathology is not merely dependent on genes, but is orchestrated by the interplay of genetic predisposition, gene x environment and epigenetic interactions. Accordingly, inborn anxiety is considered a polygenic, multifactorial trait, likely to be shaped by environmentally driven plasticity at the genomic level. We here took advantage of the extreme genetic predisposition of the selectively bred high (HAB) and low anxiety (LAB) mouse model exhibiting high vs low anxiety-related behavior and tested whether and how beneficial (enriched environment) vs detrimental (chronic mild stress) environmental manipulations are capable of rescuing phenotypes from both ends of the anxiety continuum. We provide evidence that (i) even inborn and seemingly rigid behavioral and neuroendocrine phenotypes can bidirectionally be rescued by appropriate environmental stimuli, (ii) corticotropin-releasing hormone receptor 1 (Crhr1), critically involved in trait anxiety, shows bidirectional alterations in its expression in the basolateral amygdala (BLA) upon environmental stimulation, (iii) these alterations are linked to an increased methylation status of its promoter and, finally, (iv) binding of the transcription factor Yin Yang 1 (YY1) to the Crhr1 promoter contributes to its gene expression in a methylation-sensitive manner. Thus, Crhr1 in the BLA is critically involved as plasticity gene in the bidirectional epigenetic rescue of extremes in trait anxiety.

Oxytocin in Brattleboro rats: increased synthesis is contrasted by blunted intrahypothalamic release from supraoptic nucleus neurones

Adult male Brattleboro rats were used to investigate the impact of the congenital absence of vasopressin on the release pattern of oxytocin (OXT) within the hypothalamic supraoptic nucleus (SON) in response to a 10-min forced swimming session and osmotic stimulation. Both immunohistochemical and in situ hybridisation data suggest that vasopressin-deficient animals have more oxytocin-synthesising neurones in the SON than homozygous wild-type controls. Unexpectedly, both forced swimming and peripheral osmotic stimulation resulted in a blunted release profile of oxytocin within the SON of vasopressin-deficient rats compared to controls. A similar intranuclear OXT response to direct osmotic stimulation of the SON by retrodialysis with hypertonic Ringer's solution in both genotypes confirmed the capability of SON neurones to locally release oxytocin in vasopressin-deficient rats, indicating an altered processing of information originating from multisynaptic inputs rather than a deficit in release capacity. Taken together with data obtained in previous studies, the present findings provide evidence suggesting that autocrine and paracrine signalling of magnocellular neurones differs within the paraventricular nucleus and the SON. Thus, significant alterations in intra-SON oxytocin mRNA levels cannot easily be extrapolated to intranuclear release profiles and the local signal intensity of this neuropeptide after physiological stimulation.

Plasma oxytocin and vasopressin do not predict neuropeptide concentrations in human cerebrospinal fluid

The involvement of the neuropeptides oxytocin (OXT) and vasopressin (AVP) in human socio-emotional behaviours is attracting increasing attention. There is ample evidence for elevated plasma levels upon a wide variety of social and emotional stimuli and scenarios, ranging from romantic love via marital distress up to psychopathology, with cause versus consequence being largely unclear. The present study examined whether plasma levels of both OXT and AVP are reflective of central neuropeptide levels, as assumed to impact upon socio-emotional behaviours. Concomitant plasma and cerebrospinal fluid (CSF) samples were taken from 41 non-neurological and nonpsychiatric patients under basal conditions. Although OXT and AVP levels in the CSF exceeded those in plasma, there was no correlation between both compartments, clearly suggesting that plasma OXT and AVP do not predict central neuropeptide concentrations. Thus, the validity of plasma OXT and AVP as potential biomarkers of human behaviour needs further clarification.

Anxiety- rather than depression-like behavior is associated with adult neurogenesis in a female mouse model of higher trait anxiety- and comorbid depression-like behavior

Adult neurogenesis has been implicated in affective disorders and the action of antidepressants (ADs) although the functional significance of this association is still unclear. The use of animal models closely mimicking human comorbid affective and anxiety disorders seen in the majority of patients should provide relevant novel information. Here, we used a unique genetic mouse model displaying higher trait anxiety (HAB) and comorbid depression-like behavior. We demonstrate that HABs have a lower rate of hippocampal neurogenesis and impaired functional integration of newly born neurons as compared with their normal anxiety/depression-like behavior (NAB) controls. In HABs, chronic treatment with the AD fluoxetine alleviated their higher depression-like behavior and protected them from relapse for 3 but not 7 weeks after discontinuation of the treatment without affecting neurogenesis. Similar to what has been observed in depressed patients, fluoxetine treatment induced anxiogenic-like effects during the early treatment phase in NABs along with a reduction in neurogenesis. On the other hand, treatment with AD drugs with a particularly strong anxiolytic component, namely the neurokinin-1-receptor-antagonist L-822 429 or tianeptine, increased the reduced rate of neurogenesis in HABs up to NAB levels. In addition, challenge-induced hypoactivation of dentate gyrus (DG) neurons in HABs was normalized by all three drugs. Overall, these data suggest that AD-like effects in a psychopathological mouse model are commonly associated with modulation of DG hypoactivity but not neurogenesis, suggesting normalization of hippocampal hypoactivity as a neurobiological marker indicating successful remission. Finally, rather than to higher depression-related behavior, neurogenesis seems to be linked to pathological anxiety.

Truncated p110 ERBB2 induces mammary epithelial cell migration, invasion and orthotopic xenograft formation, and is associated with loss of phosphorylated STAT5

Truncated-ERBB2 isoforms (t-ERBB2s), resulting from receptor proteolysis or alternative translation of the ERBB2 mRNA, exist in a subset of human breast tumors. t-ERBB2s lack the receptor extracellular domain targeted by therapeutic anti-ERBB2 antibodies and antibody–drug conjugates, including trastuzumab, trastuzumab-DM1 and pertuzumab. In clinical studies, expression of t-ERBB2 in breast tumors correlates with metastasis as well as trastuzumab resistance. By using a novel immuno-microarray method, we detect a significant t-ERBB2 fraction in 18 of 31 (58%) of immunohistochemistry (IHC)3+ ERBB2+ human tumor specimens, and further show that t-ERBB2 isoforms are phosphorylated in a subset of IHC3+ samples (10 of 31, 32%). We investigated t-ERBB2 biological activity via engineered expression of full-length and truncated ERBB2 isoforms in human mammary epithelial cells (HMECs), including HMEC and MCF10A cells. Expression of p110 t-ERBB2, but not p95m (m=membrane, also 648CTF) or intracellular ERBB2s, significantly enhanced cell migration and invasion in multiple cell types. In addition, only expression of the p110 isoform led to human breast epithelial cell (HMLE) xenograft formation in vivo. Expression of t-ERBB2s did not result in hyperactivation of the phosphoinositide kinase-3/AKT or mitogen-activated protein kinase signaling pathways in these cells; rather, phosphoproteomic array profiling revealed attenuation of phosphorylated signal transducer and activator of transcription 5 (STAT5) in p110-t-ERBB2-expressing cells compared to controls. Short hairpin-mediated silencing of STAT5 phenocopied p110-t-ERBB2-driven cell migration and invasion, while expression of constitutively active STAT5 reversed these effects. Thus, we provide novel evidence that (1) expression of p110 t-ERBB2 is sufficient for full transformation of HMEC, yielding in vivo xenograft formation, and (2) truncated p110 t-ERBB2 expression is associated with decreased phosphorylation of STAT5.

FINDRISK questionnaire combined with HbA1c testing as a potential screening strategy for undiagnosed diabetes in a healthy population

Despite the efforts to control the epidemic of diabetes the total number of people living with diabetes is still steadily rising. In order to detect people at risk, cost-effective, convenient, and sensitive screening tools to assess the diabetes risk and to detect undiagnosed type 2 diabetes need to be developed and implemented in the primary care setting. To evaluate the combination of the well established FINDRISK questionnaire and HbA1c testing as a potential screening strategy the data obtained from 671 blood donors were analyzed for a potential correlation with the results of an oral glucose tolerance test. Based on the oral glucose tolerance test, 65 blood donors (9.7%) were newly diagnosed with diabetes, 336 (50.1%) with prediabetes, and 270 (40.2%) had a normal test result. Of the 401 blood donors diagnosed with prediabetes or diabetes 322 (80.3%) had a HbA1c between 5.7% and 6.4% and 27 (6.7%) with a HbA1c of 6.5% or greater. The majority of the blood donors newly diagnosed with diabetes or prediabetes (n=327) had a FINDRISK result of 12 points or higher. ROC analyses confirmed that the optimal cut off levels were for FINDRISK ≥ 12 points and for HbA1c ≥ 5.9%. Thus, a 3-step screening strategy applying the FINDRISK questionnaire followed by HbA1c testing and performing an oral glucose tolerance test on selected individuals could be a cost-saving approach for screening large populations and identifying people at risk for diabetes or undiagnosed diabetes.

Genetic predisposition to anxiety-related behavior predicts predator odor response

While rodents have a keen sense of smell and largely depend on olfactory cues for operating in their environment, most of the widely used tests to assess anxiety-related behavior largely ignore the olfactory system, being primarily based on fear of brightly lit, novel and open spaces. Here, we aimed at testing whether the genetic predisposition to anxiety predicts the predator odor response in mice. In the first experiment, using the 3-chamber avoidance test in CD-1 mice, trimethylthiazoline (TMT), a synthetic fox fecal odor, was shown to induce stronger behavioral and neuroendocrine effects than cat odor and butyric acid, respectively, and was therefore chosen as aversive odor for the following series of experiments. In this series, bidirectionally, selectively inbred CD-1 mice with either high (HAB), intermediate (NAB) or low (LAB) anxiety-related behavior responded differently to TMT, with HABs spending significantly less time than both NABs and LABs in the chamber harbouring the predator odor. Importantly, this result is not confounded by any deficit of the olfactory system, as LAB and NAB mice, while not or only moderately responding to TMT, responded to both the pleasant odor of female urine and the repugnant odor of butyric acid. Probably due to the strength of TMT, a similar increase in corticosterone levels upon predator odor exposure was observed in all three groups. Together, the results suggest that, dependent on the genetic predisposition to extremes in anxiety-related behavior, mice differentially interpret the odor of a potential predator, making this type of avoidance behavior highly predictable.

Altered GABA transmission in a mouse model of increased trait anxiety

Anxiety disorders are the most prevalent central nervous system diseases imposing a high social burden to our society. Emotional processing is particularly controlled by GABA-ergic transmission in the amygdala. Using in situ hybridization and immunohistochemistry we now investigated changes in the expression of GABA synthesizing enzymes (GAD65 and GAD67), GABA_A (α1–5, β1–3, γ1–2) and GABA_B receptor subunits (GBBR1, GBBR2) in amygdaloid nuclei of high anxiety-related behavior (HAB) mice in comparison to mice selected for normal anxiety-related behavior (NAB). Levels of GAD65 and GAD67 mRNAs and protein, as well as those of GABA were increased in the amygdala of HAB mice. Relative to NAB controls, mRNA expression of the GABA_A receptor subunits β1, β2 and γ2 was specifically increased in the basolateral amygdala of HAB mice while transcription of α5 and γ1 subunits was reduced in the central and medial amygdala. On the protein level, increases in β2 and γ2 subunit immunoreactivities were evident in the basolateral amygdala of HAB mice. No change in GABA_B receptor expression was observed. These findings point towards an imbalanced GABA-ergic neurotransmission in the amygdala of HAB mice. On the other hand, FosB, a marker for neuronal activity, was increased in principal neurons of the basolateral amygdala in HAB mice, reflecting activation of excitatory neurons, possibly as a consequence of reduced GABA-ergic tonic inhibition through α5 and γ1 containing receptors. Ultimately these mechanisms may lead to the compensatory activation of GABA transmission, as indicated by the increased expression of GAD65/67 in HAB mice.

Abstract P5-06-03: Truncated ERBB2 Receptors: Diagnostic and Therapeutic Targets

Background:

Patients with ERBB2+ breast cancer have aggressive disease and poor prognoses. It is now apparent that many ERBB2+ tumors also express truncated ERBB2 receptors (t-ERBB2s), namely p110 and p95. Increased expression of t-ERBB2s by breast tumors correlates with increased nodal involvement, distant metastasis, and poor clinical outcome in patients. Because t-ERBB2s lack the epitope bound by trastuzumab, expression of high levels of these isoforms may designate patients who would be better treated with alternative anti-ERBB2 therapy such as lapatinib; unfortunately, there is currently no clinical method to distinguish full-length p185- versus t-ERBB2 in patient tumor samples. Materials and Methods:

Recombinant forms of p185-, p110- and p95-ERBB2 were constructed using standard cloning techniques and expressed in human mammary epithelial cells (HMLE) via retroviral vector. The expression and subcellular localization of constructs were confirmed by western blot analysis and confocal microscopy. The ability of p185- and t-ERBB2 constructs to transform HMLE cells was evaluated using soft agar assays, and the effects on migration and invasion of these cells were investigated by transwell assays. Finally, the in vivo tumor formation by p185- vs. t-ERBB2 expressing cells was evaluated in immunodeficient mice. Additionally, a novel proximity-based antibody-capture method method to discern full-length versus t-ERBB2 in patient tumor samples was assessed (COPIA). Block tumors and fine-needle aspirates from patient tumor samples were used for quantifying total and phosphorylated ERBB2 receptors.

Results and Discussion:

Recombinant p185- and t-ERBB2 constructs were stably expressed in HMLE cells, and were correctly targeted to the cell membrane, as shown by confocal immunofluorescence microscopy and immunoblot. Expression of p110 t-ERBB2 increased migration and invasion of HMLE cells compared to p185 ERBB2 (P<0.0001), while p110, p95m and p185 ERBB2s were equally effective at enhancing anchorage-independent growth. In vivo, expression of p110 t-ERBB2 but not other isoforms led to increased tumor formation in mice compared to controls (P<0.005). No apparent phenotypes were elicited by expression of intracellular t-ERBB2 isoforms. Using COPIA testing, t-ERBB2 isoforms were detected in strongly ERBB2- positive tumors (16 of 31 samples, 52%) and were phosphorylated in 10 of 31 (32%). As expected, t-ERBB2s were not detected in ERBB2-negative tumor samples.

Truncated ERBB2s, particularly p110, may be major pathogenic drivers in ERBB2+ cancers. These isoforms may accelerate disease progression by promoting invasion and metastasis, and likely mediate resistance to trastuzumab and other therapies. Thus, t-ERBB2s represent attractive novel targets for diagnosis and treatment of ERBB2+ breast cancers.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-06-03.

Intrahippocampal corticosterone response in mice selectively bred for extremes in stress reactivity: a microdialysis study

The hypothalamic-pituitary-adrenocortical (HPA) axis is one of the major stress hormone systems, and glucocorticoids (GCs) play a pivotal role in homeostatic processes throughout the body and brain. A dysregulation of the HPA axis, leading to an aberrant secretion of GCs, is associated with affective disorders such as major depression. In the present study, three mouse lines selectively bred for high (HR), intermediate (IR) or low (LR) stress reactivity were used to elucidate the temporal dynamics of intrahippocampal corticosterone (CORT) in response to a standardised stressor. In particular, we addressed the question of whether the distinct differences in HPA axis reactivity between the three mouse lines, as determined by plasma CORT measurements, are present in the central nervous system as well, and if the respective endophenotype is brought about by alterations in blood-brain barrier (BBB) functionality. We applied in vivo microdialysis in the hippocampus, demonstrating that the concentrations of CORT released from the adrenals in response to restraint stress are not only distinctly different in the plasma, but can also be found in the central nervous system, although the differences between the three mouse lines were attenuated, particularly between IR and LR animals. Additionally, a time lag of approximately 60 min was observed in all three lines regarding intrahippocampal peak concentrations of CORT after the onset of the stressor. Furthermore, we showed that the penetration and clearance of CORT in the hippocampal tissue was not affected by differences in BBB functionality because the multidrug resistance 1 P-glycoprotein (Mdr1 Pgp) was equally expressed in HR, IR and LR mice. Furthermore, we could exclude surgical damage of the BBB because peripherally-injected dexamethasone, which is a high affinity substrate for the Mdr1 Pgp and therefore restricted from entering the brain, could only be detected in the plasma and was virtually absent in the brain.

Proteomic-based genotyping in a mouse model of trait anxiety exposes disease-relevant pathways

In our biomarker identification efforts, we have reported earlier on a protein that differs in its electrophoretic mobility between mouse lines bred either for high or low trait anxiety. The altered electrophoretic behavior of enolase phosphatase (EP) is now identified to be caused by two single-nucleotide polymorphisms. In both cases, the genetic polymorphism introduces an amino acid change in the protein's sequence resulting in differential mobility on SDS gels. This was shown by recombinantly expressing the two EP isoforms. Functional studies indicate that the EP isoform from the high anxiety mouse line has a lower enzymatic activity than does its low anxiety mouse counterpart. EP is a member of the methionine salvage pathway that is responsible for the synthesis of S-adenosyl-L-methionine, a natural compound with potential antidepressant activities. In addition, it is linked to the polyamine pathway whose members have functions in anxiety/depression-related behaviors. In a freely-segregating F2 panel, both single-nucleotide polymorphisms were significantly associated with locomotion-independent trait anxiety, further supporting a functional role of EP for this phenotype. The study shows that proteomic analysis can reveal genotypic differences relevant for the phenotype. The identified protein alterations, in turn, can expose metabolic pathways pertinent to the behavioral phenotype.