Cell Therapy for Type 1 Diabetes

Acknowledgements The work described in this review was supported by a grant from the MRC. K.R.M. is supported by a fellowship from the Scottish Translational Medicines and Therapeutics Initiative through the Wellcome Trust.Peer reviewedPublisher PD

Lin28A induces energetic switching to glycolytic metabolism in human embryonic kidney cells

Background: Loss of a cell’s capacity to generate sufficient energy for cellular functions is a key hallmark of the ageing process and ultimately leads to a variety of important age-related pathologies such as cancer, Parkinson’s disease and atherosclerosis. Regenerative medicine has sought to reverse these pathologies by reprogramming somatic cells to a more juvenile energetic state using a variety of stem cell factors. One of these factors, Lin28, is considered a candidate for modification in the reprogramming of cellular energetics to ameliorate the ageing process while retaining cell phenotype. Results: Over-expression of Lin28A resulted in key changes to cellular metabolism not observed in wild-type controls. Extracellular pH flux analysis indicated that Lin28A over expression significantly increased the rate of glycolysis, whilst high resolution oxygen respirometry demonstrated a reduced oxygen consumption. Western blot and real-time PCR analysis identified Hexokinase II as one of the key modulators of glycolysis in these cells which was further confirmed by increased glucose transport. A metabolic switching effect was further emphasised by Western blot analysis where the oxygen consuming mitochondrial complex IV was significantly reduced after Lin28A over expression. Conclusions: Results from this study confirm that Lin28A expression promotes metabolic switching to a phenotype that relies predominantly on glycolysis as an energy source, while compromising oxidative phosphorylation. Mechanisms to augment regulated Lin28A in age related pathologies that are characterised by mitochondria dysfunction or in differentiated and aged post-mitotic cells is the future goal of this work

A STUDY CORRELATING INVESTMENT WITH POLITICAL, RELIGIOUS, AND MORAL ATTITUDES

The study was to determine the correlation between a person\u27s investment in society, as measured by economic factors, and a person\u27s liberal attitudes about that society. The attitude areas used to measure liberal-conservative attitudes were political, religious, and moral. The hypothesis stated that as investment increased, the scale of liberal attitudes in politics, religion, and morals would decrease. A significant negative correlation would support the hypothesis. A significant positive correlation indicated a reverse of the hypothesis, that is an increase in investment showed an increase in liberal attitudes. Demographic factors controlled in this study were, sex, age, marital status and geographic area. Each of these controlled areas was tested for the attitude areas, political, religious, and moral. The statistical test used was the Pearson Product-Moment Correlation. This was computed from the raw data by the IBM 1401 computer and the Monroe Epic 3000 memory calculator. A level of .05 or 5% was determined as the level of significance. The study showed there was no significant correlation between the two major variables of investment in society and a decrease in liberal attitudes. When the component variables of politics, religion, and morals were correlated with the independent variable, investment in society, morals did show a -.3910 correlation in the direction predicted, which was significant at the .01 level. The population for the study was six extension classes from Kansas State College of Pittsburg, and one Lions Club, of the organization of Lions International, from Girard, Kansas. When certain demographic factors were controlled some areas showed a .05 level of significance to support the hypothesis. These areas were: geographic areas, Girard and Shawnee Mission; age groups, 25 to 34 and Over 65; sex, females; and marital status, Never Married

Integral-Based Identification of an Inhomogeneity Model in Respiratory Mechanics

4-pagesIndividualized models of respiratory mechanics may help to reduce potential harmful effects of ventilation therapy by predicting the outcome of certain ventilator settings. The underlying models are commonly identified by iterative error-mapping methods, such as the Levenberg-Marquardt Algorithm, requiring initial estimates for the patient specific parameters. The quality of the initial estimates has a significant influence on identification efficiency and results. An iterative integral-based parameter identification method was applied to a linear 2nd order respiratory mechanics model. The method was compared to the Levenberg-Marquardt Algorithm using clinical data from 13 Acute Respiratory Distress Syndrome (ARDS) patients. The Iterative Integral-Based Method converged to the Levenberg-Marquardt solution two times faster and was independent of initial estimates. These investigations reveal that the Iterative Integral-Based Method is beneficial with respect to computing time, operator independence and robustness

Influence of 2-methoxyestradiol and sex on hypoxia-induced pulmonary hypertension and hypoxia-inducible factor‐1‐α

Background: Women are at greater risk of developing pulmonary arterial hypertension, with estrogen and its downstream metabolites playing a potential role in the pathogenesis of the disease. Hypoxia‐inducible factor‐1‐α (HIF1α) is a pro‐proliferative mediator and may be involved in the development of human pulmonary arterial hypertension. The estrogen metabolite 2‐methoxyestradiol (2ME2) has antiproliferative properties and is also an inhibitor of HIF1α. Here, we examine sex differences in HIF1α signaling in the rat and human pulmonary circulation and determine if 2ME2 can inhibit HIF1α in vivo and in vitro. Methods and Results: HIF1α signaling was assessed in male and female distal human pulmonary artery smooth muscle cells (hPASMCs), and the effects of 2ME2 were also studied in female hPASMCs. The in vivo effects of 2ME2 in the chronic hypoxic rat (male and female) model of pulmonary hypertension were also determined. Basal HIF1α protein expression was higher in female hPASMCs compared with male. Both factor‐inhibiting HIF and prolyl hydroxylase‐2 (hydroxylates HIF leading to proteosomal degradation) protein levels were significantly lower in female hPASMCs when compared with males. In vivo, 2ME2 ablated hypoxia‐induced pulmonary hypertension in male and female rats while decreasing protein expression of HIF1α. 2ME2 reduced proliferation in hPASMCs and reduced basal protein expression of HIF1α. Furthermore, 2ME2 caused apoptosis and significant disruption to the microtubule network. Conclusions: Higher basal HIF1α in female hPASMCs may increase susceptibility to developing pulmonary arterial hypertension. These data also demonstrate that the antiproliferative and therapeutic effects of 2ME2 in pulmonary hypertension may involve inhibition of HIF1α and/or microtubular disruption in PASMCs

Role of the aryl hydrocarbon receptor in Sugen 5416-induced experimental pulmonary hypertension

Rationale: Rats dosed with the vascular endothelial growth factor (VEGF) inhibitor Sugen 5416 (Su), placed in hypoxia then restored to normoxia has become a widely used model of pulmonary arterial hypertension (PAH). The mechanism by which Su exaccerbates pulmonary hypertension is, however, unclear. Objectives: We investigated Su-activation of the aryl hydrocarbon receptor (AhR) in patient human pulmonary arterial smooth muscle cells (hPASMCs) and patient blood outgrowth endothelial cells (BOECs). We also examined the effect of AhR on aromatase and estrogen levels in the lung. Methods, Measurements and Main Results: Protein and mRNA analysis demonstrated that CYP1A1 was very highly induced in the lungs of Su/hypoxic (Su/Hx) rats. The AhR antagonist CH223191 (8mg/kg/day) reversed the development of PAH in this model in vivo and normalized lung CYP1A1 expression. Increased lung aromatase and estrogen levels in Su/Hx rats were also normalized by CH223191 as was AhR nuclear translocator (ARNT [HIF-1β]) which is shared by HIF-1α and AhR. Su reduced HIF1α expression in hPASMCs. Su induced proliferation in BOECs and increased apoptosis in human pulmonary microvascular endothelial cells (hPMECs) and also induced translocation of AhR to the nucleus in hPASMCs. Under normoxic conditions, hPASMCs do not proliferate to Su. However when grown in hypoxia (1%) Su induced hPASMC proliferation. Conclusion: In combination with hypoxia, Su is proliferative in patient hPASMCs and patient BOECs and Su/Hx-induced PAH in rats may be facilitated by AhR-induced CYP1A1, ARNT and aromatase. Inhibition of the AhR receptor may be a novel approach to the treatment of pulmonary hypertension

Traversing the Fuzzy Valley: Problems caused by reliance on default simulation and parameter identification programs for discontinuous models

invited, 6-pagesThe Levenberg-Marquardt parameter identification method is often used in tandem with numerical Runge-Kutta model simulation to find optimal model parameter values to match measured data. However, these methods can potentially find erroneous parameter values. The problem is exacerbated when discontinuous models are analyzed. A highly parameterized respiratory mechanics model defines a pressure-volume response to a low flow experiment in an acute respiratory distress syndrome patient. Levenberg-Marquardt parameter identification is used with various starting values and either a typical numerical integration model simulation or a novel error-stepping method. Model parameter values from the error-stepping method were consistently located close to the error minima (median deviation: 0.4%). In contrast, model values from numerical integration were erratic and distinct from the error minima (median deviation: 1.4%). The comparative failure of Runge-Kutta model simulation was due to the method’s poor handling of model discontinuities and the resultant lack of smoothness in the error surface. As the Leven-berg-Marquardt identification system is an error gradient decent method, it depends on accurate measurement of the model-to-measured data error surface. Hence, the method failed to converge accurately due to poorly defined error surfaces. When the error surface is imprecisely identified, the parameter identification process can produce sub-optimal results. Particular care must be used when gradient decent methods are used in conjunction with numerical integration model simulation methods and discontinuous models

Impaired mitochondrial respiration in human carotid plaque atherosclerosis: a potential role for Pink1 in vascular smooth muscle cell energetics

Background and aims: DNA damage and mitochondrial dysfunction are thought to play an essential role in ageing and the energetic decline of vascular smooth muscle cells (VSMCs) essential for maintaining plaque integrity. We aimed to better understand VSMCs and identify potentially useful compensatory pathways that could extend their lifespan. Moreover, we wanted to assess if defects in mitochondrial respiration exist in human atherosclerotic plaques and to identify the appropriate markers that may reflect a switch in VSMC energy metabolism. Methods: Human plaque tissue and cells were assessed for composition and evidence of DNA damage, repair capacity and mitochondrial dysfunction. Fresh plaque tissue was evaluated using high resolution oxygen respirometry to assess oxidative metabolism. Recruitment and processing of the mitochondrial regulator of autophagy Pink1 kinase was investigated in combination with transcriptional and protein markers associated with a potential switch to a more glycolytic metabolism. Results: Human VSMC have increased nuclear (nDNA) and mitochondrial (mtDNA) damage and reduced repair capacity. A subset of VSMCs within plaque cap had decreased oxidative phosphorylation and expression of Pink1 kinase. Plaque cells demonstrated increased glycolytic activity in response to loss of mitochondrial function. A potential compensatory glycolytic program may act as energetic switch via AMPKinase and hexokinase 2 (Hex2). Conclusions: We have identified a subset of plaque VSMCs required for plaque stability that have increased mitochondrial dysfunction and decreased oxidative phosphorylation. Pink1 kinase may initiate a cellular response to promote a compensatory glycolytic program associated with upregulation of AMPKinase and Hexokinase 2