Suppression of plasma free fatty acids reduces myocardial lipid content and systolic function in type 2 diabetes

BACKGROUND AND AIM

Type 2 diabetes (T2DM) is closely associated with the development of heart failure, which might be related with impaired substrate metabolism and accumulation of myocardial lipids (MYCL). The aim of this study was to investigate the impact of an acute pharmacological inhibition of adipose tissue lipolysis leading to reduced availability of circulating FFA on MYCL and heart function in T2DM.

METHODS AND RESULTS

8 patients with T2DM (Age: 56 ± 11; BMI: 28 ± 3.5 kg/m(2); HbA1c: 7.29 ± 0.88%) were investigated on two study days in random order. Following administration of Acipimox or Placebo MYCL and heart function were measured by (1)H-magnetic-resonance-spectroscopy and tomography at baseline, at 2 and at 6 h. Acipimox reduced circulating FFA by -69% (p < 0.001), MYCL by -39 ± 41% (p < 0.001) as well as systolic heart function (Ejection Fraction (EF): -13 ± 8%, p = 0.025; Cardiac Index: -16 ± 15%, p = 0.063 compared to baseline). Changes in plasma FFA concentrations strongly correlated with changes in MYCL (r = 0.707; p = 0.002) and EF (r = 0.651; p = 0.006). Diastolic heart function remained unchanged.

CONCLUSIONS

Our results indicate, that inhibition of adipose tissue lipolysis is associated with a rapid depletion of MYCL-stores and reduced systolic heart function in T2DM. These changes were comparable to those previously found in insulin sensitive controls. MYCL thus likely serve as a readily available energy source to cope with short-time changes in FFA availability.

Fasting and postprandial liver glycogen content in patients with type 1 diabetes mellitus after successful pancreas-kidney transplantation with systemic venous insulin delivery

BACKGROUND

In patients with type 1 diabetes mellitus (T1DM), insulin is usually replaced systemically (subcutaneously) and not via the physiological portal route. According to previous studies, the liver's capacity to store glycogen is reduced in T1DM patients, but it remains unclear whether this is due to hyperglycaemia, or whether the route of insulin supply could contribute to this phenomenon. T1DM patients after successful pancreas-kidney transplantation with systemic venous drainage (T1DM-PKT) represent a suitable human model to further investigate this question, because they are normoglycaemic, but their liver receives insulin from the pancreas transplant via the systemic route.

MATERIALS AND METHODS

In nine T1DM-PKT, nine controls without diabetes (CON) and seven patients with T1DM (T1DM), liver glycogen content was measured at fasting and after two standardized meals employing (13) C-nuclear-magnetic-resonance-spectroscopy. Circulating glucose and glucoregulatory hormones were measured repeatedly throughout the study day.

RESULTS

The mean and fasting concentrations of peripheral plasma glucose, insulin, glucagon and C-peptide were comparable between T1DM-PKT and CON, whereas T1DM were hyperglycaemic and hyperinsulinaemic (P < 0·05 vs T1DM-PKT and CON). Total liver glycogen content at fasting and after breakfast did not differ in the three groups. After lunch, T1DM-PKT and T1DM had a 14% and 21% lower total liver glycogen content than CON (P < 0·02).

CONCLUSION

In spite of normalized glycaemic control, postprandial liver glycogen content was reduced in T1DM-PKT with systemic venous drainage. Thus, not even optimized systemic insulin substitution is able to resolve the defect in postprandial liver glycogen storage seen in T1DM patients.

Effects of pioglitazone versus glimepiride exposure on hepatocellular fat content in type 2 diabetes

AIMS

Thiazoledinediones decrease blood glucose by their insulin-sensitizing properties. Here, we examined whether pioglitazone plus nateglinide (PIO) interferes with hepatocellular lipid (HCL) content and/or improves insulin sensitivity in well-controlled non-obese patients with type 2 diabetes mellitus (T2DM).

METHODS

Sixteen patients [body mass index (BMI): 28 ± 1 kg/m(2) ; HbA1c: 7.1 ± 0.6%] were studied in a randomized, double-blind, 12-week parallel group trial, whereas matched healthy humans [non-diabetic control subjects (CON), BMI: 26 ± 1 kg/m(2)] were studied once. Treatment with pioglitazone (30 mg/day) plus nateglinide (PIO arm) to control for glimepiride-induced insulin secretion was compared to treatment with glimepiride (2 mg/day) plus placebo (GLI arm). Multinuclei magnetic resonance spectroscopy (MRS) was combined with pancreatic normoglycaemic-two-step-insulin clamps and stable isotopes to assess glucose turnover, glucose transport/phosphorylation, HCL and intramyocellular lipid (IMCL) contents, non-esterified fatty acids (NEFA) and adipokines.

RESULTS

At baseline, HCL was approximately 5.6-fold higher in T2DM (p < 0.05 vs. CON). This was paralleled by approximately doubled leptin : adiponectin ratios (p < 0.05). HCL decreased by approximately 39% (p < 0.05) after PIO and only tended to decrease after GLI (p = 0.12). Treatment with PIO did not affect leptin : adiponectin ratios, but slightly improved (p < 0.05) insulin-mediated NEFA suppression, which related to lower HCL. PIO further prevented the insulin-induced increase in IMCL content of soleus and tibialis anterior muscles. Peripheral and hepatic insulin sensitivity, glucose transport and glycaemic control did not change in both groups.

CONCLUSION

Short-term, low-dose thiazolidendione treatment improves insulin sensitivity of lipolysis and HCL, without affecting muscle and liver insulin sensitivity. It appears that metabolic PIO action in T2DM is primarily mediated via a decline in HCL associated with greater sensitivity of lipolysis to insulin.

Sensitivity calibration of an imaging extreme ultraviolet spectrometer-detector system for determining the efficiency of broadband extreme ultraviolet sources

We report on the absolute sensitivity calibration of an extreme ultraviolet (XUV) spectrometer system that is frequently employed to study emission from short-pulse laser experiments. The XUV spectrometer, consisting of a toroidal mirror and a transmission grating, was characterized at a synchrotron source in respect of the ratio of the detected to the incident photon flux at photon energies ranging from 15.5 eV to 99 eV. The absolute calibration allows the determination of the XUV photon number emitted by laser-based XUV sources, e.g., high-harmonic generation from plasma surfaces or in gaseous media. We have demonstrated high-harmonic generation in gases and plasma surfaces providing 2.3 μW and μJ per harmonic using the respective generation mechanisms.

Influence of age, performance status, cancer activity, and IL-6 on anxiety and depression in patients with metastatic breast cancer

Depression and anxiety are the core disorders causing emotional distress in patients (pts) with metastatic breast cancer. The aim of our study was to screen metastatic breast cancer outpatients for anxiety and depression, and to investigate the influence of age, Karnofsky Performance Status (KPS), cancer activity, and inflammation as represented by IL-6 levels on these two mood disorders. Pts treated with chemotherapy for metastatic breast cancer (n = 70) were assessed using the Hospital Anxiety and Depression Scale (HADS) for symptoms (scores 0-21) and caseness (score ≥11) of clinical depression and anxiety. Blood samples for IL-6 concentrations were collected at 10:00 a.m. A total of 22 (31.4 %) pts were diagnosed with caseness of clinical depression and 23 (32.9 %) pts with clinical anxiety, while 12 pts were diagnosed positive for both mood disorders. Depression and anxiety were positively but moderately correlated (Spearman's r (2) = 0.24, p < 0.001). IL-6 was significantly correlated with symptoms of depression (r (2) = 0.42, p < 0.001) and to a lesser extent to symptoms of anxiety (r (2) = 0.16, p = 0.001). In addition, IL-6 was positively associated with tumor progression (p < 0.001). Multiple linear regression analysis showed that tumor progression (standardized b = 0.226, p = 0.047), symptoms of anxiety (b = 0.292, p = 0.016), and IL-6 (b = 0.314, p = 0.007) were independently associated with clinical depression, whereas anxiety was linked to tumor progression (b = 0.238, p = 0.030), symptoms of depression (b = 0.407, p < 0.001) and age (b = -0.381, p < 0.001), but not to IL-6 (b = 0.168, p = 0.134). Even though a positive correlation between depression and anxiety exists, clinical parameters like age, cancer activity, KPS, and IL-6 do influence depression and anxiety differently. Unlike clinical depression, anxiety is not associated with increased IL-6 levels, however, shows a reciprocal correlation with age.

MIP-3α expression in macrophages is NOD dependent

BACKGROUND

The first identified susceptibility gene for Crohn's disease, NOD2, acts as a sensor for the bacterial-wall peptidoglycan fragment muramyl dipeptide (MDP) and activates the transcription factor nuclear factor-κB (NF-κB). Upon NF-κB activation, intestinal macrophages (IMACs) induce expression of macrophage inflammatory protein (MIP)-3α to attract memory T lymphocytes. We therefore investigated the influence of NOD2 ligation of IMAC differentiation and functional MIP-3α induction.

METHODS

Human embryonal kidney HEK293 cells were transfected with NOD2 wild-type (NOD2(WT)) and the NOD2 SNP13 variant (NOD2(L1007fsinsC)) and stimulated with MDP. Recruitment of CD45R0+ and Th17 cells was determined by immunohistochemistry.

RESULTS

Endogenous NOD2 stimulation was followed by a dose-dependent increase in MIP-3α secretion in MONO-MAC-6 (MM6) cells. MIP-3α mRNA was also significantly (*p < 0.05) induced in HEK293 transfected with NOD2(WT) via MDP ligation. In vivo cell-cell contacts between IMACs and CD45R0+ memory T cells as well as recruitment of Th17 cells in patients of NOD2 variants were unchanged as compared to wild-type patients.

CONCLUSION

Our data demonstrate a dose-dependent increase in MIP-3α secretion in the human myeloid cell line MM6 upon MDP. However, MIP-3α-driven recruitment of Th17 cells or CD45R0+ memory T lymphocytes is not affected in patients carrying heterozygous NOD2 variants.