Glucose-dependent insulinotropic peptide secretion is induced by inflammatory stimuli in an interleukin-1-dependent manner in mice.

Recently, glucagon-like peptide-1 (GLP-1) levels have been found to be increased in response to inflammatory stimuli, leading to insulin secretion and prevention of hyperglycaemia during endotoxemia in mice. In the present study, we assess the relevance of the other incretin hormone, glucose-dependent insulinotropic peptide (GIP), as a regulator of glucose metabolism under inflammatory conditions. We found that lipopolysaccharide (LPS) increased GIP secretion in a time- and dose-dependent manner in C57BL/6J mice. To elucidate the underlying mechanisms, mice were injected with inflammatory cytokines known to be released by LPS. Circulating GIP levels significantly increased in response to interleukin (IL)-1ß but not IL-6 or tumour necrosis factor (TNF)-α administration. Using respective knockout mice we found that LPS-mediated GIP secretion was selectively dependent on IL-1 signalling. To evaluate the functional relevance of inflammatory GIP secretion we pretreated mice with the GIP-receptor antagonist (Pro3)GIP. This blunted LPS-induced TNF-α and IL-6 secretion but did not affect LPS-induced insulin secretion or blood glucose-lowering. In conclusion, GIP provides a novel link between the immune system and the gut, with proinflammatory-immune modulatory function but minor glucose regulatory relevance in the context of acute endotoxemia.

Intramyocardial gene therapy with naked DNA encoding vascular endothelial growth factor improves collateral flow to ischemic myocardium.

Both VEGF protein and VEGF DNA in combination with an adenoviral vector have been shown to enhance collateral formation in a porcine model of chronic myocardial ischemia. We sought to determine whether direct intramyocardial injection of naked DNA encoding for VEGF could similarly improve myocardial perfusion. Initially, 23 nonischemic pigs received either 200 microg of plasmid DNA encoding beta-galactosidase (pCMVbeta, n = 11) or 500 microg of phVEGF165 (n = 12) into four separate sites in the myocardium via a small anterolateral thoracotomy incision in the fourth intercostal space. Two additional groups of pigs received an intramyocardial injection of either phVEGF165 (n = 6) or pCMVbeta (n = 7) 3 to 4 weeks after implantation of an ameroid constrictor around the left circumflex coronary artery. The injections caused no change in heart rate or blood pressure, and no ventricular arrhythmias or histologic evidence of inflammation. VEGF protein was detected by Western blot in VEGF-treated animals, with the strongest bands closest to the injection site. Plasma VEGF concentration (ELISA) increased from 3+/-2 to 27+/-13 pg/ml (p = 0.035) by day 4 after treatment. No increase in VEGF protein was noted in pCMVbeta-treated animals whereas these did stain positive for beta-Gal. Resting myocardial blood flow (colored microspheres) was significantly reduced in the ischemic versus nonischemic territory in control animals (1.07+/-0.05 versus 1.32+/-0.05; p < 0.05) but not VEGF-treated pigs (1.32+/-0.24 versus 1.13+/-0.12; p = NS). Maximal vasodilatation with adenosine significantly increased flow to the ischemic region in VEGF-treated pigs (2.16+/-0.57 versus 1.32+/-0.24; p < 0.05) but not controls (1.31+/-0.05 versus 1.17+/-0.06;p = NS). Collateral filling of the occluded circumflex artery improved in five of six VEGF-treated pigs (mean change in Rentrop score, +1.5). We conclude that direct intramyocardial transfection phVEGF165 is safe and capable of producing sufficient VEGF protein to enhance collateral formation and myocardial perfusion. This approach may offer an alternative therapy for patients with intractable myocardial ischemia not amenable to PTCA or CABG.

Lovastatin maintains nitric oxide--but not EDHF-mediated endothelium-dependent relaxation in the hypercholesterolemic rabbit carotid artery.

The endothelium contributes to the regulation of vascular tone by producing nitric oxide (NO) and the endothelium-derived hyperpolarising factor (EDHF). In hypercholesterolemia, endothelium-dependent relaxation is impaired but can be restored by treatment with lovastatin (LOVAS). We investigated the effects of LOVAS on NO and EDHF-mediated relaxation. Rabbits were fed 1% cholesterol diet for 4 weeks and 0.5%) cholesterol for the following 12 weeks (CHOL-group). The LOVAS group additionally received 10 mg of lovastatin over the last 12-week period. Experiments were performed in carotid artery rings. Relaxant responses to acetylcholine (ACh) were recorded in the presence of indomethacin. Nitro-L-arginine (NOARG, 100 microM) and potassium chloride (KCl, 35 mM) were used to differentiate between NO- and EDHF-mediated relaxations. Cholesterol impaired ACh-induced relaxations and this effect was prevented by LOVAS (control 100+/-1%, CHOL 81+/-6%, LOVAS 98+/-1%). In the presence of NOARG, relaxations to ACh were not different between the LOVAS and CHOL groups (control 78+/-4%, CHOL 64+/-6%, LOVAS 64+/-5%). When KCl was used, ACh-induced relaxations were similar in the LOVAS and control group (control 75+/-5%, CHOL 49+/-6%, LOVAS 76+/-2%). In arteries treated with NOARG and KCl together, no relaxations were observed. Relaxations of arteries from the control group were not affected by 18 h preincubation with lovastatin (10 microM). Lovastatin selectively maintains nitric oxide-mediated endothelium-dependent relaxation in hypercholesterolemic rabbit carotid arteries.

N(G)-nitro-L-arginine- and indomethacin-resistant endothelium-dependent relaxation in the rabbit renal artery: effect of hypercholesterolemia.

Studies were designed to compare the N(G)-nitro-L-arginine- and indomethacin-resistant, endothelium-dependent relaxation to acetylcholine in isolated renal artery rings from normal and cholesterol-fed rabbits. It was assumed that the resistant part in response to acetylcholine is mediated by the endothelial-derived hyperpolarizing factor (EDHF). Rabbits were fed normal (n = 15) or cholesterol enriched chow (n = 13, 1% cholesterol for 4 weeks, 0.5% for 12 weeks). In organ chamber experiments, renal artery rings were precontracted with 0.1-1 microM phenylephrine or 35 mM KCl, and relaxed with acetylcholine (0.001-10 microM) in the presence of 10 microM indomethacin. Studies were performed in the presence or absence of: 100 microM N(G)-nitro-L-arginine (L-NOARG) to inhibit the nitric oxide pathway, 100 nM charybdotoxin (CTX) or 1 mM tetrabutylammonium (TBA) to inhibit Ca2+-activated K+ channels, and 100 microM SKF 525a to inhibit cytochrome P450 monoxygenase pathway. In normal arteries, L-NOARG partially inhibited acetylcholine-induced relaxation. The resistant part was almost abolished when the arteries were depolarized with KCl, or when L-NOARG was combined with either CTX, TBA or SKF 525a. In arteries from hypercholesterolemic animals, the relaxation to acetylcholine was only slightly impaired as compared to normal animals. However, in comparison to arteries from normal animals, the L-NOARG-resistant part of acetylcholine-induced endothelium-dependent relaxation was enhanced. It is speculated that differences in the balance between nitric oxide (NO)- and EDHF-mediated control of vascular tone may maintain acetylcholine-induced vasodilatation of the renal artery in hypercholesterolemia.

[Postsurgical computed tomography of uncemented hip arthroplasty]. / Postoperative Computertomographie zementfreier Hüftprothesenschäfte.

PURPOSE: Presentation of the value of postsurgical computed tomography (CT) to diagnose loosening of uncemented femoral stems. MATERIALS AND METHODS: Incremental CT and spiral CT were performed on six femora with implanted uncemented stems after the entire femora were embedded in polymethylmethacrylate. The femora were subsequently sectioned (thickness 1 mm, separation 8 mm) and the medial and lateral contact areas of the prosthetic stem compared with the CT data. RESULTS: The CT showed a contact of femoral stem and cortical bone between 0.4 mm (3.4 %) and 4.8 mm (47.1 %) and the section specimens between 0.9 mm (8.7 %) and 3.4 mm (36.7 %). No correlation was found between the results (r = 0.61), since the individual differences were up to 24 % in almost all sections. CONCLUSIONS: Neither single-slice nor two-slice CT is capable of demonstrating the direct bone-endoprosthesis contact. Multidetector row CT (MDCT) is conceivably more accurate to measure the cortical contact of the femoral stem.

Precision of the measurements of periprosthetic bone mineral density in hips with a custom-made femoral stem.

Our aim was to determine the precision of the measurements of bone mineral density (BMD) by dual-energy x-ray absorptiometry in the proximal femur before and after implantation of an uncemented implant, with particular regard to the significance of retro- and prospective studies. We examined 60 patients to determine the difference in preoperative BMD between osteoarthritic and healthy hips. The results showed a preoperative BMD of the affected hip which was lower by a mean of 4% and by a maximum of 9% compared with the opposite side. In addition, measurements were made in the operated hip before and at ten days after operation to determine the effect of the implantation of an uncemented custom-made femoral stem. The mean increase in the BMD was 8% and the maximum was 24%. Previous retrospective studies have reported a marked loss of BMD on the operated side. The precision of double measurements using a special foot jig showed a modified coefficient of variation of 0.6% for the non-operated side in 15 patients and of 0.6% for the operated femur in 20 patients. The effect of rotation on the precision of the measurements after implantation of an uncemented femoral stem was determined in ten explanted femora and for the operated side in ten patients at 10 degrees rotation and in 20 patients at 30 degrees rotation. Rotation within 30 degrees influenced the precision in studies in vivo and in vitro by a mean of 3% and in single cases in up to 60%. Precise prediction of the degree of loss of BMD is thus only possible in prospective cross-sectional measurements, since the effect of the difference in preoperative BMD, as well as the apparent increase in BMD after implantation of an uncemented stem, is not known from retrospective studies. The DEXA method is a reliable procedure for determining periprosthetic BMD when positioning and rotation are strictly controlled.

[Optimized polymethyl methacrylate-embedding enables exact section examination of the femur with an uncemented femoral stem]. / Optimierte Polymethylmethacrylat-Einbettung ermöglicht exakte Schnittuntersuchung proximaler Femora mit zementfreier Endoprothese.

AIM: Embedding of larger bones, as described in this article, is not possible without marked modifications of the methods followed for small, undecalcified bone specimens. Problems such as turbidity of the PMMA, incomplete hardening of the medullary cavity due to insufficient infiltration and, especially, uncontrolled polymerization with excessive bubbling make analysis of the specimens impossible. Thus, modifications with respect to the infiltration times in the individual solutions, the benzoyl peroxide quantities added and the temperature during the polymerization phase were undertaken. METHOD: The infiltrations were performed under vacuum. A cooling circulation was created in a standard water bath with a circulator pump to facilitate extraction of the polymerization heat. The use of PMMA blocks as filling material and polymerization inductors was especially important. RESULTS: There was no turbidity or excessive bubbling of the PMMA in any of the specimens embedded with this method. Analysis of the sections showed a low-bubble medullary cavity with 01 bubble/cm(2). Up to 10 bubbles/cm(2) were observed only in the large cancellous space in the trochanteric region over a length of 56 cm. All bubbles were a maximum of 1.5 mm in size. CONCLUSION: With the described method it is possible to embed large bones in PMMA.

[The course of inflammatory mediators after elective orthopedic interventions]. / Entzündungsparameterverlauf nach elektiven orthopädischen Eingriffen.

PURPOSE OF THE STUDY: The aim of the study was to characterize the changes of C-reactive protein, erythrocyte sedimentation rate, white blood count and body temperature by serial measurements after different types of uncomplicated orthopedic surgery. METHODS: The uncomplicated course of 180 patients after elective total hip and knee arthroplasties, ventral and dorsal spinal fusions and diagnostic knee and shoulder arthroscopies were analyzed. RESULTS: The maximal CRP-values were recorded on the second or third day after operation. The peak levels correlated with the extent of the procedures and reached 1.28-17.71 mg/dl. The ESR increased to maximal rates five to six days after surgery and remained elevated during the 14 days of the investigation period. WBC and body temperature showed a slow and uncharacteristic increase followed by a slow and irregular decrease. CONCLUSION: Awareness of the typical pattern of CRP, ESR, WBC and body temperature may help to evaluate the early postoperative course. The CRP is a sensitive marker. ESR, WBC and body temperature are less costly but a poor diagnostic aid for the early detection of postoperative complications especially infections.

Retroinfusion of NFkappaB decoy oligonucleotide extends cardioprotection achieved by CD18 inhibition in a preclinical study of myocardial ischemia and retroinfusion in pigs.

Myocardial reperfusion injury is partially mediated by postischemic inflammation. Beyond acute PMN recruitment, postischemic inflammation comprises subacute PMN adhesion, eg via NFkappaB activation. In a pig model of 60-min LAD occlusion by PTCA ballon inflation and 1 to 7 days of reperfusion, we investigated the impact of targeted NFkappaB decoy oligonucleotide (ODN) transfection in the area at risk (AAR) on infarct size and regional myocardial function. After 55 min of LAD occlusion, liposomes containing NFkappaB ODN were selectively retroinfused into the anterior interventricular vein for 5 min. Then, retroinfusion was stopped and reperfusion was initiated. Where indicated, CD18 antibody IB4 was infused systemically at 30 min of ischemia. Methylen blue and tetrazolium-red staining were used for quantification of the infarct size. Subendocardial segment shortening (SES) by sonomicrometric crystals in infarct area and AAR was assessed under pacing (expressed as % of control region). NFkappaB decoy ODN retroinfusion reduced infarct size (36 +/- 4% versus 49 +/- 5% in control hearts at day 7), whereas functional reserve of the AAR (SES 73 +/- 17% versus 46 +/- 18% at 180/min) tended to improve. Similar effects were observed after IB4 infusion (38 +/- 5% infarct size, 85 +/- 7% SES at 180/min). A combination of NFkappaB decoy ODN retroinfusion and IB4 infusion further decreased infarct size (26 +/- 2%) and improved functional reserve (SES 94 +/- 6% at 180/min). We conclude that NFkappaB decoy ODN transfection by retroinfusion is feasible in pig hearts and provides postischemic cardioprotection in addition to CD18 blockade.