Blood borne macrophages are essential for the triggering of muscle regeneration following muscle transplant

The transplantation of satellite cells may constitute a strategy for rebuilding muscle fibres in inherited myopathies. However, its development requires a great understanding of the role of environmental signals in the regenerative process. It is therefore essential to identify the key events triggering and controlling this process in vivo. We investigated whether macrophages play a key role in the course of the regenerative process using skeletal muscle transplants from transgenic pHuDes-nls-LacZ mice. Before grafting, transplants were conditioned with macrophage inflammatory protein 1-beta (MIP 1-beta; stimulating the macrophages infiltration or vascular endothelial growth factor (VEGF) stimulating angiogenesis). Treatment of transplants with MIP 1-beta and VEGF both accelerated and augmented monocyte-macrophage infiltration and satellite cell differentiation and/or proliferation, as compared to controls. In addition, VEGF treatment enhanced the number of newly formed myotubes. When a complete depletion of host monocyte-macrophages was experimentally induced, no regeneration occurred in transplants. Our data suggest that the presence of blood borne macrophages is required for triggering the earliest events of skeletal muscle regeneration. The understanding of macrophage behaviour after muscle injury should allow us to develop future strategies of satellite cell transplantation as a treatment for muscular dystrophies.

Effect of glucose and heparin on mesangial alpha 1(IV)COLL and MMP-2/TIMP-2 mRNA expression

Mesangial cells are responsible for the synthesis of mesangial matrix as well as its degradation, which is mediated by a number of proteolytic activities, including metalloproteinases (MMPs). Imbalanced matrix protein metabolism may be responsible for mesangial expansion and glomerulosclerosis in diabetic nephropathy. Heparin prevents this complication. In human and murine mesangial cell cultures, RT-PCR was able to detect mRNA expression for a number of molecules involved in the mesangial extracellular matrix turnover: type IV collagen [alpha 1(IV)COLL], MMP-1, MMP-2, MMP-3, MMP-9 and MMP-10, and the tissue inhibitors TIMP-1 and TIMP-2. The expression of mRNA for alpha 1(IV)COLL and MMP-2/TIMP-2 balance was studied in human cells in the presence of high glucose and heparin. mRNAs for all the studied molecules were expressed at different levels. Interestingly, a shift in the balance of alpha 1(IV)COLL, MMP-2 and TIMP-2 was observed in high glucose, which was partially reversed by heparin supplementation. The new equilibrium was mostly due to the down-regulation of type IV collagen expression, rather than further reduction of potential proteolysis. Our data, while extending the list of potential mediators of mesangial matrix catabolism, highlight a molecular mechanism by which the pathogenesis of diabetic nephropathy may be sustained, and at the same time suggest that heparin may have the potential to correct this abnormality.

[Lovastatin in the treatment of hypercholesterolemia in non-insulin-dependent diabetes mellitus patients]

PURPOSE

To evaluate the effects of lovastatin as an hypocholesterolemic agent in non-insulin dependent diabetic (NIDDM) patients with high cholesterol plasma levels.

METHODS

Twenty NIDDM patients were included in this study. Hypercholesterolemia was defined as LDL-cholesterol plasma levels above 160mg/dl in female patients and above 130mg/dl in male patients or in women presenting any other risk factor for cardiovascular disease. From the 20 patients included, 18 had also high levels of arterial blood pressure. They were evaluated for admission in the study after they have substituted the antihypertensive medication for at least 6 weeks, from beta-blockers or diuretics to angiotensin converting enzyme inhibitors or calcium channel blockers. Lovastatin was administered in a initial daily dose of 20mg to all patients for 6 weeks. After this period this dose was increased to 40mg in 11 patients with LDL-cholesterol levels above 130mg/dl. All patients were treated for a total period of 24 weeks.

RESULTS

Lovastatin therapy for 24 weeks reduced LDL-cholesterol and total cholesterol plasma levels in 30% and 21%, respectively, while no changes in HDL-cholesterol or triglycerides plasma levels were observed. The medication was well tolerated and no changes in bilirrubins or transaminases plasma levels were detected. In 9 patients the serum levels of alkaline phosphatase showed an elevation and the mean level of all group increased from 109 +/- 59 to 188 +/- 60m mu/ml (p < 0.05). This was an isolated abnormality without any other clinical manifestation.

CONCLUSION

Lovastatin in NIDDM showed to be an efficient agent to reduce high levels of LDL-cholesterol and total cholesterol. However, the importance of the abnormality observed in serum alkaline phosphatase levels deserves further investigation. In this condition we recommend discontinuation of lovastatin therapy.

Thermal behaviour and binary phase diagram of (S)-(+)-4,4'-(1-methyl-1,2-ethandiyl)-bis-(2,6-piperazinedione) (dexrazoxane), a cardioprotective agent, and of its (R)-(-)-enantiomer

The binary phase diagram of (S)-(+)-4,4'-(1-methyl-1,2-ethandiyl)-bis-(2,6-piperazinedione), 1 (dexrazoxane), a cardioprotective agent, and of its (R)-(-)-enantiomer, 2, has been investigated by differential scanning calorimetry (DSC); the equimolecular mixture of 1 and 2 corresponds to a racemic compound (racemate) whose melting point is higher than that of the enantiomers. Thermal behaviour (DSC) is examined and discussed in comparison with the data obtained by other physical methods (IR spectroscopy and X-ray powder diffraction).

[Dynamic evaluation of prolactin secretion in acromegaly (author's transl)]

The basal PRL levels and after estimulation with synthetic TRH were evaluated in 12 patients with active acromegaly, and in 12 normal individuals. None of the patients had galactorrhea and 5 of them had tumoral supra-sellar extension. Basal hyperprolactinemia was detected in 66% of the patients. After TRH stimulation, only 4 patients exhibited a percentual increment greater than 100% over the PRL basal value. PRL response to TRH was negative in 8 patients. The high PRL levels can be explained by the parallel production of GH and PRL by the tumoral cells, nevertheless a disturbance of the normal hypothalamic control cannot be excluded.