Hyponatremia-related liver steatofibrosis and impaired spermatogenesis: evidence from a mouse model of the syndrome of inappropriate antidiuresis.

PURPOSE: Hyponatremia is the most frequent electrolytic disorder in clinical practice. In addition to neurological symptoms, hyponatremia, even when mild/moderate and chronic, has been related to other manifestations, such as bone demineralization and increased risk of fractures. To better elucidate tissue alterations associated with reduced serum sodium concentration [Na+], we developed an in vivo model of hyponatremia secondary to the Syndrome of Inappropriate Antidiuresis. METHODS AND RESULTS: Hyponatremia was induced in Foxn1nu/nu mice by subcutaneous infusion of the vasopressin analog 1-deamino [8-D-arginine] vasopressin (dDAVP) for 14 days via osmotic mini-pumps. Mice in the control group were infused with isotonic saline solution. Serum [Na+] progressively decreased, with a nadir of 123.4 ± 2.3 mEq/L (mean ± SD, dDAVP 0.3 ng/h) and 111.6 ± 4.7 mEq/L (mean ± SD, dDAVP 0.5 ng/h). Evident signs of liver steatofibrosis were observed at histology in hyponatremic mice. Accordingly, the expression of proteins involved in lipid metabolism (SREBP-1, PPARα and PPARγ) and in myofibroblast formation (αSMA and CTGF) significantly increased. Furthermore, heme oxygenase 1 expression was up-regulated in Kupffer and hepatic stellate cells in the liver of hyponatremic mice. Testis alterations were also observed. In particular, the thickness of the seminiferous epithelium appeared reduced. The expression levels of PCNA and PTMA, which are involved in DNA replication and germ cells maturation, were markedly reduced in the testis of hyponatremic mice. CONCLUSION: Overall, these findings shed new light on the possible consequences of chronic hyponatremia and prompt a more thorough evaluation of hyponatremic patients.

Emerging ciliopathies: are respiratory cilia compromised in Usher syndrome?

PURPOSE: Usher syndrome is a ciliopathy involving photoreceptors and cochlear hair cells (sensory cilia): since sensory and motor ciliopathies can overlap, we analysed the respiratory cilia (motile) in 17 patients affected by Usher syndrome and 18 healthy control subject. PATIENTS AND METHODS: We studied the mucociliary transport time with the saccharine test, ciliary motility and ultrastructure of respiratory cilia obtained by nasal brushing; we also recorded the classical respiratory function values by spirometry. RESULTS: All enrolled subjects showed normal respiratory function values. The mean mucociliary transport time with saccharine was 22.33 ± 17.96 min, which is in the range of normal values. The mean ciliary beat frequency of all subjects was 8.81 ± 2.18 Hz, which is a value approaching the lower physiological limit. None of the classical ciliary alterations characterizing the "ciliary primary dyskinesia" was detected, although two patients showed alterations in number and arrangement of peripheral microtubules and one patient had abnormal ciliary roots. CONCLUSIONS: Respiratory cilia in Usher patients don't seem to have evident ultrastructural alterations, as expected, but the fact that the ciliary motility appeared slightly reduced could emphasize that a rigid distinction between sensory and motor ciliopathies may not reflect what really occurs.

ADMA correlates with portal pressure in patients with compensated cirrhosis.

BACKGROUND: Chronic liver diseases are frequently complicated by portal hypertension, an important component of which is the increased intrahepatic vascular resistance, in part related to endothelial dysfunction. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO synthase, is an established mediator and marker of endothelial dysfunction. We therefore investigated the possible implication of ADMA in chronic liver diseases-induced portal hypertension. MATERIALS AND METHODS: We studied 39 consecutive patients with compensated hepatitis C virus (HCV) related chronic liver diseases. All patients underwent hepatic venous pressure gradient (HVPG) measurement, and simultaneous blood sampling from the hepatic vein and the pulmonary artery, for ADMA and nitrite/nitrate (NOx) plasma level determinations. RESULTS: A positive correlation between HVPG and ADMA concentrations in hepatic veins (ADMA-h) was found (r = 0.77, P < 0.0001). Moreover, a negative correlation between HVPG and NOx concentrations in the hepatic veins (NO-h) (r = -0.50, P = 0.005), and between ADMA-h and NO-h was observed (r = -0.40, P = 0.02). ADMA concentrations in pulmonary artery (ADMA-p) (0.55 +/- 0.13 micromol L(-1)) were significantly higher than in hepatic veins (0.47 +/- 0.09 micromol L(-1)) (P < 0.0001). CONCLUSIONS: These results suggest that ADMA may play a pathophysiological role in portal hypertension by contributing to the relative intrahepatic NO deficiency typical of endothelial dysfunction.

Effects of metformin on glucagon-like peptide-1 levels in obese patients with and without Type 2 diabetes.

Metformin has been shown to increase glucagon-like peptide-1 (GLP-1) levels after an oral glucose load in obese non-diabetic subjects. In order to verify if this effect of the drug was also present in obese Type 2 diabetic patients who have never been treated with hypoglycemic drugs, 22 Type 2 diabetic and 12 matched non-diabetic obese patients were studied. GLP-1 was measured before and after a 100 g glucose load at baseline, after a single oral dose of 850 mg of metformin, and after 4 weeks of treatment with metformin 850 mg three times daily. Post-load GLP-1 levels were significantly lower in diabetic patients. A single dose of metformin did not modify GLP-1 levels. After 4 weeks of treatment, fasting GLP-1 increased in diabetic patients (3.8 vs 4.9 pmol/l; p<0.05), while the incremental area under the curve of GLP-1 significantly increased in both diabetic [93.6 (45.6-163.2) vs 151.2 (36.0-300.5) pmol x min/l; p<0.05] and non-diabetic [187.2 (149.4-571.8) vs 324.0 (238.2-744.0) pmol x min/l; p<0.05] subjects. In conclusion, GLP-1 levels after an oral glucose load in obese type 2 diabetic patients were increased by 4 weeks of metformin treatment in a similar fashion as in obese subjects with normal glucose tolerance.

Fasting plasma glucose and glycated haemoglobin in the screening of diabetes and impaired glucose tolerance.

The use of fasting plasma glucose (FPG) only has been proposed for the screening and diagnosis of diabetes, but its sensitivity has been reported to be unsatisfactory. The use of HbA1C, alone or combined with FPG, has been suggested for the screening of diabetes and impaired glucose tolerance (IGT). In a sample of 1215 adult subjects without previously known diabetes, we assessed the sensitivity and specificity of FPG and HbA1C in diagnosing diabetes and IGT, determined by oral glucose tolerance test (OGTT). All lean diabetic patients, and 85% of overweight and obese diabetic individuals, had FPG > or =7 mmol/l. FPG >6.1 mmol/l had a sensitivity of 98.8% and a specificity of 32.9%; HbA1C had a lower specificity and sensitivity for the screening of diabetes. A screening strategy for diabetes based on FPG, with OGTT in all overweight subjects with FPG >6.1 mmol/l, is suggested. Neither FPG nor HbA1C is effective in the screening of IGT; although combined FPG and HbA1C could be useful for case finding, screening for IGT with OGTT is advisable in all subjects at high risk.

Quantitative in situ evaluation of telomeres in fluorescence in situ hybridization-processed sections of cutaneous melanocytic lesions and correlation with telomerase activity.

BACKGROUND: Telomere length is correlated with cellular ageing and immortalization processes. In some human cancers telomere length measurement has proved to be of diagnostic and prognostic value. Results comparable with the traditional terminal restriction fragment length determination by Southern blotting have been obtained in metaphase and interphase cells in some studies by fluorescence in situ hybridization (FISH) analysis; FISH additionally allows for the quantification of telomeres at the cellular level. OBJECTIVES: In this study, 32 melanocytic lesions were analysed by FISH, aiming at investigating possible telomere differences among various benign and malignant lesions and correlation with telomerase activity (TA) level. METHODS: FISH was performed on paraffin sections from six common naevi, eight Spitz naevi, 12 melanomas, six melanoma metastases and nine control samples of normal skin. Telomere mean maximum diameter (Feret max), area and number per nuclear area were calculated by image analysis on fluorescent images elaborated through KS400 and in situ imaging system (ISIS) for FISH analysis programs. Mean TA level was also calculated in all lesions and correlated with telomere parameters. RESULTS: Telomere number per nuclear area was significantly lower in melanomas and metastases than in benign common and Spitz naevi and in control skin (7 small middle dot24 +/- 3.3; 6.11 +/- 3 vs. 14.46 +/- 5.6; 16.92 +/- 7.8; and 12.59 +/- 3.4, respectively; P < 0 .001). No significant differences were found for the other telomere parameters. In common and Spitz naevi, telomere number was positively correlated with Feret max (P = 0.046 and P < 0.0001, respectively). TA was significantly higher in melanomas and metastases than in the other groups (70.18 +/- 25.2; 105.07 +/- 30 vs. 2.16 +/- 2.4; 2 .99 +/- 2.1; 2 +/- 1.2, respectively; P< or = 0. 001) and it was inversely correlated with telomere number per nuclear area in melanomas (P = 0.0041). No other significant correlations were found. CONCLUSIONS: Encouraging results have been obtained from quantitative telomere evaluation in the diagnosis of melanocytic lesions, although an analysis of a larger number of cases would be necessary to provide more reliable data. An extreme shortening of some telomeres probably results in the decrease of telomeric signals and the lower mean number of detectable telomeres in melanomas and metastases. In melanomas, telomere number per nuclear area is also inversely correlated with TA levels. Quantitative FISH of melanocytic lesions could give more specific information at the cellular level in telomere and telomerase fields of investigation.

Platelet Activation in Hypercholesterolemic Patients Submitted to Therapeutic Plasmapheresis. An Ultrastructural Study.

Therapeutic plasmapheresis has been recommended as the choice therapy in patients with familial hypercholesterolemia. Little is known about the effect of plasmapheresis on platelet behavior. By means of electron microscopy we have studied the platelet plasma membrane of 4 patients with familial hypercholesterolemia who were submitted to repeated plasmaphereses. After each procedure of plasmapheresis, at the 15th day, morphometrical studies revealed a statistically significant increase in the surface density of the Open Canalicular System, which is considered a marker of platelet activation. However, during 12 months of plasmapheresis, a significant mean decrease in the morphometric parameters was observed. On one hand, these results indicate the necessity to consider the blood hemocoagulatory state in the patient who has been submitted to the above mentioned treatment, since the variation of these parameters after the therapeutic procedure, in a short time, could be potentially harmful to the patient; on the other hand, these results indicate, for the first time, the ability of the procedure to improve platelet behavior after repeated treatments on long term basis.

Morphological aspects of endothelial cell-monocyte interactions in culture.

Monocytes obtained from the blood of healthy volunteers were added to cultures of bovine aortic endothelial cells (BAEC) at increasing time intervals (from 1 h to 24 h). Cultures of BAEC without the added blood elements were used as controls. The ultrastructural features of cellular interactions were studied by transmission electron microscopy. After 4 h, in the co-cultured endothelial cells focal cytoplasmic lesions appeared in the areas where activated monocytes were strictly in contact. Adhering monocytes frequently appeared apoptotic. After 24 h, pseudopod-like cytoplasmic projections originating from the endothelial cells gave rise to areas of close contact between the BAEC and the monocytes. These data reveal until now unknown endothelial cell taxis toward blood cells.