Effects of a typical acute oral calcium load on arterial properties and endothelial function in healthy subjects.

BACKGROUND/OBJECTIVES: Often recommended, calcium supplements have been incriminated as increasing the risk of cardiovascular events, whereas dietary calcium has generally been exonerated. As a first step to address the vascular safety of such dietary measures at the clinical nutritionist toolbox, we sought to determine and compare the acute effects of a typical oral calcium load, provided either as a supplement or as food, on vascular parameters assessed noninvasively in healthy subjects. SUBJECTS/METHODS: In this acute, cross-over, random-order intervention, 11 young and healthy vitamin D-sufficient volunteers (8 women/3 men, 33±6.1 years, body mass index 22.6±2.3 kg/m(2)), ingested 600 mg of calcium twice, once as calcium citrate and the other time from dairy products. Biochemical, vascular and hemodynamic parameters, before and 2 h after each challenge, were compared. Arterial stiffness was studied by measuring pulse wave velocity, augmentation index and large (C1) and small (C2) arterial compliance. Endothelial function was assessed by flow-mediated dilation (FMD). RESULTS: Despite effective calcium loading accompanied by a significant 60% parathyroid hormone level reduction on both occasions, there were no clinically significant changes in the vascular parameters neither in comparison with baseline, nor between the studies. A decrease in heart rate with no change in cardiac output was noticed after the supplement. CONCLUSIONS: An effective calcium load has no clinically significant untoward effect on the vascular properties of young healthy subjects, regardless of its source. Additional studies should determine whether this holds true for chronic calcium supplementation, particularly in subjects with a priori vascular impairment.

Low uric acid levels in serum of patients with ALS: further evidence for oxidative stress?

BACKGROUND: The exact cause of amyotrophic lateral sclerosis (ALS) is unknown. Oxidative stress is one of the factors implicated in the etiology of ALS as well as in that of other neurodegenerative diseases. Uric acid is an important natural antioxidant that may reduce oxidative stress. The objective of this study was to prospectively determine the serum uric acid levels in ALS patients and allegedly healthy individuals and to correlate those values with measures of ALS disease progression among the patients. METHODS: The ALS patients and well-matched controls underwent blood tests for serum uric acid levels which were then correlated with the patients' disability status, as expressed by the ALS Functional Rating Scale (ALSFRS-R). RESULTS: Eighty-six ALS patients and 86 well-matched controls participated. The ALS patients' mean+/-SD uric acid level was significantly lower (4.78+/-1.3 mg/dl) than that of the controls (5.76+/-1.26 mg/dl) (p<0.0001). The findings were similar for a second examination performed after an interval of at least 6 months. There was a correlation between the relative decrease of serum uric acid levels among patients (the difference between the patients' level and the controls' level) and the rate of disease progression (ALSFRS-R decline) (p<0.0001, r=0.624). CONCLUSIONS: ALS patients had lower serum uric acid levels than healthy individuals. The decreased uric acid levels were correlated to the rate of disease progression (ALSFRS-R decline), further demonstrating the possible role of oxidative stress in the induction and propagation of the disease.

Low-grade systemic inflammation in patients with amyotrophic lateral sclerosis.

OBJECTIVE: To prospectively determine the intensity of systemic low-grade inflammation in patients with amyotrophic lateral sclerosis (ALS). PATIENTS AND METHODS: Patients with ALS and matched healthy controls underwent blood tests for inflammation-sensitive biomarkers: erythrocyte sedimentation rate (ESR), quantitative fibrinogen, wide-range C-reactive protein (wrCRP) concentrations, leukocyte count and neutrophil-to-lymphocyte ratio (NLR). The correlation between these inflammatory biomarkers and disability status of the patients, expressed by the ALS Functional Rating Scale (ALSFRS-R), was evaluated. RESULTS: Eighty patients with ALS and 80 matched controls were included. wrCRP, fibrinogen, ESR and NLR values were significantly elevated in patients compared with controls. There was a significant correlation between the ALSFRS-R score and wrCRP, ESR and fibrinogen levels. This correlation persisted on sequential examinations. CONCLUSIONS: A systemic low-grade inflammation was detected in patients with ALS and correlated with their degree of disability. A heightened systemic inflammatory state is apparently associated with a negative prognosis in ALS.

The clinical significance of bile duct sludge: is it different from bile duct stones?

BACKGROUND: Some patients with suspected common bile duct (CBD) stones are found to have sludge and no stones. Although sludge in the gallbladder is a precursor of gallbladder stones, the significance of bile duct sludge (BDS) is poorly defined. This study aimed to compare BDS with bile duct stones in terms of frequency, associated risk factors, and clinical outcome after endoscopic therapy. METHODS: The study enrolled 228 patients who underwent therapeutic endoscopic retrograde cholangiopancreatography (ERCP) for suspected choledocholithiasis. The patients were divided into two groups: patients with BDS but no stones on ERCP and patients with CBD stones. The presence of risk factors for bile duct stones (age, periampullary diverticulum, ductal dilation or angulation, previous open cholecystectomy) were assessed at ERCP. Follow-up data (36 +/- 19 months) were obtained from medical records and by patient questioning. RESULTS: Bile duct sludge occurred in 14% (31/228) of patients and was more common in females. After endoscopic clearance, CBD stones recurred in 17% (33/197) of the patients with CBD stones, and in 16% (5/31) of the patients with BDS (p = 0.99). Common bile duct dilation was less common in the sludge group. The other known risk factors for recurrent CBD stones (age, previous open cholecystectomy, bile duct angulation, and the presence of a peripampullary diverticulum) were not statistically different between the two groups. CONCLUSIONS: The findings indicate that the clinical significance of symptomatic BDS is similar to that of CBD stones. Bile duct sludge seems to be an early stage of choledocholithiasis.

Overexpression of amyloid precursor protein reduces epsilon protein kinase C levels.

Alzheimer's disease (AD) is characterized by extracellular deposits of amyloid beta peptide (Abeta), a peptide that is generated upon proteolytic cleavage of amyloid precursor protein (APP). The events leading to the development of AD and their sequence are not yet fully understood. Protein kinase C (PKC) has been suggested to have a significant role in controlling neuronal degeneration and in the aberrant signal transduction taking place in AD. Several studies document a deficit in PKC levels and activity in brains of AD patients when compared with those of normal controls. Such a decrease in PKC could have serious implications since certain PKC isozymes were shown to drive the APP proteolytic cleavage into a non-amyloidogenic pathway. Reduced levels of distinct PKC isozymes could thus contribute to driving APP processing toward an amyloidogenic pathway. The direct cause for the down-regulation of PKC in AD brains is still unknown. In that respect, we tested in this study whether APP may play a role in PKC reduction. We show in three different cell lines (CHO, COS and BOSC) that overexpression of APP leads to decreased PKC levels. This decrease was found to be specific for the epsilon PKC isozyme whereas the levels of delta, alpha and conventional PKC remained unchanged. Furthermore, we observed this decrease for both active, membrane-associated and inactive, cytosolic epsilon PKC. APP-driven decrease in epsilon PKC is most likely mediated by a factor in the culture medium, since transfer of medium from cultured cells overexpressing APP to naïve, non-overexpressing cells, has also led to the selective decrease in epsilon PKC levels. Taken together, our results suggest that APP expression levels may play a role in the decrease of epsilon PKC levels in AD brains and could thus affect the responsiveness of AD brain tissues to growth factors and neurotransmitters.