Amylin serum levels are upregulated in patients with systemic lupus erythematosus.

OBJECTIVES: Amylin is a pancreatic hormone that participates in glucose homeostasis. We aimed to investigate how serum amylin levels are expressed in patients with systemic lupus erythematosus (SLE) compared to matched controls, and their possible relationship to disease-related characteristics, such as activity or damage. METHODS: 144 SLE patients and 96 non-diabetic sex- (female 96% vs. 91%, p=0.43) and age-matched controls (49±11 vs. 51±8 years, p=0.09) were included. Amylin, insulin and C-peptide serum levels, as well as insulin resistance indexes were assessed in both groups. Multivariable regression analysis was performed to compare amylin between groups and to explore its interrelations with SLE features. The analyses were adjusted for glucocorticoids intake and for insulin resistance classic risk factors. RESULTS: Patients with SLE exhibited significant higher serum levels of amylin when compared to controls after multivariable analysis (beta coef. 1.56 [95%CI 1.01-2.11], p=0.000). Moreover, SLE patients not on prednisone (beat coef. 1.54 [95%CI 0.98-2.10] ng/ml, p=0.000) and those on prednisone (beta coef. 1.51 [95%CI 0.96-2.07] ng/ml, p=0.000) disclosed higher amylin serum levels compared to controls in the fully multivariable analysis. Hyperamylinaemia in SLE patients remained significant even adjusting for differences in the insulin resistance and beta cell production rates between patients and controls. The damage produced by the disease and its severity were independently and positively associated with amylin serum levels. CONCLUSIOINS: Amylin is upregulated in SLE patients compared to controls, regardless of the insulin resistance that SLE may present. The damage produced by the disease and its severity independently explains this upregulation.

Beta-cell function is disrupted in patients with systemic lupus erythematosus.

OBJECTIVES: To investigate how markers of beta-cell secretion (proinsulin-processing metabolites) are expressed in SLE patients and their potential relation to features associated with the disease such as activity or damage. METHODS: One hundred and forty-four SLE patients and 69 nondiabetic sex- and age-matched controls were assessed. Beta-cell secretion molecules, as measured by insulin, split and intact proinsulins, and C-peptide levels were analysed in both groups. Multiple regression analysis was performed to compare proinsulin propeptides between groups and to explore the interrelations with SLE features. Analyses were adjusted for glucocorticoid intake and for insulin resistance classic risk factors. RESULTS: Fully multivariable analysis demonstrated that regardless of glucocorticoid use, SLE patients exhibited higher levels of split proinsulin. Likewise, the split proinsulin-to-insulin ratio was upregulated in patients with SLE undergoing glucocorticoid therapy [beta coeficient 0.19 (95% Confidence Interval 0.07, 0.30), P = 0.002] or not [beta coef. 0.09 (95% CI: 0.01, 0.17), P = 0.025]. Similar results were found for the intact proinsulin-to-insulin ratio, although differences were only statistically significant for patients taking glucocorticoids [beta coef. 0.08 (95% CI: 0.03, 0.12), P = 0.001]. SLE damage score was associated with higher serum levels of intact [beta coef. 0.51 (95% CI 0.17, 0.86) pmol/l, P = 0.004] and split proinsulins [beta coef. 1.65 (95% CI 0.24, 3.06) pmol/l, P = 0.022] after multivariable analysis, including disease duration and prednisone use. CONCLUSION: Among patients with SLE, proinsulin-processing metabolites, a marker of beta-cell disruption, are upregulated compared with matched controls. This disproportionate hyperproinsulinemia can be explained by the damage produced by the disease and occurs independently of prednisone use.

Brain-derived neurotrophic factor among patients with alcoholism.

BACKGROUND: Brain-derived neurotrophic factor (BDNF) is involved in neurogenesis and in the protection against oxidative damage and neuronal apoptosis. After exercise, there is an increased expression of this myokine, especially in skeletal muscle and brain. Low BDNF levels have been described in neurodegenerative diseases. Alcoholics show both muscle atrophy and brain atrophy. Thus, this study was performed in order to analyze serum BDNF levels among alcoholics and their associations with brain atrophy and muscle strength. METHODS: Serum BDNF values were determined to 82 male alcoholics and 27 age-matched controls, and compared with handgrip strength, with the presence of brain atrophy, assessed by computed tomography, and with the intensity of alcoholism and liver function derangement. RESULTS: BDNF levels and handgrip strength were significantly lower among patients. Handgrip strength was correlated with BDNF values, both in the whole population and in alcoholics, especially in patients over 59 years of age. BDNF was poorly related to liver dysfunction but showed no relationship with brain atrophy or age. CONCLUSION: Chronic alcoholics show decreased BDNF serum levels that are related to muscle function impairment rather than to age, brain atrophy, liver dysfunction, or the amount of ethanol consumed.

Impaired beta cell function is present in nondiabetic rheumatoid arthritis patients.

INTRODUCTION: To investigate how markers of ß-cell secretion (proinsulin-processing metabolites) are expressed in rheumatoid arthritis (RA) patients and their potential relation with the insulin resistance (IR) observed in these patients. METHODS: The 101 RA patients and 99 nondiabetic sex- and age-matched controls were included. IR by homeostatic model assessment (HOMA2), and ß-cell secretion, as measured by insulin, split and intact proinsulin, and C-peptide levels were determined for both groups. Multiple regression analysis was performed to compare IR between groups and to explore the interrelations between RA features, proinsulin metabolites, and IR. Data were adjusted for glucocorticoids intake and for IR classic risk factors. RESULTS: Compared with controls, RA patients showed higher HOMA-IR (ß coef., 0.40 (95% CI, 0.20 to 0.59); P=0.00). When data were adjusted for glucocorticoids intake, noncorticosteroid patients maintained a higher IR index (ß, 0.14 (0.05 to 0.24); P=0.00). Impaired insulin processing in RA patients was detected by the onset of elevated split proinsulin levels (ß, 0.70 pmol/L (0.38 to 1.02); P=0.00). These data remained significant also when adjusted for prednisone intake (ß, 0.19 (0.00 to 0.36) pmol/L; P=0.04). Split proinsulin-to-C-peptide ratios were higher in RA patients undergoing corticosteroid therapy (ß, 0.25 (0.12 to 0.38); P=0.03) and were nearly significant in comparison between noncorticosteroids patients and controls (ß, 0.16 (-0.02 to 0.34); P=0.08). Interestingly, the impact of HOMA-IR on the ratio of intact proinsulin to C-peptide was higher in controls compared with patients (ß, 6.23 (1.41 to 11.06) versus 0.43 (-0.86 to 1.71); P=0.03). CONCLUSIONS: ß-Cell function is impaired in nondiabetic and in RA patients not taking corticoids by a mechanism that seems to be, at least in part, independent of IR.