Vitamin D in mild cognitive impairment and Alzheimer's disease. A study in older Greek adults

BACKGROUND

In recent years, accumulating evidence has linked vitamin D deficiency to cognitive dysfunction and dementia. This study aimed at determining the relevance of serum 25-hydroxyvitamin D concentrations in mild cognitive impairment (MCI) and Alzheimer's disease (AD) in older Greek adults. It also examined whether the vitamin D level could be considered a predisposing factor for conversion from MCI to AD.

METHODS

The study enrolled 350 subjects aged 65 years and over, allocated into three groups consisting of 103 healthy subjects (HS), 109 individuals with MCI, and 138 patients with AD, respectively. Serum 25-hydroxyvitamin D [25(OH)D] concentrations, measured in ng/ml, were determined by electrochemiluminescence, and we used the Mini-Mental State Examination (MMSE) and the Cambridge Cognition Examination (CAMGOG) to evaluate the subjects' cognitive status. One follow-up examination was performed for the MCI patients 30 months ± three months after the initial evaluation.

RESULTS

Compared to HS, serum 25(OH)D levels were significantly decreased in individuals with MCI (p =0.012) and patients with AD (p <0.001). Moreover, serum 25(OH)D concentrations were significantly decreased in patients with AD compared to individuals with MCI (p =0.003) and also significantly lower in individuals with MCI who progressed to AD compared to those who remained MCI (p =0.028). After adjusting for confounders, multivariate analysis revealed that an increase of vitamin D concentration by one ng/mL reduces the risk of MCI by 4 % (OR =0.96, 95 % CI =0.92-0.99, p =0.006), the risk of AD by 8 % (OR =0.92, 95 % CI =0.89-0.95, p <0.001), and in an individual with MCI reduces the risk of conversion to AD by 10 % (OR =0.90, 95 % CI =0.83-0.96, p =0.003).

CONCLUSIONS

The present study reveals that serum vitamin D levels are significantly decreased in subjects with MCI and patients with AD compared to HS. Additionally, individuals with MCI who progressed to AD presented significantly lower vitamin D levels than those who remained MCI. These results suggest that preserving adequate vitamin D status in older adults could delay or prevent cognitive decline. HIPPOKRATIA 2020, 24(3): 120-126.

Alpha1-microglobulin as an early biomarker of sepsis-associated acute kidney injury: a prospective cohort study

BACKGROUND

Sepsis emerges as the leading risk factor for acute kidney injury (AKI) development in critically ill patients. Much effort has been invested so far on early diagnosis of AKI using promising biomarkers. This study aimed to determine whether urine alpha1-microglobulin (α1m), a lipocaline member previously used as an indicator of proximal tubular dysfunction, can early predict the development of sepsis-associated AKI (SAAKI) in critically ill patients.

METHODS

A prospective, observational study was conducted in a single center Intensive Care Unit (ICU). Patients with normal renal function admitted to the ICU followed for sepsis and AKI development. Urine α1m levels were analyzed in pooled samples from 24-hour urine collections on sepsis onset and at various time points thereafter. The diagnostic performance of urine α1m was assessed using thenonparametriccalculation of the area under the curve (AUC) of the receiver operating characteristic (ROC) curve.

RESULTS

Among 286 critically ill patients admitted to our ICU in a year, 45 patients with sepsis met the inclusion criteria. SAAKI developed in 16 septic patients (35.6%). Urine α1m levels were significantly elevated in all septic patients (average value of all samples on the day of sepsis: 46.02 ± 7.17 mg/l) and showed a trend to increase in patients who finally developed SAAKI. The AUC for SAAKI prediction according to α1m urine levels 24-hours before SAAKI onset was 0.739 (sensitivity 87.5%, specificity 62.07%, cutoff level 47.9 mg/l). Urine α1m 24-hours before SAAKI, serum creatinine on sepsis onset and Acute Physiology and Chronic Health Evaluation II (APACHE II) score on sepsis onset emerged as the most powerful independent predictors of SAAKI. The combination of these three parameters improved the AUC for SAAKI prediction to 0.944.

CONCLUSION

Urine α1m levels might help in the early prediction of SAAKI development and may prove useful biomarker. The pathogenetic implications of α1m in sepsis and SAAKI need further investigation. Hippokratia 2014; 18 (3): 262-268.

Body fat distribution by anthropometric and MRI-based techniques in relation to insulin secretion and action in men with diabetes

AIM

Differences in fat accumulation and distribution might be responsible for the greater insulin resistance (IR) in type 2 diabetes. The study aims at examining the relationship between fat accumulation and distribution, and insulin secretion and action, by multilevel methodological approach.

METHODS

Thirty-three diabetic men (D), and 28 sex, age and BMI-matched controls (C) were studied for glucose and insulin during OGTT, insulin resistance and sensitivity, employing HOMA and Matsuda index respectively, and, fat accumulation and distribution by anthropometrics, Bioimpendance Analysis (BIA), and multiple slices MRI of abdomen and hip.

RESULTS

D exhibited higher HOMA compared to C (P<0.001), and lower Matsuda index (P=0.062). No differences in fat distribution by anthropometric or MRI measurements were observed; however, fat accumulation by BIA was higher in D (P=0.035). HOMA correlated to basal, AUC, and peak insulin in both groups (all P<0.001); with weight (r=0.415, P=0.031), hip circumference (HC) (r=0.482, P=0.011), %fat (r=0.400, P<0.05) in C; and with weight, BMI, total and %fat, and waist and HC when all subjects were considered as a group. Matsuda inversely correlated with basal, AUC, and peak insulin (all P<0.001), and HC (r=-0.406, P=0.032) in C. HOMA strongest correlated with L3-L4 subcutaneous (r=0.551, P=0.003) in C, and with L3-L4 visceral (r=0.456, P=0.022) in D.

CONCLUSION

The greater IR in diabetic patients may not be interpreted by differences in fat distribution. IR correlates with different fat compartments in healthy and diabetic subjects of comparable fat distribution, suggesting differences in fat function.

Monocyte chemoattractant protein 1 is correlated with glycemic control and peripheral arterial disease in type 2 diabetic patients with metabolic syndrome

We evaluated the serum levels of monocyte chemoattractant protein 1 (MCP-1) and their association with peripheral arterial disease (PAD) in 199 patients with type 2 diabetes mellitus (T2DM) and metabolic syndrome ([MetS], group A) in comparison with 109 healthy controls (group B). In group A, MCP-1 levels were significantly (P < .001) higher than group B and exhibited a positive correlation with HbA1c (P < .001) and a negative correlation with ankle-brachial index (P < .001). In the same group, patients with PAD had significantly higher MCP-1 levels compared with those without PAD (P < .001). In conclusion, T2DM patients with MetS exhibit higher serum MCP-1 levels. The latter is associated with worse glycemic control and PAD. These results suggest a potential contributory role for MCP-1 in the pathogenesis of PAD in the presence of hyperglycemia and MetS in T2DM.

Peripheral neuropathy is associated with increased serum levels of uric acid in type 2 diabetes mellitus

We assessed serum uric acid (SUA) levels in patients with type 2 diabetes mellitus (T2DM) with or without peripheral neuropathy (diagnosed by the Neuropathy Disability score [NDS]). We enrolled 64 patients with T2DM with peripheral neuropathy (group A: 31 men, mean age 63.0 ± 2.8 years) and 66 age-, gender-, renal function- and T2DM duration-matched patients without neuropathy (group B: 32 men, mean age 62.4 ± 3.1 years). Serum uric acid was significantly higher in group A (P < .001). There was a significant correlation between SUA and NDS in both groups (group A: r(s) = .93, P < .001; group B: r( s) = .95, P < .001). C-reactive protein (CRP) was also significantly higher in group A (P < .001) and correlated significantly with SUA in both groups (group A: r(s) = .93, P < .001; group B: r(s) = .87, P < .001). Serum uric acid is increased in patients with T2DM with neuropathy versus those without. Whether SUA is involved in the pathogenesis of T2DM peripheral neuropathy remains to be established.

The fatty acid amide hydrolase (FAAH) Pro129Thr polymorphism is not associated with severe obesity in Greek subjects

Fatty amid acid hydrolase (FAAH) has been implicated at both protein and gene level with obesity. An association between Pro129Thr variant of the FAAH gene and obesity has been described, but various studies have yielded conflicting results. Our aim was to determine whether this polymorphism is related to severe obesity and whether it confers a risk for variability of quantitative metabolic traits in a cohort of Greek obese subjects. Two groups of severely obese subjects (BMI > 40 kg/m (2)) were studied: a group of 158 metabolically healthy and a group of 145 obese subjects with metabolic syndrome, which were compared to a control group consisting of 121 lean individuals. We did not find any association between the Pro129Thr polymorphism with severe obesity in both subgroups of obese subjects, between these two subgroups (p= 0.11) or on basic anthropometric characteristics in the three groups. Statistically significant differences were found for glucose and HDL in metabolically healthy subjects and HDL in the control group. The borderline significant p-values were not significant after correction for multiple testing. We were unable to find robust evidence of an association of the Pro129Thr variant with severe obesity, and any related quantitative traits among the obese Greek subjects examined.

The alteration of dialysate cancer antigen 125 concentration under a biocompatible bicarbonate peritoneal dialysis solution and the preservation of the mesothelial cell viability

BACKGROUND

The importance to maintain the peritoneal membrane integrity for peritoneal dialysis (PD) patients by using biocompatible solutions (with low or no glucose as osmotic factor and low in glucose degradation products-GDPs, without lactate as a buffer and with normal pH) becomes progressively more evident. The aim of the present study was to investigate the clinical effects of a novel bicarbonate-based biocompatible PD fluid, evaluating the alteration in the concentrations of dialysate marker CA125, a glucoprotein indicator of mesothelial cell mass. PATIENTS AND METHODS; This is a single-center, prospective cohort study of 12 stable CAPD patients (4 women, 8 men), mean age 71.3 +/- of 6.01 years, mean PD duration 31.9 +/- 21.33 months, treated with the usual conventional PD solutions (with increased GDPs, low pH, and lactate as a buffer system). After a six-month period, the patients changed for the next six-month period into bicarbonate PD solutions (BicaVera, Fresenius), after which they returned into their previous schema of conventional solutions for another six months. The dialysate marker of CA125 was repeatedly estimated at the beginning of the study (T0), after six months phase with the bicarbonate solutions (T6), and at the end of study (T12), after the second six-month use of the conventional PD solutions. All the samples were taken at the end of a four-hour dwell of an exchange with PD solution 2.5% glucose.

RESULTS

The dialysate mean value of CA125 at the beginning of the study (Td0-with conventional PD solutions) was 15.07 +/- 5.72U/mL. After six months with bicarbonate PD solutions, the mean CA125 value increased to 111.97 +/- 66.21U/mL, while the mean values dropped again to 22.72 +/- 16.06 U/mL at the end of the study, after the patients' return for another six months to the conventional solutions use. There was a statistically significant difference between the mean CA125 levels at the beginning (Td0) and the middle of the study (Td6; p = 0.00079) as well as between the mean levels of CA125 in the middle (Td6) and at the end of the study (Td12; p = 0.0014). In contrast, comparing the mean dialysate values of CA125 at the beginning (Td0) and at the end of the study (Td12), no statistically significant difference was revealed (p = 0.13).

CONCLUSIONS

For the use of the bicarbonate-based PD, more biocompatible solutions for six months produced a statistically significant increase in the dialysate concentration of the mesothelial cell mass indicator CA125. The decrease at the end of the study of CA125 mean value at a level similar with that observed at the beginning, after the six-month period of the conventional PD solutions, indicates that the clinical use of the new bicarbonate-based PD solutions may have an advantageous role in the preservation of peritoneal cell mass, maintaining also the integrity and longevity of the peritoneal membrane.