Cox proportional hazard model analysis of survival in end-stage renal disease patients with small-sized high-density lipoprotein particles

Revealing the Role of High-Density Lipoprotein in Colorectal Cancer

Colorectal cancer (CRC) is a highly prevalent malignancy with multifactorial etiology, which includes metabolic alterations as contributors to disease development. Studies have shown that lipid status disorders are involved in colorectal carcinogenesis. In line with this, previous studies have also suggested that the serum high-density lipoprotein cholesterol (HDL-C) level decreases in patients with CRC, but more recently, the focus of investigations has shifted toward the exploration of qualitative properties of HDL in this malignancy. Herein, a comprehensive overview of available evidences regarding the putative role of HDL in CRC will be presented. We will analyze existing findings regarding alterations of HDL-C levels but also HDL particle structure and distribution in CRC. In addition, changes in HDL functionality in this malignancy will be discussed. Moreover, we will focus on the genetic regulation of HDL metabolism, as well as the involvement of HDL in disturbances of cholesterol trafficking in CRC. Finally, possible therapeutic implications related to HDL will be presented. Given the available evidence, future studies are needed to resolve all raised issues concerning the suggested protective role of HDL in CRC, its presumed function as a biomarker, and eventual therapeutic approaches based on HDL.

Paraoxonase 1 and atherosclerosis-related diseases

A direct and an indirect relationship between paraoxonase 1 (PON1) and atherosclerosis exists. Given PON1's physical location within high-density lipoprotein (HDL) particles and its recognized enzyme activity, it is certainly reasonable to suggest that PON1 facilitates the antiatherogenic nature of HDL particles. PON1 also plays a role in regulating reverse cholesterol transport, antioxidative, anti-inflammatory, antiapoptotic, vasodilative, and antithrombotic activities and several endothelial cell functions. HDL dysfunctionality is a more recent issue and seems to be centered on pathological conditions affecting HDL structure and size profiles. This review is focused on the role of PON1 status in different atherosclerosis-related diseases that we have studied over the last twenty years (coronary heart disease, acute ischemic stroke, diabetes mellitus type 2, end-stage renal disease, chronic obstructive pulmonary disease, and sarcoidosis) with the aim to determine the true value of PON1 as a biomarker. The role of PON1 in cancer is also covered, as risk factors and mechanisms underlying both atherosclerosis and cancer share common features.

Association of Dyslipidemia, Oxidative Stress, and Inflammation With Redox Status in VLDL, LDL, and HDL Lipoproteins in Patients With Renal Disease

Some cardiovascular complications in patients with chronic kidney disease and end-stage renal disease may be caused by structurally and functionally modified lipoproteins. Redox status (advanced oxidation protein products [AOPPs]), prooxidant–antioxidant balance, total protein sulfhydryl (SH-groups), and paraoxonase 1 (PON1) activity were assessed in 77 renal patients and 20 controls. Lipoproteins were isolated using ultracentrifugation. PON1, PON3, and pentraxin-3 concentration were determined by enzyme-linked immunosorbent assay (ELISA). Dyslipidemia-Oxy-Inflammation (DOI) score was calculated as a sum of dyslipidemia, oxidative stress, and inflammation scores. The dyslipidemia score ( P < .001), oxy score ( P < .01), inflammation score (P < .001), and the DOI score ( P < .001) were higher in patient groups compared with controls. The very-low-density lipoprotein (VLDL) fraction contained the highest amount of AOPP ( P < .001) compared with other lipoprotein fractions in all groups. The low-density lipoprotein (LDL) fraction contained elevated AOPP in all groups compared with the high-density lipoprotein (HDL) fraction ( P < .001). Significant positive correlation was observed between AOPP in LDL fraction and DOI score (ρ = 0.510, P < .01). Dyslipidemia, oxidative stress, and inflammation play an interactive role in renal disease and are mutually associated with redox status in VLDL, LDL, and HDL lipoproteins in plasma of renal patients.

Downregulation of AdipoR1 is Associated with increased Circulating Adiponectin Levels in Serbian Chronic Kidney Disease Patients

BACKGROUND

Since the rise in plasma adiponectin levels in chronic kidney disease (CKD) patients has not yet been elucidated, we sought to investigate if patients on hemodialysis (HD) have altered expression of adiponectin receptors in peripheral blood mononuclear cells (PBMCs) compared to healthy subjects.

METHODS

This study included 31 patients with chronic kidney disease on HD and 33 healthy subjects (CG). Circulating adiponectin levels were measured by ELISA while AdipoR1 and AdipoR2 mRNA levels in PBMCs were determined by real-time PCR.

RESULTS

Plasma adiponectin levels were significantly higher in patients compared to control group (P=0.036). After adjustment for age, BMI and creatinine, this difference became even more significant (P=0.004). In both groups adiponectin correlated with creatinine (CG: r=-0.472, P=0.006; HD: r=-0.375, P=0.038), triglycerides (CG: r=- 0.490, P=0.004; HD: r=-0.488, P=0.005), insulin (CG: r=-0.386, P=0.038; HD: r=-0.506, P=0.012) and high density lipoprotein cholesterol (HDL-C) (CG: r=-0.672, P<0.001; HD: r=-0.584, P=0.001). Significantly lower expression of PBMCs AdipoR1 mRNA was found in patients compared to CG (P=0.034), while AdipoR2 mRNA levels were similarly expressed in PBMCs in both groups.

CONCLUSIONS

Complex pathological processes in CKD cause downregulation of AdipoR1 which could ultimately influence AdipoR1 protein levels leading to a state of ≫adiponectin resistance≪.

Using a web-based nutrition algorithm in hemodialysis patients

OBJECTIVES

The purpose of this study was to test the ability of a newly developed nutrition algorithm on (1) clinical utility and (2) ability to capture patient outcomes.

RESEARCH DESIGN

This was a prospective observational study, using a practice based research network structure, involving renal dietitians and hemodialysis [HD] patients.

SETTING

This study took place in HD outpatient units in five different countries.

SUBJECTS

Hundred chronic HD patients were included in this study. To select subjects, dietitians screened and consented patients in their facilities until 4 patients "at nutrition risk" based on the algorithm screening tool were identified. Inclusion criteria were patients aged older than 19 years, not on hospice or equivalent, able to read the informed consent and ask questions, and receiving HD.

MAIN OUTCOME MEASURE

The ability of the algorithm screening tool is to identify patients at nutrition risk, to guide clinicians in logical renal-modified nutrition care process chains including follow-up on relevant parameters, and capture change in outcomes over 3 months. Statistics were performed using SPSS version 20.0 and significance was set at P < .05.

RESULTS

One hundred patients on HD, enrolled by 29 dietitians, were included in this analysis. The average number of out-of-range screening parameters per patient was 3.7 (standard deviation 1.5, range 1-7), and the most prevalent risk factors were elevated parathyroid hormone (PTH; 62.8%) and low serum cholesterol (56.5%). At the initial screening step, 8 of the 14 factors led to chains with nonrandom selection patterns (by χ(2) test with P < .05). In the subsequent diagnosis step, patients diagnosed within the insufficient protein group (n = 38), increased protein intake by 0.11 g/kg/day (P = .022). In patients with a diagnosis in the high PTH group, PTH decreased by a mean of 176.85 pg/mL (n = 19, P = .011) and in those with a diagnosis in the high phosphorous group, serum phosphorous decreased by a mean of 0.91 mg/dL (n = 33, P = .006). Finally, the relative likelihood of each assessment being completed after making the related diagnosis at the previous visit compared with those for whom that diagnosis was not made was assessed, including the likelihood of a patient's protein intake assessed after a diagnosis in the insufficient protein group was made (odds ratio = 4.08, P < .05).

CONCLUSIONS

This study demonstrates the clinical utility of a web-based HD-specific nutrition algorithm, including the ability to track changes in outcomes over time. There is potential for future research to use this tool and investigate the comparative impact of nutrition interventions.

Role of HDL dysfunction in end-stage renal disease: a double-edged sword

End-stage renal disease (ESRD) is associated with a significant propensity for development of atherosclerosis and cardiovascular mortality. The atherogenic diathesis associated with ESRD is driven by inflammation, oxidative stress, and dyslipidemia. Reduced high-density lipoprotein cholesterol (HDL-C) level and high-density lipoprotein (HDL) dysfunction are the hallmarks of ESRD-related dyslipidemia. Clinical and laboratory studies have revealed that ESRD is associated with significantly reduced serum apolipoprotein A-I (ApoA-I) and HDL-C level as well as altered HDL composition. Furthermore, although ESRD is associated with impaired HDL antioxidant and anti-inflammatory properties in most patients, in a small subset, HDL may in fact have a pro-oxidant and proinflammatory effect. Therefore, it is no surprise that serum HDL-C level is not a dependable indicator of cardiovascular disease burden in ESRD, and markers such as HDL function are critical to accurately identifying patients at risk for cardiovascular disease and mortality in ESRD.

Circulating cell-free DNA in hemodialysis patients predicts mortality

BACKGROUND

Circulating cell-free DNA (CFD) appears following cell damage and DNA release, and increases in hemodialysis (HD) patients particularly following HD. We hypothesized that CFD is an integrative marker of tissue damage and can be an independent predictor for all-cause mortality in HD patients.

METHODS

In a prospective study, CFD levels before and after HD were evaluated in 31 chronic HD patients with no acute disease, using the reported rapid non-cumbersome inexpensive fluorometric assay developed in our laboratory. Follow-up levels were assessed at 18 months in 22 patients. All-cause mortality was a primary endpoint.

RESULTS

During 42 months of follow-up, 13 of the 31 (41.9%) patients died. The decedents were older than the survivors (mean age 69.9 versus 61.5 years, P = 0.06), but did not differ in end-stage renal disease (ESRD) duration, gender, albumin and hemoglobin, diabetes mellitus and weight. Post-dialysis CFD levels were significantly lower in survivors (median 688 versus 880 ng/mL, P = 0.01). The sensitivity and specificity of CFD levels of 850 ng/mL to predict 42 months (3.5 years) mortality were 73 and 75%, respectively, and the area under the receiver-operating characteristic curve was 0.77 [95% confidence interval (CI) 0.60-0.94]. The Cox proportional hazard regression model showed that CFD higher than 850 ng/mL adjusted for age, ESRD duration, weight and creatinine (stepwise model) was highly predictive of all-cause death with a hazard ratio of 8.0 (95% CI 2.3-28.5, P = 0.001).

CONCLUSIONS

Post-dialysis CFD level is an independent predictor of all-cause mortality in patients undergoing HD. We propose that CFD detection is an inexpensive applicable tool for identifying patients at risk and their follow-up.