Serum Uremic Toxins and Histological Findings of the Blood Vessels in Dialysis Patients

A Correlation Between Histological Findings of the Blood Vessels in Patients With Chronic Renal Failure and Serum Uremic Toxins and Its Diagnostic Performance in the Assessment of the Cardiovascular Morbidity and Mortality

Patients treated by chronic renal replacement therapy are exposed to cardiovascular problems and suffer from an accelerated and sever atherosclerosis. Classical risk factors for atherosclerosis and cardiovascular diseases (CVD) do not explain the full risk of CVD in the dialysis patients. Additional risk factors are therefore likely to exist. The uremic syndrome is attributed to the progressive retention of a large number of compounds, which under normal conditions are excreted by the healthy kidneys. Uremic toxins such are parathormone (PTH), vitamin D and phosphates, cause development of renal osteodystrophy (ROD), i.e. disordered calcium and phosphate metabolism. Both conditions of hyperparathyroid and adynamic bone disease (ABD) lead to an elevated calcium x phosphate product and increased vascular calcification, which might occur in intimal and medial layer of the vessel wall. It is important to consider these processes separately, as the vascular consequences (occlusion with atheromatosis and vascular stiffening through medial calcification) are different. Moreover, the difference between uremic and non-uremic intimal plaque is not the size but its composition, with markedly increased calcium content. Hence, these observations have an important socio-economic impact because of the increased cardiovascular morbidity and mortality.

The investigators hypothesized that uremic toxins in dialysis patients influence directly and/or indirectly the development of atherosclerosis, vascular calcifications and CVD.

Study Overview

• Status: Completed
• Conditions: Chronic Renal Failure

Detailed Description

Rationale: Patients treated by chronic renal replacement therapy are exposed to cardiovascular problems and suffer from an accelerated and sever atherosclerosis. Classical risk factors for atherosclerosis and cardiovascular diseases (CVD) do not explain the full risk of CVD in the dialysis patients. Additional risk factors are therefore likely to exist. The uremic syndrome is attributed to the progressive retention of a large number of compounds, which under normal conditions are excreted by the healthy kidneys. Uremic toxins such are parathormone (PTH), vitamin D and phosphates, cause development of renal osteodystrophy (ROD), i.e. disordered calcium and phosphate metabolism. Both conditions of hyperparathyroid and adynamic bone disease (ABD) lead to an elevated calcium x phosphate product and increased vascular calcification, which might occur in intimal and medial layer of the vessel wall. It is important to consider these processes separately, as the vascular consequences (occlusion with atheromatosis and vascular stiffening through medial calcification) are different. Moreover, the difference between uremic and non-uremic intimal plaque is not the size but its composition, with markedly increased calcium content. Hence, these observations have an important socio-economic impact because of the increased cardiovascular morbidity and mortality.

Hypothesis: We hypothesized that uremic toxins in dialysis patients influence directly and/or indirectly the development of atherosclerosis, vascular calcifications and CVD.

Objectives:

To asses the histology of arterial vessels in patients with end-stage renal failure and to evaluate its relationship with serum uremic toxins.

To determine the biochemical and clinical risk factors that might influence the development of vascular calcifications and their diagnostic performance in the assessment of CVD morbidity and mortality.

Methods: A cross-sectional study will be conducted at the Department of Nephrology Skopje. After the initial assessment patients will be followed for 2 years as the prospective part of the study.

Seventy-five to ninety patients will be included, during one-year period or until proposed number of patients is recruited. The study cohort will be divided to 3 subgroups: 1) patients at the initiation of dialysis therapy, 2) patients on regular dialysis treatment for a few years and 3) patients undergoing renal transplantation. During the follow-up period cardiovascular and cerebrovascular events and the moment of their occurrence will be recorded, as well as the peripheral vascular diseases. Moreover, clinical, laboratory data and arterial vessel samples for histology will be collected at the moment of inclusion.

Expected outcomes: We expect the determination of high correlation coefficient between histological parameters and various uremic toxins, which are responsible for development atherosclerosis and vascular calcifications, leading to an accelerated progression of CVD in dialysis patients. This determination could help to design new preventive therapeutic tools in these patients. The result of this work will impose a positive impact on quality of life and therapeutic costs related to atherosclerosis not only in the dialysis populations but also in the pre-dialysis chronic renal failure populations and kidney transplant recipients.

• Study Type: Observational
• Enrollment (Actual): 100

Contacts and Locations

Study Locations

• Macedonia, The Former Yugoslav Republic of
  • Skopje, Macedonia, The Former Yugoslav Republic of, 1000
    • Department of Nephrology, University Clinical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

CKD patients with a need for dialysis within a few months CKD patients on dialysis with thormbosis of AV fistula CKD patients on dialysis scheduled for kidney transplantation

Description

Inclusion Criteria:

• Chronic renal failure patients with a need for creation of AV fistula
• Dialysis patients with a need of reanastomosing of the AV fistula (thrombosis or insufficient blood flow)

Exclusion Criteria:

• Diabetes
• Malignant disease
• Prior treatment with corticosteroids

Study Plan

How is the study designed?

Design Details

• Observational Models: Case-Crossover
• Time Perspectives: Prospective

Collaborators and Investigators

• Sponsor: University of Skopje
• Collaborators: Ministry of Science and Education, R. Macedonia
• Investigators: Principal Investigator: Goce Spasovski, MD, PhD, Department of Nephrology, University Clinical Center, Vodnjanska 17, 1000 Skopje, R. Macedonia; Study Chair: Momir Polenakovic, MD, PhD, Macedonian Academy of Science and Arts

Study record dates

Study Major Dates

• Study Start: December 1, 2006
• Primary Completion (Actual): November 1, 2008
• Study Completion (Actual): January 1, 2010

Study Registration Dates

• First Submitted: December 12, 2006
• First Submitted That Met QC Criteria: December 14, 2006
• First Posted (Estimate): December 15, 2006

Study Record Updates

• Last Update Posted (Estimate): February 9, 2010
• Last Update Submitted That Met QC Criteria: February 8, 2010
• Last Verified: December 1, 2008

More Information

Terms related to this study

• Keywords: Dialysis; vascular calcifications; uremic toxins; renal osteodystrophy
• Additional Relevant MeSH Terms: Kidney Diseases; Urologic Diseases; Renal Insufficiency, Chronic; Kidney Failure, Chronic; Renal Insufficiency
• Other Study ID Numbers: 13-1001/2-05

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No