How Does the Diabetes Drug, Pioglitazone, Reduce Protein Loss in the Urine?

September 15, 2009 updated by: Christchurch Hospital

A Study on the Anti-proteinuric Effects of Pioglitazone in Patients With Type 2 Diabetes.

Pioglitazone is an insulin sensitising drug used in the treatment of patients with type 2 diabetes. In addition to its blood sugar lowering effect, pioglitazone also has a number of other beneficial effects, one of which is to reduce the loss of protein in the urine. The mechanism of this protein "sparing effect" of pioglitazone is not fully understood. The proposed study will investigate whether pioglitazone has beneficial effects on the filtration characteristics of filters in the kidney that are responsible for retaining protein in the body. The effect of pioglitazone on the size of the pores in the filters and also the electrostatic charge barriers that surround these pores will be investigated. The clinical study will involve 12 patients with type 2 diabetes with minimal urine protein loss, taking low dose pioglitazone for 3 months. Blood and urine samples will be collected at the beginning, mid point and end of the study and used to measure the concentration of specific proteins of different size and electrostatic charge. This data will be used to identify and characterise changes in the filtration properties of the kidney filters during the study.

Study Overview

Status

Unknown

Conditions

Intervention / Treatment

Detailed Description

In addition to their insulin sensitising action, thiazolidinediones (TZDs) have beneficial effects on vascular function. These include a decrease in proteinuria and amelioration of diabetic nephropathy. Although the anti-proteinuric effect of TZDs is well established the mechanism(s) underlying these changes has yet to be determined. Possible mechanisms include altered renal haemodynamics, maintenance of anionic electrostatic filtration barriers in the glomerular basement membrane and pleiotropic effects.

The target of TZDs, the peroxisome proliferator-activated receptors (PPARs), directly modulate vessel wall function. The kidney differentially expresses all PPAR isoforms and there is evidence that TZDs have pleiotropic effects in the kidney over and above their metabolic and haemodynamic actions. These effects include a direct action on cultured mesangial cells, inhibition of in vivo mesangial expansion, reduction in podocyte injury, and decreased production of type IV collagen and urinary endothelin-1 levels in early stage diabetic nephropathy.

Glomerular ultrafiltration of plasma proteins is governed by the size of the filtration pores and the extent of anionic sites in the basement membrane and podocyte slit pore junction. It is possible that the anti-proteinuric effect of TZDs is attributable to an increase in size and/or charge selectivity in the glomerular filtration barrier. A Medline search showed there have been no studies on the effect of TZDs on protein ultrafiltration. The aim of the proposed study is to measure urinary protein size and charge selectivity in patients with early stage diabetic nephropathy before and after treatment with the TZD, pioglitazone.

Study Type

Interventional

Enrollment (Anticipated)

12

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • New Zealand
    • Canterbury
      • Christchurch, Canterbury, New Zealand, 8001
        • Christchurch Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 70 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Diabetes mellitus, Type 2
  • Age 18-70 yrs

Exclusion Criteria:

  • Overt proteinuria (urine albumin:creatinine ratio >10.0
  • Plasma creatinine 0.15 mmol/L
  • HbA1c >10%
  • Hear failure Class III or IV
  • Peripheral oedema
  • Abnormal liver function (serum AST >2.5 times upper limit of normal)
  • Pregnancy or breastfeeding
  • History of urinary tract infections
  • Serious concomitant disorder

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: 1
Open label arm
Drug: Pioglitazone
15-45 mg/day
Other Names:
  • Actos
  • Batch number A490463

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Reduction in proteinuria
Time Frame: 3 months
3 months

Secondary Outcome Measures

Outcome Measure
Time Frame
Reduction in non-fasting plasma glucose concentration
Time Frame: 3 months
3 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Christchurch Hospital

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

September 1, 2008

Primary Completion (Anticipated)

December 1, 2009

Study Completion (Anticipated)

March 1, 2010

Study Registration Dates

First Submitted

September 8, 2008

First Submitted That Met QC Criteria

September 8, 2008

First Posted (Estimate)

September 9, 2008

Study Record Updates

Last Update Posted (Estimate)

September 16, 2009

Last Update Submitted That Met QC Criteria

September 15, 2009

Last Verified

September 1, 2009

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • H6E-AY-O017

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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