The purpose of this study is to determine the effects of pioglitazone, once daily (QD), on low grade inflammation and vascular function in hypertensive patients.

Patients with insulin resistance and an activated inflammation are prone for cardiovascular complications like myocardial infarction or stroke. Pharmacological interventions reducing vascular inflammation are thought to reduce cardiovascular risk in diabetic and in non-diabetic patients.

Intervention with ACE inhibitors like ramipril is an established and widely used treatment for patients with high blood pressure, proven to reduce cardiovascular risk. Treatment of non-diabetic patients with pioglitazone has shown to improve the cardiovascular risk profile in non-diabetic patients beyond its effect on blood glucose levels.

The purpose of this study is to evaluate effects on low grade inflammation and vascular function of pioglitazone in non-diabetic, hypertensive patients with pre treatment with angiotensin converting enzyme inhibitors (that will be replaced by the study medication at time of randomization).

Inclusion Criteria:

• Has arterial hypertension.
• Is on stable treatment with an Angiotensin Converting Enzyme inhibitor at least for 12 weeks.
• Has a high sensitive C-Reactive Protein value greater than 1.0 mg/L and less than 10.0 mg/L.
• Females of childbearing potential who are sexually active must agree to use adequate contraception, and can neither be pregnant nor lactating from Screening throughout the duration of the study.

Exclusion Criteria:

• Manifests or has newly detected diabetes mellitus type 2 according to World Health Organization criteria.
• Has Type 1 Diabetes.
• Has acute infections.
• Chronic inflammatory diseases which cause elevated CRP-values (e.g. rheumatic diseases, pyelonephritis or osteomyelitis).
• Use of acetyl salicylic acid and/or Non-steroidal Anti-inflammatory Drugs or Cox-2-inhibitors within the last 4 weeks prior to screening visit, use of Rifampicin within the last 12 weeks prior to screening visit.
• Uncontrolled hypertension (repeated blood pressure greater than 180/100 mmHg for at least three times within two weeks); persistent hypotension (systolic less than 90 mmHg) or hemodynamic instability.
• Anamnestic history of hypersensitivity to the study drugs or to drugs with similar chemical structures.
• History of severe or multiple allergies.
• Treatment with any other investigational drug within 3 months before trial entry.
• Has a progressive, fatal disease.
• History of drug or alcohol abuse within the last 5 years.
• A history of significant cardiovascular (New York Heart Association stage I - IV, hemodynamic relevant aortic or mitral valve stenosis, hypertrophic obstructive cardiomyopathy), respiratory, gastrointestinal, hepatic (alanine aminotransferase greater than 2.5 times the normal reference range), renal (creatinine greater than 2.0 mg/dL), or hematological disease, history of macular edema.
• State after kidney transplantation, hemodynamic relevant renal artery stenosis (bilateral or unilateral in case of single kidney).
• Blood donation within the last 30 days.
• Serum potassium greater than 5.5 mmol/L.
• History of hyperaldosteronism.
• Treatment with thiazolidinediones within 3 months prior to screening.
• Acute myocardial infarction, open heart surgery or cerebral events (stroke/transient ischemic attack) within 30 days prior to screening visit.
• If statin therapy applicable: Change of medication within the last 12 weeks.
• History of angioneurotic edema (hereditary or idiopathic as consequence of previous Angiotensin Converting Enzyme inhibitor treatment).
• Dialysis or hemofiltration.
• Low Density Lipoprotein apheresis with dextran sulphate.
• Allergic to toxic agents derived from insects.