This study will be a prospective, clinical pilot study in CKD patients to show whether
Empagliflozin in addition to ACEi treatment significantly increases Ang 1-7 levels compared
to ACEi treatment alone.
Null and alternative hypotheses:
H0: Empagliflozin in addition to ACEi treatment does not increase Ang 1-7 levels more than
ACEi treatment alone.
H1: Empagliflozin in addition to ACEi treatment significantly increases Ang 1-7 levels
compared to ACEi treatment alone
Methodology:
Two groups of 24 chronic kidney disease (CKD) patients, respectively, with and without type 2
diabetes will be randomized into the study medication or placebo group. The number of
patients per treatment arms is n = 12. Included and consented patients will be subjected to
an initial 2-week run-in period for conversion of current RAS blocking medications to ACEi
therapy with enalapril or ramipril and respective dose titration to 10 mg enalapril 2 x daily
and 10 mg ramipril 1 x daily. Additional antihypertensive medication will be standardized as
feasible, with the primary goal of keeping blood pressure as recommended by KDIGO. Following
the 2-week run-in phase, all study patients will be subjected to blood collection including
the first RAS quantification (RAS Fingerprint) and assessment of HDL composition, as well as
urinary analysis and bioimpedance fluid status assessment (BCM measurement). Subsequently,
patients will be randomized to either receive empagliflozin (at a dose of 10 mg daily) or
placebo. Subsequently, biweekly study visits including electrolyte and glucose (plasma and
urine) monitoring as well as BCM measurement will take place. After 12 weeks of study
medication intake, a concluding study visit will be scheduled for final RAS quantification
(RAS Fingerprint) and HDL analyses as well as final blood and urinary analysis and BCM
measurement. Initially, blood and urine will be collected at the clinical visit as part of
the routine blood obtainment (no additional effort on patients). From these routine
measurements we will be able to extract information regarding the patient's current CKD stage
as well as other relevant laboratory parameters (e.g. HbA1c, UACR, etc.). Furthermore, we
will document the patient's current medication and significant comorbidities.
Primary analysis variable/endpoint:
The difference of Ang 1-7 increase from baseline between a 3-month treatment with
empagliflozin on top of ACEi treatment compared to ACEi treatment alone
Most important secondary analysis variables/endpoints:
1. Simultaneous quantitative changes of multiple RAS effector angiotensin levels determined
by mass-spectrometry
2. Recurrence of Ang II levels determined by mass-spectrometry
3. HDL parameters (protein composition of HDL)
4. Renal parameters (albuminuria reduction measured by urinary albumin-creatinine ratio
(UACR), renal function (estimated glomerular filtration rate (GFR), serum-creatinine)
5. Urinary electrolyte levels
6. Urinary glucose levels
7. Urinary RAS metabolites (angiotensinogen, ACE and ACE2 levels, ACE2 activity)
8. Blood pressure determined by ambulatory blood pressure measurements
9. Body volume determined by bioimpedance fluid status assessment (BCM measurement)
10. OCR and ECAR in PBMCs determined by Seahorse Flux Analyzer
11. Assessment of reduction of salt sensitivity by using salt sensitivity test with
empagliflozin