The prevalence of diabetes is increasing, with type 2 diabetes mellitus comprising over 90% of cases. Diabetes mellitus complications, including diabetic retinopathy (DR), impose significant health burdens. GLP-1 receptor agonists (GLP-1RAs) and dual GIP/GLP-1 receptor agonists show promise in improving cardiovascular and kidney outcomes, but their effects on retinal microvasculature and neuroprotection remain unclear. This study investigates the impact of GLP-1RAs (semaglutide, liraglutide) and GIP/GLP-1-dual agonists (tirzepatide) on ocular blood flow and retinal function in DM patients.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DIAGNOSTIC
Masking
NONE
Enrollment
20
Laser Speckle Flowgraphy (LSFG)
• Optical Coherence Tomography (OCT)
• Optical Coherence Tomography Angiography (OCT-A)
Medical University Vienna
Vienna, State of Vienna, Austria
RECRUITINGOcular blood flow (LSFG)
Ocular Blood Flow measured by Laser Speckle Flowgraphy (LSFG) in arbitrary units
Time frame: From enrollment to last study day (=5-11 weeks)
Retinal vessel diameter
Retinal vessel diameter with DVA
Time frame: From enrollment to last study day (=5-11 weeks)
Retinal oxygen saturation
Retinal oxygen saturation with DVA
Time frame: From enrollment to last study day (=5-11 weeks)
Retinal oxygen extraction
Retinal oxygen extraction will be calculated from measurements of ocular blood flow and retinal oxygen saturation. The calculation will be based on a formula integrating these parameters to estimate retinal oxygen extraction. Unit of Measure: Arbitrary units
Time frame: From enrollment to last study day (=5-11 weeks)
Oxygen and carbon dioxide partial pressure in arterialized blood
Oxygen and carbon dioxide partial pressure in arterialized blood
Time frame: From enrollment to last study day (=5-11 weeks)
Central retinal thickness
Central retinal thickness with OCT
Time frame: From enrollment to last study day (=5-11 weeks)
Retinal nerve fiber layer thickness
Retinal nerve fiber layer thickness with OCT
Time frame: From enrollment to last study day (=5-11 weeks)
Retinal and choroidal microvasculature
Retinal and choroidal microvasculature with OCT-A
Time frame: From enrollment to last study day (=5-11 weeks)
Capillary blood glucose level
Capillary blood glucose level in mg/dL
Time frame: From enrollment to last study day (=5-11 weeks)
Autonomic and sensomotoric neuropathy measurements
Short-term spectral analysis of Heart rate variability (HRV) is obtained from recordings consisting of 256 seconds of artifact free recordings. Parameters of frequency-domain HRV are measured within the low-frequency band and high-frequency band, as well as total spectral variability. Outcome variables are spectral power (ms2) in both frequency bands as well as cumulative indices.
Time frame: From enrollment to last study day (=5-11 weeks)
Ocular perfusion pressure
Ocular perfusion pressure is calculated from systemic blood pressure and intraocular pressure. Unit of measurement: mmHg
Time frame: From enrollment to last study day (=5-11 weeks)
Intraocular pressure
Intraocular pressure
Time frame: From enrollment to last study day (=5-11 weeks)
Systemic hemodynamics - Blood pressure
Systolic and diastolic blood pressure is measured. Unit: mmHg
Time frame: From enrollment to last study day (=5-11 weeks)
Schirmer I Test
Schirmer I Test is performed. Unit of measuremnt: mm
Time frame: From enrollment to last study day (=5-11 weeks)
Finger sweat sampling
Finger sweat samples will be collected using stamped-out filter paper applied to the fingertip under standardized conditions. Samples will be analyzed using an untargeted multi-omics approach. Proteomic, eicosadomic, and metabolomic profiles will be assessed using high-resolution mass spectrometry platforms. Unit of Measure: Arbitrary units (normalized intensity values)
Time frame: From enrollment to last study day (=5-11 weeks)
Systemic hemodynamics - Heart rate
Heart rate is measured. Unit: Hz
Time frame: From enrollment to last study day (=5-11 weeks)
Systemic hemodynamics - Oxygen saturation
Oxygen saturation is measured. Unit: %
Time frame: From enrollment to last study day (=5-11 weeks)
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