Curcumin and Retinal Study

Overview

To test how two weeks of curcumin supplementation would cross the blood brain barrier (BBB) and attach to amyloid beta proteins, to assess the feasibility (safety and bioavailability), and to explore the resulting abundance/composition of gut microbiota.

Full Title of Study: “Curcumin and Retinal Amyloid-beta Pilot Study”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Other
    • Masking: Triple (Participant, Investigator, Outcomes Assessor)
  • Study Primary Completion Date: March 31, 2025

Detailed Description

Alzheimer's disease (AD) leads to progressive cognitive decline. Increased amyloid beta (Aβ) burden and Aβ deposits have been shown in the AD retina. Aβ accumulation inside retinal pericytes in AD and pericyte degeneration in the retina mirror prominent features of brain AD pathology. Curcumin, a derivative of turmeric, has a high affinity for amyloid beta. Thus, curcumin would bind to amyloid beta plaques and emit a strong fluorescent signal, suggesting it can be a powerful diagnostic tool for AD. Emerging evidence has shown the connection between the brain and GI tract (gut microbiome), and its potential implications for both metabolic and neurologic diseases including AD. This pilot study is to test how two weeks of curcumin supplementation would cross the blood brain barrier and attach to amyloid beta proteins and to explore the resulting abundance/composition of gut microbiota. The investigators plan to recruit subjects through direct person-to-person solicitation in the Ophthalmology clinics, health fairs, community events, flyers, non-solicited email system, campus announcements, Clinical Research Institute Volunteer Database website, local radio, newspapers, senior newsletters, and TV scripts. The Clinical Research Institute Volunteer database will also be queried and potential subjects contacted as requested in their form. The investigators plan to enroll approximately 100-150 patients to obtain 30-40 qualified subjects at the start of the study. After screening, qualified participants will be randomly assigned to a low curcumin group or high curcumin group. Thus, this pilot study would focus on characterizing the distribution, manifestation, and prevalence of curcumin-loaded retinal Aβ deposits in study subjects with existing Aβ plaque (primary outcome). In addition, this study will assess safety, bioavailability, and fecal microbiome composition (secondary outcome). All outcomes will be assessed at baseline and after 2 weeks of intervention. Data will be analyzed statistically.

Interventions

  • Drug: Low curcumin group
    • One curcumin capsule (250 mg curcumin) after each meal, 3 times a day for 2 weeks.
  • Drug: High curcumin group
    • One curcumin capsule (500 mg curcumin) after each meal, 3 times a day for 2 weeks.

Arms, Groups and Cohorts

  • Active Comparator: Low curcumin group
  • Active Comparator: High curcumin group

Clinical Trial Outcome Measures

Primary Measures

  • Retinal imaging- amyloid fluorescent intensity
    • Time Frame: Baseline
    • To access amyloid fluorescent intensity
  • Retinal imaging-amyloid fluorescent deposit number
    • Time Frame: Baseline
    • To access amyloid fluorescent deposit number
  • Retinal imaging-amyloid fluorescent location
    • Time Frame: Baseline
    • To access amyloid fluorescent location
  • Retinal imaging-amyloid fluorescent intensity
    • Time Frame: After 2 weeks
    • To access amyloid fluorescent intensity
  • Retinal imaging-amyloid fluorescent deposit number
    • Time Frame: After 2 weeks
    • To access amyloid fluorescent deposit number
  • Retinal imaging-amyloid fluorescent location
    • Time Frame: After 2 weeks
    • To access amyloid fluorescent location

Secondary Measures

  • Bioavailability- curcumin concentrations in plasma
    • Time Frame: Baseline
    • To measure curcumin concentrations in plasma
  • Bioavailability-curcumin concentrations in red blood cells
    • Time Frame: Baseline
    • To measure curcumin concentrations in red blood cells
  • Bioavailability-curcumin concentrations in plasma
    • Time Frame: After 2 weeks
    • To measure curcumin concentrations in plasma
  • Bioavailability-curcumin concentrations in red blood cells
    • Time Frame: After 2 weeks
    • To measure curcumin concentrations in red blood cells
  • Liver function-serum AST
    • Time Frame: Baseline
    • To assess serum AST
  • Liver function-serum ALT
    • Time Frame: Baseline
    • To assess serum ALT
  • Kidney function-serum BUN
    • Time Frame: Baseline
    • To assess serum BUN
  • Liver function-serum ALT
    • Time Frame: After 2 weeks
    • To assess serum ALT
  • Kidney function-serum BUN
    • Time Frame: After 2 weeks
    • To assess serum BUN
  • Gut microbiome-abundance
    • Time Frame: Baseline
    • To measure the abundance of intestinal bacterial in feces
  • Gut microbiome-composition
    • Time Frame: Baseline
    • To measure the composition of intestinal bacterial in feces
  • Gut microbiome-abundance
    • Time Frame: After 2 weeks
    • To measure the abundance of intestinal bacterial in feces
  • Gut microbiome-composition
    • Time Frame: After 2 weeks
    • To measure the composition of intestinal bacterial in feces

Participating in This Clinical Trial

Inclusion:

  • Both male and female, age 40 – 89 years. – Diagnosed with Aβ deposits in retina (peripheral superior quadrants)–to be confirmed after consent obtained. If there is documentation the potential participant has been diagnosed with Aβ deposits in retina within 6 months before the consent session, we will use this diagnosis/documentation for eligibility criteria. Otherwise, the ophthalmic exam will be repeated after consent is obtained for the study. – No pre-existing liver or kidney diseases by self-report. Exclusion: – Patients with ocular diseases (macular degeneration, severe diabetes retinopathy) – Had used systemic antibiotics within 1 month prior to the start of the study intervention – Had taken any turmeric or curcumin products within 2 weeks prior to the start of the study intervention – Had a known allergy to black pepper – Women that are pregnant or breastfeeding

Gender Eligibility: All

Minimum Age: 40 Years

Maximum Age: 89 Years

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • Texas Tech University Health Sciences Center
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Official(s)
    • Chwan-Li (Leslie) Shen, PhD, Principal Investigator, Texas Tech University Health Sciences Center
  • Overall Contact(s)
    • Chwan-Li (Leslie) Shen, PhD, 8067432815, leslie.shen@ttuhsc.edu

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