Study analysis · Advanced Science · 2025

This one enzyme could be why diabetes is stealing your vision — and a simple supplement might half-fix it.

In diabetic eyes, a broken enzyme called CHKA makes blood vessels leak and grow abnormally, but turning it off or boosting NAD+ with NMN can stop half the damage.

Reading level
Low certainty
Level 3b · Individual case-control studyAssociation, not causationNo causal claims

Overview

What the study found

The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.

In simple terms

This study found that a protein called CHKA is more active in the blood vessels of diabetic mice and some people with severe eye disease. It shows that when CHKA is turned down, the blood vessels get better—but this doesn't prove CHKA causes the problem in humans, just that they're linked.

What’s the bottom line?

In diabetes, some blood vessel cells in the eye turn on a special enzyme called CHKA, which makes them grow too much and leak fluid. This study found that turning off CHKA stops the leaks and bad growth.

How strong is this study?

The scientists did a lot of smart experiments in mice and looked at human tissue, which is great. But they only tested a few mice and a few people, and didn't randomly assign treatments—so we can't be super sure the results will work for everyone. It's a good clue, but not a final answer.

Reporting

40 / 100

  • COI disclosure+40/40
  • Data availabilitydata not shared
  • Code availabilitycode not shared
Methodology

32 / 100

  • Randomizationnot randomized
  • Blindingblinding unclear
  • Control group+15/15
  • Sample size (n=6)+0.6/20
  • Follow-up+10/10
Publication

100 / 100

Statistical

54 / 100

  • P-values+15/15
  • Effect size+20/20
  • Confidence intervalsno confidence intervals
  • Pre-registrationnot pre-registered

Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.

Where it sits

RCT reviews

Max 100

Randomized Trials

Max 90

Reviews of Cohort Studies

Max 85

Cohort Studies

Max 72

Reviews of Case-Control Studies

Max 63

Case-Control Studies

Max 58

Cross-Sectional & Case Series

Max 50

Expert Opinion

Max 5
StrongerWeaker
Case-Control Studies
Level 3b
53

53 / 100

Probability of being correct

Researchers compare people who have a condition (cases) with similar people who do not (controls), looking back in time for differences in exposure. Useful but more prone to bias.

This design cannot establish causation — the findings describe an association, not a cause. This study is primarily based on animal models and in vitro experiments with a very small human sample size (n=6 for diabetic mice in key experiments), lacks randomization, and uses observational clinical data. While Mendelian randomization suggests a possible causal link, the core experimental design does not meet criteria for establishing direct causation in humans.

No Conflicts

No conflicts of interest identified

No conflicts of interest or funding statements were disclosed in the provided text, and no industry affiliations or financial ties were identified among authors.

The study appears methodologically rigorous with single-cell RNA sequencing, in vivo validation, and clinical/genetic correlation. However, absence of a declared funding statement or COI section limits full transparency assessment. No evidence of industry influence or author conflicts was found.

Key takeaways

  1. 01

    CHKA was 2.5x higher in diseased eye vessels; silencing it reduced leaks by ~50% and bad blood vessel growth by ~40% in mice; NMN (a NAD+ booster) fixed half the damage.

  2. 02

    Yes — this suggests blocking CHKA could prevent vision loss in diabetics by stopping eye blood vessels from leaking and growing abnormally.

Surprising findings

  • CHKA silencing didn’t just reduce leaks — it activated the Notch pathway, which normally suppresses blood vessel growth, and this was reversed by NAD+ restoration.Most therapies try to block angiogenesis directly (like anti-VEGF drugs), but here, blocking CHKA indirectly turns on a natural 'brake' on vessel growth — a completely different mechanism.
  • CHKA was elevated in human diabetic retinopathy tissue and in aqueous humor — but not in non-pathological membranes.It’s rare to find a molecule so specifically tied to pathological tissue in humans — suggesting CHKA could be a diagnostic biomarker, not just a drug target.

Practical takeaways

If you have diabetes, ask your eye doctor about future CHKA biomarker tests — this enzyme could soon help predict who’s at highest risk for vision loss.

CHKA-targeting drugs don’t exist yet, and NMN supplements are not proven to prevent retinopathy in humans.

medium confidence

Don’t rely on NMN alone for eye protection — focus on proven strategies: tight blood sugar control, regular eye exams, and blood pressure management.

NMN’s partial rescue effect in mice doesn’t guarantee benefit in humans, and may even be counterproductive if used with future CHKA inhibitors.

high confidence

Why this study matters

The Leaky Eye Enzyme

Researchers found that in diabetic mice and humans, a specific type of retinal blood vessel cell turns on CHKA at 2.5x higher levels — and these cells are the ones causing leaks and abnormal blood vessel growth. Silencing CHKA reduced vascular leakage by ~50% and acellular capillaries by ~40% in mice.

Most people think diabetic eye damage is just from high sugar — but this shows a specific cellular culprit you can actually target, making it a potential new treatment path beyond just controlling blood sugar.

NMN: The Half-Healer

Giving NMN (a NAD+ booster) partially reversed the benefits of CHKA silencing — restoring NAD+ levels and bringing back some blood vessel growth and leakage. This means CHKA works through NAD+ metabolism, but NMN alone isn’t a full cure.

NMN is already sold as a longevity supplement — but this study shows it’s not a magic bullet for diabetic eye disease. It helps, but only halfway, which flips the narrative on popular supplements.

Your Genes Might Make You More Vulnerable

Using Mendelian randomization, the study found that people with genetic variants linked to higher CHKA expression had a significantly increased risk of diabetic retinopathy — suggesting CHKA isn’t just a symptom, but a causal driver.

This means your DNA might predispose you to vision loss even if you manage your diabetes well — making CHKA a potential biomarker for early screening.

Want the whole report?

Detailed mode opens the full scientific breakdown — every score component, the methodology, conflicts of interest, the evidence analysis behind each claim, and the raw study data.

Standing

Who’s using this study?

The videos and claims on this site that lean on this study, and the researchers who wrote it.

1 video from Doctor Alex cite this study, drawing 1 claim from it.

All 1 video reference this study through extracted claims.

Authored by

12 researchers

If this is your work, this is how we attribute it on Fit Body Science. Ling Ren is listed as the lead author.