March 2012
Volume 53, Issue 14
ARVO Annual Meeting Abstract  |   March 2012
Palmitoylethanolamide Intake Ameliorates Systemic Endothelial Function In Ocular Hypertensive Patients
Author Affiliations & Notes
  • Ernesto Strobbe
    Ophthalmology Department, University of Bologna, Bologna, Italy
  • Mauro Cellini
    Ophthalmology Department, University of Bologna, Bologna, Italy
  • Emilio C. Campos
    Ophthalmology Department, University of Bologna, Bologna, Italy
  • Footnotes
    Commercial Relationships  Ernesto Strobbe, None; Mauro Cellini, None; Emilio C. Campos, None
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science March 2012, Vol.53, 5101. doi:
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      Ernesto Strobbe, Mauro Cellini, Emilio C. Campos; Palmitoylethanolamide Intake Ameliorates Systemic Endothelial Function In Ocular Hypertensive Patients. Invest. Ophthalmol. Vis. Sci. 2012;53(14):5101.

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      © ARVO (1962-2015); The Authors (2016-present)

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To assess the action and safety of palmitoylethanolamide (PEA) on peripheral vascular endothelial function in ocular hypertensive patients (OHT).


A prospective randomized double-blind placebo controlled cross-over study. Forty OHT patients were enrolled and compared with 40 healthy age-matched controls. Possible confounders that could affect endothelial function from the study samples were eliminated. Participants underwent an endothelium dependent flow mediated vasodilation (FMD) evaluation using high-resolution 2-dimensional ultrasonographic imaging of the brachial artery at baseline (T0). Then, OHT patients were randomly assigned to receive either PEA or a matching placebo for three months (T1). The first medication period was followed by two-month washout period (T2), and the patients subsequently received either PEA or the placebo (depending on the first drug received) for another three months (T3). FMD evaluations were repeated at times T2 and T3.


OHT patients showed significantly lower FMD values compared to controls (6.06±0.60% vs. 10.85±1.80%; p<0.002) at baseline but no significance difference was demonstrated in ET-1 plasma levels. Three-month PEA intake led to significantly improved FMD values in OHT patients (8.46±1.09% vs. 6.08±0.62%; p<0.001; r=0.96) compared to placebo intake (6.05±0.68% vs. 6.04±0.58%; p<0.355). After 2 months of washout, subjects who had been given PEA therapy maintained better FMD values than at the baseline (6.59±0.33% vs. 6.08±0.62%; p<0.003). Then, each patient switched to the other treatment, depending on the first drug received and at T3, subjects who started PEA intake showed a significant improvement in their FMD values (8.52±1.07% vs. 6.05±0.68%; p<0.001; r=0.79), whereas the FMD values in patients who were taking the placebo were reduced from 6.59±0.33% to 6.19±0.41% (p<0.001).


This study shows that PEA ameliorates peripheral endothelial function in patients with OHT, and its positive effect lasts longer than the period of PEA consumption. PEA was well tolerated, and no side effects during the treatment period were observed. We suppose that its capacity to modify endocannabinoid levels in the eye could ameliorate the regulation of microcirculation and guarantee the necessary ocular blood flow demand, reducing the susceptibility of OHT patients to developing a glaucomatous optic neuropathy.

Clinical Trial: ISRCTN72647928

Keywords: intraocular pressure • neurotransmitters/neurotransmitter systems 

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