Curcumin-Based Treatment for Macular Edema from Uncommon Etiologies: Efficacy and Safety Assessment

Curcumin Supplementation and Human Disease: A Scoping Review of Clinical Trials

Medicinal properties of turmeric (Curcuma longa L.), a plant used for centuries as an anti-inflammatory, are attributed to its polyphenolic curcuminoids, where curcumin predominates. Although "curcumin" supplements are a top-selling botanical with promising pre-clinical effects, questions remain regarding biological activity in humans. To address this, a scoping review was conducted to assess human clinical trials reporting oral curcumin effects on disease outcomes. Eight databases were searched using established guidelines, yielding 389 citations (from 9528 initial) that met inclusion criteria. Half focused on obesity-associated metabolic disorders (29%) or musculoskeletal disorders (17%), where inflammation is a key driver, and beneficial effects on clinical outcomes and/or biomarkers were reported for most citations (75%) in studies that were primarily double-blind, randomized, and placebo-controlled trials (77%, D-RCT). Citations for the next most studied disease categories (neurocognitive [11%] or gastrointestinal disorders [10%], or cancer [9%]), were far fewer in number and yielded mixed results depending on study quality and condition studied. Although additional research is needed, including systematic evaluation of diverse curcumin formulations and doses in larger D-RCT studies, the preponderance of current evidence for several highly studied diseases (e.g., metabolic syndrome, osteoarthritis), which are also clinically common, are suggestive of clinical benefits.

Assessment of the Anti-inflammatory Effects of NORFLO® ORO in Acute Relapses of HLA-B27-associated Autoimmune Uveitis: A Multicenter, Randomized, Placebo-controlled, Double-blind Clinical Study

BACKGROUND

An effective therapy to reduce the number and severity of HLA-B27-related acute anterior uveitis (AAU) recurrences represents a clinical need. Curcumin is a promising therapeutic option in various inflammatory eye diseases. To enhance its absorption and eye tissue selectivity, a phospholipidic-curcumin complex (PHBC) has been formulated (Iphytoone®, Eye Pharma S.p.A.).

AIMS

This study investigates if PHBC is effective and safe to decrease the number and intensity of HLA-B27-related AAU relapses.

METHODS

HLA-B27-related AAU patients were randomly divided to receive PHBC or placebo for 12 months (NCT03584724).

RESULTS

Compared with the previous year, the number of relapses decreased in both groups. The proportion of responders was significantly higher in the PBHC group. The severity of attacks was comparable. The study drug was well tolerated.

CONCLUSIONS

A beneficial effect of PHBC treatment is suggested because the proportion of responders was significantly higher in this group of patients.

Curcumin in Retinal Diseases: A Comprehensive Review from Bench to Bedside

Recent evidence in basic science is leading to a growing interest in the possible role of curcumin in treating retinal diseases. Curcumin has been demonstrated to be able to modulate gene transcription and reduce ganglion cell apoptosis, downgrade VEGF, modulate glucose levels and decrease vascular dysfunction. So far, the use of curcumin has been limited by poor bioavailability; to overcome this issue, different types of carriers have been used. Multiple recent studies disclosed the efficacy of using curcumin in treating different retinal conditions. The aim of this review is to comprehensively review and discuss the role of curcumin in retinal diseases from bench to bedside.

Effectiveness of a Hydrophilic Curcumin-Based Formulation in Coadjuvating the Therapeutic Effect of Intravitreal Dexamethasone in Subjects With Diabetic Macular Edema

Purpose: This study evaluates if the addition of a curcumin formulation with a polyvinylpyrrolidone-hydrophilic carrier (CHC; Diabec^®, Alfa Intes, Italy) to intravitreal injections of dexamethasone (DEX-IVT) can affect the morphological retinal characteristics, extending the steroid re-treatment period in patients with diabetic macular edema (DME).

Methods: A randomized controlled clinical trial was carried out in DME patients, randomly assigned to receive DEX-IVT or DEX-IVT and a CHC. The evaluation of the mean difference of central retinal thickness (CRT) was the primary aim. Secondary aims were the evaluations of best-corrected visual acuity, differences in the predetermined retinal layer thickness, the number/time of re-treatment, and the assessment of safety.

Results: A total of 73 DME patients were included (35 in the control group and 38 in the combined therapy group). In both the control and combined therapy groups, the mean CRT change from T₀ to the 6 months’ evaluation was significant (p = 0.00). The mean CRT result was significantly different at month 4 (p = 0.01) between the control and combined therapy groups, with a greater reduction in the combined therapy group, in particular, in patients with ≤10 years of diabetes. A trend of CRT reduction in the combined therapy group has been observed also considering patients with subfoveal neuroretinal detachment. In addition, we observed that the reduction of inner retinal layer thickness was greater in the combination group, in comparison with controls.

Conclusion: The combination of a CHC to DEX-IVT is a promising therapeutic option in case of DME, in particular, for patients with early-stage diabetes and with an inflammatory phenotype. Further studies will be necessary to confirm these findings.

Systemic Curcumin-Human Serum Albumin in Proliferative Vitreoretinal Retinopathy: A Pilot Study

Objectives The purpose of this study is to compare the risks of novel postoperative curcumin infusion in patients with increased proliferative vitreoretinal retinopathy (PVR) after retinal detachment with steroid infusion or no treatment. Methods This was a prospective, non-randomized pilot study of 15 eyes of 15 patients (mean age 68 ± 7 years) with retinal detachment, macula off, and flare >15 pc/ms. Postoperatively, the patients received either curcumin-HSA (human serum albumin) infusion (C, n=5), prednisolone infusion (P, n=5), or no therapy (N, n=5) for three days. The outcome measures included postoperative PVR rate, the number of vitreoretinal surgeries (VRS) required, epiretinal membrane development, and visual acuity (VA).  Results All patients had a preoperative VA of hand movements, macula-off detachment situation, and two quadrants rhegmatogenous retinal detachment. Patients underwent VRS at a mean time of 5.6 ± 1.5 (C), 4.9 ± 2.0 (P), 4.7 ± 1.2 (N) days after first recognized symptoms. Postoperative PVR developed just in one eye (P) after 16 days and required VRS due to PVR retinal detachment. The remaining 14 patients of group C and N did not develop PVR. BCVA improved six months post surgery to 0.56 ± 0.31 (P), 0.53 ± 0.19 (D), 0.53 ± 0.17 (N) logMAR. There were no side effects nor complications related to the postoperative infusions.  Conclusions In this pilot study, we demonstrated that a postoperative application of curcumin infusion is a safe option in patients with an increased risk of PVR. Whether or not PVR can be reduced by curcumin infusion would require to be investigated in larger, randomized clinical trials.

Recent Advances and Disputes About Curcumin in Retinal Diseases

Curcumin belongs to the group of so-called phytocompounds, biologically active molecules produced by plants exerting a beneficial effect on health. Curcumin shows a wide spectrum of different properties, being an anti-inflammatory, antioxidant, antimicrobial and antimutagenic molecule. The purpose of the review is to examine what literature reported on the characteristics of curcumin, particularly, on the beneficial and controversial aspects of this molecule, aiming for a better therapeutic management of retinal diseases. The retina is a constant target of oxidative stress, this tissue being characterized by cells rich in mitochondria and by vessels and being, obviously, continuously reached from photons affecting its layers. Particularly, the retinal ganglion cells and the photoreceptors are extremely sensitive to oxidative stress damage and it is well known that an imbalance in reactive oxygen species is often involved in several retinal diseases, such as uveitis, age-related macular degeneration, diabetic retinopathy, central serous chorioretinopathy, macular edema, retinal ischemia-reperfusion injury, proliferative vitreoretinopathy, hereditary tapeto-retinal degenerations, and retinal and choroidal tumors. To date, several studies suggest that oral treatment with curcumin is generally well tolerated in humans and, in addition, it seems to have no negative effects: therefore, curcumin is a promising candidate as a retinal disease therapy. Unfortunately, the primary limitation of curcumin is represented by its poor bioavailability, in fact only a minimal fraction of this substance can reach the blood stream in the form of a biologically active compound. However, many steps have been made in several fields. In the future, it is expected that the strategies developed until now to allow curcumin to reach the target tissues in adequate concentrations could be ameliorated and, above all, large in vivo studies on humans are needed to demonstrate the total safety of these compounds and their effectiveness in different eye diseases.