The effects of Curcumin and Crocin on the inflammatory phase of thyroid eye disease: a randomized controlled clinical trial

doi:10.21203/rs.3.rs-3351031/v1

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The effects of Curcumin and Crocin on the inflammatory phase of thyroid eye disease: a randomized controlled clinical trial

https://doi.org/10.21203/rs.3.rs-3351031/v1

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Objective

A randomized, triple-blinded study was designed to assess the influences of curcumin and crocin on clinical findings and serologic markers, including IL-6 and TNF-α, of the inflammatory phase of thyroid eye disease (TED).

Methods

The curcumin and crocin were added to the traditional care of the patients after randomizing to placebo, curcumin, and crocin groups. Before interventions, CAS was evaluated and a blood sample (to measure the serum levels of IL-6 and TNF-α) was taken. The CAS was reassessed in the first and second months and the blood sampling was repeated in the second month afterward.

Results

A total of 46 TED cases (22 to 64 years old) were enrolled, 16 patients in the Placebo group, 17 patients in the Curcumin group, and 13 patients in the Crocin group. CAS, TNF-α, and IL-6 significantly reduced in all patients, regardless of their group and received drugs. No statistically significant difference was observed in the reduction of CAS score and TNF-α level in a two-month follow-up between the study groups.

Conclusion

Daily consumption of 30 milligrams (mg) of crocin or 80 mg of curcumin in addition to standard care could be effective in decreasing CAS in TED patients.

Thyroid eye disease

clinical activity score

curcumin

crocin

IL-6

TNF-α

serum inflammatory biomarkers

Thyroid eye disease (TED) is an inflammatory disorder with a wide variety of clinical signs and symptoms. Proptosis and lid retraction is the most common presentation of TED. The pathogenesis of the disease is open to new investigations already(1). Previous studies have suggested the imbalance of pro-inflammatory and anti-inflammatory factors as the core pathogenesis of TED(2). Some known autoantibodies such as anti-thyrotropin receptor antibodies and antibodies against insulin-like growth factor type 1 (IGF-1) receptors have a great role in the activation of the humoral and cellular immune system against orbital fibroblasts, leading the orbital fibroblasts to differentiate into adipocytes with increased thyrotropin receptor expression(3). Extraocular muscle enlargement and expanded orbital fat are believed to be the consequences of these immunologic imbalances(3). The orbital fibroblasts produce high levels of interleukin 1 (IL-1), interleukin 6 (IL-6), Interferon-γ (INF- γ), hyaluronan, and tumor necrosis factor-alpha (TNF-α), which causes the exacerbation of the inflammation and the occurrence of a vicious cycle(4). Expanded orbital tissues lead to compressive optic neuropathy and venous drainage impairment(5).

Previous studies showed the therapeutic effects of immunomodulating agents, including anti-IL-6 agents and TNF- α inhibitors in TED. However, the side effects of immunomodulatory medications are considerable in some cases(4).

Curcumin (diferuloylmethane) is the active substance of turmeric (Curcuma longa) rhizome hydroalcoholic extract. Curcumin has been used for a long time in Chinese and alternative medicine respecting its anti-inflammatory and anti-oxidant effects. Curcumin modulates several inflammatory pathways, inhibiting inflammatory cytokines such as IL-6 and TNF-α and growth factors such as platelet-derived growth factor (PDGF)(6, 7). Crocin is the active component of saffron (Crocus sativus Linn) extract. Crocin acts as an anti-inflammatory and antioxidant substance via inhibition of reactive oxygen species synthesis, lipid peroxidation, and the expression of IL-1, IL-6, and TNF-α genes (8, 9). The experimental and clinical evidence of the beneficial effects of Curcumin and Crocin in ophthalmic inflammatory diseases has been shown in previous studies(10, 11).

This study aims to investigate the anti-inflammatory effects of oral curcumin and crocin on the clinical severity and serum inflammatory biomarkers in TED.

This is a randomized, triple-blinded study. We evaluated the efficacy of adjuvant treatment with Curcumin or Crocin besides the routine care and corticosteroid therapy (as needed) for TED patients who were referred to the orbit clinic of the Khatam Al-Anbia Eye Hospital.

This study was done according to the Declaration of Helsinki, and the Mashhad University of Medical Sciences ethical committee approved this study (Ir.mums.medical.rec.1397/006). We obtained informed consent from the patients.

All participants underwent a complete ophthalmic examination including best-corrected distance visual acuity (BCVA) measurement with thumbing E chart, slit-lamp biomicroscopy, Goldmann applanation tonometry, and dilated fundus examination (using a + 90D condensing lens). We used the clinical activity score (CAS)(12) system to determine the activity status of TED in the patients. CAS includes the evaluation of 7 items as follows: spontaneous orbital pain, gaze-evoked orbital pain, eyelid swelling, eyelid erythema, conjunctival redness, chemosis, and inflammation of the caruncle or plica. Each item is rated one (if that item is positive) or zero. In follow-up exams, three items were added as follows: an increase of more than 2 millimeters proptosis, a decrease in uniocular ocular excursion in any one direction of more than 8 degrees, and a decrease of visual acuity equivalent to one Snellen line. A score of 4 or more is considered active in follow-up visits.

Patients entered the study if they fulfilled the inclusion criteria and signed the informed consent. The inclusion criteria were clinical activity score (CAS) equal to or more than 1, age 18–60 years old, and no previous treatment for TED. Exclusion criteria were systemic anti-inflammatory treatment, treatment disruption, follow-up disruption, and severe drug adverse effects. According to the initial CAS score, patients were divided into two groups as follows: the clinically active group, patients with CAS ≥ 4, and the clinically inactive group, patients with CAS < 4. All clinical evaluations were performed by one of the researchers. Our standard treatment protocol for clinically active TED is 500 mg weekly intravenous methylprednisolone pulse for six consecutive weeks. Clinically inactive patients are observed without receiving steroids. Lifestyle modification is recommended for all patients with TED.

Participants were randomly allocated into three groups and received either curcumin, crocin, or placebo adjuvant as follows: 80mg curcumin soft gels (Sina Curcumin®, Exir Nano Sina), 30 mg crocin soft gels (Krocina®, Sami Saz), and 80 mg polysorbate soft gels with the same size and shape as the placebo. All patients in each sub-group received treatment for two months. Patient demographic and clinical data, including the CAS, were collected for analysis on the first, 1-month, and 2-month follow-up visits. Besides, TNF-α and IL-6 plasma levels were measured at the first and the 2-month follow-up visits (Fig. 1).

Statistical analysis

We used the IBM SPSS software version 22 for statistical analysis. Mean ± standard deviation (SD) was used as descriptive statistics for quantitative variables, and median and interquartile range were used to describe qualitative variables. The changing pattern in the clinical course of the patients in each sub-group was investigated with the repeated measure ANOVA test during the study period. Furthermore, the significance of changes in serum levels of the inflammatory biomarkers in each sub-group was assessed utilizing the T-test.

In this study, a total of 46 TED cases were enrolled, 16 patients in the Placebo group, 17 patients in the Curcumin group, and 13 patients in the Crocin group. The participant’s age range was 22 to 64 years old. There was no significant difference in age and sex between groups (Table 1).

Table 1

Comparison of independent variables between intervention groups
Variable		Placebo	Curcumin	crocin	p-value
Gender (No.)	*Male	2	2	6	0.070
Gender (No.)	Female	14	15	7
**Age (Mean ± SEM)		35 ± 10	34.5 ± 9.4	41.7 ± 9.7	0.107
*Chi-square
** ANOVA test

CAS values, TNF-α, and IL-6 levels significantly reduced in all patients during the study period, regardless of the group (Table 2–4). Curcumin and crocin groups had a 68% and 64% decrement in CAS score that was more than the placebo group (51%) but was not statistically significant (p-value = 0.37).

Table 2

CAS changes during the study period in different groups of participants.
Group name	CAS (baseline)	CAS (month 1)	CAS (month 2)	p-value**
Placebo	2.18 ± 1.22	1.06 ± 0.68	0.81 ± 0.75	< 0.001
Curcumin	3.17 ± 0.63	3.51 ± 0.6	0.94 ± 0.96	< 0.001
Crocin	4.61 ± 1.12	2.15 ± 1.67	0.761 ± 0.641	< 0.001
**Repeated measure ANOVA

Table 3

Serum TNF-α changes during the study period in different groups of participants.
Group name	TNF-α (baseline) (pg/mL)	TNF-α (month 2) (pg/mL)	p-value**
Placebo	392 ± 32	364 ± 28	< 0.001
Curcumin	368 ± 43	346 ± 41	0.032
Crocin	401 ± 58	368 ± 71	0.004
**paired T-test

Table 4

Serum IL-6 changes during the study period in different groups of participants.
Group name	IL-6 pre (baseline) (pg/mL)	IL-6 (month 2) (pg/mL)	p-value**
Placebo	392 ± 32	364 ± 28	< 0.001
Curcumin	368 ± 43	346 ± 41	0.011
Crocin	401 ± 58	368 ± 71	0.005
**paired T-test

Regarding the anti-inflammatory effects of Curcumin and Crocin in the two subgroups of patients based on the disease activity (initial CAS score), the Curcumin group showed more decreasing effects in both initial clinically inactive (CAS < 4) and clinically active (CAS ≥ 4) groups. Although the difference was not significant in initially clinically inactive subgroups, we found a statistically significant difference between the three subgroups of patients in the initially clinically active patients (p = 0.016) (Table 5).

Table 5

Comparison of CAS decrease considering the initial CAS
	Placebo Percent (No.)	Curcumin Percent (No.)	Crocin Percent (No.)	p-value
CAS decrease in cases with initial CAS < 4	41.66 ± 46.87 (12)	56.94 ± 32.14 (12)	- (no cases)	0.362⁺
CAS decrease in cases with initial CAS ≥ 4 cases	81.25 ± 12.5 (4)	95.00 ± 11.18 (5)	63.34 ± 23.71 (13)	0.016*
⁺ T-test
*ANOVA test

In this study, we evaluated the anti-inflammatory effects of curcumin and crocin in clinical and serologic biomarkers of TED. Our findings demonstrate a decrease in CAS and inflammatory indices occurred in all three groups. The CAS values in the curcumin (68%) and crocin (64%) groups showed a greater decrease than in the placebo group. In patients with CAS > 4, the curcumin group showed a statistically significant effect on decreasing CAS in comparison to the other groups (P = 0.016).

In our study, there was no statistically significant difference in TNF-α and IL-6 serum levels decrement between the three groups. Previous studies have shown the reducing effects of crocin and curcumin on serum inflammatory biomarkers(6, 9). Lee et al. studied the effects of curcumin on fibroblast of patients with Grave’s disease and showed a dose-dependent decrement in inflammatory factors like monocyte chemo-attractant protein-1 (MCP-1), Intracellular adhesion molecule 1 (ICAM-1), IL-8, IL-6, and also in lipid droplets during adipose differentiation(13). Conney et al. showed that curcumin is a potent inhibitor of arachidonic acid-induced inflammation in vivo in mouse skin, and this compound is also a potent inhibitor of epidermal lipoxygenase and cyclooxygenase activity in vitro(14). Mishra et al. in a review article concluded that curcumin may have an affinity to bind hyaluronan protein and cessation of orbital swelling and therefore can be used for therapeutic purposes in TED which is consistent with the results of this study(15). In another study by Mohammadi et al., curcumin induced a significant decrease in serum IL-6, TNF-α, and expression of CRP compared to the placebo in a model of polycystic ovarian syndrome(16). Studies have shown that curcumin is an anti-inflammatory, antioxidant, and anti-apoptotic compound with an excellent safety profile(17). This substance works by affecting various cell transduction signaling pathways such as PI3K, STAT3, TLR-4, AMPK, and NLRP3 inflammasome (18–20). Pharmaceutical studies showed that the liposomal form of curcumin enhances the bioavailability and therapeutic potential(21). Xiang Li et al. investigated inflammatory biomarkers in rheumatoid arthritis on 60 rats that were treated with crocin and methotrexate(22). Crocin administration revealed a significant reduction in the serum content of TNF-α, IL-1β, and IL-6(23, 24). Yang et al. studied the effects of crocin on inflammation due to hemorrhagic shock and indicated that this natural compound significantly decreased the serum levels of proinflammatory cytokine TNF-α and IL-6(25). In our study, TNF-α and IL-6 decreased although it was not statistically significant. Studies have shown that the consumption of crocin can lead to the improvement of the cellular antioxidative system including superoxide dismutase (SOD), catalase, and glutathione reductase activity(26, 27). Also, inflammatory biomarkers such as toll-like receptors (TLR-4) and IL-6 decrease following crocin consumption. Furthermore, anti-fibrotic effects of crocin through TGF-β reduction have been reported previously(28). The pathophysiology of TED and immunomodulatory effects of crocin and curcumin are summarized in Fig. 2.

Our results suggested that crocin and curcumin, as an anti-inflammatory supplement, may be effective in reducing the TNF-α and IL-6 levels and lead to decreasing CAS of patients with TED. The use of systemic anti-inflammatory compounds with fewer systemic side effects can help in reducing the corticosteroid dose in patients. During the consumption of curcumin and crocin, no serious side effect was reported, which is similar to previous investigations.

To our knowledge, this study is the first randomized controlled clinical trial regarding the anti-inflammatory effects of crocin and curcumin in patients with TED. However, a small sample size and a short-term follow-up period are major limitations.

This clinical trial showed that daily consumption of 30mg crocin or 80mg curcumin in addition to the main drugs could be effective in decreasing CAS of TED patients.

Ethics approval

This clinical trial was approved by the Ethics Committee of Mashhad University of Medical Sciences with Ir.mums.medical.rec.1397/006 code number and registered to the Iranian Registry of Clinical Trials with the IRCT20171207037777N1 registration number.

Conflicts of interest statement

There are no conflicts of interest.

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No competing interests reported.

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The effects of Curcumin and Crocin on the inflammatory phase of thyroid eye disease: a randomized controlled clinical trial

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Results

Conclusion

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Introduction

Methods

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Results

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