Subchronic application of humic acids and associated compounds provokes histological changes of goitre in the rat

COVID-19 associated thyroid dysfunction and other comorbidities and its management using phytochemical-based therapeutics: a natural way

The present severe acute respiratory syndrome-2 (SARS-CoV-2) mediated Coronavirus pandemic (COVID-19) and post-COVID-19 complications affect human life drastically. Patients who have been cured of COVID-19 infection are now experiencing post-COVID-19 associated comorbidities, which have increased mortality rates. The SARS-CoV-2 infection distresses the lungs, kidneys, gastrointestinal tract, and various endocrine glands, including the thyroid. The emergence of variants which includes Omicron (B.1.1.529) and its lineages threaten the world severely. Among different therapeutic approaches, phytochemical-based therapeutics are not only cost-effective but also have lesser side effects. Recently a plethora of studies have shown the therapeutic efficacy of various phytochemicals for the treatment of COVID-19. Besides this, various phytochemicals have been found efficacious in treating several inflammatory diseases, including thyroid-related anomalies. The method of the phytochemical formulation is quick and facile and the raw materials for such herbal preparations are approved worldwide for human use against certain disease conditions. Owing to the advantages of phytochemicals, this review primarily discusses the COVID-19-related thyroid dysfunction and the role of key phytochemicals to deal with thyroid anomaly and post-COVID-19 complications. Further, this review shed light on the mechanism via which COVID-19 and its related complication affect organ function of the body, along with the mechanistic insight into the way by which phytochemicals could help to cure post-COVID-19 complications in thyroid patients. Considering the advantages offered by phytochemicals as a safer and cost-effective medication they can be potentially used to combat COVID-19-associated comorbidities.

Humic substances in drinking water and the epidemiology of thyroid disease

Thyroid diseases are common in all populations but the type and frequency depends on environmental factors. In Denmark geographical differences in iodine intake are caused by different iodine contents of drinking water, which varies from < 1 to 139 microg iodine per litre. Comparative epidemiologic studies have demonstrated considerable differences in type and occurrence of thyroid disease with more goitre and hyperthyroidism in Aalborg with water iodine content around 5 microg/L, and more hypothyroidism in Copenhagen with water iodine around 20 microg/L. In Denmark, iodine in ground water is bound in humic substances, which have probably leached from marine sediments in the aquifers. Interestingly, humic substances in water from other parts of the world have goitrogenic properties, especially humic substances from coal and shale. Humic substances are heterogeneous mixtures of naturally occurring molecules, produced by decomposition of plant and animal tissues. The effect of humic substances in drinking water on the epidemiology of thyroid disease probably depends on the source of aquifer sediments.

Toxicology review and risk assessment of resorcinol: thyroid effects

Resorcinol administered at high doses to rodents can disrupt thyroid hormone synthesis and can produce goitrogenic effects. These effects were not seen in a 2-year bioassay at doses of up to 520 mg/kg/day. There are species-specific differences in synthesis, binding, and transport of thyroid hormone that complicate interpretation of goitrogenesis in rodents. Clinical case reports from patients undergoing resorcinol therapy for dermatological indications reveal thyroid side effects when copious amounts of resorcinol-containing ointments are applied to integrity-compromised skin for months to years. Effect levels were greater than 34 mg/kg/day. Occupational epidemiology studies provide no evidence that exposure to resorcinol at levels greater than found in the general environment causes thyroid dysfunction. Studies investigating the relationship between endemic goiter and exposure to "phenolics," including resorcinol, in drinking water do not fulfill accepted scientific criteria for establishing resorcinol as a cause of thyroid disease. Those reports neither quantify exposure levels nor demonstrate dose-response relationships or rule out confounding by the multiple other chemicals present in water supplies, by bacterial contamination of water, or by nutritional factors. A risk assessment comparing potential worst-case exposures to resorcinol through its use in dermatological preparations supports the conclusion that under real-world conditions, human exposures to resorcinol are not expected to cause adverse effects on thyroid function.

Performance and ileal histomorphology of rats treated with humic acid preparations*

As humic acid (HA) substances have antiphlogistic, adsorptive, antitoxic and antimicrobial properties, we studied the possible effects of Farmagülatör, an organic HA preparation, on the rat performance, nutrient retention, ileal histomorphology and hydroxyproline (HP) content of the ileum in two experiments. In experiment 1, 48 male Wistar albino rats were allotted to three dietary treatments. Each was randomly assigned to four cages, each with four rats. The treatments consisted of a control diet (C) with no addition of Farmagülator Dry or Liquid, a treatment with addition of 2.5 g/kg Farmagülator Dry (FDry) and a control diet containing no FDry, but the rats had 3.5 ml/l Farmagülator Liquid in drinking water (FLiquid). The experiment lasted for 20 days. Changes in live weight were recorded at days 10 and 20 of the experiment. At the end of 20 days, all rats were killed to collect samples of intestinal tissues for the measurements of histological parameters. In experiment 2, 30 rats weaned at 21 days of age were divided into three groups, each with 10 rats, and individually caged in metabolism cages for 10 days. The above three treatments were randomly assigned to rats for 10 days to record body weight and feed intake. During the last 5 days, faecal outputs were collected to determine the dry matter and nitrogen retention. In experiment 1, FDry and FLiquid rats significantly (p<0.05) gained more live weight than the control rats. Improved weight gain with HA preparations was found to be highly associated with a high epithelial surface area as there were significantly (p<0.05) longer villi heights and crypt depths and increased HP contents of ileum in the HA treated rats compared with the control rats. Although the increased weight gain in FLiquid rats did not significantly (p>0.05) differ from the control rats in experiment 2 in contrast to the result in experiment 1, the FDry rats significantly (p < 0.05) gained more weight than the control rats. This was primarily found to be associated with significantly (p<0.05) increased feed intake and nitrogen retention in FDry rats compared with the control rats. It can be concluded that HA preparations, especially FDry, caused increased weight gain in rats as overall of two experiments. The improved weight gain only by FDry preparation was associated with increased ileal epithelial mass, increased feed intake, improved feed : gain ratio and increased nitrogen retention in rats.

Association of Anion Gap with Thyroid Dysfunction and Nodular Goiter in Capd Patients

Objective

To investigate the association of clinical parameters and serum anion gap with thyroid dysfunction and nodular goiter in continuous ambulatory peritoneal dialysis (CAPD) patients.

Design

Cross-sectional study.

Setting

Single dialysis unit and outpatient clinic.

Patients

This study included 89 uremic patients on CAPD. Gender ratio was 50 males to 39 females (M/F = 1.28); mean age was 54.8 years.

Main Outcome Measures

We investigated the prevalence of nodular goiter and thyroid dysfunction with a 10-MHz high-frequency ultrasound scanner and immunoassay kits.

Results

Nodular goiter was detected in 52.8% (47/89) of the CAPD patients. Patients with nodular goiter were older than those without goiter (57.7 vs 51.5 years, p < 0.05). Nodular goiter was found more frequently in females than in males (66.7% vs 44.0%, p < 0.05). Patients with nodular goiter had longer duration of CAPD than patients without goiter (51.6 ± 42.9 vs 31.0 ± 28.1 months, p < 0.02). In addition, CAPD patients with goiter had a higher serum anion gap (AG) (16.8 ± 3.3 vs 14.0 ± 4.5 mEq/L, p < 0.02) and a lower weekly creatinine clearance (55.9 ± 12.6 vs 64.6 ± 21.1 L/week/1.73 m2, p < 0.05) than patients without goiter. As serum AG gradually increased, significant alteration of thyroid parameters developed in the following sequence: ( 1 ) reduction of total T3 level at an AG level of 15, ( 2 ) elevation of thyrotropin (TSH) and increased prevalence of goiter at an AG of 18, and ( 3 ) reduction of free T4 and total T4 levels and elevation of TSH, with further increased frequency of goiter at an AG of 20 mEq/L.

Conclusion

According to this study, age, gender, dialysis duration, serum AG, and weekly creatinine clearance are correlated with prevalence of goiter in CAPD patients. Sequential alteration of thyroid function and increasing frequency of nodular goiter correlated with higher serum AG. There are two explanations for this correlation: the level of serum AG may be an indirect index of the level of serum goitrogens, and higher serum AG and increased frequency of nodular goiters might be a reflection of loss of residual renal function. Therefore, thyroid function screening and goiter detection using ultrasound should be considered when examining CAPD patients with progressively elevating serum anion gap.

Inhibition of endogenous thyroid hormone receptor-beta and peroxisome proliferator-activated receptor-alpha activities by humic acid in a human-derived liver cell line

Humic acid (HA), know to be ubiquitous in the natural environment, is present in almost all soil, surface water, and plants. Earlier studies indicate that HA can affect thyroid economy via binding with iodide, inhibiting both thyroid peroxidase and hepatic 5'-deiodinase in rodents. However, the effect of HA, a peroxisome proliferator in rodents, on thyroid hormone receptor (TR) and peroxisome proliferator-activated receptor (PPAR) in human cells has not yet been examined. In this study, we demonstrate that the malic enzyme activity and the transcriptional activities of endogenous TR and PPAR were inhibited after treatment with HA in human hepatocyte Chang liver cell line. Although the protein expression levels of TR-beta, PPAR-alpha and retinoid X receptor-alpha (RXRalpha) were not changed significantly by HA treatment, both the binding abilities of endogenous TR-beta on thyroid hormone response element (TRE) and PPAR-alpha on the PPAR response element (PPRE) were inhibited by HA treatment. The study of the subcellular distribution of HA, relying on the inherent HA fluorescence, showed that HA distributed in the intracellular compartments including cytoplasm and nucleus. The 50% binding inhibition values (CI(50)) of HA on ME-TRE (malic enzyme gene-TRE) and ACOX-PPRE (acylCoA oxidase gene-PPRE) were 19.31 and 19.94 microg/mL, respectively. These results suggest that HA-induced endemic goiter may link in part to the disruption of TRbeta and PPARalpha function in human Chang liver cells. This model may be useful in the investigation of environmental goitrogens.