Dimethylsulfoxide maintains human thyroid cells in suspension culture, facilitating synthesis and release of thyroid hormone

Long-term cell fate and functional maintenance of human hepatocyte through stepwise culture configuration

Human hepatocyte culture system represents by far the most physiologically relevant model for our understanding of liver biology and diseases; however, its versatility has been limited due to the rapid and progressive loss of genuine characteristics, indicating the inadequacy of in vitro milieu for fate maintenance. This study, therefore, is designed to define environmental requirements necessary to sustain the homeostasis of terminally differentiated hepatocytes. Our study reveals that the supplementation of dimethyl sulfoxide (DMSO) is indispensable in mitigating fate deterioration and promoting adaptation to the in vitro environment, resulting in the restoration of tight cell-cell contact, cellular architecture, and polarity. The morphological recovery was overall accompanied by the restoration of hepatocyte marker gene expression, highlighting the interdependence between the cellular architecture and the maintenance of cell fate. However, beyond the recovery phase culture, DMSO supplementation is deemed detrimental due to the potent inhibitory effect on a multitude of hepatocyte functionalities while its withdrawal results in the loss of cell fate. In search of DMSO substitute, our screening of organic substances led to the identification of dimethyl sulfone (DMSO2), which supports the long-term maintenance of proper morphology, marker gene expression, and hepatocytic functions. Moreover, hepatocytes maintained DMSO2 exhibited clinically relevant toxicity in response to prolonged exposure to xenobiotics as well as alcohol. These observations suggest that the stepwise culture configuration consisting of the consecutive supplementation of DMSO and DMSO2 confers the microenvironment essential for the fate and functional maintenance of terminally differentiated human hepatocytes.

Multidisciplinary utilization of dimethyl sulfoxide: pharmacological, cellular, and molecular aspects

DMSO is an amphipathic molecule with a highly polar domain and two apolar methyl groups, making it soluble in both aqueous and organic media. It is one of the most common solvents for the in vivo administration of several water-insoluble substances. Despite being frequently used as a solvent in biological studies and as a vehicle for drug therapy, the side-effects of DMSO (undesirable for these purposes) are apparent from its utilization in the laboratory (both in vivo and in vitro) and in clinical settings. DMSO is a hydrogen-bound disrupter, cell-differentiating agent, hydroxyl radical scavenger, intercellular electrical uncoupler, intracellular low-density lipoprotein-derived cholesterol mobilizing agent, cryoprotectant, solubilizing agent used in sample preparation for electron microscopy, antidote to the extravasation of vesicant anticancer agents, and topical analgesic. Additionally, it is used in the treatment of brain edema, amyloidosis, interstitial cystitis, and schizophrenia. Several systemic side-effects from the use of DMSO have been reported, namely nausea, vomiting, diarrhea, hemolysis, rashes, renal failure, hypertension, bradycardia, heart block, pulmonary edema, cardiac arrest, and bronchospasm. Looking at the multitude of effects of DMSO brought to light by these studies, it is easily understood how many researchers working with DMSO (or studying one of its specific effects) might not be fully aware of the experiences of other groups who are working with it but in a different context.

Amiodarone stimulates interleukin-6 production in cultured human thyrocytes, exerting cytotoxic effects on thyroid follicles in suspension culture

To investigate whether amiodarone increases interleukin-6 (IL-6) production in thyrocytes, human follicles obtained from subtotally thyroidectomized patients with Graves' disease were cultured in serum-free medium supplemented with various concentrations of bovine thyrotropin (bTSH) and amiodarone. The follicles gradually formed monolayer cells and secreted triiodothyronine (T3), thyroglobulin (Tg), and IL-6 for at least 14 days. TSH dose-dependently increased T3 and Tg but not IL-6 levels in the conditioned medium. Amiodarone exerted no significant effect on T3, Tg, or IL-6 concentrations at 0.1-1 microM. In contrast, at 10-20 microM, it decreased T3 and Tg, but increased IL-6 levels, and these changes were accompanied by increased expression of IL-6 mRNA. Amiodarone-induced IL-6 production was inhibited by prednisolone at 10(-7) M. Electron microscopic examination revealed that the thyroid follicles in the suspension culture remained intact at 1 microM, but that cytotoxic effects (decreased microvilli and increased onion-like inclusion bodies) occurred at higher concentrations (10-25 microM). These in vitro findings indicate that amiodarone does not impair thyroid function at clinically attainable serum levels (1 microM), but exerts cytotoxic effect by inducing the production of a proinflammatory cytokine (IL-6) at higher concentrations. Because amiodarone-induced IL-6 production was inhibited by prednisolone, it is reasonable to administer glucocorticoids to patients with amiodarone-induced destructive thyrotoxicosis (type II).

Hexamethylenebisacetamide (HMBA) is a growth factor for human, ovine and porcine thyroid cells

Hexamethylenebisacetamide (HMBA) provokes in murine erythroleukemia cells (MELC) a commitment to terminal differentiation leading to the activation of the expression of hemoglobin. HMBA has been tested also in other cells from colon cancer, melanoma or lung cancer. However it has not yet been tested in the thyroid. We demonstrate in this paper that HMBA in kinetics and concentration-response experiments increases the proliferation of human thyroid cells isolated from Graves'-Basedow patients. It also acts like a growth factor for ovine and porcine thyroid cells, respectively, from the OVNIS line and the ATHOS line. This molecule which is a differentiating factor in the MELC system and a growth factor in human thyroid cell cultures represents a potential to get human thyroid cell lines expressing specialized functions.

Effect of furazolidone on tissue sulphydryl groups, ascorbic acid, and lipid peroxide levels in the rat, and the influence of dimethylsulphoxide thereon

The concentrations of sulphydryl groups (SH), ascorbic acid (AA) and lipid peroxide (LP) were measured in the liver, kidney and brain of rats 24 h after treatment with furazolidone at single oral doses of 75, 150 and 300 mg/kg. The drug produced significant reductions in the concentrations of SH, and significant increases in the concentrations of LP, in the tissues studied. The level of AA was significantly decreased in the livers (but not the kidneys or brains) of rats treated with furazolidone at a dose of 300 mg/kg. The concentrations of AA in the tissues of rats treated with lower doses were unaffected. In another experiment, furazolidone was given orally to rats at a dose of 300 mg/kg, together with a subcutaneous injection of dimethylsulphoxide (DMSO) at a dose of 8 g/kg, and SH measured in the liver 24 h later. DMSO alone had no significant effect on SH concentration. However, when DMSO was given concomitantly with furazolidone, SH concentration was significantly less depressed than when furazolidone was given alone. It is concluded that DMSO protected tissues against toxicity induced by furazolidone.

Effects of inorganic iodide, epidermal growth factor and phorbol ester on hormone synthesis by porcine thyroid follicles cultured in suspension

Porcine thyroid follicles cultured in suspension for 96 h synthesized and secreted thyroid hormones in the presence of thyrotropin (TSH). The secretion of newly synthesized hormones was assessed by determining the contents of thyroxine (T4) and triiodothyronine (T3) in the media and by paperchromatographic analysis of 125I-labelled hormones in the media where the follicles were cultured in the presence and absence of inhibitors of hormone synthesis. The hormone synthesis and secretion was modified by exogenously added NaI (0.1-100 microM). The maximal response was obtained at 1 microM. Thyroid peroxidase (TPO) activity in the cultured follicles with TSH for 96 h was dose-dependently inhibited by NaI. One hundred microM of NaI completely inhibited TSH-induced TPO activity. Moreover, both epidermal growth factor (EGF: 10(-9) and 10(-8) M) and phorbol 12-myristate 13-acetate (PMA: 10(-8) and 10(-7) M) inhibited de novo hormone synthesis. An induction of TPO activity by TSH was also inhibited by either agent. These data provide direct evidences that thyroid hormone synthesis is regulated by NaI as well as TSH at least in part via regulation of TPO activity and also that both EGF and PMA are inhibitory on thyroid hormone formation.