Effects of therapeutic agents on cellular respiration as an indication of metabolic activity

Thyroid-related hormones as potential markers of hypoxia/ischemia

This study aimed to investigate the usefulness of the thyroid-related hormones as markers of acute systemic hypoxia/ischemia to identify deaths caused by asphyxiation due to neck compression in human autopsy cases. The following deaths from pathophysiological conditions were examined: mechanical asphyxia and acute/subacute blunt head injury; acute/subacute non-head blunt injury; sharp instrument injury as the hemorrhagic shock condition; drowning as alveolar injury; burn; and death due to cardiac dysfunction. Blood samples were collected from the left and right cardiac chambers and iliac veins, and serum triiodothyronine (T3), thyroxine (T4), thyroglobulin (Tg), and thyroid-stimulating hormone (TSH) levels were measured using electrochemiluminescence immunoassays. Two types of thyroid cell lines were used to confirm independent thyroid function under the condition of hypoxia (3% O₂). The human thyroid carcinoma cell line (HOTHC) cell line derived from human anaplastic thyroid carcinoma and the UD-PTC (sample of the second resection papillary thyroid carcinoma) cell line derived from human thyroid papillary adenoma, which forms Tg retention follicles, were used to examine the secretion levels of T3, T4, and Tg hormones. The results showed a strong correlation between T3 and T4 levels in all blood sampling sites, while the TSH and Tg levels were not correlated with the other markers. Serum T3 and T4 levels were higher in cases of mechanical asphyxia and acute/subacute blunt head injury, representing hypoxic and ischemic conditions of the brain as compared to those in other causes of death. In the thyroid gland cell line, T4, T3, and Tg levels were stimulated after exposure to hypoxia for 10-30 min. These findings suggest that systemic advanced hypoxia/ischemia may cause a rapid and TSH-independent release of T3 and T4 thyroid hormones in autopsy cases. These findings demonstrate that increased thyroid-related hormone (T3 and T4) levels in the pathophysiological field may indicate systemic hypoxia/ischemia.

Effect of antipsychotics on mitochondrial bioenergetics of rat ovarian theca cells

BACKGROUND

Antipsychotics (APs) are widely prescribed drugs, which are well known to cause reproductive adverse effects through mechanisms yet to be determined. The purpose of this study was to investigate the effect of antipsychotics on mitochondrial bioenergetics of rat ovarian theca cells as a possible mechanism of reproductive toxicity.

METHODS

Isolated rat theca interstitial cells (TICs) were treated with two typical (chlorpromazine [CPZ] and haloperidol [HAL]) and two atypical APs (risperidone [RIS] and clozapine [CLZ]). The effects of these APs on TICs bioenergetics (ATP content, mitochondrial complexes I and III activities, oxygen consumption rates (OCRs), mitochondrial membrane potential (MPP) and lactate production) and on steroidogenesis (androstenedione and progesterone synthesis) were investigated.

RESULTS

All APs resulted in a concentration-dependent decrease in the ATP content of TICs. All APs at their estimated IC₅₀s (6μM, 21μM, 35μM and 37μM for CPZ, HAL, CLZ and RIS respectively) significantly decreased TICs OCRs (p<0.0001), MPP (p<0.0001) and significantly (p=0.0003) inhibited mitochondrial complex I activity. Only typical APs inhibited complex III (p=0.005). Also, APs at IC₅₀s increased TICs lactate production to varying degrees. All APs used at their IC₅₀s significantly inhibited progesterone (p=0.0022) and androstenedione (p=0.0027) production. Only CPZ was found to inhibit these hormones at the low concentration (1μM).

CONCLUSION

All four antipsychotics seem to inhibit mitochondrial bioenergetics and steroidogenesis in rat's ovarian theca cells. These findings support the hypothesis that APs-induced reproductive toxicity may be through mechanisms involving mitochondrial insult>. Further research is required to establish the link between APs-induced mitochondrial dysfunction and disordered steroidogenesis.

Prognostic significance of the mitochondrial scoring system in ovarian cancer

We report a mitochondrial (MT) scoring system related to response to platinum treatment in ovarian cancer (OC). Ultra-thin sections of surgical specimens of primary tumors prepared from 41 OC patients were examined by electron microscopy. The ovarian carcinoma cell line 2008 and its platinum-resistant variant C13 were used as controls. Seven independent MT features, including MT diameter, pattern of cresta structure, electron density, MT distribution, pattern of distribution, ovoid ratio and MT architecture, were examined. Each of the seven parameters was assigned a point score of 0-2 and was summed up with a total score of 14. Clinical response and in vitro sensitivity to platinum, taxane, irinotecan and doxorubicin were evaluated. Clinical information was available for 37 of the 41 cases. Twenty-four cases were stage III and, histologically, 16 serous, 6 endometrioid and 6 clear cell carcinoma were included. All of the patients underwent surgery followed by 6 cycles of taxane and platinum chemotherapy. Fifteen patients exhibited a response, while 22 were resistant to treatment. The total MT score was 5.13±1.13 (mean ± SE) in the 15 responsive cases and 11.41±0.43 in the 22 resistant cases (P<0.001). Receptor operative characteristic (ROC) analysis revealed that the resistant total 'cut-off' score was ≥10 points (P<0.05; AUC=0.86) with 95.5% sensitivity and 80.0% specificity. The MT scoring system correlated well with response to drugs, with the exception of doxorubicin. The progression-free survival (PFS) curves showed an absolute difference in the 6-month PFS of 10% (83 vs. 73%) and in the 12-month PFS of 21% (80 vs. 59%), in favor of patients with low MT scores. This MT scoring system correlates very closely with clinical response as well as cellular sensitivity to chemotherapy, resulting in an association with PFS.

Direct effects of doxorubicin on skeletal muscle contribute to fatigue

Chemotherapy-induced fatigue is a multidimensional symptom. Oxidative stress has been proposed as a working mechanism for anthracycline-induced cardiotoxicity. In this study, doxorubicin (DOX) was tested on skeletal muscle function. Doxorubicin induced impaired ex vivo skeletal muscle relaxation followed in time by contraction impediment, which could be explained by DOX-induced changes in Ca²⁺ responses of myotubes in vitro. The Ca²⁺ responses in skeletal muscle, however, could not be explained by oxidative stress.

A new respirometric endpoint-based biosensor to assess the relative toxicity of chemicals on immobilized human cells

Several functional and biochemical parameters have been proposed as biomarkers of effect of environmental pollutants. A rapid biosensor working with immobilized human U-937 cells was developed and applied to environmentally relevant chemicals with different structures and toxicological pathways, i.e. benzalkonium chloride, clofibric acid, diclofenac, mercury nitrate, ofloxacin, and sodium dodecyl sulphate. Respiration of cells was relied upon as a comprehensive biochemical effect for screening purposes. Analytical parameter (DeltappmO(2)) and toxicological index (respiratory inhibition, delta%) measured after 1h of exposure were utilized for dose-response relationship study. Results (toxicity rating scales based on delta(50)% and steepness) were compared with those obtained by the same approach previously optimized on Saccharomyces cerevisiae. The toxicity rating scale obtained by the biomarker based on human mitochondrial and cell metabolic activities compared well with previous scale obtained on yeast cells and with available in-vivo acute toxicity indexes; respiration was confirmed as toxicological endpoint reliably measurable by the biosensor.

Small cell carcinoma of the ovary: clinical and biological study

Ovarian small cell carcinoma of hypercalcemic type is a rare neoplasm that typically occurs in young females. We describe three cases of ovarian small cell carcinoma of hypercalcemic type occurring in patients aged 24, 37, and 25 years. The first patient had stage IIc disease and had primary surgery with a left salpingo-oophorectomy and omentectomy, followed by chemotherapy with cisplatin and etoposide. Upon a second relapse, pelvic lymphadenectomy was performed, followed by chemotherapy with docetaxel. She is alive for 4 years without any recurrence after the initial treatment. In vitro drug-sensitivity assay revealed the tumor cells were sensitive to taxane and resistant to irinotecan. The second patient had stage III disease and had primary debulking surgery with bilateral salpingo-oophorectomy, simple hysterectomy, omentectomy, low-anterior resection, and lymphadenectomy, followed by chemotherapy with paclitaxel and carboplatin. Four months after the initial treatment she relapsed and died. The tumor cells were sensitive to platinum, taxane, and doxorubicin, but resistant to irinotecan. The third patient had stage III disease and had right salpingo-oophorectomy, omentectomy, and lymphadenectomy, followed by chemotherapy with cisplatin, cyclophosphamide, and doxorubicin. She relapsed 4 months after completing the chemotherapy and died 5 months after secondary debulking surgery. The tumor cells were sensitive to platinum, taxane, and doxorubicin, but resistant to irinotecan. The drug-sensitivity assays suggested that a non-irinotecan, taxane-containing combination might have been suitable as first-line chemotherapy for these patients. However, an effect of such a regimen was seen in only one patient with early-stage disease, and this questions the validity of chemosensitivity testing.

Effect of sodium azide on the metabolic activity of cultured fetal cells

Sodium azide is a highly toxic substance. However, the mechanism of its toxicity has not been fully established. In the present study, we attempted to investigate the toxicity of sodium azide in various cultured fetal cells, using changes in cellular respiration as an indicator of metabolic inhibition to elucidate tissue-specificity. The human fetal cell lines used in this study included myocardial cells, nerve cells, fibroblasts, hepatocytes and renal tubular epithelial cells. The cells were seeded in wells at a density of 2 x 10(6)cells/2mL, sodium azide was added at a concentration of 0.01 ng/mL to 10 microg/mL, and the respiration of each type of cell was measured 1 h later using a dissolved oxygen meter. The concentration at which sodium azide inhibited metabolic activity was lower in the nerve and myocardial cells than in the fibroblasts, hepatocytes and renal tubular epithelial cells. These findings may serve to clarify the dynamic mechanisms of sodium azide toxicity in vivo.