Calin A. Tatu

Health impacts of coal and coal use: possible solutions

Abstract Coal will be a dominant energy source in both developed and developing countries for at least the first half of the 21st century. Environmental problems associated with coal, before mining, during mining, in storage, during combustion, and postcombustion waste products are well known and are being addressed by ongoing research. The connection between potential environmental problems with human health is a fairly new field and requires the cooperation of both the geoscience and medical disciplines. Three research programs that illustrate this collaboration are described and used to present a range of human health problems that are potentially caused by coal. Domestic combustion of coal in China has, in some cases, severely affected human health. Both on a local and regional scale, human health has been adversely affected by coals containing arsenic, fluorine, selenium, and possibly, mercury. Balkan endemic nephropathy (BEN), an irreversible kidney disease of unknown origin, has been related to the proximity of Pliocene lignite deposits. The working hypothesis is that groundwater is leaching toxic organic compounds as it passes through the lignites and that these organics are then ingested by the local population contributing to this health problem. Human disease associated with coal mining mainly results from inhalation of particulate matter during the mining process. The disease is Coal Workers Pneumoconiosis characterized by coal dust-induced lesions in the gas exchange regions of the lung; the coal workers “black lung disease”.

Tumour-associated fibroblasts and mesenchymal stem cells: more similarities than differences

Tumour‐associated fibroblasts (TAFs) are part of the tumour stroma, providing functional and structural support for tumour progression and development. The origin and biology of TAFs are poorly understood, but within the tumour environment, TAFs become activated and secrete different paracrine and autocrine factors involved in tumorigenesis. It has been shown that bone marrow mesenchymal stem cells (MSCs) can be recruited into the tumours, where they proliferate and acquire a TAF‐like phenotype. We attempted to determine to what extent TAFs characteristics in vitro juxtapose to MSCs’ definition, and we showed that TAFs and MSCs share immunophenotypic similarities, including the presence of certain cell surface molecules [human leukocyte antigen‐DR subregion (HLA‐DR), CD29, CD44, CD73, CD90, CD106 and CD117]; the expression of cytoskeleton and extracellular matrix proteins, such as vimentin, α‐smooth muscle actin, nestin and trilineage differentiation potential (to adipocytes, chondrocytes and osteoblasts). When compared to MSCs, production of cytokines, chemokines and growth factors showed a significant increase in TAFs for vascular endothelial growth factor, transforming growth factor‐β1, interleukins (IL‐4, IL‐10) and tumour necrosis factor α. Proliferation rate was highly increased in TAFs and fibroblast cell lines used in our study, compared to MSCs, whereas ultrastructural details differentiated the two cell types by the presence of cytoplasmic elongations, lamellar content lysosomes and intermediate filaments. Our results provide supportive evidence to the fact that TAFs derive from MSCs and could be a subset of ‘specialized’ MSCs.

Health Effects of Toxic Organic Substances from Coal: Toward “Panendemic” Nephropathy

Coal contains myriad organic compounds, some known to be toxic and others that are potentially toxic. Toxic organic compounds found in coal of particular interest include: i) condensed aromatic structures (e.g., polycyclic aromatic hydrocarbons), which can act as mutagens, cancer promoters, and endocrine disrupters; ii) aromatic amines, which have probable nephrotoxic activity; and iii) heterocyclic compounds, which may be carcinogenic and nephrotoxic. Toxic organic compounds can be leached from coal into water supplies, and longterm human exposure to these compounds may lead to disease occurrence, including cancer and renal disease. Despite these potential hazards, little is known about the impact and toxicity of organic substances derived from coal in water supplies. One example of a disease hypothesized to be linked to coal-derived toxic organic compounds in water supplies is Balkan endemic nephropathy (BEN). In this paper, we summarize results from our studies linking BEN to the leaching of toxic organic compounds from low rank (lignite) Pliocene coal deposits into water supplies (well and spring water) of the rural villages where the disease occurs. We also introduce the idea of panendemic nephropathy (PEN) for BEN-like diseases that are linked to coal-derived toxic organic compounds in water supplies, but that occur outside the Balkans. Preliminary results supporting the PEN hypothesis are presented, with results from proposed PEN areas in Wyoming (WY) and Louisiana (LA). Results of toxicological studies of the effects of organic compounds isolated from water supplies in BEN and PEN areas on human cell cultures are also discussed. China, India, Turkey, and Portugal represent other areas where BEN-like diseases may occur, as a result of the presence of extensive low rank coal deposits and rural populations using untreated water in contact with coal in these nations.

Possible health impacts of naturally occurring uptake of aristolochic acids by maize and cucumber roots: links to the etiology of endemic (Balkan) nephropathy

The original publication of the article includes errors in the affiliation of Vuk Maksimović, Calin A. Tatu and Jelena D. Maksimović and in the Acknowledgments. The correct affiliation and Acknowledgments appear in this erratum. Acknowledgments This work was supported by the Serbian Ministry of Science (grant number 173040). All the experiments were performed on equipment provided by the Institute for Multidisciplinary Research and Serbian Ministry of Science. Part of this work was supported by grants from the US Geological Survey (Reston, VA, USA), University of Medicine and Pharmacy, Timisoara, Romania, and NATO (CLG grant # 980104).

Improvement of ursolic and oleanolic acids' antitumor activity by complexation with hydrophilic cyclodextrins.

Ursolic and oleanolic acids have been brought into the spotlight of research due to their chemopreventive, anti-inflammatory and immunomodulatory properties. The most important disadvantage of ursolic and oleanolic acids is their weak water solubility which limits their bioavailability. Pentacyclic triterpenes can form inclusion complexes with different types of cyclodextrins which provide the hydrophilic matrix requested for the molecular dispersion of drugs in order to become more water soluble. The aim of the current study is the complexation of ursolic and oleanolic acids with hydrophilic cyclodextrins in order to achieve an improvement of their pharmacological effect. After the virtual screening of the binding affinities between ursolic and oleanolic acids and various cyclodextrins, 2-hydroxypropyl-β-cyclodextrin and 2-hydroxypropil-γ-cyclodextrin were selected as host-molecules for the inclusion complexation. Using the scanning electron microscopy, differential scanning calorimetry and X-ray diffraction the formation of real inclusion complexes between ursolic and oleanolic acids and the two cyclodextrins was confirmed. The anti-proliferative potential of the complexes was tested in vitro on several melanoma cell lines, using the pure compounds as reference. The complexes exhibited higher in vitro anti-proliferative activity as compared to the pure compounds; this improvement was significant for ursolic acid complexes, the highest activity being reported for the 2-hydroxypropil-γ-cyclodextrin complex. Weaker results were recorded for the oleanolic acid complexes where 2-hydroxypropyl-β-cyclodextrin proved to be the most fitted inclusion partner. The entrapment of the two active compounds inside ramified hydrophilic cyclodextrins proved to be a suitable option to increase their anti-proliferative activity.

Artificial Device for Extracorporeal Blood Oxygenation in Rats

Blood oxygenation devices are an essential component of any cardiopulomonary bypass circuit in various species of laboratory animals. When using larger animals like dogs or pigs, the human and pediatric blood oxygenators could be easily used, but the disadvantage of these species is the scarcity of biochemical and genetic assays for experimental follow-up. However, small rodents like rats have plenty of biochemical assays, but their size requires special oxygenators adapted for their small blood volume and often primed with blood of another animal or other physiological solution. We showed the new design of a blood oxygenator with direct blood-gas contact in an open circuit, specially designed for rats in which the blood oxygenation takes place in a slowly rotating plastic tube with blood spread onto its inner walls in a thin layer. The oxygenator is simple and efficient, does not require priming with the blood of another rat, has a small dead volume, is reusable, and easy to clean and sterilize.

Balkan endemic nephropathy and aristolochic acid I: an investigation into the role of soil and soil organic matter contamination, as a potential natural exposure pathway

Aristolochic acids (AAs) are carcinogenic and nephrotoxic plant alkaloids present in Aristolochia species, used in traditional medicine. Recent biomolecular and environmental studies have incriminated these toxins as an etiological agent in Balkan endemic nephropathy (BEN), a severe kidney disease occurring in the Balkan Peninsula. The questions on how the susceptible populations are exposed to these toxins have not yet been clearly answered. Exposure to AAs through the food chain, and environmental pollution (soil/dust), could provide an explanation for the presence of BEN in the countries where no folkloric use of the plant has been documented (Bulgaria, Croatia). Additional exposure pathways are likely to occur, and we have shown previously that AAs can contaminate crop plants through absorption from soil, under controlled laboratory environment. Here, we attempt to provide additional support to this potential exposure pathway, by revealing the presence of AAI in soil and soil organic matter samples collected from BEN and non-BEN areas. The samples were processed in order to be analyzed by high-pressure liquid chromatography, and ion trap mass spectrometry. Our results showed the presence of AAI in small concentrations, both in BEN and non-BEN soils, especially where Aristolochia plants and seeds were present.

Enucleation: a possible mechanism of cancer cell death

There are few major morphologies of cell death that have been described so far: apoptosis (type I), cell death associated with autophagy (type II), necrosis (type III) and anchorage‐dependent mechanisms—anoikis. Here, we show for the first time a possibly novel mechanism inducing tumour cell death under in vitro conditions—enucleation. We pursued the influence of colloidal suspensions of Fe3O4 nanoparticles on tumour cell lines (SK‐BR‐3 and MCF‐7 breast cancer cell lines) grown according to standard cell culture protocols. Magnetite nanoparticles were prepared by combustion synthesis and double layer coated with oleic acid. Scanning and transmission electron microscopy revealed that tumour cells developed a network of intracytoplasmic stress fibres, which induce extrusion of nuclei, and enucleated cells die. Normal adult mesenchymal stem cells, used as control, did not exhibit the same behaviour. Intact nuclei were found in culture supernatant of tumour cells, and were visualized by immunofluorescence. Enucleation as a potential mechanism of tumour cell death might open new horizons in cancer biology research and development of therapeutic agents capable of exploiting this behaviour.

Balkan endemic nephropathy, the haematopoietic system and the environmental connection

We previously reported the detection of an increased subpopulation of cytotoxic T lymphocytes in patients with Balkan (endemic) nephropathy (BEN) and in area controls (individuals free of clinical syndrome but born in a BEN endemic area and having a family history of BEN). Extending the flow-cytometric analyses to other populations of peripheral blood leucocytes, we found a decrease in the proportion of B lymphocyte subset and an increased proportion of eosinophils in BEN patients and in area controls. Although these numerical alterations cannot be categorically linked to the aetiopathogeny of the disease, it is presumed that they can be induced by the same factor(s) causing the kidney damage, through a direct haemato- and lymphotoxic effect.

Effects of ursolic and oleanolic on SK‑MEL‑2 melanoma cells: In vitro and in vivo assays

Among the triterpenoids, oleanolic acid (OA) and its isomer, ursolic acid (UA) are promising therapeutic candidates, with potential benefits in the management of melanoma. In this study, we aimed to examine the in vitro and in vivo anti-invasive and anti-metastatic activity of OA and UA to determine their possible usefulness as chemopreventive or chemotherapeutic agents in melanoma. For the in vitro experiments, the anti-proliferative activity of the triterpenic compounds on SK-MEL-2 melanoma cells was examined. The anti-invasive potential was assessed by testing the effects of the active compound on vascular cell adhesion molecule (VCAM) and intercellular adhesion molecule (ICAM) adhesion to melanoma cells. Normal and tumor angiogenesis were evaluated in vivo by chicken embryo chorioallantoic membrane (CAM) assay. The two test triterpenoid acids, UA and OA, exerted differential effects in vitro and in vivo on the SK-MEL-2 melanoma cells. UA exerted a significant and dose-dependent anti-proliferative effect in vitro, compared to OA. The cytotoxic effects in vitro on the melanoma cells were determined by the examining alterations in the cell cycle phases induced by UA that lead to cell arrest in the S phase. Moreover, UA was found to affect SK-MEL-2 melanoma cell invasiveness by limiting the cell adhesion capacity to ICAM molecules, but not influencing their adhesion to VCAM molecules. On the whole, in this study, by assessing the effects of the two triterpenoids in vivo, our results revealed that OA had a greater potential to impair the invasive capacity and tumor angiogenesis compared with UA.