Impact of the uremic milieu on the osteogenic potential of mesenchymal stem cells.

Human mesenchymal stem cells (hMSCs), the precursors of osteoblasts during osteogenesis, play a role in the balance of bone formation and resorption, but their functioning in uremia has not been well defined. To study the effects of the uremic milieu on osteogenic properties, we applied an in vitro assay culturing hMSCs in osteogenic medium supplemented with serum from healthy donors and from uremic patients on hemodialysis. Compared to control, serum from uremic patients induces, in hMSC cultures, a modification of several key regulators of bone remodeling, in particular a reduction of the ratio Receptor Activator of Nuclear factor Kappa B Receptor (RANKL) over osteoprotegerin, indicating an adaptive response of the system to favor osteogenesis over osteoclastosis. However, the levels of osteopontin, osteocalcin, and collagen type I, are increased in cell medium, while BMP-2, and alizarin red staining were decreased, pointing to a reduction of bone formation favoring resorption. Selected uremic toxins, such as p-cresylsulfate, p-cresylglucuronide, parathyroid hormone, indoxyl sulfate, asymmetric dimethylarginine, homocysteine, were able to mimic some of the effects of whole serum from uremic patients. Serum from cinacalcet-treated patients antagonizes these effects. Hydrogen sulfide (H2S) donors as well as hemodialysis treatment are able to induce beneficial effects. In conclusion, bone modifications in uremia are influenced by the capability of the uremic milieu to alter hMSC osteogenic differentiation. Cinacalcet, H2S donors and a hemodialysis session can ameliorate the hampered calcium deposition.

Partial response to cinacalcet treatment in a patient with secondary hyperparathyroidism undergoing hemodialysis: a case report.

INTRODUCTION: In the treatment of secondary hyperparathyroidism of chronic kidney disease, calcimimetics - allosteric modulators of the calcium-sensing receptor - inhibit glandular hyperplasia and significantly reduce circulating parathyroid hormone levels. They have a major impact on the management of secondary hyperparathyroidism. CASE PRESENTATION: We present the clinical case of a 41-year-old Caucasian man undergoing chronic hemodialysis, who had a parathyroidectomy to treat severe secondary hyperparathyroidism resistant to cinacalcet treatment. Preoperatively, 24 months after high-dose cinacalcet hydrochloride, we observed a persistently elevated intact parathyroid hormone serum level, and detected clear parathyroid gland hyperplasia regression on ultrasound. We performed a three-gland parathyroidectomy, which was assumed to be total, associated with a hemithyroidectomy. Our patient then entered a hypoparathyroid state. A histopathological examination showed that the removed parathyroid glands were of small size, with a total weight of 1g, associated with a multifocal small papillary thyroid cancer. CONCLUSION: In the management of secondary hyperparathyroidism, cinacalcet hydrochloride effectively reduces total parathyroid gland hyperplasia. However, a persisting elevated intact parathyroid hormone serum level may be observed, demonstrating that reduced parathyroid hyperplastic tissue may still be associated with severe secondary hyperparathyroidism. Even if calcimimetics are very effective in secondary hyperparathyroidism treatment, further studies are necessary for a better understanding of their actions.

Therapeutic strategies in pulmonary hypertension.

Pulmonary hypertension (PH) is a life-threatening condition characterized by elevated pulmonary arterial pressure. It is clinically classified into five groups: patients in the first group are considered to have pulmonary arterial hypertension (PAH) whereas patients of the other groups have PH that is due to cardiopulmonary or other systemic diseases. The management of patients with PH has advanced rapidly over the last decade and the introduction of specific treatments especially for PAH has lead to an improved outcome. However, despite the progress in the treatment, the functional limitation and the survival of these patients remain unsatisfactory and there is no cure for PAH. Therefore the search for an "ideal" therapy still goes on. At present, two levels of treatment can be identified: primary and specific therapy. Primary therapy is directed at the underlying cause of the PH. It also includes a supportive therapy consisting in oxygen supplementation, diuretics, and anticoagulation which should be considered in all patients with PH. Specific therapy is directed at the PH itself and includes treatment with vasodilatators such as calcium channel blockers and with vasodilatator and pathogenetic drugs such as prostanoids, endothelin receptor antagonists and phosphodiesterase type-5 inhibitors. These drugs act in several pathogenetic mechanisms of the PH and are specific for PAH although they might be used also in the other groups of PH. Finally, atrial septostomy and lung transplantation are reserved for patients refractory to medical therapy. Different therapeutic approaches can be considered in the management of patients with PH. Therapy can be established on the basis of both the clinical classification and the functional class. It is also possible to adopt a goal-oriented therapy in which the timing of treatment escalation is determined by inadequate response to known prognostic indicators.

To survive is not enough. Quality of life in CKD--the need for a new generation of health-oriented economists.

CKD is utilized as a paradigm, a chronic disease which allows decades of life conquered with great effort through a machine, a life with many losses and many dependencies. We must understand the patient's needs, which are not related to availability of drugs and machines and hospitals. We cannot provide good medical care with the limited amount of national product devoted to health care. Society is much older than ever before. We need a new cadre of economists working on health care with vision and ability, keeping in mind that there are no resources and there are no expenses which can be cut in medical care nowadays. We have to switch from curative medicine towards prevention, by implementing clinical research, bearing in mind that in the Western world, democracy was granted through the correct allocation of resources. The search for happiness and good quality of life are old concepts born in the Mediterranean area over the centuries, starting with Hesiod and Homer, and sleep and dreams were being investigated centuries before Freud was born.

Reduction of the genomic damage level in haemodialysis patients by folic acid and vitamin B12 supplementation.

BACKGROUND: Cancer incidence and genomic damage of peripheral lymphocytes are elevated in patients with end-stage renal failure. Among other uraemic toxins, homocysteine (Hcy) levels are increased in most of these patients. In healthy individuals, plasma Hcy correlates with the degree of genomic damage observed in peripheral blood lymphocytes (PBL). The accumulation of Hcy can be reduced by supplementation with folic acid and vitamin B12. The aim of this study was to analyse whether this supplementation can also lower the genomic damage in PBL of haemodialysis patients. This may ultimately help to reduce cancer incidence in renal patients. METHODS: In a prospective study with 27 patients, we analysed the genomic damage in dialysis patients before and at different time points after the initiation of folate/vitamin B12 supplementation. Genomic damage was measured by the frequency of micronuclei, a subset of chromosomal aberrations, in PBL. RESULTS: Supplementation with folic acid and vitamin B12 (more markedly with both) reduced the micronucleus frequency in PBL of dialysis patients. This was not mediated by altered lymphocyte proliferation capacity or changes in DNA cytosine-methylation. Plasma-Hcy was lowered more efficiently by the combined folic acid/vitamin B12 supplementation, and lymphocyte DNA of this group exhibited a nonsignificant trend for a reduction of 1,N(6)-etheno-2'-deoxyadenosine, a marker for oxidative stress. CONCLUSIONS: A reduction of the genomic damage in PBL can be achieved in dialysis patients by supplementation with folic acid and vitamin B12. This may be mediated by Hcy reduction.