It has been previously reported that serum levels of 70-kDa heat shock protein (Hsp70) are elevated in peripheral artery disease. The aim of the present study was to examine whether increased serum Hsp70 levels are related to the extent of arterial calcification and standard laboratory parameters of patients with peripheral artery disease, as well as to markers of inflammation (C-reactive protein), atherosclerosis (homocysteine), and calcification (fetuin-a). One hundred eighty chronic atherosclerotic patients with significant carotid stenosis and/or lower extremity vascular disease were enrolled in this crosssectional study. Systemic atherosclerosis and calcification was assessed by ultrasound (carotid intima-media thickness (IMT), presence of calcification at the abdominal aorta, carotid and femoral bifurcations, and aortic and mitral cardiac valves). Standard serum markers of inflammation, diabetes, renal function, ankle-brachial indexes, and traditional risk factors for atherosclerosis were noted. Serum Hsp70 levels were measured with enzyme-linked immunosorbent assay. Standard laboratory parameters (clinical chemistry), C-reactive protein (CRP), and homocysteine levels were determined by an autoanalyzer using the manufacturer's kits. Fetuin-a levels were measured by radial immunodiffusion. Patients' median age was 64 (57-71) years, 69% were men, and 34.5% had diabetes. Serum heat shock protein 70 levels were significantly higher in patients with more severe arterial calcification (p< 0.02) and showed significant positive correlations with serum bilirubin (r=0.23, p=0.002) and homocysteine levels (r= 0.18, p=0.02). Serum Hsp70 did not correlate with body mass index, IMT, CRP, or fetuin-a levels in this cohort. Logistic regression analysis confirmed the association between sHsp70 and calcification score (OR, 2.189; CI, p=0.016) and this correlation remained significant (OR, 2.264; CI, 1.021-5.020, p=0.044) after the adjustment for age, sex, eGFR, smoking, CRP, and homocysteine levels. Our data show that serum Hsp70 levels correlate with the severity of atherosclerosis in patients with carotid artery disease and chronic lower limb ischemia. These data support a putative role for plasma Hsp70 in the development of arterial calcification. Nevertheless, further studies are required to investigate the usefulness of circulating Hsp70 level as a marker of atherosclerotic calcification.

Arginine vasopressin (AVP) made by hypothalamic neurons is released into the circulation to stimulate water resorption by the kidneys and restore water balance after blood loss. Patients who lack this antidiuretic hormone suffer from central diabetes insipidus. We observed that many of these patients were anemic and asked whether AVP might play a role in red blood cell (RBC) production. We found that all three AVP receptors are expressed in human and mouse hematopoietic stem and progenitor cells. The AVPR1B appears to play the most important role in regulating erythropoiesis in both human and mouse cells. AVP increases phosphorylation of signal transducer and activator of transcription 5, as erythropoietin (EPO) does. After sublethal irradiation, AVP-deficient Brattleboro rats showed delayed recovery of RBC numbers compared to control rats. In mouse models of anemia (induced by bleeding, irradiation, or increased destruction of circulating RBCs), AVP increased the number of circulating RBCs independently of EPO. In these models, AVP appears to jump-start peripheral blood cell replenishment until EPO can take over. We suggest that specific AVPR1B agonists might be used to induce fast RBC production after bleeding, drug toxicity, or chemotherapy.

Background aims: Bone marrow-derived mesenchymal stromal cells (MSCs) have been reported to suppress T-cell proliferation and used to alleviate the symptoms of graft-versus-host disease (GVHD). MSCs are a mixed cell population and at this time there are no tools to isolate the cells responsible for the T-cell suppression. We wanted to find a way to enhance the immunemodulatory actions of MSCs and tried varying the temperature at which they were cultured. Methods: We cultured human MSCs derived from healthy volunteers at different temperatures and tested their ability to switch macrophage character from pro-inflammatory to antiinflammatory (M1 type to M2 type). Using an enzyme-linked immunosorbent assay (ELISA), we showed that when MSCs are cultured at higher temperatures their ability to induce co-cultured macrophages to produce more interleukin-10, (IL-10) (an anti-inflammatory cytokine) and less tumor necrosis factor alpha, (TNFα) (a pro-inflammatory cytokine) is increased. We performed Western blots and immunocytochemistry to screen for changes that might underlie this effect. Results: We found that in hyperthermia the heat shock protein, HSF1, translocated into the nucleus of MSCs. It appears to induce the COX 2 /PGE 2 (Cyclooxygenase2/Prostaglandin E 2) pathway described earlier as a major mechanism of MSC-directed immune-suppression. Conclusion: Hyperthermia increases the efficacy of MSC-driven immune-suppression. We propose that changing the time of MSC administration to patients to mid-to-late afternoon when the body temperature is naturally highest might be beneficial. Warming the patient could also be considered.

Recent studies have highlighted a significant association between the severity of atherosclerosis and bone mineral density (BMD) among healthy subjects, although its connection to angiographically determined peripheral artery disease (PAD) has never been investigated. We evaluated the connection between the angiographic severity and site specificity of peripheral atherosclerosis and osteoporosis among patients with chronic lower limb ischemia. In our cross-sectional study we investigated 172 patients with PAD. The anatomic sites of the lesions were analyzed. The severity of atherosclerosis was diagnosed using the Bollinger angiographic score (BS). BMD was measured at the lumbar spine (l-BMD) and at femoral (f-BMD) and radial (r-BMD) sites by dual-energy X-ray absorptiometry. Dyslipidemia, the level of vitamin D(3), and different bone turnover markers were also noted. Among PAD patients, regardless of the lesion site, we did not find any association between BMD and BS. Among patients with iliac disease, BS was associated with l-BMD (p = 0.038, r = -0.467) and with f-BMD (p = 0.002, r = -0.642). The level of r-BMD among patients with iliac disease was not associated with BS (p = 0.233, r = -0.306). We did not find any difference between the group of patients with and that without dyslipidemia and low or normal levels of vitamin D(3). Our results show a connection between the severity of atherosclerosis and osteoporosis among patients with PAD, specific to the site of the lesion. The findings regarding dyslipidemia, bone markers, and site specificity support the hypothesis that reduced blood flow is the key factor responsible for the inverse association of BMD with atherosclerosis.