Efficient limitation of intracellular edema and sodium accumulation by cardioplegia is dissociated from recovery of rat hearts from cold ischemic storage.

Energy deficiency and disturbances of sodium and water homeostasis are considered as mechanisms of injury during hypothermic preservation of cardiac muscle. The present study attempts to characterize the effect of potassium (K+) and magnesium (Mg2+) cardioplegia on these mechanisms. Cellular parameters were measured by multinuclear NMR spectroscopy in isolated rat hearts during 12 h of ischemia at 4 degrees C and 2 h of normothermic reperfusion with an isoosmotic Krebs-Henseleit (KH) solution. Potassium and magnesium cardioplegia (a) reduced the rate of ATP hydrolysis and cellular acidification during early stages of ischemia; (b) caused an early cessation of the phase of fast sodium influx after 40 min (P<0.001 vs 120 min with KH); (c) reduced intracellular sodium accumulation to 148-165 micromol/gdw after 12 h (P<0.01 vs 268+/-15 micromol/gdw with KH); (d) decreased ischemic volumes to 2.7+/-0.1 and 2.8+/-0.1 ml/gdw after 8 and 12 h of storage, respectively (P<0.005 v 3.0 and 3.3 ml/gdw with KH). Quantitative analysis of these parameters showed that both hypothermia and cardioplegia increased the relative contribution of sodium to intracellular water accumulation by a factor of 2-2.5. In view of the marked reduction in absolute sodium and water contents, the data indicate that cold cardioplegia limits the increase in intracellular osmolarity. Myocardial mechanical and metabolic recoveries, and cellular viability deteriorated during prolongation of the ischemic period from 8 to 12 h in all experimental groups (P<0.005). Reperfusion was efficient in reversing intracellular sodium and water accumulation in hearts stored with cardioplegia, in contrast to hearts stored in KH. Magnesium, but not potassium cardioplegia, lowered interstitial water contents (P<0.01 v KH), increased intracellular magnesium concentrations (P<0.001), improved mechanical and metabolic recoveries (P<0.01) and cellular viability (P<0.001). These results indicate (a) cardioplegia reduces intracellular sodium (by approximately 46%) and water accumulation (by 66%) during cold ischemia; (b) both hypothermia and cardioplegia limit the rise in intracellular osmolarity and increase the contribution of sodium to cellular swelling; (c) intracellular sodium and water contents were dissociated from myocardial viability and recovery from cold ischemia in potassium and magnesium cardioplegic solutions. It is concluded that intracellular sodium and water accumulation are not dominant factors in determination of cardiac outcome from ischemia.     

Stem cell therapy for white matter disorders: don’t forget the microenvironment!

White matter disorders (WMDs) are a major source of handicap at all ages. They often lead to progressive neurological dysfunction and early death. Although causes are highly diverse, WMDs share the property that glia (astrocytes and oligodendrocytes) are among the cells primarily affected, and that myelin is either not formed or lost. Many WMDs might benefit from cell replacement therapies. Successful preclinical studies in rodent models have already led to the first clinical trials in humans using glial or oligodendrocyte progenitor cells aiming at (re)myelination. However, myelin is usually not the only affected structure. Neurons, microglia, and astrocytes are often also affected and are all important partners in creating the right conditions for proper white matter repair. Composition of the extracellular environment is another factor to be considered. Cell transplantation therapies might therefore require inclusion of non-oligodendroglial cell types and target more than only myelin repair. WMD patients would likely benefit from multimodal therapy approaches involving stem cell transplantation and microenvironment-targeting strategies to alter the local environment to a more favorable state for cell replacement. Furthermore most proof-of-concept studies have been performed with human cells in rodent disease models. Since human glial cells show a larger regenerative capacity than their mouse counterparts in the host mouse brain, microenvironmental factors affecting white matter recovery might be overlooked in rodent studies. We would like to stress that cell replacement therapy is a highly promising therapeutic option for WMDs, but a receptive microenvironment is crucial.     

The Role of IL-37 in Non-Cancerous Diseases

IL-37 is a newly discovered cytokine belonging to IL-1 family consisting of 11 members, which have similar β-barrel structures and associate with Ig-like receptors. Extensive studies have been done with IL-37 since its discovery. These studies suggest that IL-37 does not only play a role in tumorigenesis, but also has anti-inflammatory properties in immune responses through the down regulation of pro-inflammatory molecules. We have previously reviewed the role of IL-37 in cancer. Here, we will focus on the role of IL-37 in non-cancerous Diseases. Such a study might be helpful to design new strategies to treat IL-37 associated diseases.     

Expression of activated Akt and PTEN in malignant melanomas: relationship with clinical outcome

Our purpose was to analyze, by immunohisto-chemistry, the expression of activated serine-threonine protein kinase B (p-Akt) and phosphatase and tensin homologue deleted on chromosome 10 (PTEN) in benign nevi and primary and metastatic melanomas and to correlate the expression level with clinical variables. We observed cytoplasmic and/or nuclear expression of p-Akt in 22 (54%) of 41 benign nevi, 112 (71.3%) of 157 primary tumors, and 50 (71%) of 70 metastases. Cytoplasmic PTEN staining was observed in 0 (0%), 152 (87.7%), and 64 (90%) of 41 nevi, 162 primary tumors, and 71 metastases, respectively. A significant positive correlation was seen between PTEN and p-Akt cytoplasmic expression (P < .001) in primary melanomas. Cytoplasmic p-Akt expression showed a positive association with cyclin A in superficial spreading (P = .038) but not in nodular (P = .22) melanomas. Cytoplasmic p-Akt and PTEN expression did not have an impact on disease-free and overall survival, but complete lack of nuclear p-Akt expression was a predictor of shorter disease-free survival (P = .025) for patients with superficial spreading melanoma.     

IS26-associated In4-type integrons forming multiresistance loci in enterobacterial plasmids

Three distinct multiresistant loci from enterobacterial plasmids each comprised an integron and an IS26-associated sequence. Sequence comparison suggested a common ancestral structure that derived from an IS26 insertion into the 5' conserved segment of an In4-type integron and evolved through acquisition of gene cassettes and IS26-mediated recruitment of additional resistance genes of diverse origin.     

Protein Expression of the Cell-Cycle Inhibitor p27Kip1 in Malignant Melanoma : Inverse Correlation with Disease-Free Survival

In the present study we analyzed, by immunohistochemistry, a panel of human melanomas for protein expression of the cyclin-dependent kinase (cdk) inhibitor p27^Kip1 and evaluated whether deregulated expression correlates with clinical outcome for this type of cancer. We found that p27^Kip1 was strongly expressed by normal melanocytes and benign nevi, whereas in malignant melanoma, a heterogeneous expression pattern was observed. In the case of nodular melanomas, the level of p27^Kip1 was found to correlate significantly with the thickness of the tumor, with less protein expressed in thicker lesions. We also found that patients having tumors with fewer than 5% p27^Kip1-staining cells had a significantly higher risk of early relapse of their disease compared with those expressing moderate or high levels. In contrast, the level of p27^Kip1 did not correlate with tumor thickness or disease-free survival in patients with superficial spreading melanomas, suggesting that p27^Kip1 may play different roles in these two major pathological subgroups of malignant melanoma. Furthermore, p27^Kip1 did not appear to have an influence on overall survival for either subgroup. When we examined the combined effect of p21^WAF1/CIP1 (another cdk inhibitor) and p27^Kip1 on clinical outcome, we found that analysis of these two cdk inhibitors together may have greater prognostic potential than either alone. In conclusion, our results suggest that virtually complete loss of p27^Kip1 protein expression has potential importance as a prognostic indicator of early relapse in patients with nodular melanoma. The results, furthermore, underscore the value of analyzing multiple cell cycle regulatory proteins to obtain the most reliable indication of prognosis.     

Toxicological Effects during and following Persistent Insulin‐Induced Hypoglycaemia in Healthy Euglycaemic Rats

New insulin analogues with a longer duration of action and a ‘peakless’ pharmacokinetic profile have been developed to improve efficacy, safety and convenience for patients with diabetes. During non‐clinical development, according to regulatory guidelines, these analogues are tested in healthy euglycaemic rats rendering them persistently hypoglycaemic. Little is known about the effect of persistent (24 hr/day) insulin‐induced hypoglycaemia (IIH) in rats, complicating interpretation of results in pre‐clinical studies with new longer‐acting insulin analogues. In this study, we investigated the effects of persistent IIH and their reversibility in euglycaemic rats. Histopathological changes in insulin‐infused animals included partly reversible axonal and reversible myofibre degeneration in peripheral nerve and skeletal muscle tissue, respectively, as well as reversible pancreatic islet atrophy and partly reversible increase in unilocular adipocytes in brown adipose tissue. Additionally, results suggested increased gluconeogenesis. The observed hyperphagia, the pancreatic, peripheral nerve and skeletal muscle changes were considered related to the hypoglycaemia. Cessation of insulin infusion resulted in transient hyperglycaemia, decreased food consumption and body‐weight loss before returning to control levels. The implications for the interpretation of non‐clinical studies with long‐acting insulin analogues are discussed.     

Cyclin A expression in superficial spreading malignant melanomas correlates with clinical outcome.

The present study analysed by immunohistochemistry the protein level of cyclin A and Ki-67 in a panel of paraffin-embedded tissue obtained from 172 primary (110 superficial and 62 nodular) and 73 metastatic melanomas, and ten benign naevi. Since cyclin A exists in the same quaternary complex in the S-phase of the cell cycle as the cdk inhibitor p21WAF1/CIP1, the levels of the two proteins were compared. Cyclin A and Ki-67 were heterogeneously expressed in the malignant tumours, whereas in benign naevi, only rare positive cells were detected. In superficial spreading melanomas, the cyclin A level was related to tumour thickness, with less expression in thinner lesions (p<0.00001), and to Ki-67 (p<0.00001) and p21WAF1/CIP1 (p=0.01) scores. Multivariate analysis showed that in addition to the depth of the primary tumour, the protein level of cyclin A was an independent indicator of relapse-free period (thickness, p<0.00001; cyclin A, p=0.0003). In contrast, in nodular melanoma, the cyclin A level was associated with Ki-67 expression, but neither cyclin A nor Ki-67 was related to tumour thickness (cyclin A, p=0.06; Ki-67, p=0.61) and neither had any impact on relapse-free (cyclin A, p=0.64; Ki-67, p=0.32) or overall (cyclinA, p=0.94; Ki-67, p=0.45) survival. In conclusion, the results indicate that cyclin A is a strong prognostic factor for patients with superficial spreading melanomas. In nodular melanomas, the proliferation rate seems to have little impact on disease progression.