[Renal-salt wasting syndrome in a patient with CDDP containing chemotherapy for recurrent non-small-cell lung cancer].

Hyponatremia is one of the major side effects that occurs after CDDP-based cancer chemotherapy. However, RSWS has rarely been reported as a cause of hyponatremia occurring after chemotherapy containing CDDP. A 70-year-old female who had recurrent lung adenocarcinoma after surgery was treated with CDDP, pemetrexed and bevacizumab-containing chemotherapy. She suffered from acute-onset consciousness disturbance and hyponatremia on day 3 of chemotherapy. Although SIADH was considered at the time of onset, the patient was subsequently diagnosed with RSWS, based on observations of dehydration, high levels of urinary sodium excretion and evidence of renal tubule failure. She recovered from these conditions without any residual disability after infusion of hypertonic saline fluid on day 13 of chemotherapy. In this report, we have described RSWS, which is rare complication that may follow CDDP-based chemotherapy. It is important, but not very easy, to distinguish between SIADH and RSWS clinically for the selection of an appropriate treatment.

Preliminary Evidence for Adipocytokine Signals in Skeletal Muscle Glucose Uptake.

The cross talk between the adipose tissue and insulin target tissues is a key mechanism for obesity-associated insulin resistance. However, the precise role of the interaction between the skeletal muscle and adipose tissue for insulin signaling and glucose uptake is questionable. L6 myocytes were co-cultured with or without 3T3-L1 adipocytes (~5 × 103 cells/cm2) up to 24 h. Glucose uptake was evaluated by 2-[3H] deoxyglucose uptake assay. Levels of mRNA expression of Glut1 and Glut4 and mitochondrial enzymes were analyzed by quantitative real-time reverse transcription polymerase chain reaction. Levels of Glut1 and Glut4 protein and phosphorylation of Akt (Ser473 and Thr308) were analyzed by immunoblotting. Study 1: co-culture with 3T3-L1 adipocytes increased glucose uptake in dose- and time-dependent manner in L6 myocytes under insulin-untreated conditions. When co-cultured with 3T3-L1 cells, reactive oxygen species production and levels of Glut1 mRNA and protein were increased in L6 cells, while these changes were abrogated and the glucose uptake partially inhibited by antioxidant treatment. Study 2: co-culture with 3T3-L1 adipocytes suppressed insulin-stimulated glucose uptake in L6 myocytes. Insulin-induced Akt phosphorylation at Ser473 decreased, which was proportional to 3T3-L1 density. Antioxidant treatment partially reversed this effect. Interactions between skeletal muscle and adipose tissues are important for glucose uptake under insulin-untreated or -treated condition through oxygen stress mechanism.

Interaction between resistin and adiponectin in the proliferation of rat vascular smooth muscle cells.

We investigated the effect between resistin and adiponectin on the proliferation of vascular smooth muscle cells (VSMCs). We confirmed that resistin significantly increases the number of rat VSMCs as well as thymidine incorporation with them, whereas adiponectin diminishes resistin-induced cell proliferation. Resistin significantly increased p42/44 mitogen-activated protein kinase (MAPK) phosphorylation within rat VSMCs, whereas adiponectin inhibited resistin-induced MAPK phosphorylation. Moreover, resistin significantly increased c-fos expression, whereas adiponectin suppressed resistin-induced c-fos expression. Cell cycle progression is a tightly controlled event that is negatively regulated by cyclin-dependent kinases inhibitors (CDKIs) such as p53, p21, and p27. Resistin significantly decreased the expression of these CDKIs, whereas adiponectin restored the resistin-induced decrease in CDKIs expression. These effects were abolished in the MAPK inhibitors. In conclusion, resistin plays a role in the development of atherosclerosis, whereas adiponectin may be an important in its prevention in insulin-resistant patients.

Pioglitazone upregulates adiponectin receptor 2 in 3T3-L1 adipocytes.

AIMS: Pioglitazone, a full peroxisome proliferator-activated receptor (PPAR)-γ agonist, improves insulin sensitivity by increasing circulating adiponectin levels. However, the molecular mechanisms by which pioglitazone induces insulin sensitization are not fully understood. In this study, we investigated whether pioglitazone improves insulin resistance via upregulation of either 2 distinct receptors for adiponectin (AdipoR1 or AdipoR2) expression in 3T3-L1 adipocytes. MAIN METHODS: Glucose uptake was evaluated by 2-[(3)H] deoxy-glucose uptake assay in 3T3-L1 adipocytes with pioglitazone treatment. AdipoR1 and AdipoR2 mRNA expressions were analyzed by qRT-PCR. KEY FINDINGS: We first confirmed that pioglitazone significantly increased insulin-induced 2-deoxyglucose (2-DOG) uptake in 3T3-L1 adipocytes. Next, we investigated the mRNA expression and regulation of AdipoR1 and AdipoR2 after treatment with pioglitazone. Interestingly, pioglitazone significantly induced AdipoR2 expression but it did not affect AdipoR1 expression. In addition, adenovirus-mediated PPARγ expression significantly enhanced the effects of pioglitazone on insulin-stimulated 2-DOG uptake and AdipoR2 expression in 3T3-L1 adipocytes. These data suggest that pioglitazone enhances adiponectin's autocrine and paracrine actions in 3T3-L1 adipocytes via upregulation of PPARγ-mediated AdipoR2 expression. Furthermore, we found that pioglitazone significantly increased AMP-activated protein kinase (AMPK) phosphorylation in insulin-stimulated 3T3-L1 adipocytes, but it did not lead to the phosphorylation of IRS-1, Akt, or protein kinase Cλ/ζ. SIGNIFICANCE: Our results suggest that pioglitazone increases insulin sensitivity, at least partly, by PPARγ-AdipoR2-mediated AMPK phosphorylation in 3T3-L1 adipocytes. In conclusion, the upregulation of AdipoR2 expression may be one of the mechanisms by which pioglitazone improves insulin resistance in 3T3-L1 adipocytes.

Adiponectin reduces proteinuria in streptozotocin-induced diabetic Wistar rats.

The aim of the paper is to investigate the effects of adiponectin in diabetic nephropathy; we used an adenovirus to over-express adiponectin (Ad-Adipo) in streptozotocin (STZ)-induced diabetic rats. Animals were injected with either Ad-Adipo or control Ad-lacZ at 10 weeks after STZ treatment, and at two weeks postadenovirus injection, renal function was assessed. The degree of proteinuria was significantly reduced in Ad-Adipo rats compared with Ad-lacZ rats. Consistent with this, the mRNA expression levels of nephrin and transforming growth factor ß (TGF-ß) were significantly increased and decreased in the renal cortex of Ad-Adipo rats, respectively. Moreover, adiponectin over-expression in STZ rats decreased markers of endothelial dysfunction, a feature of diabetic nephropathy disease progression. Endothelin 1 (ET-1), plasminogen activator inhibitor 1 (PAI-1) and inducible nitric oxide synthase (iNOS) mRNA expression levels were significantly reduced in the renal cortex of Ad-Adipo rats, respectively. Concurrently, mRNA expression levels of endothelial nitric oxide synthase (eNOS), a positive regulator of endothelial function, were significantly increased in the renal cortex of Ad-Adipo rats. We have shown that chronic hyperadiponectinemia significantly alleviated the progression of proteinuria in early stage diabetic nephropathy. The mechanism whereby adiponectin decreases proteinuria involves an increase in nephrin expression, and an improvement of the endothelial dysfunction due to decreases in ET-1 and PAI-1, and an increase in eNOS expression in the renal cortex. Thus, over-expression of adiponectin has beneficial effects on early stage diabetic nephropathy.