Plasma C1q/TNF-related protein 9: a promising biomarker for diabetic renal vascular injury.

BACKGROUND: Adipocytokines are associated with the pathophysiology of type 2 diabetes (T2DM). METHODS: We analyzed the relationship between levels of the plasma C1q/tumor necrosis factor-related protein 9 (CTRP9) and other adipocytokines or the endothelial function in patients with T2DM, and analyzed their trending manner. RESULTS: CTRP9 was detected in plasma from 14 out of a total of 28 patients. The values were not normally distributed. In comparing between groups in which CTRP9 was or was not detected, there were statistically significant differences in the high molecular weight adiponectin (HAN) and the urinary albumin/creatinine ratio (ACR). This indicates that both CTRP9 and HAN reflect the pathophysiology of renal involvement in T2DM. HAN correlated with Body Mass Index, ACR, and homeostasis model assessment of insulin resistance. However, CTRP9 did not correlate with HAN or any other parameters. CONCLUSIONS: CTRP9 independently trends in a different manner from HAN, and may reflect diabetic renal vascular risk in association with atherosclerosis and abnormal glucose metabolism besides of impaired vaso-relaxation in patients with T2DM.

Non-superiority of Kakkonto, a Japanese herbal medicine, to a representative multiple cold medicine with respect to anti-aggravation effects on the common cold: a randomized controlled trial.

OBJECTIVE: Kakkonto, a Japanese herbal medicine, is frequently used to treat the common cold not only with a physician's prescription, but also in self-medication situations. This study aimed to examine whether Kakkonto prevents the aggravation of cold symptoms if taken at an early stage of illness compared with a well-selected Western-style multiple cold medicine. METHODS: This study was a multicenter, active drug-controlled, randomized trial. Adults 18 to 65 years of age who felt a touch of cold symptoms and visited 15 outpatient healthcare facilities within 48 hours of symptoms onset were enrolled. The participants were randomly assigned to two groups: one treated with Kakkonto (Kakkonto Extract-A, 6 g/day) (n=209) and one treated with a Western-style multiple cold medicine (Pabron Gold-A, 3.6 g/day) (n=198) for at most four days. The primary outcome of this study was the aggravation of cold, nasal, throat or bronchial symptoms, scored as moderate or severe and lasting for at least two days within five days after entry into the study. RESULTS: Among the 410 enrollees, 340 (168 in the Kakkonto group and 172 in the Pabron group) were included in the analyses. The proportion of participants whose colds were aggravated was 22.6% in the Kakkonto group and 25.0% in the Pabron group (p=0.66). The overall severity of the cold symptoms was not significantly different between the groups. No harmful adverse events occurred in either group. CONCLUSION: Kakkonto did not significantly prevent the progression of cold symptoms, even when prescribed at an early stage of the disease.

Influence of loxoprofen use on recovery from naturally acquired upper respiratory tract infections: a randomized controlled trial.

OBJECTIVE: To investigate whether loxoprofen, one of the nonsteroidal anti-inflammatory drugs, prolongs the recovery process of naturally acquired upper respiratory tract infections (URTIs) in the clinical setting. METHODS: A double-blind, randomized, placebo-controlled trial was conducted in 23 outpatient facilities in Japan. Patients aged 18 through 65 years suffering from URTIs were randomly assigned to receive loxoprofen or its placebo. The primary outcome was duration of illness in days. RESULTS: A total of 174 patients were available for the analyses. Duration of illness was 8.94 +/- 3.20 days in the loxoprofen group compared to 8.39 +/- 3.39 days in the placebo group (P=.19). The number of days with limited daily activities was fewer in the loxoprofen group than in the placebo group (2.12 +/- 2.05 days vs. 2.68 +/- 2.54 days, P=.17). Although severe symptoms were less frequent on days 1, 2, and 3 in the loxoprofen group (27%, 33%, and 29%, respectively) than in the placebo group (32%, 39%, and 37%, respectively), symptoms were more frequent on days 6 through 12 in the loxoprofen group (difference, 5-13%). Adverse events were more common in the loxoprofen group (9.5% vs. 1.1%, P=.051). CONCLUSION: Loxoprofen did not significantly modify the recovery process of URTIs except for a slight tendency to delay.

Effects of salt loading on blood pressure in mice lacking the prostanoid receptor gene.

BACKGROUND: This study examined whether targeted disruption of the genes for the prostacyclin receptor (IP) or the thromboxane A2 receptor (TP) confers a susceptibility to salt-dependent hypertension. METHODS AND RESULTS: Eight female IP- or TP-deficient mice were examined. Baseline systolic blood pressure (SBP) did not differ between TP(-/-) and TP(+/+), but was significantly lower in the IP(-/-) group than in the IP(+/+). With a high salt diet, SBP in IP(-/-) gradually increased. In contrast, SBP in the IP(+/+), TP(-/-), or TP(+/+) groups remained unchanged. CONCLUSIONS: The prostacyclin receptor may participate in the maintenance of baseline BP. With salt loading, BP adaptation may take place, at least in part, via IP mediated signals.

Functional genomics of the dopaminergic system in hypertension.

Abnormalities in dopamine production and receptor function have been described in human essential hypertension and rodent models of genetic hypertension. Under normal conditions, D(1)-like receptors (D(1) and D(5)) inhibit sodium transport in the kidney and intestine. However, in the Dahl salt-sensitive and spontaneously hypertensive rats (SHRs) and in humans with essential hypertension, the D(1)-like receptor-mediated inhibition of epithelial sodium transport is impaired because of an uncoupling of the D(1)-like receptor from its G protein/effector complex. The uncoupling is receptor specific, organ selective, nephron-segment specific, precedes the onset of hypertension, and cosegregates with the hypertensive phenotype. The defective transduction of the renal dopaminergic signal is caused by activating variants of G protein-coupled receptor kinase type 4 (GRK4: R65L, A142V, A486V). The GRK4 locus is linked to and GRK4 gene variants are associated with human essential hypertension, especially in salt-sensitive hypertensive subjects. Indeed, the presence of three or more GRK4 variants impairs the natriuretic response to dopaminergic stimulation in humans. In genetically hypertensive rats, renal inhibition of GRK4 expression ameliorates the hypertension. In mice, overexpression of GRK4 variants causes hypertension either with or without salt sensitivity according to the variant. GRK4 gene variants, by preventing the natriuretic function of the dopaminergic system and by allowing the antinatriuretic factors (e.g., angiotensin II type 1 receptor) to predominate, may be responsible for salt sensitivity. Subclasses of hypertension may occur because of additional perturbations caused by variants of other genes, the quantitative interaction of which may vary depending upon the genetic background.

Desensitization of human renal D1 dopamine receptors by G protein-coupled receptor kinase 4.

BACKGROUND: The D1 dopamine receptor, expressed in several nephron segments, participates in the regulation of water and electrolyte transport. Because the renal D1 receptor is desensitized in genetic hypertension, we sought to determine the mechanism(s) of the desensitization of D1 receptors endogenously expressed in renal proximal tubules. METHODS: The mechanisms involved in the homologous desensitization of the D1 receptor in human renal proximal tubule cells were studied by measuring the production of cAMP in response to stimulation or inhibition of G protein-coupled receptor kinase (GRK) activity and expression. Protein expression was assessed by immunoblotting. RESULTS: In human renal proximal tubule cells, the D1 agonist, fenoldopam, increased cAMP accumulation (73 +/- 2%). Fenoldopam pre-treatment decreased the responsiveness to subsequent fenoldopam stimulation (t(1/2) approximately equal to 20 min) with complete desensitization at 30 minutes. Recovery occurred gradually (t(1/2) approximately equal to 20 min) with full recovery at 60 minutes. Forskolin pretreatment minimally affected the fenoldopam effect, indicating a minor involvement of protein kinase A in the homologous desensitization process. Because GRKs are involved in the homologous desensitization process, we determined the consequences of inhibition of GRK expression and activity. Heparin, an inhibitor of GRK activity, decreased the expression of GRK2 and GRK4 and attenuated the desensitization of the D1 receptor (85 +/- 1%). Antisense oligonucleotides (GRK4> GRK2) blunted the D1 receptor desensitization. However, the first 20 minutes of homologous desensitization were not affected by either heparin or GRK antisense oligonucleotides. CONCLUSION: These studies document the critical role of GRK4, relative to GRK2, in the homologous desensitization of D1 receptors in renal proximal tubule cells. However, the early phase of homologous desensitization is regulated by a non-GRK-mediated pathway.

G protein-coupled receptor kinase 4 gene variants in human essential hypertension.

Essential hypertension has a heritability as high as 30-50%, but its genetic cause(s) has not been determined despite intensive investigation. The renal dopaminergic system exerts a pivotal role in maintaining fluid and electrolyte balance and participates in the pathogenesis of genetic hypertension. In genetic hypertension, the ability of dopamine and D(1)-like agonists to increase urinary sodium excretion is impaired. A defective coupling between the D(1) dopamine receptor and the G protein/effector enzyme complex in the proximal tubule of the kidney is the cause of the impaired renal dopaminergic action in genetic rodent and human essential hypertension. We now report that, in human essential hypertension, single nucleotide polymorphisms of a G protein-coupled receptor kinase, GRK4gamma, increase G protein-coupled receptor kinase (GRK) activity and cause the serine phosphorylation and uncoupling of the D(1) receptor from its G protein/effector enzyme complex in the renal proximal tubule and in transfected Chinese hamster ovary cells. Moreover, expressing GRK4gammaA142V but not the wild-type gene in transgenic mice produces hypertension and impairs the diuretic and natriuretic but not the hypotensive effects of D(1)-like agonist stimulation. These findings provide a mechanism for the D(1) receptor coupling defect in the kidney and may explain the inability of the kidney to properly excrete sodium in genetic hypertension.