COMMD5 is involved in the mechanisms of hypotension after parathyroidectomy in patients receiving hemodialysis.

BACKGROUND: Secondary hyperparathyroidism (SHPT) is a common complication of end-stage renal disease. Parathyroidectomy (PTx) is often employed for treatment of severe SHPT. However, PTx may cause hypotension via unknown mechanisms. COMM domain-containing protein 5 (COMMD5) in the parathyroid glands has been linked to blood pressure regulation of spontaneously hypertensive rats. OBJECTIVE: To explore the relationship between COMMD5 levels and reduced BP after PTx in patients receiving hemodialysis (HD). METHODS AND RESULTS: (1) The study cohort included 31 patients receiving HD who underwent PTx. Serum COMMD5 levels were higher post-PTx vs. pre-PTx. (2) Sprague-Dawley rats (n = 22) were assigned to a 5/6 nephrectomy group or sham surgery group, vascular rings of the thoracic aorta from rats with CKD were incubated with COMMD5, and changes in vascular tension were compared. COMMD5 inhibited vasoconstriction of vascular rings with intact endothelium, but had no effect on vascular rings without the endothelium. (3) Human umbilical vein endothelial cells were stimulated with COMMD5 or small interfering RNA (siRNA). The expression levels of atrial natriuretic peptide (ANP) and endothelial nitric oxide synthase (eNOS) were up-regulated and down-regulated, respectively. CONCLUSIONS: Serum COMMD5 levels were increased after PTx in SHPT patients. COMMD5 promoted high expression of ANP and eNOS in endothelial cells, leading to vasodilation and resulting in hypotension.

GAP-43 ameliorates Podocyte injury by decreasing nuclear NFATc1 expression.

Podocyte injury is sufficient to cause glomerulosclerosis and proteinuria, eventually leading to kidney failure. Previous studies found that podocytes and neurons had similar biological characteristics. Growth-associated protein-43 (GAP-43) is a growth cone protein in neurons, and a marker of axonal and synaptic growth. However, it is not known whether GAP-43 is expressed in podocytes. Compared with normal glomerular podocytes, GAP-43 was significantly reduced in patients with glomerular diseases. GAP-43 also significantly reduced in lipopolysaccharide (LPS)-treated podocytes. We found that the decreased expression of nephrin, the cell marker of the podocyte, was significantly recovered with GAP-43 overexpression. In contrast, the migration ability in LPS-treated podocyte was reduction after GAP-43 overexpressing. Moreover, overexpression of GAP-43 attenuated podocyte apoptosis by up-regulating the ratio of Bcl-2/Bax with LPS treatment. Finally, Plaue and Rcan1 which are downstream target gene of NFATc1 decreased with overexpression of GAP-43 podocytes. We concluded that GAP-43 attenuated podocyte injury by inhibiting calcineurin/NFATc1 signaling. The findings may provide a promising treatment for podocyte injury-related diseases.

Thromboxane A2 is involved in the development of hypertension in chronic kidney disease rats.

Hypertension is one of the most common complications of chronic kidney disease (CKD). Some research has indicated that changes in large artery function especially caused by thromboxane A2 (TXA2) may be a novel factor acting to induce hypertension in CKD. We studied the 5/6 nephrectomy rat model and measured serum levels of creatinine (Cr), calcium (Ca), phosphorus (P), TXA2-stable metabolites (thromboxane B2, TXB2), and caudal artery pressure after nephrectomy. The tension variations in thoracic aortas were measured after stimulating by vasoconstrictor/vasodilator using the cumulative concentration administration method and then tested the expression of TXA2 receptors in the thoracic aortas through western blots. The CKD rats developed uremia, electrolyte imbalances，and hypertension. They also exhibited a significant increase in TXB2 concentration. The aortic rings of CKD rats showed an increased contraction response to U46619 (a TXA2 analogue) and the expression of TXA2 receptors also enhanced. In the meanwhile, the diastolic function decreased in the CKD group. Our results demonstrate that the impairment of artery contractile function caused by the increase of TXA2 receptors on the wall of aortic rings may be involved in hypertension in CKD rats.

Receptor activator of NF-κB mediates podocyte injury in diabetic nephropathy.

Receptor activator of NF-κB (RANK) expression is increased in podocytes of patients with diabetic nephropathy. However, the relevance of RANK to diabetic nephropathy pathobiology remains unclear. Here, to evaluate the role of podocyte RANK in the development of diabetic nephropathy, we generated a mouse model of podocyte-specific RANK depletion (RANK-/-Cre T), and a model of podocyte-specific RANK overexpression (RANK TG), and induced diabetes in these mice with streptozotocin. We found that podocyte RANK depletion alleviated albuminuria, mesangial matrix expansion, and basement membrane thickening, while RANK overexpression aggravated these indices in streptozotocin-treated mice. Moreover, streptozotocin-triggered oxidative stress was increased in RANK overexpression but decreased in the RANK depleted mice. Particularly, the expression of NADPH oxidase 4, and its obligate partner, P22phox, were enhanced in RANK overexpression, but reduced in RANK depleted mice. In parallel, the transcription factor p65 was increased in the podocyte nuclei of RANK overexpressing mice but decreased in the RANK depleted mice. The relevant findings were largely replicated with high glucose-treated podocytes in vitro. Mechanistically, p65 could bind to the promoter regions of NADPH oxidase 4 and P22phox, and increased their respective gene promoter activity in podocytes, dependent on the levels of RANK. Taken together, these findings suggested that high glucose induced RANK in podocytes and caused the increase of NADPH oxidase 4 and P22phox via p65, possibly together with the cytokines TNF- α, MAC-2 and IL-1 ß, resulting in podocyte injury. Thus, we found that podocyte RANK was induced in the diabetic milieu and RANK mediated the development of diabetic nephropathy, likely by promoting glomerular oxidative stress and proinflammatory cytokine production.

Integrin ß3 overexpression contributes to podocyte injury through inhibiting RhoA/YAP signaling pathway.

Axis formed by integrin ß3 (ITGß3)-Ras homolog gene family, member A (RhoA), and Yes-associated protein (YAP) plays an important role in atherosclerosis. In addition, ITGß3 overexpression was noted in high-glucose (HG) exposure podocytes. However, the ITGß3-RhoA-YAP axis on HG-induced podocyte injury remains unclear. This study aimed to investigate whether ITGß3 regulates podocyte injury by regulating the RhoA-YAP axis. The function and potential mechanism of ITGß3 were observed through in vitro wound-healing assays, flow cytometry, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and western blot assay. Results showed that HG treatment increased the ability of wound closure and apoptosis; however, in spite of HG treatment, ITGß3 inhibition mitigated the ability of wound closure and apoptosis in podocytes. By contrast, overexpression of ITGß3 increased the wound closure and apoptosis abilities of podocytes. Under HG treatment, ITGß3 knockdown is associated with upregulation of RhoA, total YAP1, and nucleus YAP1, whereas ITGß3 overexpression has opposite effect. In addition, RhoA overexpression in podocytes reverses the effect of ITGß3 overexpression on the wound closure and apoptosis abilities of podocytes, rescue the expression of YAP in ITGß3 overexpression podocytes. Taken together, ITGß3 overexpression promotes podocytes injury by inhibiting RhoA-YAP axis. This will provide a new clue for preventing podocyte from damage.

The Krüppel-like factor 15-NFATc1 axis ameliorates podocyte injury: a novel rationale for using glucocorticoids in proteinuria diseases.

Podocyte injury and loss contribute to proteinuria, glomerulosclerosis and eventually kidney failure. Recent studies have demonstrated that the loss of Kruppel-like factor 15 (KLF15) in podocytes increases the susceptibility to injury; however, the mechanism underlying the protective effects on podocyte injury remains incompletely understood. Herein, we showed that KLF15 ameliorates podocyte injury through suppressing NFAT signaling and the salutary effects of the synthetic glucocorticoid dexamethasone in podocyte were partially mediated by the KLF15-NFATc1 axis. We found that KLF15 was significantly reduced in glomerular cells of proteinuric patients and in ADR-, LPS- or HG-treated podocyets in vitro. Overexpression of KLF15 attenuated podocyte apoptosis induced by ADR, LPS or HG and resulted in decreased expression of pro-apoptotic Bax and increased expression of anti-apoptotic Bcl-2. Conversely, the flow cytometry analysis and TUNEl assay demonstrated that loss of KLF15 accelerated podocyte apoptosis and we further found that 11R-VIVIT, a specific NFAT inhibitor, and NFATc1-siRNA rescued KLF15-deficient induced podocyte apoptosis. Meanwhile, Western blot and RT-qPCR showed that the expression of NFATc1 was up-regulated in KLF15 silenced podocytes and reduced in KLF15 overexpressed podocytes. Mechanistically, ChIP analysis showed that KLF15 bound to the NFATc1 promoter region -1984 to -1861base pairs upstream of the transcription start site and the binding amount was decreased after treatment with LPS. The dual-luciferase reporter assay indicated that NFATc1 was a direct target of KLF15. In addition, we found that in vitro treatment with dexamethasone induced a decrease of NFATc1 expression in podocytes and was abrogated by knockdown of KLF15. Hence, our results identify the critical role of the KLF15-NFATc1 axis in podocyte injury and loss, which may be involved in mediating the salutary effects of dexamethasone in podocytes.

Clinical features of severe patients infected with 2019 novel coronavirus: a systematic review and meta-analysis.

BACKGROUND: 2019 novel coronavirus disease (COVID-19) has posed significant threats to public health. To identify and treat the severe and critical patients with COVID-19 is the key clinical problem to be solved. The present study aimed to evaluate the clinical characteristics of severe and non-severe patients with COVID-19. METHODS: We searched independently studies and retrieved the data that involved the clinical characteristics of severe and non-severe patients with COVID-19 through database searching. Two authors independently retrieved the data from the individual studies, assessed the study quality with Newcastle-Ottawa Scale and analyzed publication bias by Begg's test. We calculated the odds ratio (OR) of groups using fixed or random-effect models. RESULTS: Five studies with 5,328 patients confirmed with COVID-19 met the inclusion criteria. Severe patents were older and more common in dyspnea, vomiting or diarrhea, creatinine >104 µmol/L, procalcitonin ≥0.05 ng/mL, lymphocyte count <1.5×109/L and bilateral involvement of chest CT. Severe patents had higher risk on complications including acute cardiac injury (OR 13.48; 95% CI, 3.60 to 50.47, P<0.001) or acute kidney injury (AKI) (OR 11.55; 95% CI, 3.44 to 38.77, P<0.001), acute respiratory distress syndrome (ARDS) (OR 26.12; 95% CI, 11.14 to 61.25, P<0.001), shock (OR 53.17; 95% CI, 12.54 to 225.4, P<0.001) and in-hospital death (OR 45.24; 95% CI, 19.43 to 105.35, P<0.001). Severe group required more main interventions such as received antiviral therapy (OR 1.69; 95% CI, 1.23 to 2.32, P=0.001), corticosteroids (OR 5.07; 95% CI, 3.69 to 6.98, P<0.001), CRRT (OR 37.95; 95% CI, 7.26 to 198.41, P<0.001) and invasive mechanical ventilation (OR 129.35; 95% CI, 25.83 to 647.68, P<0.001). CONCLUSIONS: Severe patients with COVID-19 had more risk of clinical characteristics and multiple system organ complications. Even received more main interventions, severe patients had higher risk of mortality.

Treatment of Uremic Tumoral Calcinosis in Maintenance Hemodialysis Patients.

BACKGROUND/AIMS: Uremic tumoral calcinosis (UTC) is a rare disease with metastatic tissue calcification in maintenance hemodialysis (HD) patients. However, limited data are available on the treatment of UTC in HD patients. This article mainly discusses the diagnostic findings and efficacy of treatment on HD patients with UTC. METHODS: A retrospective analysis was conducted based on the data of 13 cases of UTC, including their clinical features, biochemical indicators, imaging findings, diagnosis, therapeutic methods, and follow-up results. Parathyroidectomy (PTX) or drug treatment was determined based on intact parathyroid hormone (iPTH) levels and clinical symptoms. RESULTS: All 13 patients were diagnosed as UTC definitely by imaging examination. The predominant areas involved were the buttocks (4 cases, 30.77%), shoulders (4 cases, 30.77%), and elbows (3 cases, 23.08%). Based on the levels of iPTH, cases were categorized into 2 different groups: PTX treatment group was associated with high levels of iPTH, while drug treatment group (lanthanum carbonate or sevelamer with sodium thiosulfate) was associated with lower iPTH levels. After PTX treatment, there was a significant decrease in serum iPTH, calcium (Ca), phosphate (P), and alkaline phosphatase levels (p < 0.05). In drug treatment group, the serum p levels were decreased significantly, along with a finding that hemoglobin levels were increased (p < 0.05). All the UTC had lessened or even disappeared after 4-6 months treatment. CONCLUSIONS: Although most UTC patients have an increased iPTH, a small number had lower iPTH levels. Based on iPTH levels and clinical symptoms, the patients were treated with PTX or drug therapy. With proper treatment, UTC disappeared without the need for surgery to remove calcinosis tissue.

Soluble Urokinase Plasminogen Activator Receptor is Associated with Coronary Artery Calcification and Cardiovascular Disease in Patients Undergoing Hemodialysis.

BACKGROUND/AIMS: Cardiovascular disease (CVD) is an important cause of morbidity and mortality in hemodialysis patients. Vascular calcification is thought to play an important role in causing CVD. Soluble urokinase plasminogen activator receptor (suPAR) is a biomarker strongly predictive of cardiovascular outcomes in the pathogenesis of diabetic patients with renal disease treated with hemodialysis. We investigated the relationship between suPAR and coronary artery calcification (CAC) in patients undergoing maintenance hemodialysis. METHODS: A total of 99 adult hemodialysis patients were enrolled in this study. Plasma samples were analyzed for suPAR with an enzyme-linked immunosorbent assay and the CAC score was determined with multidetector computed tomography. The occurrence of cardiovascular events and all-cause mortality during follow-up were recorded from January 1, 2010 to June 1, 2016. RESULTS: In 99 patients treated with maintenance hemodialysis, 91 (91.9%) had varying degrees of CAC, and suPAR correlated positively with the CAC score in a Spearman analysis. In a mean follow-up period of 33 months, 36 patients (36.4%) experienced at least one cardiovascular event. When the quartiles of suPAR concentrations were used as the cutoff points for a subgroup analysis, the incidence of CVD and all-cause mortality was much higher in the higher quartiles of suPAR. In a univariate Cox regression analysis, high suPAR was a risk factor for CVD and all-cause mortality. CONCLUSION: suPAR is associated with the CAC score and is a risk factor for new-onset CVD in patients undergoing hemodialysis.