Kaoru Yasuda

Dysfunctional Endothelial Progenitor Cells in Chronic Kidney Disease

Putative endothelial progenitor cells play a role in organ regeneration, and their incompetence may be important in the development of chronic kidney disease. The mechanisms of this incompetence are broad and range from poor mobilization, viability, and engraftment to impaired differentiation into mature endothelial cells. By contrasting the role of endothelial progenitor cells in tissue regeneration with their developing incompetence in chronic kidney disease, we emphasize the importance of designing rational pharmacologic strategies to tackle such incompetence in the broader search for therapies to attenuate chronic disease.

A murine model of neonatal diabetes mellitus in Glis3-deficient mice.

Glis3 is a member of the Gli‐similar subfamily. GLIS3 mutations in humans lead to neonatal diabetes, hypothyroidism, and cystic kidney disease. We generated Glis3‐deficient mice by gene‐targeting. The Glis3 −/− mice had significant increases in the basal blood sugar level during the first few days after birth. The high levels of blood sugar are attributed to a decrease in the Insulin mRNA level in the pancreas that is caused by impaired islet development and the subsequent impairment of Insulin‐producing cell formation. The pancreatic phenotypes indicate that the Glis3‐deficient mice are a model for GLIS3 mutation and diabetes mellitus in humans.

Comparison of Percutaneous Coronary Intervention with Medication in the Treatment of Coronary Artery Disease in Hemodialysis Patients

It has been reported that percutaneous coronary intervention (PCI) is beneficial for coronary artery disease (CAD) among the general population. However, its effects in patients who are on hemodialysis (HD) remain unclear. A prospective cohort study was performed to clarify whether PCI has a therapeutic advantage over medical therapy among HD patients with CAD. A follow-up study to 5 yr was conducted among 259 HD patients with ischemic heart disease. Mean follow-up was 39 mo. Patients were divided into three groups: 122 patients without significant stenosis, 88 patients who had significant stenosis and were treated with PCI, and 49 patients who had significant stenosis and were treated with medication only. The primary end point was cardiac death, and the secondary end point was all-cause death. The results showed that the 5-yr cardiac survival rate was 41.6% in the medication group, 77.1% in the PCI group (P = 0.0006), and 84.5% in the nonstenosis group (P < 0.0001). The 5-yr all-cause survival rate was 19.3% in the medication group, 48.4% in the PCI group (P = 0.004), and 64.3% in the nonstenosis group (P < 0.0001). Even after adjustment for other risk factors, effects of PCI on the risk for cardiac and all-cause death remained significant and independent (odds ratio 0.14; 95% confidence interval 0.08 to 0.25, P = 0.0006; and odds ratio 0.37; 95% confidence interval 0.26 to 0.54, P = 0.0062, respectively). Results were consistent when the therapeutic effect of PCI or medication was analyzed using propensity-matched patients. These data suggested that PCI could improve the prognosis of HD patients with CAD. PCI would be recommended for HD patients with CAD.

Low circulating CD34+ cell count is associated with poor prognosis in chronic hemodialysis patients

Circulating CD34-positive (CD34(+)) cells, a population that includes endothelial progenitor cells, are believed to contribute to vascular homeostasis. Here we determine the prognostic value of CD34(+) cell measurements in 216 chronic hemodialysis patients. A total of 43 cardiovascular events and 13 deaths occurred over an average 23 months follow-up in this cohort. A cutoff number for circulating CD34(+) cells was determined by receiver operating characteristic curve analysis to maximize the power of the CD34(+) cell count in predicting future cardiovascular events. Based on this, 93 patients were categorized as having low and 123 patients as having high numbers of CD34(+) cells, determined by flow cytometry at the time of enrollment. Both cumulative cardiovascular event-free survival and all-cause survival were significantly less in the group of patients with low numbers of CD34(+) cells. By multivariate analyses, a low level of circulating CD34(+) cells was an independent and significant predictor for both cardiovascular events and all-cause mortality. Our study shows that a reduced number of circulating CD34(+) cells is significantly associated with vascular risks and all-cause mortality in patients on chronic hemodialysis. These cells may be a useful biomarker.

Low Serum Cultured Adipose Tissue-Derived Stromal Cells Ameliorate Acute Kidney Injury in Rats:

Current studies suggest that mesenchymal stromal cells (MSCs) improve acute kidney injury (AKI) via paracrine/ endocrine effects. We established human adipose tissue-derived stromal cells (hASCs) cultured in low (2%) serum (hLASCs), which have great potential of tissue regeneration. The present study was performed to investigate the therapeutic effects of hLASCs on AKI and to clarify the mechanisms involved. In low serum, hASCs proliferated well, while human bone marrow-derived stromal cells (hBMSCs) did not. hLASCs secreted higher levels of hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) than did hASCs cultured in high (20%) serum (hHASCs) or hBMSCs cultured in high serum (hHBMSCs). AKI was induced in nude rats by folic acid, and hLASCs, hHASCs or control medium were administered into the renal subcapsules. hLASCs significantly attenuated acute renal damage, while hHASCs showed far less effect. Furthermore, interstitial fibrosis observed on day 14 was less pronounced in the hLASCs group. Cell tracking experiment showed no evidence of transdifferentiation. Intravenous injection of hLASCs or hHBMSCs or subcapsular injection of hHBMSCs did not ameliorate AKI. Concerning the mechanisms, our in vivo experiments showed that HGF knockdown by siRNA impaired the ability of hLASCs to protect the kidney from acute injury whereas VEGF knockdown did not. In conclusion, hLASCs, but not hHASCs or hHBMSCs, ameliorated AKI via paracrine effects, and HGF is one of the key mediators.

Increased urethral resistance by periurethral injection of low serum cultured adipose-derived mesenchymal stromal cells in rats

Objectives:  To evaluate the effects of a periurethral injection of low serum cultured adipose tissue‐derived mesenchymal stromal cells (LASC) and to develop a new autologous cell therapy for stress urinary incontinence.

Enhanced progenitor cell recruitment and endothelial repair after selective endothelial injury of the mouse kidney.

Primary and/or secondary injury of the renal microvascular endothelium is a common finding in various renal diseases. Besides well-known endothelial repair mechanisms, including endothelial cell (EC) proliferation and migration, homing of extrinsic cells such as endothelial progenitor cells (EPC) and hematopoietic stem cells (HSC) has been shown in various organs and may contribute to microvascular repair. However, these mechanisms have so far not been studied after selective microvascular injury in the kidney. The present study investigated the time course of EPC and HSC stimulation and homing following induction of selective EC injury in the mouse kidney along with various angiogenic factors potentially involved in EC repair and progenitor cell stimulation. Erythropoietin was used to stimulate progenitor cells in a therapeutic approach. We found that selective EC injury leads to a marked stimulation of EPCs, HSCs, and various angiogenic factors to orchestrate microvascular repair. Angiogenic factors started to increase as early as 30 min after disease induction. Progenitor cells could be first detected in the circulation and the spleen before they selectively homed to the diseased kidney. Injection of a high dose of erythropoietin 2 h after disease induction markedly attenuated vascular injury through nonhemodynamic mechanisms, possibly involving vascular endothelial growth factor release.

Geriatric nutritional risk index accurately predicts cardiovascular mortality in incident hemodialysis patients

BACKGROUND Cardiovascular disease (CVD) is a leading cause of death in end-stage renal disease (ESRD) patients. Protein-energy wasting (PEW) or malnutrition is common in this population, and is associated with increasing risk of mortality. The geriatric nutritional risk index (GNRI) has been developed as a tool to assess the nutritional risk, and is associated with mortality not only in elderly patients but also in ESRD patients. However, whether the GNRI could predict the mortality due to CVD remains unclear in this population. We investigated the prognostic value of GNRI at initiation of hemodialysis (HD) therapy for CVD mortality in a large cohort of ESRD patients. METHODS Serum albumin, body weight, and height for calculating GNRI were measured in 1568 ESRD patients. Thereafter, the patients were divided into quartiles according to GNRI levels [quartile 1 (Q1): < 84.9; Q2: 85.0-91.1; Q3: 91.2-97.2; and Q4: >97.3], and were followed up for up to 10 years. RESULTS GNRI levels independently correlated with serum C-reactive-protein levels (β = -0.126, p < 0.0001). Rates of freedom from CVD mortality for 10 years were 57.9%, 73.3%, 80.8%, and 89.2% in Q1, Q2, Q3, and Q4, respectively (p < 0.0001). The GNRI was an independent predictor of CVD mortality (hazard ratio 3.42, 95% confidence interval 2.05-5.70, p < 0.0001 for Q1 vs. Q4). C-index was also greater in an established CVD risk model with GNRI (0.749) compared to that with albumin (0.730), body mass index (0.732), and alone (0.710). Similar results were observed for all-cause mortality. CONCLUSION GNRI at initiation of HD therapy could predict CVD mortality with incremental value of the predictability compared to serum albumin and body mass index in ESRD patients.

Autologous cell therapy for cisplatin-induced acute kidney injury by using non-expanded adipose tissue-derived cells

BACKGROUND AIMS Recent studies have demonstrated that cultured mesenchymal stromal cells derived from adipose tissue are useful for regenerative cell therapy. The stromal vascular fraction (SVF) can be obtained readily without culturing and may be clinically applicable. We investigated the therapeutic effects of SVF and used it in the treatment of acute kidney injury (AKI). METHODS Liposuction aspirates were obtained from healthy donors who had provided written informed consent. We harvested the SVF and determined the growth factor secretion and anti-apoptotic ability with conditioned medium. To investigate the effect of SVF on AKI, cisplatin was injected into rats and SVF was administrated into the subcupsula of the kidney. RESULTS Both human and rat SVF cells secreted vascular endothelial growth factor-A (VEGF) and hepatocyte growth factor (HGF). Human SVF-conditioned media had an anti-apoptotic effect, which was inhibited by anti-HGF antibody (Ab) but not by anti-VEGF Ab. In vivo, SVF significantly ameliorated renal function, attenuated tubular damage and increased the cortical blood flow speed. In the SVF-treated group, VEGF levels in the cortex and HGF levels in both the cortex and medulla, especially tubules in the medulla, were significantly higher. Immunostaining revealed that SVF cells expressing VEGF and HGF and remained in the subcapsule on day 14. CONCLUSIONS The present study demonstrates that a subcapsular injection of non-expanded SVF cells ameliorates rat AKI, and that the mechanism probably involves secretion of renoprotective molecules. Administration of human SVF may be clinically applicable and useful as a novel autologous cell therapy against kidney diseases.

Association of Cardiac Valvular Calcifications and C-Reactive Protein With Cardiovascular Mortality in Incident Hemodialysis Patients: A Japanese Cohort Study

BACKGROUND Cardiac valve calcification is seen frequently in patients undergoing dialysis. Serum C-reactive protein (CRP) level also is reported to predict future cardiovascular events. We investigated the association among valve calcification, CRP level, and mortality in patients with end-stage renal disease who were just beginning hemodialysis (HD) therapy. STUDY DESIGN Observational cohort. SETTING & PARTICIPANTS 1,290 consecutive patients who just started HD therapy were enrolled and were followed up to 10 years. PREDICTOR Patients were divided into 3 groups according to number of calcified valves: those without valve calcification, those with calcification in a single (aortic or mitral) valve, and those with calcification in both valves. They also were divided into tertiles according to CRP level. OUTCOMES Cardiovascular and all-cause mortality. MEASUREMENTS Echocardiography and CRP measurement were performed within 1 month after beginning HD therapy. RESULTS During follow-up (median, 51 months), 335 (25.9%) patients died, including 156 (12.1%) of cardiovascular disease. The adjusted HR for cardiovascular mortality was 2.80 (95% CI, 1.63-4.81) for 2 calcifications versus 0 (P < 0.001). Furthermore, the risk of cardiovascular mortality was 3.66-fold higher in patients with calcifications in both valves (highest tertile of CRP) compared with patients without valve calcification (lowest tertile of CRP; P < 0.001). LIMITATIONS Precise medical treatments or therapeutic interventions were not evaluated. CONCLUSIONS Valve calcification and elevated CRP levels were not only related to additively increased risk of mortality, but also improved the prediction of mortality in patients with end-stage renal disease who had just begun HD therapy.