Personalised prediction of maintenance dialysis initiation in patients with chronic kidney disease stages 3-5: a multicentre study using the machine learning approach.

BACKGROUND: Optimal timing for initiating maintenance dialysis in patients with chronic kidney disease (CKD) stages 3-5 is challenging. This study aimed to develop and validate a machine learning (ML) model for early personalised prediction of maintenance dialysis initiation within 1-year and 3-year timeframes among patients with CKD stages 3-5. METHODS: Retrospective electronic health record data from the Taipei Medical University clinical research database were used. Newly diagnosed patients with CKD stages 3-5 between 2008 and 2017 were identified. The observation period spanned from the diagnosis of CKD stages 3-5 until the maintenance dialysis initiation or a maximum follow-up of 3 years. Predictive models were developed using patient demographics, comorbidities, laboratory data and medications. The dataset was divided into training and testing sets to ensure robust model performance. Model evaluation metrics, including area under the curve (AUC), sensitivity, specificity, positive predictive value, negative predictive value and F1 score, were employed. RESULTS: A total of 6123 and 5279 patients were included for 1 year and 3 years of the model development. The artificial neural network demonstrated better performance in predicting maintenance dialysis initiation within 1 year and 3 years, with AUC values of 0.96 and 0.92, respectively. Important features such as baseline estimated glomerular filtration rate and albuminuria significantly contributed to the predictive model. CONCLUSION: This study demonstrates the efficacy of an ML approach in developing a highly predictive model for estimating the timing of maintenance dialysis initiation in patients with CKD stages 3-5. These findings have important implications for personalised treatment strategies, enabling improved clinical decision-making and potentially enhancing patient outcomes.

The Role of Autophagy in Type 2 Diabetic Kidney Disease Management.

Diabetic kidney disease (DKD), or diabetic nephropathy (DN), is one of the most prevalent complications of type 2 diabetes mellitus (T2DM) and causes severe burden on the general welfare of T2DM patients around the world. While several new agents have shown promise in treating this condition and potentially halting the progression of the disease, more work is needed to understand the complex regulatory network involved in the disorder. Recent studies have provided new insights into the connection between autophagy, a physiological metabolic process known to maintain cellular homeostasis, and the pathophysiological pathways of DKD. Typically, autophagic activity plays a role in DKD progression mainly by promoting an inflammatory response to tissue damage, while both overactivated and downregulated autophagy worsen disease outcomes in different stages of DKD. This correlation demonstrates the potential of autophagy as a novel therapeutic target for the disease, and also highlights new possibilities for utilizing already available DN-related medications. In this review, we summarize findings on the relationship between autophagy and DKD, and the impact of these results on clinical management strategies.

De novo podocytopathy following moderna COVID-19 vaccine: A case report and racial disproportionality in adverse effect reports.

In this study, we report a case of de novo minimal change disease shortly after the second dose of the Moderna COVID-19 vaccine. A previously healthy 51-year-old Asian man presented with lower-limb edema and foamy urine 3 days after receiving the second dose of the vaccine. Laboratory data revealed the following: serum creatinine, 0.65 mg/dl; serum albumin, 1.3 g/dl; urine protein-to-creatinine ratio, 15.3 g. A renal biopsy was performed, and minimal change in the disease was confirmed. The patient achieved complete remission in the tenth week after starting treatment with prednisolone (1 mg/kg/day). Ethnic differences may influence the adverse effects of drugs and vaccines. However, there is very limited data to address the influence of ethnic diversity on disease prevalence, clinical presentation, and treatment outcomes in COVID-19 vaccine-associated glomerulonephritis.

Genetic insight into primary glomerulonephritis.

Primary glomerulonephritis is a major global health concern and a disorder with significant heritable components. Rapid advances in sequencing technologies have led to genome-wide, high-throughput investigations of the genetic basis of complex human traits. Genetic studies have successfully mapped several susceptibility loci and disease-causing genes for different subtypes of primary glomerulonephritis. These studies have revealed that IgA nephropathy-associated genes have a highly complex, polygenic and pleiotropic genetic architecture and that genetic susceptibility to membranous nephropathy may be driven by a few large-effect loci. Furthermore, both susceptibility genes and high-penetrant gene mutations reportedly contribute to the development of the most heterogeneous phenotype of focal segmental glomerulosclerosis. The genetic heterogeneity between each glomerular disease type and within different populations has indicated disease-specific and ethnicity-specific underlying molecular mechanisms for the disorders. The findings from genome-wide association studies (GWAS) have mainly included variants on or near the major histocompatibility (MHC) loci, highlighting the molecular basis for the shared pathogenesis of the immune-mediated disease. Recent studies with increased sample sizes and higher resolutions of genome-wide imputation have provided novel insights into the pathogenesis of glomerular disorders. Further integration of results from genomic studies with functional genomics datasets can indicate novel targets for drug discovery as well as potential tools for patient diagnosis and stratification. However, larger GWASs and sequencing studies in independent cohorts and more standardized inclusion of phenotypes across studies are required for each subtype of glomerular disease.

Contact Laxative Use and the Risk of Arteriovenous Fistula Maturation Failure in Patients Undergoing Hemodialysis: A Multi-Center Cohort Study.

Laxatives are commonly prescribed for constipation management; however, they are recognized as an independent factor associated with cardiovascular diseases. Arteriovenous fistula (AVF) is the closest to the ideal model of hemodialysis (HD) vascular access and part of the cardiovascular system. Our study aims to explore the association of contact laxative use with AVF maturation outcomes in patients undergoing HD. We conducted a multi-center cohort study of 480 contact laxative users and 472 non-users who had undergone initial AVF creation. All patients were followed until the outcomes of AVF maturation were confirmed. Multivariable logistic regression models were performed to evaluate the risk of AVF maturation failure imposed by laxatives. Here, we found that patients who used contact laxatives were significantly associated with an increased risk of AVF maturation failure compared to non-users (adjusted odds ratio, 1.64; p = 0.003). Notably, the risk of AVF maturation failure increased when increasing their average daily doses and cumulative treatment days. In conclusion, our study found a significant dose- and duration-dependent relationship between contact laxative use and an increased risk of AVF maturation failure. Thus, laxatives should be prescribed with caution in this population. Further studies are needed to validate these observations and investigate the potential mechanisms.

Allogeneic adipose tissue-derived stem cells ELIXCYTE® in chronic kidney disease: A phase I study assessing safety and clinical feasibility.

The purpose of this phase I clinical trial is to assess the safety and tolerability of allogeneic adipose tissue-derived stem cells (ADSCs) among chronic kidney disease (CKD) patients. 12 eligible CKD patients with an estimated glomerular filtration rate (eGFR) of 15-44 ml/min/1.73 m2 received one dose of intravenous allogeneic ADSCs (ELIXCYTE® ), as 3 groups: 3 low dose (6.4 × 107 cells in total of 8 ml), 3 middle dose (19.2 × 107 cells in total of 24 ml) and 6 high dose (32.0 × 107 cells in total of 40 ml) of ELIXCYTE® and evaluated after 48 weeks. Primary endpoint was the safety profiles in terms of incidence of adverse events (AEs) and serious adverse event (SAE). Two subjects in high dose group experienced a total of 2 treatment-related AEs which are Grade 1 slow speech and Grade 1 bradyphrenia after the infusion. One subject in middle dose group experienced an SAE unlikely related to treatment, grade 2 proteinuria. No fatal AE was reported in this study. An increase in eGFR was observed in 7 out of 12 subjects (58%) at Week 24 and in 6 of 12 subjects (50%) by Week 48. By Week 24, an increase in eGFR by more than 20% among all CKD patients with baseline eGFR â‰§ 30 ml/min/1.73 m2 as compared to only 2 subjects in baseline eGFR < 30 ml/min/1.73 m2  group. No significant reduction in proteinuria was noted among all subjects. This phase I trial demonstrated single-dose intravenous ELIXCYTE was well tolerated in moderate-to-severe CKD patients and its preliminary efficacy warrants future studies.

Deletion of STAT3 from Foxd1 cell population protects mice from kidney fibrosis by inhibiting pericytes trans-differentiation and migration.

Signal transduction and activator of transcription 3 (STAT3) is a key transcription factor implicated in the pathogenesis of kidney fibrosis. Although Stat3 deletion in tubular epithelial cells is known to protect mice from fibrosis, vFoxd1 cells remains unclear. Using Foxd1-mediated Stat3 knockout mice, CRISPR, and inhibitors of STAT3, we investigate its function. STAT3 is phosphorylated in tubular epithelial cells in acute kidney injury, whereas it is expanded to interstitial cells in fibrosis in mice and humans. Foxd1-mediated deletion of Stat3 protects mice from folic-acid- and aristolochic-acid-induced kidney fibrosis. Mechanistically, STAT3 upregulates the inflammation and differentiates pericytes into myofibroblasts. STAT3 activation increases migration and profibrotic signaling in genome-edited, pericyte-like cells. Conversely, blocking Stat3 inhibits detachment, migration, and profibrotic signaling. Furthermore, STAT3 binds to the Collagen1a1 promoter in mouse kidneys and cells. Together, our study identifies a previously unknown function of STAT3 that promotes kidney fibrosis and has therapeutic value in fibrosis.

The Kidney-Related Effects of Polystyrene Microplastics on Human Kidney Proximal Tubular Epithelial Cells HK-2 and Male C57BL/6 Mice.

BACKGROUND: Understanding the epidemic of chronic kidney disease of uncertain etiology may be critical for health policies and public health responses. Recent studies have shown that microplastics (MPs) contaminate our food chain and accumulate in the gut, liver, kidney, muscle, and so on. Humans manufacture many plastics-related products. Previous studies have indicated that particles of these products have several effects on the gut and liver. Polystyrene (PS)-MPs (PS-MPs) induce several responses, such as oxidative stress, and affect living organisms. OBJECTIVES: The aim of this study was to investigate the effects of PS-MPs in kidney cells in vitro and in vivo. METHODS: PS-MPs were evaluated in human kidney proximal tubular epithelial cells (HK-2 cells) and male C57BL/6 mice. Mitochondrial reactive oxygen species (ROS), endoplasmic reticulum (ER) stress, inflammation, and autophagy were analyzed in kidney cells. In vivo, we evaluated biomarkers of kidney function, kidney ultrastructure, muscle mass, and grip strength, and urine protein levels, as well as the accumulation of PS-MPs in the kidney tissue. RESULTS: Uptake of PS-MPs at different concentrations by HK-2 cells resulted in higher levels of mitochondrial ROS and the mitochondrial protein Bad. Cells exposed to PS-MPs had higher ER stress and markers of inflammation. MitoTEMPO, which is a mitochondrial ROS antioxidant, mitigated the higher levels of mitochondrial ROS, Bad, ER stress, and specific autophagy-related proteins seen with PS-MP exposure. Furthermore, cells exposed to PS-MPs had higher protein levels of LC3 and Beclin 1. PS-MPs also had changes in phosphorylation of mitogen-activated protein kinase (MAPK) and protein kinase B (AKT)/mitogen-activated protein kinase (mTOR) signaling pathways. In an in vivo study, PS-MPs accumulated and the treated mice had more histopathological lesions in the kidneys and higher levels of ER stress, inflammatory markers, and autophagy-related proteins in the kidneys after PS-MPs treatment by oral gavage. CONCLUSIONS: The results suggest that PS-MPs caused mitochondrial dysfunction, ER stress, inflammation, and autophagy in kidney cells and accumulated in HK-2 cells and in the kidneys of mice. These results suggest that long-term PS-MPs exposure may be a risk factor for kidney health. https://doi.org/10.1289/EHP7612.

Therapeutic Effect of Calcimimetics on Osteoclast-Osteoblast Crosslink in Chronic Kidney Disease and Mineral Bone Disease.

We have previously demonstrated calcimimetics optimize the balance between osteoclastic bone resorption and osteoblastic mineralization through upregulating Wingless and int-1 (Wnt) signaling pathways in the mouse and cell model. Nonetheless, definitive human data are unavailable concerning therapeutic effects of Cinacalcet on chronic kidney disease and mineral bone disease (CKD-MBD) and osteoclast-osteoblast interaction. We aim to investigate whether Cinacalcet therapy improves bone mineral density (BMD) through optimizing osteocytic homeostasis in a human model. Hemodialysis patients with persistently high intact parathyroid hormone (iPTH) levels > 300 pg/mL for more than 3 months were included and received fixed dose Cinacalcet (25 mg/day, orally) for 6 months. Bone markers presenting osteoclast-osteoblast communication were evaluated at baseline, the 3rd and the 6th month. Eighty percent of study patients were responding to Cinacalcet treatment, capable of improving BMD, T score and Z score (16.4%, 20.7% and 11.1%, respectively). A significant correlation between BMD improvement and iPTH changes was noted (r = -0.26, p < 0.01). Nonetheless, baseline lower iPTH level was associated with better responsiveness to Cinacalcet therapy. Sclerostin, an inhibitor of canonical Wnt/ß-catenin signaling, was decreased from 127.3 ± 102.3 pg/mL to 57.9 ± 33.6 pg/mL. Furthermore, Wnt-10b/Wnt 16 expressions were increased from 12.4 ± 24.2/166.6 ± 73.3 pg/mL to 33.8 ± 2.1/217.3 ± 62.6 pg/mL. Notably, procollagen type I amino-terminal propeptide (PINP), a marker of bone formation and osteoblastic activity, was increased from baseline 0.9 ± 0.4 pg/mL to 91.4 ± 42.3 pg/mL. In contrast, tartrate-resistant acid phosphatase isoform 5b (TRACP-5b), a marker of osteoclast activity, was decreased from baseline 16.5 ± 0.4 mIU/mL to 7.7 ± 2.2 mIU/mL. Moreover, C-reactive protein levels were suppressed from 2.5 ± 0.6 to 0.8 ± 0.5 mg/L, suggesting the systemic inflammatory burden may be benefited after optimizing the parathyroid-bone axis. In conclusion, beyond iPTH suppression, our human model suggests Cinacalcet intensifies BMD through inhibiting sclerostin expression and upregulating Wnt-10b/Wnt 16 signaling that activates osteoblastic bone formation and inhibits osteoclastic bone resorption and inflammation. From the perspective of translation to humans, this research trial brings a meaningful insight into the osteoblast-osteoclast homeostasis in Cinacalcet therapy for CKD-MBD.

Nicotine Causes Nephrotoxicity through the Induction of NLRP6 Inflammasome and Alpha7 Nicotinic Acetylcholine Receptor.

Current cigarette smoking is associated with chronic kidney disease (CKD) or death from end-stage renal disease (ESRD). Mainstream cigarette smoke includes over 4000 compounds. Among the compounds present in tobacco smoke, nicotine is one of a large number of biologically stable and active compounds present in tobacco. However, the mechanisms by which nicotine exacerbates kidney disease progression have not been identified. It is known that the inflammasomes constitute an important innate immune pathway and contribute to the pathophysiology of diverse kidney diseases. The relationship between inflammasomes and nicotine-induced kidney damage still remains unclear. In the present study, we studied the mechanisms of nicotine-induced nephrotoxicity. We found that nicotine decreased cell viability and induced reactive oxygen species (ROS) generation in human kidney cells. Furthermore, nicotine significantly increased the expression of the alpha7 nicotinic acetylcholine receptor (α7nAChR). Nicotine activated the NLRP6 inflammasome and induced endoplasmic reticulum (ER) stress. Nicotine caused mild apoptosis and necrosis but triggered significant autophagy in human kidney cells. In addition, nicotine induced the NLRP6 inflammasome and autophagy via α7nAChR. In an animal model, the histological analysis in kidney showed evident changes and injury. The results indicated that α7nAChR, IRE1α, LC3 and NLRP6 expression in kidney sections was markedly increased in the nicotine groups. These findings suggest that nicotine causes kidney damage by modulating α7nAChR, NLRP6 inflammasome, ER stress and autophagy.

Lactoferrin Contributes a Renoprotective Effect in Acute Kidney Injury and Early Renal Fibrosis.

Patients with acute kidney injury (AKI) who survive the acute stage are at notable risk for chronic kidney disease (CKD) progression. There is no single therapy that can effectively prevent the AKI to CKD transition. Autophagy is a cytoplasmic component degradation pathway and has complex functions in several diseases, such as renal fibrosis. Previous research has shown that lactoferrin has important functions in antioxidant defense and other defense systems, protecting kidneys against various injuries. The present study investigated the effect of lactoferrin in protecting against the AKI to CKD transition. We identified 62 consensus genes with two-fold changes in clinical kidney tissues from AKI and CKD patients. Among the 62 overlay genes, the mRNA levels of LTF were significantly upregulated in the kidney tissues of AKI and CKD patients. Lactoferrin induced autophagy via the activation of the AMPK and inhibition of Akt/mTOR pathway in human kidney proximal tubular cells. Lactoferrin suppressed oxidative stress-induced cell death and apoptosis by augmenting autophagy. Lactoferrin has an antifibrotic role in human kidney tubular cells. In a mouse model of folic acid-induced AKI to CKD transition, treatment with lactoferrin recovered renal function and further suppressed renal fibrosis through the inhibition of apoptosis and the induction of autophagy. These findings identify lactoferrin as a potential therapeutic target for the prevention of the AKI to CKD transition.

Lactotransferrin Downregulation Drives the Metastatic Progression in Clear Cell Renal Cell Carcinoma.

: Clear cell renal cell carcinoma (ccRCC) is the main type of RCC, which is the most common type of malignant kidney tumor in adults. A subpopulation (>30%) of ccRCC patients develop metastasis; however, the molecular mechanism remains largely unknown. Here, we found that LTF, the gene encoding lactotransferrin, is dramatically downregulated in primary tumors compared to normal tissues derived from ccRCC patients deposited in The Cancer Genome Atlas (TCGA) database and is a favorable prognostic marker. Moreover, LTF downregulation appears to be more dominant in metastatic ccRCC. LTF overexpression suppresses migration ability in A498 ccRCC cells with high metastatic potential, whereas LTF knockdown fosters cellular migration in poorly metastatic ccRCC cells. Gene set enrichment analysis demonstrated that LTF expression inversely correlates with the progression of epithelial-mesenchymal transition (EMT) in ccRCC, which was further confirmed by RT-PCR experiments. Therapeutically, the administration of recombinant LTF protein significantly suppresses the cell migration ability and lung metastatic potential of ACHN cells, as well as LTF-silenced A498 cells. The gene knockdown of lipoprotein receptor-related protein 1 (LRP1) robustly blocked recombinant LTF protein-induced inhibition of cellular migration and gene expression of EMT markers in ACHN cells. LTF downregulation and LRP1 upregulation combined predicted a poor overall survival rate in ccRCC patients compared to that with either factor alone. Our findings uncover a new mechanism by which LTF may interact with LRP1 to inhibit metastatic progression in ccRCC and also reveal the therapeutic value of recombinant LTF protein in treating metastatic ccRCC.

Potent Impact of Plastic Nanomaterials and Micromaterials on the Food Chain and Human Health.

Plastic products are inexpensive, convenient, and are have many applications in daily life. We overuse plastic-related products and ineffectively recycle plastic that is difficult to degrade. Plastic debris can be fragmented into smaller pieces by many physical and chemical processes. Plastic debris that is fragmented into microplastics or nanoplastics has unclear effects on organismal systems. Recently, this debris was shown to affect biota and to be gradually spreading through the food chain. In addition, studies have indicated that workers in plastic-related industries develop many kinds of cancer because of chronic exposure to high levels of airborne microplastics. Microplastics and nanoplastics are everywhere now, contaminating our water, air, and food chain. In this review, we introduce a classification of plastic polymers, define microplastics and nanoplastics, identify plastics that contaminate food, describe the damage and diseases caused by microplastics and nanoplastics, and the molecular and cellular mechanisms of this damage and disease as well as solutions for their amelioration. Thus, we expect to contribute to the understanding of the effects of microplastics and nanoplastics on cellular and molecular mechanisms and the ways that the uptake of microplastics and nanoplastics are potentially dangerous to our biota. After understanding the issues, we can focus on how to handle the problems caused by plastic overuse.

Promising therapeutic effect of thapsigargin nanoparticles on chronic kidney disease through the activation of Nrf2 and FoxO1.

Pathophysiological states cause misfolded protein accumulation in the endoplasmic reticulum (ER). Then, ER stress and the unfolded protein response (UPR) are activated. Targeting ER stress may enhance the adaptive UPR and then protect the cell against pathogenic environments. In the present study, we utilized nanotechnology to synthesize thapsigargin nanoparticles (TG NPs) which induced ER stress and the UPR pathway, to study the role of ER stress and autophagy in chronic kidney disease (CKD). We found that the mRNA levels of ER stress- and autophagy-related molecules were elevated in the renal tissue of CKD patients compared to those of healthy individuals. Furthermore, TG NPs induced the UPR pathway and autophagy in HK-2 human kidney tubular epithelial cells. TG NPs protected HK-2 cells against oxidative stress-induced cell death through the activation of Nrf2 and FoxO1. The siRNA-mediated inhibition of Nrf2 or FoxO1 resulted in enhanced oxidative stress-induced cytotoxicity in HK-2 cells. In a mouse model of adenine diet-induced CKD, TG NPs and KIM-1-TG NPs ameliorated renal injury through the stimulation of ER stress and its downstream pathways. Our findings suggest that the induction of ER stress using pharmacological agents may offer a promising therapeutic strategy for preventing or interfering with CKD progression.

Dysregulation of the miR-25-IMPA2 axis promotes metastatic progression in clear cell renal cell carcinoma.

BACKGROUND: The molecular mechanism underlying clear cell renal cell carcinoma (ccRCC) metastasis remains unclear. We therefore aimed to elucidate the role of IMPA2 in ccRCC metastatic progression. METHODS: Using the Cancer Genome Atlas (TCGA) database and immunohistochemistry (IHC) staining, we investigated differences in IMPA2 mRNA and protein expression, as well as their clinical relevance, in ccRCC. To investigate the function of IMPA2 in ccRCC metastasis, we performed in vitro migration and in vivo lung colony-forming assays. We further explored the effect of microRNA (miR)-25 on IMPA2 expression by performing a luciferase reporter assay. FINDINGS: We show that ccRCC expresses relatively lower transcript levels of IMPA2 than normal kidney tissue. IMPA2 downregulation was greater in high-grade ccRCC than in low-grade ccRCC and was correlated with a poor prognosis in ccRCC patients. Importantly, we demonstrate that IMPA2 expression is inversely associated with the metastatic potential of ccRCC cells. We found that IMPA2 knockdown promotes, but overexpression suppresses, the cellular migration and lung colony-forming abilities of ccRCC cells. By using in silico and luciferase reporter assays, we found that IMPA2 expression is primarily influenced by miR-25 in ccRCC cells. Significantly, the inhibition of miR-25 function restored IMPA2 expression, thereby diminishing the metastatic potential of ccRCC cells. INTERPRETATION: We conclude that miR-25-mediated IMPA2 downregulation constitutes a novel signature for cancer metastasis and poor outcomes in ccRCC. We further postulate that the therapeutic targeting of miR-25 can be useful for preventing the metastatic progression of ccRCC associated with IMPA2 downregulation. FUND: This study was supported by the Ministry of Science and Technology, Taiwan (MOST 107-2314-B-038-094, MOST 106-2314-B-038-069-MY3, MOST 105-2320-B-038-021-MY3 and MOST 107-2320-B-038-056).

High-level expression of ARID1A predicts a favourable outcome in triple-negative breast cancer patients receiving paclitaxel-based chemotherapy.

Paclitaxel-based chemotherapy is a common strategy to treat patients with triple-negative breast cancer (TNBC). As paclitaxel resistance is still a clinical issue in treating TNBCs, identifying molecular markers for predicting pathologic responses to paclitaxel treatment is thus urgently needed. Here, we report that an AT-rich interaction domain 1A (ARID1A) transcript is up-regulated in paclitaxel-sensitive TNBC cells but down-regulated in paclitaxel-resistant cells upon paclitaxel treatment. Moreover, ARID1A expression was negatively correlated with the IC50 concentration of paclitaxel in the tested TNBC cell lines. Kaplan-Meier analyses revealed that ARID1A down-regulation was related to a poorer response to paclitaxel-based chemotherapy in patients with TNBCs as measured by the recurrence-free survival probability. The pharmaceutical inhibition with p38MAPK-specific inhibitor SCIO-469 revealed that p38MAPK-related signalling axis regulates ARID1A expression and thereby modulates paclitaxel sensitivity in TNBC cells. These findings suggest that ARID1A could be used as a prognostic factor to estimate the pathological complete response for TNBC patients who decide to receive paclitaxel-based chemotherapy.

Far-infrared protects vascular endothelial cells from advanced glycation end products-induced injury via PLZF-mediated autophagy in diabetic mice.

The accumulation of advanced glycation end products (AGEs) in diabetic patients induces vascular endothelial injury. Promyelocytic leukemia zinc finger protein (PLZF) is a transcription factor that can be activated by low-temperature far-infrared (FIR) irradiation to exert beneficial effects on the vascular endothelium. In the present study, we investigated the influence of FIR-induced PLZF activation on AGE-induced endothelial injury both in vitro and in vivo. FIR irradiation inhibited AGE-induced apoptosis in human umbilical vein endothelial cells (HUVECs). PLZF activation increased the expression of phosphatidylinositol-3 kinases (PI3K), which are important kinases in the autophagic signaling pathway. FIR-induced PLZF activation led to autophagy in HUVEC, which was mediated through the upregulation of PI3K. Immunofluorescence staining showed that AGEs were engulfed by HUVECs and localized to lysosomes. FIR-induced autophagy promoted AGEs degradation in HUVECs. In nicotinamide/streptozotocin-induced diabetic mice, FIR therapy reduced serum AGEs and AGEs deposition at the vascular endothelium. FIR therapy also reduced diabetes-induced inflammatory markers in the vascular endothelium and improved vascular endothelial function. These protective effects of FIR therapy were not found in PLZF-knockout mice. Our data suggest that FIR-induced PLZF activation in vascular endothelial cells protects the vascular endothelium in diabetic mice from AGE-induced injury.

The role of hypoxia-inducible factor-1α in zinc oxide nanoparticle-induced nephrotoxicity in vitro and in vivo.

BACKGROUND: Zinc oxide nanoparticles (ZnO NPs) are used in an increasing number of products, including rubber manufacture, cosmetics, pigments, food additives, medicine, chemical fibers and electronics. However, the molecular mechanisms underlying ZnO NP nephrotoxicity remain unclear. In this study, we evaluated the potential toxicity of ZnO NPs in kidney cells in vitro and in vivo. RESULTS: We found that ZnO NPs were apparently engulfed by the HEK-293 human embryonic kidney cells and then induced reactive oxygen species (ROS) generation. Furthermore, exposure to ZnO NPs led to a reduction in cell viability and induction of apoptosis and autophagy. Interestingly, the ROS-induced hypoxia-inducible factor-1α (HIF-1α) signaling pathway was significantly increased following ZnO NPs exposure. Additionally, connective tissue growth factor (CTGF) and plasminogen activator inhibitor-1 (PAI-1), which are directly regulated by HIF-1 and are involved in the pathogenesis of kidney diseases, displayed significantly increased levels following ZnO NPs exposure in HEK-293 cells. HIF-1α knockdown resulted in significantly decreased levels of autophagy and increased cytotoxicity. Therefore, our results suggest that HIF-1α may have a protective role in adaptation to the toxicity of ZnO NPs in kidney cells. In an animal study, fluorescent ZnO NPs were clearly observed in the liver, lungs, kidneys, spleen and heart. ZnO NPs caused histopathological lesions in the kidney and increase in serum creatinine and blood urea nitrogen (BUN) which indicate possible renal possible damage. Moreover, ZnO NPs enhanced the HIF-1α signaling pathway, apoptosis and autophagy in mouse kidney tissues. CONCLUSIONS: ZnO NPs may cause nephrotoxicity, and the results demonstrate the importance of considering the toxicological hazards of ZnO NP production and application, especially for medicinal use.

Bone loss in chronic kidney disease: Quantity or quality?

Chronic kidney disease (CKD) patients experience bone loss and fracture because of a specific CKD-related systemic disorder known as CKD-mineral bone disorder (CKD-MBD). The bone turnover, mineralization, and volume (TMV) system describes the morphological bone lesions in renal osteodystrophy related to CKD-MBD. Bone turnover and bone volume are defined as high, normal, or low, and bone mineralization is classified as normal or abnormal. All types of bone histology related to TMV are responsible for both bone quantity and bone quality losses in CKD patients. This review focuses on current bone quantity and bone quality losses in CKD patients and finally discusses potential therapeutic measures.

Peroxisome Proliferator-Activated Receptor α Protects Renal Tubular Cells from Gentamicin-Induced Apoptosis via Upregulating Na+/H+ Exchanger NHE1.

Peroxisome proliferator-activated receptor (PPAR)-α is a transcription factor that has been reported to inhibit gentamicin-induced apoptosis in renal tubular cells. However, the antiapoptotic mechanism of PPARα is still unknown. In this study, we found that PPARα overexpression induced Na+/H+ exchanger-1 (NHE1) expression in the rat renal tubular cells NRK-52E. Beraprost, a PPARα ligand, also increased NHE1 expression in the renal tubules in normal mice, but not in PPARα knockout mice. Chromatin immunoprecipitation assays revealed that two PPARα binding elements were located in the rat NHE1 promoter region. Na+/H+ exchanger activity also increased in the PPARα-overexpressed cells. Flow cytometry showed that the PPARα-overexpressed cells were resistant to apoptosis-induced shrinkage. Cariporide, a selective NHE1 inhibitor, inhibited the antiapoptotic effect of PPARα in the gentamicin-treated cells. The interaction between NHE1 and ezrin/radixin/moesin (ERM) and between ERM and phosphatidylinositol 4,5-bisphosphate in the PPARα-overexpressed cells was more than in the control cells. ERM short interfering RNA (siRNA) transfection inhibited the PPARα-induced antiapoptotic effect. PPARα overexpression also increased the phosphoinositide 3-kinase (PI3K) expression, which is dependent on NHE1 activity. Increased PI3K further increased the phosphorylation of the prosurvival kinase Akt in the PPARα-overexpressed cells. Wortmannin, a PI3K inhibitor, inhibited PPARα-induced Akt activity and the antiapoptotic effect. We conclude that PPARα induces NHE1 expression and then recruits ERM to promote PI3K/Akt-mediated cell survival in renal tubular cells. The application of PPARα activation reduces the nephrotoxicity of gentamicin and may expand the clinical use of gentamicin.