Early induction of osteoactivin expression in rat renal tubular epithelial cells after unilateral ureteral obstruction

Impact of low pneumoperitoneum on renal function and acute kidney injury biomarkers during robot-assisted radical prostatectomy (RARP): a randomised clinical trial

The objective of this study was to evaluate the effect of low pneumoperitoneum pressure (Pnp) on renal function and renal injury biomarkers during robot-assisted radical prostatectomy (RARP). A single-centre, triple-blinded, randomised clinical trial was conducted with 98 patients undergoing RARP, who were assigned to either standard Pnp of 12 mmHg or low Pnp of 7 mmHg. The primary outcome was urinary neutrophil gelatinase-associated lipocalin (u-NGAL), and several other kidney injury biomarkers were assessed as secondary outcomes. Acute kidney injury (AKI) was evaluated using the Kidney Disease Improving Global Outcomes (KDIGO) criteria, the gold standard method for defining AKI. The trial was registered on ClinicalTrials.gov (NCT04755452). Patients in the low Pnp group had significantly lower levels of u-NGAL (mean difference - 39.9, 95% CI - 73.7 to - 6.1, p = 0.02) compared to the standard Pnp group. No significant differences were observed for other urinary biomarkers. Interestingly, there was a significant difference in intraoperative urine production between the groups (low Pnp median: 200 mL, IQR: 100-325 vs. standard Pnp median: 100 mL, IQR: 50-200, p = 0.01). Similarly, total postoperative urine production also varied significantly (low Pnp median: 1325 mL, IQR: 1025-1800 vs. standard Pnp median: 1000 mL, IQR: 850-1287, p = 0.001). The occurrence of AKI, as defined by the KDIGO criteria, did not differ significantly between the groups. Low Pnp during RARP resulted in lower u-NGAL levels, suggesting a potential benefit in terms of reduced renal injury. However, the lack of a notable difference in AKI as defined by the KDIGO criteria indicates that the clinical significance of this finding may be limited. Further research is needed to validate and expand on these results, ultimately defining the optimal Pnp strategy for RARP and improving patient outcomes.

Low-Intensity Shockwave Therapy (LI-ESWT) in Diabetic Kidney Disease: Results from an Open-Label Interventional Clinical Trial

Purpose

Treatment with low-intensity shockwave therapy (LI-ESWT) is associated with angiogenesis and is suggested as a treatment for different types of vascular diseases. It was hypothesized that LI-ESWT improves the renal filtration barrier and halts the progression of GFR decline in diabetic kidney disease (DKD) potentially through VEGF and NO formation. We present the first data on LI-ESWT in human DKD.

Methods

The study was designed as an interventional, prospective, one-arm, Phase 1 study. We investigated change in GFR and albuminuria in 28 patients with DKD treated with six sessions of LI-ESWT over three weeks. The patients were followed for six months. Urine excretion of kidney injury markers, vascular endothelial growth factor (VEGF) and nitric oxide metabolites (NOx) was studied after LI-ESWT.

Results

There were no significant changes in GFR and albuminuria up to six months after LI-ESWT compared to baseline. Urine VEGF was transiently reduced one month after LI-ESWT, but there were no other significant changes in urine VEGF or NOx after LI-ESWT. Secondary analysis showed that NOx increased after LI-ESWT in patients who had low levels of NOx at baseline. Kidney injury marker trefoil factor 3 (TFF3) increased acutely after the first session of LI-ESWT indicating transient endothelial repair. Other markers of kidney injury were stable in relation to LI-ESWT.

Conclusion

LI-ESWT treatment did not significantly improve kidney function and albumin excretion. It is concluded that LI-ESWT is not harmful. A randomized blinded study should be performed to clarify whether adjunctive treatment with LI-ESWT is superior to standard treatment of DKD.

Glycoprotein Nonmetastatic Melanoma Protein B (GPNMB) Ameliorates the Inflammatory Response in Periodontal Disease

Glycoprotein nonmetastatic melanoma protein B (GPNMB) is a type I transmembrane protein that can modulate osteoblasts and bone mineralization. Periodontal disease (PD) is characterized by gum inflammation, alveolar bone resorption, and tooth loss. In this study, we found that GPNMB is highly expressed in inflamed periodontal tissue through microarray and immunohistochemistry (IHC) assays. The role of GPNMB in the pathogenesis of PD was evaluated with primary human periodontal ligament cells (hPDLCs) treated with lipopolysaccharide (LPS) and a GPNMB-expressing lentivirus (lenti-GP). In the hPDLCs treated with LPS and lenti-GP, the expression of tumor necrosis factor (TNF)-α and interleukin (IL)-6 was suppressed and that of IL-10 was upregulated. GPNMB significantly decreased apoptosis in the hPDLCs treated with LPS. GPNMB could upregulate the expression of Jumonji domain-containing protein 3 (Jmjd3), a histone 3 lysine 27 (H3K27) demethylase that is linked to the modulation of the inflammatory response and apoptosis. Taken together, our data find that GPNMB is highly expressed in gum tissue with PD and may be an anti-inflammatory player in the pathogenesis of PD.

The Matrix Metalloproteinase-13 Inhibitor Poricoic Acid ZI Ameliorates Renal Fibrosis by Mitigating Epithelial-Mesenchymal Transition

SCOPE

Fibrosis plays a key role in the progression of various diseases. Matrix metalloproteinases (MMPs) are important for epithelial-mesenchymal transition (EMT), which contributes to organ fibrosis. Four new poricoic acids are identified, poricoic acid ZI, ZJ, ZK, and ZL, as novel MMP inhibitors from edible mushroom Poria cocos.

METHODS

Molecular docking, siRNA techniques, TGF-β1-treated renal cells, and unilateral ureteral obstructed (UUO) mice are used to explore the potential efficacy of the novel MMP inhibitors in mitigating the fibrotic process.

RESULTS

Treatment with four poricoic acids downregulates profibrotic protein expression in TGF-β1-induced HK-2 cells. Similar results are observed in NRK-52E and NRK-49F cells, indicating that poricoic acids can suppress EMT. Furthermore, both in vitro and in vivo experiments demonstrate that poricoic acid ZI (PZI) exerts a stronger inhibitory effect on protein expression and enzymatic activity of MMP-13 than the other three compounds, which is consistent with the docking results. The inhibitory effect of PZI on MMP-13 is partially attenuated by MMP-13 RNAi in HK-2 cells and UUO mice.

CONCLUSIONS

The findings indicate that as a specific MMP-13 inhibitor, PZI attenuates EMT and renal fibrosis. Therefore, the MMP-13 inhibitor PZI can be a novel therapeutic candidate for limiting EMT and renal fibrosis.

Plasma biomarkers improve prediction of diabetic kidney disease in adults with type 1 diabetes over a 12-year follow-up: CACTI study

Background

The objective of the study was to determine whether plasma biomarkers of kidney injury improve the prediction of diabetic kidney disease (DKD) in adults with type 1 diabetes (T1D) over a period of 12 years.

Methods

Participants (n = 527, 53% females) in the Coronary Artery Calcification in T1D (CACTI) Study were examined during 2002-04, at a mean (± standard deviation) age of 39.6 ± 9.0 years with 24.8 years as the median duration of diabetes. Urine albumin-to-creatinine (ACR) and estimated glomerular filtration rate (eGFR) by CKD-EPI (chronic kidney disease epidemiology collaboration) creatinine were measured at the baseline and after mean follow-up of 12.1 ± 1.5 years. Albuminuria was defined as ACR ≥30 mg/g and impaired GFR as eGFR <60 mL/min/1.73 m2. Kidney injury biomarkers (Meso Scale Diagnostics) were measured on stored baseline plasma samples. A principal component analysis (PCA) identified two components: (i) kidney injury molecule-1, calbindin, osteoactivin, trefoil factor 3 and vascular endothelial growth factor; and (ii) β-2 microglobulin, cystatin C, neutrophil gelatinase-associated lipocalin and osteopontin that were used in the multivariable regression analyses.

Results

Component 2 of the PCA was associated with increase in log modulus ACR [β ± standard error (SE): 0.16 ± 0.07, P = 0.02] and eGFR (β ± SE: -2.56 ± 0.97, P = 0.009) over a period of 12 years after adjusting for traditional risk factors (age, sex, HbA1c, low-density lipoprotein cholesterol and systolic blood pressure and baseline eGFR/baseline ACR). Only Component 2 of the PCA was associated with incident-impaired GFR (odds ratio 2.08, 95% confidence interval 1.18-3.67, P = 0.01), adjusting for traditional risk factors. The addition of Component 2 to traditional risk factors significantly improved C-statistics and net-reclassification improvement for incident-impaired GFR (ΔAUC: 0.02 ± 0.01, P = 0.049, and 29% non-events correctly reclassified, P < 0.0001).

Conclusions

Plasma kidney injury biomarkers can help predict development of DKD in T1D.

Growth and repair factors, osteoactivin, matrix metalloproteinase and heat shock protein 72, increase with resolution of inflammation in musculotendinous tissues in a rat model of repetitive grasping

BACKGROUND

Expression of the growth factor osteoactivin (OA) increases during tissue degeneration and regeneration, fracture repair and after denervation-induced disuse atrophy, concomitant with increased matrix metalloproteinases (MMPs). However, OA's expression with repetitive overuse injuries is unknown. The aim of this study was to evaluate: 1) OA expression in an operant rat model of repetitive overuse; 2) expression of MMPs; 3) inflammatory cytokines indicative of injury or inflammation; and 4) the inducible form of heat shock protein 70 (HSPA1A/HSP72) as the latter is known to increase during metabolic stress and to be involved in cellular repair. Young adult female rats performed a high repetition negligible force (HRNF) food retrieval task for up to 6 weeks and were compared to control rats.

METHODS

Flexor digitorum muscles and tendons were collected from 22 young adult female rats performing a HRNF reaching task for 3 to 6 weeks, and 12 food restricted control (FRC) rats. OA mRNA levels were assessed by quantitative polymerase chain reaction (qPCR). OA, MMP-1, -2, -3, and -13 and HSP72 protein expression was assayed using Western blotting. Immunohistochemistry and image analysis was used to evaluate OA and HSP72 expression. ELISA was performed for HSP72 and inflammatory cytokines.

RESULTS

Flexor digitorum muscles and tendons from 6-week HRNF rats showed increased OA mRNA and protein expression compared to FRC rats. MMP-1, -2 and -3 progressively increased in muscles whereas MMP-1 and -3 increased in tendons with HRNF task performance. HSP72 increased in 6-week HRNF muscles and tendons, compared to controls, and co-localized with OA in the myofiber sarcolemma. IL-1alpha and beta increased transiently in tendons or muscles in HRNF week 3 before resolving in week 6.

CONCLUSION

The simultaneous increases of OA with factors involved in tissue repair (MMPs and HSP72) supports a role of OA in tissue regeneration after repetitive overuse.

Osteoactivin attenuates skeletal muscle fibrosis after distraction osteogenesis by promoting extracellular matrix degradation/remodeling

The aim of this study was to determine whether osteoactivin attenuated skeletal muscle fibrosis caused by distraction osteogenesis. Tibial osteotomies were performed on wild-type and osteoactivin-transgenic (OA-Tg) mice, and tibiae were distracted for 2 weeks. Ankle plantar flexion torque and the gastrocnemius muscles were analyzed. The amount and area of collagenous tissue and the passive torque were reduced in the OA-Tg group at 8 weeks after osteotomy. Transcript levels of matrix metalloprotease (mmp)-3 and MMP-9 were upregulated, and MMP-3 and MMP-9 proteins were increased in the OA-Tg group. Osteoactivin-mediated increase in MMPs may attenuate skeletal muscle fibrosis.

Role of inflammation in the aging bones

Chronic inflammation in aging is characterized by increased inflammatory cytokines, bone loss, decreased adaptation, and defective tissue repair in response to injury. Aging leads to inherent changes in mesenchymal stem cell (MSC) differentiation, resulting in impaired osteoblastogenesis. Also, the pro-inflammatory cytokines increase with aging, leading to enhanced myelopoiesis and osteoclastogenesis. Bone marrow macrophages (BMMs) play pivotal roles in osteoblast differentiation, the maintenance of hematopoietic stem cells (HSCs), and subsequent bone repair. However, during aging, little is known about the role of macrophages in the differentiation and function of MSC and HSC. Aged mammals have higher circulating pro-inflammatory cytokines than young adults, supporting the hypothesis of increased inflammation with aging. This review will aid in the understanding of the potential role(s) of pro-inflammatory (M1) and anti-inflammatory (M2) macrophages in differentiation and function of osteoblasts and osteoclasts in relation to aging.

Lysosomal stress in obese adipose tissue macrophages contributes to MITF-dependent Gpnmb induction

In obesity, adipose tissue (AT) contains crown-like structures where macrophages surround nonviable adipocytes. To understand how AT macrophages (ATMs) contribute to development of insulin resistance, we examined their character in more detail. In silico analysis of F2 mouse populations revealed significant correlation between adipose glycoprotein nonmetastatic melanoma protein B (Gpnmb) expression and body weight. In obese mice and obese individuals, Gpnmb expression was induced in ATMs. Cultured RAW264.7 cells were used to obtain insight into the mechanism of Gpnmb regulation. Gpnmb was potently induced by lysosomal stress inducers, including palmitate and chloroquine, or Torin1, an inhibitor of mammalian target of rapamycin complex 1 (mTORC1). These stimuli also provoked microphthalmia transcription factor (MITF) translocation to the nucleus, and knockdown of MITF by short hairpin RNA indicated its absolute requirement for Gpnmb induction. In agreement with our in vitro data, reduced mTORC1 activity was observed in isolated ATMs from obese mice, which coincided with increased nuclear MITF localization and Gpnmb transcription. Aberrant nutrient sensing provokes lysosomal stress, resulting in attenuated mTORC1 activity and enhanced MITF-dependent Gpnmb induction. Our data identify Gpnmb as a novel marker for obesity-induced ATM infiltration and potentiator of interleukin-4 responses and point toward a crucial role for MITF in driving part of the ATM phenotype.

Comprehensive characterization of mesenchymal stem cells from human placenta and fetal membrane and their response to osteoactivin stimulation

Mesenchymal stem cells (MSCs) are the most promising seed cells for cell therapy and can be isolated from various sources of human adult tissues such as bone marrow (BM-MSC) and adipose tissue. However, cells from these tissues must be obtained through invasive procedures. We, therefore, characterized MSCs isolated from fresh placenta (Pl-MSC) and fetal membrane (Mb-MSC) through morphological and fluorescent-activated cell sorting (FACS). MSC frequency is higher in membrane than placenta (2.14%  ± 0.65 versus 15.67%  ± 0.29%). Pl/Mb-MSCs in vitro expansion potential was significantly higher than BM-MSCs. We demonstrated that one of the MSC-specific marker is sufficient for MSC isolation and that culture in specific media is the optimal way for selecting very homogenous MSC population. These MSCs could be differentiated into mesodermal cells expressing cell markers and cytologic staining consistent with mature osteoblasts and adipocytes. Transcriptomic analysis and cytokine arrays demonstrated broad similarity between placenta- and membrane-derived MSCs and only discrete differences with BM-MSCs with enrichment of networks involved in bone differentiation. Pl/Mb-MSCs displayed higher osteogenic differentiation potential than BM-MSC when their response to osteoactivin was evaluated. Fetal-tissue-derived mesenchymal cells may, therefore, be considered as a major source of MSCs to reach clinical scale banking in particular for bone regeneration.

Expression and immunolocalization of Gpnmb, a glioma-associated glycoprotein, in normal and inflamed central nervous systems of adult rats

Glycoprotein nonmetastatic melanoma B (Gpnmb) is a type I transmembrane protein implicated in cell differentiation, inflammation, tissue regeneration, and tumor progression. Gpnmb, which is highly expressed in glioblastoma cells, is a potential therapeutic target. However, little is known about its expression, cellular localization, and roles in non-tumorous neural tissues. In this study, we examined Gpnmb expression in the central nervous system of adult rats under both normal and inflammatory conditions. Reverse transcription-polymerase chain reaction analysis revealed that Gpnmb mRNA was expressed in the cerebrum, cerebellum, brain stem, and spinal cord of normal adult rats. Immunoperoxidase staining revealed that Gpnmb-immunoreactive cells were widely distributed in the parenchyma of all brain regions examined, with the cells being most prevalent in the hippocampal dentate gyrus, cerebellar cortex, spinal dorsal horn, choroid plexus, ependyma, periventricular regions, and in layers II and III of the cerebral cortex. Double immunofluorescence staining showed that these cells were co-stained most frequently with the microglia/macrophage marker OX42, and occasionally with the radial glia marker RC2 or the neuronal marker NeuN. Furthermore, an intraperitoneal injection of bacterial endotoxin lipopolysaccharide increased the number of Gpnmb and OX42 double-positive cells in the area postrema, which is one of the circumventricular organs, indicating infiltration of hematogenous macrophages. These results suggest that Gpnmb, which is expressed in microglia and macrophages in non-tumorous neural tissues, plays an important role in the regulation of immune/inflammatory responses.

Comparison of bone morphogenetic protein-2 and osteoactivin for mesenchymal cell differentiation: effects of bolus and continuous administration

Current osteoinductive protein therapy utilizes bolus administration of large doses of bone morphogenetic proteins (BMPs), which is costly, and may not replicate normal bone healing. The limited in vivo biologic activity of BMPs requires the investigation of growth factors that may enhance this activity. In this study, we utilized the C3H10T1/2 murine mesenchymal stem cell line to test the hypotheses that osteoactivin (OA) has comparable osteoinductive effects to bone morphogenetic protein-2 (BMP-2), and that sustained administration of either growth factor would result in increased osteoblastic differentiation as compared to bolus administration. Sustained release biodegradable hydrogels were designed, and C3H10T1/2 cells were grown on hydrogels loaded with BMP-2 or OA. Controls were grown on unloaded hydrogels, and positive controls were exposed to bolus growth factor administration. Cells were harvested at several time points to assess osteoblastic differentiation. Alkaline phosphatase (ALP) staining and activity, and gene expression of ALP and osteocalcin were assessed. Treatment with OA or BMP-2 resulted in comparable effects on osteoblastic marker expression. However, cells grown on hydrogels demonstrated osteoblastic differentiation that was not as robust as cells treated with bolus administration. This study shows that OA has comparable effects to BMP-2 on osteoblastic differentiation using both bolus administration and continuous release, and that bolus administration of OA has a more profound effect than administration using hydrogels for sustained release. This study will lead to a better understanding of appropriate delivery methods of osteogenic growth factors like OA for repair of fractures and segmental bone defects.

Temporal and spatial expression of osteoactivin during fracture repair

We previously identified osteoactivin (OA) as a novel secreted osteogenic factor with high expression in developing long bones and calvaria, and that stimulates osteoblast differentiation and matrix mineralization in vitro. In this study, we report on OA mRNA and protein expression in intact long bone and growth plate, and in fracture calluses collected at several time points up to 21 days post-fracture (PF). OA mRNA and protein were highly expressed in osteoblasts localized in the metaphysis of intact tibia, and in hypertrophic chondrocytes localized in growth plate, findings assessed by in situ hybridization and immunohistochemistry, respectively. Using a rat fracture model, Northern blot analysis showed that expression of OA mRNA was significantly higher in day-3 and day-10 PF calluses than in intact rat femurs. Using in situ hybridization, we examined OA mRNA expression during fracture healing and found that OA was temporally regulated, with positive signals seen as early as day-3 PF, reaching a maximal intensity at day-10 PF, and finally declining at day-21 PF. At day-5 PF, which correlates with chondrogenesis, OA mRNA levels were significantly higher in the soft callus than in intact femurs. Similarly, we detected high OA protein immunoexpression throughout the reparative phase of the hard callus compared to intact femurs. Interestingly, the secreted OA protein was also detected within the newly made cartilage matrix and osteoid tissue. Taken together, these results suggest the possibility that OA plays an important role in bone formation and serves as a positive regulator of fracture healing.

Cross-study and cross-omics comparisons of three nephrotoxic compounds reveal mechanistic insights and new candidate biomarkers

The European InnoMed-PredTox project was a collaborative effort between 15 pharmaceutical companies, 2 small and mid-sized enterprises, and 3 universities with the goal of delivering deeper insights into the molecular mechanisms of kidney and liver toxicity and to identify mechanism-linked diagnostic or prognostic safety biomarker candidates by combining conventional toxicological parameters with "omics" data. Mechanistic toxicity studies with 16 different compounds, 2 dose levels, and 3 time points were performed in male Crl: WI(Han) rats. Three of the 16 investigated compounds, BI-3 (FP007SE), Gentamicin (FP009SF), and IMM125 (FP013NO), induced kidney proximal tubule damage (PTD). In addition to histopathology and clinical chemistry, transcriptomics microarray and proteomics 2D-DIGE analysis were performed. Data from the three PTD studies were combined for a cross-study and cross-omics meta-analysis of the target organ. The mechanistic interpretation of kidney PTD-associated deregulated transcripts revealed, in addition to previously described kidney damage transcript biomarkers such as KIM-1, CLU and TIMP-1, a number of additional deregulated pathways congruent with histopathology observations on a single animal basis, including a specific effect on the complement system. The identification of new, more specific biomarker candidates for PTD was most successful when transcriptomics data were used. Combining transcriptomics data with proteomics data added extra value.