Nephrotic-range proteinuria: a potential risk factor for failure of tixagevimab-cilgavimab prophylaxis.

BACKGROUND: Pre-exposure prophylaxis with tixagevimab-cilgavimab has been shown to reduce the incidence of SARS-CoV-2 infection in immunocompromised individuals. Individuals with nephrotic-range proteinuria can lose immunoglobulins such as tixagevimab-cilgavimab in the urine and, therefore, may derive less benefit from tixagevimab-cilgavimab. There are no published studies evaluating the association of nephrotic-range proteinuria with failure of tixagevimab-cilgavimab prophylaxis. METHODS: We conducted a retrospective observational cohort study of all individuals at our center who received tixagevimab-cilgavimab while they had nephrotic-range proteinuria. Each individual in the nephrotic group was matched 1:3 with controls who were matched for B cell depletion therapy in addition to the total dose and date of first tixagevimab-cilgavimab administration. The primary outcome was the development of breakthrough SARS-CoV-2 infection after receiving tixagevimab-cilgavimab. RESULTS: Sixteen patients received tixagevimab-cilgavimab between January 1st, 2022, and June 30th, 2022, at a time when they had nephrotic-range proteinuria. Proteinuria levels and serum creatinine levels were higher while serum albumin levels were lower in the nephrotic group compared to the control group. At a median follow-up of 251 days, 38% of individuals in the nephrotic group had developed breakthrough SARS-CoV-2 infections, compared to only 13% in the control group at a median follow-up of 238 days. Nephrotic-range proteinuria was associated with a higher incidence of breakthrough infection (log-rank P = 0.04). CONCLUSIONS: Nephrotic-range proteinuria may increase the risk of failure of tixagevimab-cilgavimab pre-exposure prophylaxis. Prospective studies to validate these findings and to evaluate the optimal dosing strategy of antibody-based prophylaxis in this group of patients are needed.

Metformin reduces insulin resistance and attenuates progressive renal injury in prepubertal obese Dahl salt-sensitive rats.

Prepubertal obesity is currently an epidemic and is considered as a major risk factor for renal injury. Previous studies have demonstrated that insulin resistance contributes to renal injury in obesity, independent of diabetes. However, studies examining the relationship between insulin resistance and renal injury in obese children are lacking. Recently, we reported that progressive renal injury in Dahl salt-sensitive (SS) leptin receptor mutant (SSLepRmutant) rats was associated with insulin resistance before puberty. Therefore, the aim of the present study was to examine whether decreasing insulin resistance with metformin will reduce renal injury in SSLepRmutant rats. Four-wk-old SS and SSLepRmutant rats were separated into the following two groups: 1) vehicle and 2) metformin (300 mg/kg/day) via chow diet for 4 wk. Chronic administration of metformin markedly reduced insulin resistance and dyslipidemia in SSLepRmutant rats. We did not detect any differences in mean arterial pressure between vehicle and metformin-treated SS and SSLepRmutant rats. Proteinuria was significantly greater in SSLepRmutant rats versus SS rats throughout the study, and metformin administration significantly reduced proteinuria in SSLepRmutant rats. At the end of the protocol, metformin prevented the renal hyperfiltration observed in SSLepRmutant rats versus SS rats. Glomerular and tubular injury and renal inflammation and fibrosis were significantly higher in vehicle-treated SSLepRmutant rats versus SS rats, and metformin reduced these parameters in SSLepRmutant rats. These data suggest that reducing insulin resistance with metformin prevents renal hyperfiltration and progressive renal injury in SSLepRmutant rats before puberty and may be therapeutically useful in managing renal injury during prepubertal obesity.NEW & NOTEWORTHY Childhood/prepubertal obesity is a public health concern that is associated with early signs of proteinuria. Insulin resistance has been described in obese children. However, studies investigating the role of insulin resistance during childhood obesity-associated renal injury are limited. This study provides evidence of an early relationship between insulin resistance and renal injury in a rat model of prepubertal obesity. These data also suggest that reducing insulin resistance with metformin may be renoprotective in obese children.

Nicorandil protects podocytes via modulation of antioxidative capacity in acute puromycin aminonucleoside-induced nephrosis in rats.

Nephrotic syndrome, characterized by proteinuria and hypoalbuminemia, results from the dysregulation of glomerular podocytes and is a significant cause of end-stage kidney disease. Patients with idiopathic nephrotic syndrome are generally treated with immunosuppressive agents; however, these agents produce various adverse effects. Previously, we reported the renoprotective effects of a stimulator of the mitochondrial ATP-dependent K+ channel (MitKATP), nicorandil, in a remnant kidney model. Nonetheless, the cellular targets of these effects remain unknown. Here, we examined the effect of nicorandil on puromycin aminonucleoside-induced nephrosis (PAN) rats, a well-established model of podocyte injury and human nephrotic syndrome. PAN was induced using a single intraperitoneal injection. Nicorandil was administered orally at 30 mg/kg/day. We found that proteinuria and hypoalbuminemia in PAN rats were significantly ameliorated following nicorandil treatment. Immunostaining and ultrastructural analysis under electron microscopy demonstrated that podocyte injury in PAN rats showed a significant partial attenuation following nicorandil treatment. Nicorandil ameliorated the increase in the oxidative stress markers nitrotyrosine and 8-hydroxy-2-deoxyguanosine in glomeruli. Conversely, nicorandil prevented the decrease in levels of the antioxidant enzyme manganese superoxide dismutase in PAN rats. We found that mitochondrial Ca2+ uniporter levels in glomeruli were higher in PAN rats than in control rats, and this increase was significantly attenuated by nicorandil. We conclude that stimulation of MitKATP by nicorandil reduces proteinuria by attenuating podocyte injury in PAN nephrosis, which restores mitochondrial antioxidative capacity, possibly through mitochondrial Ca2+ uniporter modulation. These data indicate that MitKATP may represent a novel target for podocyte injury and nephrotic syndrome.NEW & NOTEWORTHY Our findings suggest that the mitochondrial Ca2+ uniporter may be an upstream regulator of manganese superoxide dismutase and indicate a biochemical basis for the interaction between the ATP-sensitive K+ channel and Ca2+ signaling. We believe that our study makes a significant contribution to the literature because our results indicate that the ATP-sensitive K+ channel may be a potential therapeutic target for podocyte injury and nephrotic syndrome.

HSPB5 suppresses renal inflammation and protects lupus-prone NZB/W F1 mice from severe renal damage.

BACKGROUND: Lupus nephritis (LN) is an inflammatory disease of the kidneys affecting patients with systemic lupus erythematosus. Current immunosuppressive and cytotoxic therapies are associated with serious side effects and fail to protect 20-40% of LN patients from end-stage renal disease. In this study, we investigated whether a small heat shock protein, HSPB5, can reduce kidney inflammation and the clinical manifestations of the disease in NZB/W F1 mice. Furthermore, we investigated whether HSPB5 can enhance the effects of methylprednisolone, a standard-of-care drug in LN, in an endotoxemia mouse model. METHODS: NZB/W F1 mice were treated with HSPB5, methylprednisolone, or vehicle from 23 to 38 weeks of age. Disease progression was evaluated by weekly proteinuria scores. At the end of the study, the blood, urine, spleens, and kidneys were collected for the assessment of proteinuria, blood urea nitrogen, kidney histology, serum IL-6 and anti-dsDNA levels, immune cell populations, and their phenotypes, as well as the transcript levels of proinflammatory chemokine/cytokines in the kidneys. HSPB5 was also evaluated in combination with methylprednisolone in a lipopolysaccharide-induced endotoxemia mouse model; serum IL-6 levels were measured at 24 h post-endotoxemia induction. RESULTS: HSPB5 significantly reduced terminal proteinuria and BUN and substantially improved kidney pathology. Similar trends, although to a lower extent, were observed with methylprednisolone treatment. Serum IL-6 levels and kidney expression of BAFF, IL-6, IFNγ, MCP-1 (CCL2), and KIM-1 were reduced, whereas nephrin expression was significantly preserved compared to vehicle-treated mice. Lastly, splenic Tregs and Bregs were significantly induced with HSPB5 treatment. HSPB5 in combination with methylprednisolone also significantly reduced serum IL-6 levels in endotoxemia mice. CONCLUSIONS: HSPB5 treatment reduces kidney inflammation and injury, providing therapeutic benefits in NZB/W F1 mice. Given that HSPB5 enhances the anti-inflammatory effects of methylprednisolone, there is a strong interest to develop HSBP5 as a therapeutic for the treatment of LN.

Relationship between Ideal Cardiovascular Health and Incident Proteinuria: A 5 Year Retrospective Cohort Study.

The objective of this study was to examine whether a higher number of ideal cardiovascular health (CVH) metrics are beneficial for lowering the risk of proteinuria. This is a retrospective cohort study with an average follow-up of 5 years. Participants between 21 and 75 years old and without a history of cardiovascular disease and proteinuria were enrolled. CVH metrics, including smoking, diet, physical activity, blood pressure, body mass index (BMI), cholesterol, and fasting glucose, were assessed by questionnaires, physical examination, and blood analysis. Proteinuria was assessed by dipstick measurement. During the follow-up period, 169,366 participants were enrolled, and 1481 subjects developed proteinuria. A higher number of ideal CVH metrics was related to a lower risk of proteinuria after adjustment. Among the components of CVH metrics, ideal blood pressure (HR = 0.33, 95% CI = 0.25-0.43), fasting glucose (HR = 0.17, 95% CI = 0.12-0.22), and BMI (HR = 0.20, 95% CI = 0.15-0.27) had beneficial effects on proteinuria. Despite no significant benefit of diet score, the corresponding lower sodium intake showed a lower risk of proteinuria (HR = 0.58, 95% CI = 0.43-0.79). Incident proteinuria was inversely related to the number of ideal CVH metrics. CVH metrics may be a predictor of proteinuria, and achieving a higher number of ideal scores should be recommended as a proteinuria prevention strategy.

Non-canonical Wnt/calcium signaling is protective against podocyte injury and glomerulosclerosis.

Activation of canonical Wnt signaling has been implicated in podocyte injury and proteinuria. As Wnts are secreted proteins, whether Wnts derived from podocytes are obligatory for promoting proteinuria remains unknown. To address this, we generated conditional knockout mice where Wntless, a cargo receptor protein required for Wnt secretion, was specifically deleted in glomerular podocytes. Mice with podocyte-specific ablation of Wntless (Podo-Wntless-/-) were phenotypically normal. However, after inducing kidney damage with Adriamycin for six days, Podo-Wntless-/- mice developed more severe podocyte injury and albuminuria than their control littermates. Surprisingly, ablation of Wntless resulted in upregulation of ß-catenin, accompanied by reduction of nephrin, podocin, podocalyxin, and Wilms tumor 1 proteins. In chronic injury induced by Adriamycin, increased albuminuria, aggravated podocyte lesions and extracellular matrix deposition were evident in Podo-Wntlessl-/- mice, compared to wild type mice. Mechanistically, specific ablation of Wntless in podocytes caused down-regulation of the nuclear factor of activated T cell 1 (NFAT1) and Nemo-like kinase (NLK), key downstream mediators of non-canonical Wnt/calcium signaling. In vitro, knockdown of either NFAT1 or NLK induced ß-catenin activation while overexpression of NLK significantly repressed ß-catenin induction and largely preserved nephrin in glomerular podocytes. Thus, our results indicate that podocyte-derived Wnts play an important role in protecting podocytes from injury by repressing ß-catenin via activating non-canonical Wnt/calcium signaling.

IL-1 receptor signaling in podocytes limits susceptibility to glomerular damage.

Interleukin (IL)-1 receptor type 1 (IL-1R1) activation triggers a proinflammatory signaling cascade that can exacerbate kidney injury. However, the functions of podocyte IL-1R1 in glomerular disease remain unclear. To study the role of IL-1R1 signaling in podocytes, we selectively ablated podocyte IL-1R1 in mice (PKO mice). We then subjected PKO mice and wild-type controls to two glomerular injury models: nephrotoxic serum (NTS)- and adriamycin-induced nephropathy. Surprisingly, we found that IL-1R1 activation in podocytes limited albuminuria and podocyte injury during NTS- and adriamycin-induced nephropathy. Moreover, deletion of IL-1R1 in podocytes drove podocyte apoptosis and glomerular injury through diminishing Akt activation. Activation of Akt signaling abrogated the differences in albuminuria and podocyte injury between wild-type and PKO mice during NTS. Thus, IL-1R1 signaling in podocytes limits susceptibility to glomerular injury via an Akt-dependent signaling pathway. These data identify an unexpected protective role for IL-1R1 signaling in podocytes in the pathogenesis of glomerular disease.NEW & NOTEWORTHY The present study establishes that activation of the receptor for interleukin-1 limits susceptibility to damage to the kidney glomerulus in preclinical mouse models by stimulating Akt signaling cascades inside the podocyte.

Clinical Experience of Proteasome Inhibitor Bortezomib Regarding Efficacy and Safety in Severe Systemic Lupus Erythematosus: A Nationwide Study.

As treatment options in advanced systematic lupus erythematosus (SLE) are limited, there is an urgent need for new and effective therapeutic alternatives for selected cases with severe disease. Bortezomib (BTZ) is a specific, reversible, inhibitor of the 20S subunit of the proteasome. Herein, we report clinical experience regarding efficacy and safety from all patients receiving BTZ as therapy for SLE in Sweden during the years 2014-2020. 8 females and 4 males were included with a mean disease duration at BTZ initiation of 8.8 years (range 0.7-20 years). Renal involvement was the main target for BTZ. Reduction of global disease activity was recorded by decreasing SLEDAI-2K scores over time and remained significantly reduced at the 6-month (p=0.007) and the 12-month (p=0.008) follow-up visits. From BTZ initiation, complement protein 3 (C3) levels increased significantly after the 2nd treatment cycle (p=0.05), the 6-month (p=0.03) and the 12-month (p=0.04) follow-up visits. The urine albumin/creatinine ratio declined over time and reached significance at the 6-month (p=0.008) and the 12-month follow-up visits (p=0.004). Seroconversion of anti-dsDNA (27%), anti-C1q (50%) and anti-Sm (67%) was observed. 6 of 12 patients experienced at least one side-effect during follow-up, whereof the most common adverse events were infections. Safety parameters (C-reactive protein, blood cell counts) mainly remained stable over time. To conclude, we report favorable therapeutic effects of BTZ used in combination with corticosteroids in a majority of patients with severe SLE manifestations irresponsive to conventional immunosuppressive agents. Reduction of proteinuria was observed over time as well as seroconversion of some autoantibody specificities. In most patients, tolerance was acceptable but mild adverse events was not uncommon. Special attention should be paid to infections and hypogammaglobinemia.

Expression of human CD47 in pig glomeruli prevents proteinuria and prolongs graft survival following pig-to-baboon xenotransplantation.

BACKGROUND: Nephrotic syndrome is a common complication of pig-to-baboon kidney xenotransplantation (KXTx) that adversely affects outcomes. We have reported that upregulation of CD80 and down-regulation of SMPDL-3b in glomeruli have an important role in the development of proteinuria following pig-to-baboon KXTx. Recently we found induced expression of human CD47 (hCD47) on endothelial cells and podocytes isolated from hCD47 transgenic (Tg) swine markedly reduced phagocytosis by baboon and human macrophages. These observations led us to hypothesize that transplanting hCD47 Tg porcine kidneys could overcome the incompatibility of the porcine CD47-baboon SIRPα interspecies ligand-receptor interaction and prevent the development of proteinuria following KXTx. METHODS: Ten baboons received pig kidneys with vascularized thymic grafts (n = 8) or intra-bone bone marrow transplants (n = 2). Baboons were divided into three groups (A, B, and C) based on the transgenic expression of hCD47 in GalT-KO pigs. Baboons in Group A received kidney grafts with expression of hCD47 restricted to glomerular cells (n = 2). Baboons in Group B received kidney grafts with high expression of hCD47 on both glomerular and tubular cells of the kidneys (n = 4). Baboons in Group C received kidney grafts with low/no glomerular expression of hCD47, and high expression of hCD47 on renal tubular cells (n = 4). RESULTS: Consistent with this hypothesis, GalT-KO/hCD47 kidney grafts with high expression of hCD47 on glomerular cells developed minimal proteinuria. However, high hCD47 expression in all renal cells including renal tubular cells induced an apparent destructive inflammatory response associated with upregulated thrombospondin-1. This response could be avoided by a short course of weekly anti-IL6R antibody administration, resulting in prolonged survival without proteinuria (mean 170.5 days from 47.8 days). CONCLUSION: Data showed that transgenic expression of hCD47 on glomerular cells in the GalT-KO donor kidneys can prevent xenograft nephropathy, a significant barrier for therapeutic applications of xenotransplantation. The ability to prevent nephrotic syndrome following KXTx overcomes a critical barrier for future clinical applications of KXTx.

The Forgotten Antiproteinuric Properties of Diuretics.

BACKGROUND: Although diuretics are one of the most widely used drugs by nephrologists, their antiproteinuric properties are not generally taken into consideration. SUMMARY: Thiazide diuretics have been shown to reduce proteinuria by >35% in several prospective controlled studies, and these values are markedly increased when combined with a low-salt diet. Thiazide-like diuretics (indapamide and chlorthalidone) have shown similar effectiveness. The antiproteinuric effect of mineralocorticoid receptor antagonists (spironolactone, eplerenone, and finerenone) has been clearly established through prospective and controlled studies, and treatment with finerenone reduces the risk of chronic kidney disease progression in type-2 diabetic patients. The efficacy of other diuretics such as amiloride, triamterene, acetazolamide, or loop diuretics has been less explored, but different investigations suggest that they might share the same antiproteinuric properties of other diuretics that should be evaluated through controlled studies. Although the inclusion of sodium-glucose cotransporter-2 inhibitors (SGLT2i) among diuretics is a controversial issue, their renoprotective and cardioprotective properties, confirmed in various landmark trials, constitute a true revolution in the treatment of patients with kidney disease. Recent subanalyses of these trials have shown that the early antiproteinuric effect induced by SGLT2i predicts long-term preservation of kidney function. Key Message: Whether the early reduction in proteinuria induced by diuretics other than finerenone and SGLT2i, as summarized in this review, also translates into long-term renoprotection requires further prospective and observational studies. In any case, it is important for the clinician to be aware of the antiproteinuric properties of drugs so often used in daily clinical practice.

CMIP interacts with WT1 and targets it on the proteasome degradation pathway.

BACKGROUND: The Wilms tumor 1 suppressor gene, WT1, is expressed throughout life in podocytes and is essential for their function. Downregulation of WT1 has been reported in podocyte diseases but the underlying mechanisms remain unclear. Podocyte injury is the hallmark of idiopathic nephrotic syndrome (INS), the most frequent glomerular disease in children and young adults. An increase in the abundance of Cmaf-inducing protein (CMIP) has been found to alter podocyte function, but it is not known whether CMIP affects WT1 expression. METHODS: Transcriptional and post-transcriptional regulation of WT1in the presence of CMIP was studied using transient transfection, mouse models, and siRNA handling. RESULTS: We showed that overproduction of CMIP in the podocyte was consistently associated with a downregulation of WT1 according to two mechanisms. We found that CMIP prevented the NF-kB-mediated transcriptional activation of WT1. We demonstrated that CMIP interacts directly with WT1 through its leucine-rich repeat domain. Overexpression of CMIP in the M15 cell line induced a downregulation of WT1, which was prevented by lactacystin, a potent proteasome inhibitor. We showed that CMIP exhibits an E3 ligase activity and targets WT1 to proteasome degradation. Intravenous injection of Cmip-siRNA specifically prevented the repression of Wt1 in lipopolysaccharides-induced proteinuria in mice. CONCLUSIONS: These data suggest that CMIP is a repressor of WT1 and might be a critical player in the pathophysiology of some podocyte diseases. Because WT1 is required for podocyte integrity, CMIP could be considered a therapeutic target in podocyte diseases.

Ouabain Protects Nephrogenesis in Rats Experiencing Intrauterine Growth Restriction and Partially Restores Renal Function in Adulthood.

Intrauterine growth restriction (IUGR) is, in general, accompanied by a reduction of the nephron number, which increases the risk of hypertension and renal dysfunction. Studies have revealed that ouabain can partially restore the number of nephrons during IUGR. However, there is limited information regarding the melioration of nephric structure and function. We used maternal malnutrition to induce an IUGR model in rats. Subsequently, we used a mini-pump to administer ouabain to IUGR rats during pregnancy. Male offspring were divided randomly into two groups. One group was fed a normal diet, whereas the other was fed an isocaloric 8% high-salt diet. Maternal malnutrition led to a reduction in the birth weight and number of nephrons in offspring. At the end of a 40-week follow-up period, offspring from the IUGR group had high blood pressure and abnormal excretion of urinary protein; these parameters were exacerbated in offspring fed a high-salt diet. However, ouabain administration during pregnancy could partially restore the number of nephrons in IUGR offspring, normalize blood pressure, and reduce urinary protein excretion, even when challenged with a high-salt diet. Pathology findings revealed that IUGR, particularly following feeding of a high-salt diet, damaged the ultrastructure of glomeruli, but these harmful effects were ameliorated in offspring treated with ouabain. Collectively, our data suggest that ouabain could rescue nephrogenesis in IUGR newborns and protect (at least in part) the structure and function of the kidney during adulthood even when encountering unfavorable environmental challenges in subsequent life.

Assessment of extended urine protein monitoring frequency in patients receiving bevacizumab.

PURPOSE: Proteinuria monitoring is required for patients receiving bevacizumab. Nonetheless, the frequency of monitoring is not specified in the package insert. A 2014 quality improvement study performed at Yale New Haven Health System (YNHHS) found that proteinuria occurred in 15% (all grade) of the 162 patients evaluated. These results led to decreasing the frequency of proteinuria monitoring from every treatment to every other treatment. The objective of this study is to assess the safety of the extended interval for urine protein (UP) monitoring. METHODS: Patients receiving at least four bevacizumab treatments at YNHHS from January to June 2017 were randomly selected and retrospectively reviewed. The following data were collected: baseline patient characteristics, comorbidities, medication history, and proteinuria monitoring. The grade, prevalence and management of proteinuria were evaluated. The minimum necessary sample size was determined to be 384 treatments to achieve a 95% confidence interval. RESULTS: Fifty-five patients and 388 bevacizumab treatments were evaluated. Urine protein was assessed in 52.5% of treatments. The incidence of proteinuria among patients was 7.2% (grade 2) and 0% (grade 3). Cumulative dose and the number of total bevacizumab doses did not affect the timing for onset or severity of proteinuria. Two patients with UP ≥ 2+ were further monitored using a 24-h urine collection test with negative results. No treatments were held due to proteinuria. CONCLUSION: Monitoring proteinuria every other treatment does not increase the frequency of adverse events. Urine protein is now monitored prior to every third bevacizumab treatment, reducing unnecessary labs and chair time.

Relationship of visceral adiposity index with new-onset proteinuria in hypertensive patients.

BACKGROUND & AIMS: Visceral adiposity index (VAI) is a sex-specific surrogate marker of adipose tissue distribution and function. Little is known about the longitudinal relationship between VAI and proteinuria. This study aimed to examine the prospective relationship of baseline VAI with new-onset of proteinuria in hypertensive patients without major cardiovascular diseases. METHODS: A total of 10 699 hypertensive patients without proteinuria (negative urine dipstick reading) at baseline from the renal sub-study of the China Stroke Primary Prevention Trial (CSPPT) were included. Participants were randomly assigned to a double-blind daily treatment with 10 mg enalapril and 0.8 mg folic acid or 10 mg enalapril alone. Participants were followed every 3 months after randomization. The primary outcome was new-onset proteinuria, defined as a urine dipstick reading of ≥1+ at the exit visit. The secondary outcome was progression of proteinuria, defined as a urine dipstick reading of trace or ≥1+ at the exit visit. RESULTS: During a median follow-up duration of 4.4 years, a total of 396 (3.7%) participants developed new-onset proteinuria, while 1236 (11.6%) participants met progression of proteinuria. When VAI was categorized into quartiles, compared with participants in quartile 1-3 (<2.99), a significantly higher risk of new-onset proteinuria (OR, 1.43; 95%CI: 1.07-1.91) and progression of proteinuria (OR, 1.23; 95%CI: 1.03-1.46) was found in those in quartile 4 (≥2.99). Moreover, the positive association was consistent in participants with or without general obesity, abdominal obesity, and dyslipidemia (all P-interactions > 0.05). CONCLUSIONS: There was a positive association between VAI levels and the risk of new-onset proteinuria in hypertensive patients.

Inhibition of apoptosis signal-regulating kinase 1 mitigates the pathogenesis of human immunodeficiency virus-associated nephropathy.

BACKGROUND: Chronic kidney disease (CKD) is a common cause of morbidity and mortality in human immunodeficiency virus (HIV)-positive individuals. Among the HIV-related kidney diseases, HIV-associated nephropathy (HIVAN) is a rapidly progressive renal disease characterized by collapsing focal glomerulosclerosis (GS), microcystic tubular dilation, interstitial inflammation and fibrosis. Although the incidence of end-stage renal disease due to HIVAN has dramatically decreased with the widespread use of antiretroviral therapy, the prevalence of CKD continues to increase in HIV-positive individuals. Recent studies have highlighted the role of apoptosis signal-regulating kinase 1 (ASK1) in driving kidney disease progression through the activation of p38 mitogen-activated protein kinase and c-Jun N-terminal kinase and selective ASK-1 inhibitor GS-444217 was recently shown to reduce kidney injury and disease progression in various experimental models. Therefore we examined the efficacy of ASK1 antagonism by GS-444217 in the attenuation of HIVAN in Tg26 mice. METHODS: GS-444217-supplemented rodent chow was administered in Tg26 mice at 4 weeks of age when mild GS and proteinuria were already established. After 6 weeks of treatment, the kidney function assessment and histological analyses were performed and compared between age- and gender-matched control Tg26 and GS-444217-treated Tg26 mice. RESULTS: GS-444217 attenuated the development of GS, podocyte loss, tubular injury, interstitial inflammation and renal fibrosis in Tg26 mice. These improvements were accompanied by a marked reduction in albuminuria and improved renal function. Taken together, GS-4442217 attenuated the full spectrum of HIVAN pathology in Tg26 mice. CONCLUSIONS: ASK1 signaling cascade is central to the development of HIVAN in Tg26 mice. Our results suggest that the select inhibition of ASK1 could be a potential adjunctive therapy for the treatment of HIVAN.

Daratumumab-based therapy for patients with monoclonal gammopathy of renal significance.

Treatment of the plasma cell clone in monoclonal gammopathy of renal significance (MGRS) is necessary in order to reduce toxic immunoglobulin load to the kidneys and salvage renal function. There are limited data on the use of daratumumab in patients with MGRS. We summarize our experience with the use of daratumumab-based therapy in 25 MGRS patients, 12 of whom were previously untreated. The median follow-up of the cohort is 14 months. The best overall haematologic response in evaluable patients was complete response (CR) in five (22%), very good partial response (VGPR) in five (22%) and partial response (PR) in seven (30%) patients for an overall response rate of 74%. Two of five patients in CR and two patients with initially detectable clones, but non-measurable immunoglobulins, had undetectable minimal residual disease (MRD) with next-generation flow cytometry (NGF) after therapy. Haematologic response rate for previously untreated patients was 83% vs. 69% for previously treated and for daratumumab combinations it was 91% vs. 64%, and with CR/VGPR 82% vs. 29%, compared to daratumumab monotherapy. At six months, 12/22 (55%) patients not on dialysis achieved a reduction of proteinuria >30%, of at least 0·5 g/24 h, without an estimated glomerular filtration rate (eGFR) reduction. The toxicity was mild and predictable. In conclusion, daratumumab-based therapy is a new option for patients with MGRS.

Urinary DPP4 correlates with renal dysfunction, and DPP4 inhibition protects against the reduction in megalin and podocin expression in experimental CKD.

This study investigated the molecular mechanisms underlying the antiproteinuric effect of DPP4 inhibition in 5/6 renal ablation rats and tested the hypothesis that the urinary activity of DPP4 correlates with chronic kidney disease (CKD) progression. Experiments were conducted in male Wistar rats who underwent 5/6 nephrectomy (Nx) or sham operation followed by 8 wk of treatment with the DPP4 inhibitor (DPP4i) sitagliptin or vehicle. Proteinuria increased progressively in Nx rats throughout the observation period. This increase was remarkably mitigated by sitagliptin. Higher levels of proteinuria in Nx rats compared to control rats were accompanied by higher urinary excretion of retinol-binding protein 4, a marker of tubular proteinuria, as well as higher urinary levels of podocin, a marker of glomerular proteinuria. Retinol-binding protein 4 and podocin were not detected in the urine of Nx + DPP4i rats. Tubular and glomerular proteinuria was associated with the reduced expression of megalin and podocin in the renal cortex of Nx rats. Sitagliptin treatment partially prevented this decrease. Besides, the angiotensin II renal content was significantly reduced in the Nx rats that received sitagliptin compared to vehicle-treated Nx rats. Interestingly, both urinary DPP4 activity and abundance increased progressively in Nx rats. Additionally, urinary DPP4 activity correlated positively with serum creatinine levels, proteinuria, and blood pressure. Collectively, these results suggest that DPP4 inhibition ameliorated both tubular and glomerular proteinuria and prevented the reduction of megalin and podocin expression in CKD rats. Furthermore, these findings suggest that urinary DPP4 activity may serve as a biomarker of renal disease and progression.

Glycyrrhizin potentially suppresses the inflammatory response in preeclampsia rat model.

OBJECTIVE: The expression of high-mobility group box 1 (HMGB1) in trophoblasts is elevated, which contributes to the development of preeclampsia. Thus, this study aimed to investigate the effect of glycyrrhizin, a natural HMGB1 inhibitor, on the development of preeclampsia. METHODS: Preeclampsia was induced in pregnant Lewis rats through oral administration of L-NAME (50 mg/kg/day) on gestational day (GD) 13-19. Glycyrrhizin (10, 30, or 60 mg/kg/day) was given by oral gavage on GD 10-19. Systolic blood pressure (SBP), diastolic blood pressure (DBP), 24-hour proteinuria, live pup birth ratio, pup weight, pup body length, and placental weight were measured. Also, the expression levels of inflammatory factors (TNF-α, iNOS, IL-1, and IL-6), HMGB1, and TLR4 in the placenta or in the serum were analyzed by enzyme-linked immunosorbent assay, RT-PCR, and Western blot analysis. RESULTS: Glycyrrhizin significantly reduced the SBP, DBP, and 24-hour proteinuria on GD 16 and 20 in a dose-dependent manner and ameliorated the pregnancy outcomes in preeclampsia rats. The elevated inflammatory molecule levels were markedly decreased by glycyrrhizin not only in the serum but also in the placenta. Moreover, the upregulated HMGB1 and TLR4 expression levels were diminished by glycyrrhizin administration. CONCLUSION: This study shows that glycyrrhizin could alleviate preeclampsia and the preeclampsia-associated inflammatory reaction, and this effect could be attributed to HMGB1 inhibition.

Inhibition of α2-adrenoceptor is renoprotective in 5/6 nephrectomy-induced chronic kidney injury rats.

In the present study, we investigated the renoprotective effects of long-term treatment with yohimbine, an α2-adrenoceptor inhibitor, in a 5/6 nephrectomy-induced chronic kidney disease (CKD) rat model. Male Sprague-Dawley rats were randomly allocated into the following groups: sham-operated, 5/6-nephrectomized (5/6 Nx), 5/6 Nx + low or high dose of yohimbine (0.3 or 3.0 mg/L in drinking water, respectively), and 5/6 Nx + hydralazine (250 mg/L in drinking water). The 5/6 Nx group presented with renal dysfunction, hypertension, noradrenaline overproduction, and histopathological injuries. Blood pressure decreased in both the yohimbine- and hydralazine-treated groups. Treatment with high dose of yohimbine, but not hydralazine, apparently attenuated urinary protein excretion and noradrenaline concentration of renal venous plasma. Renal fibrosis and upregulated fibrosis-related gene expression were suppressed by high dose of yohimbine. Furthermore, yohimbine, but not hydralazine, treatment ameliorated the urinary concentration ability. These findings suggest that long-term yohimbine treatment can be a useful therapeutic option to prevent the progression of CKD.