Abstract 304: Combination therapy of cisplatin with cilastatin enables to increase the dose of cisplatin for enhancing its antitumor effect by suppressing nephrotoxicity

Cisplatin is an anticancer drug widely used in the treatment of many cancers, including lung cancers. Although cisplatin causes various types of adverse events, the main dose-limiting toxicity of cisplatin is nephrotoxicity. Megalin is an endocytic receptor expressed at the apical membranes of proximal tubules. We previously demonstrated that cisplatin was reabsorbed through megalin and caused kidney injury. Cilastatin, an inhibitor of renal dehydropeptidase-I and used with imipenem, blocked the binding of cisplatin to megalin and reduced the nephrotoxicity induced by cisplatin. In the current study, we precisely evaluated the effect of cilastatin-mediated suppression of cisplatin nephrotoxicity to safely enhance the antitumor activity of cisplatin. BALB/c mice were administrated cisplatin with or without cilastatin. Tubular dilation or atrophy, brush border loss, tubular cell lysis and cast formation were observed in mice treated with cisplatin alone. However, these kidney injuries were decreased or disappeared in mice treated with cisplatin and cilastatin. Cilastatin also decreased the urinary levels of N-acetyl-β-D-glucosaminidase and neutrophil gelatinase-associated lipocalin, proximal tubular injury markers. Next, SCID mice were injected s.c. with A549, a human lung cancer cell line, and treated with cisplatin with or without cilastatin. Cilastatin did not affect the antitumor activity of cilastatin. Notably, A549 did not express megalin. Combined with cilastatin, the mice were successfully treated with 1.5 times dose of cisplatin with enhanced antitumor effects of cisplatin but without nephrotoxicity. In conclusion, cilastatin effectively suppressed nephrotoxicity of cisplatin by blocking the binding of cisplatin to megalin. These findings indicated that we could administer cisplatin into cancer patients without nephrotoxicity if we used cilastatin. Moreover, we might increase the dose of cisplatin and improve the outcome of cancer patients.

Citation Format: Masashi Arita, Satoshi Watanabe, Nobumasa Aoki, Miho Takahashi, Satoshi Shoji, Koichiro Nozaki, Kosuke Ichikawa, Rie Kondo, Shoji Kuwahara, Junta Tanaka, Toshiyuki Koya, Akihiko Saito, Toshiaki Kikuchi. Combination therapy of cisplatin with cilastatin enables to increase the dose of cisplatin for enhancing its antitumor effect by suppressing nephrotoxicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 304.

Association of estimated dietary acid load with albuminuria in Japanese adults: a cross-sectional study

Background

Acid-base imbalance might promote the progression of chronic kidney disease (CKD), but whether nutrient-derived dietary acid load increases the risk of albuminuria or even high normoalbuminuria is unclear.

Methods

A Japanese cohort comprising 3250 men and 3434 women aged 40–97 years with urine albumin-to-creatinine ratio (ACR) < 33.9 mg/mmol or estimated glomerular filtration rate ≥ 15 ml/min/1.73 m² were assessed. We performed a cross-sectional evaluation of the association between net endogenous acid production (NEAP), estimated as dietary protein to potassium content ratio, and the presence of high normoalbuminuria (ACR: 1.13–3.38 mg/mmol) or microalbuminuria.

Results

Median NEAP was 43.4 (interquartile range (IQR): 34.2–53.4) mEq/day in men and 35.0 (IQR: 27.7–43.6) mEq/day in women. Median ACR was 1.11 (IQR: 0.57–2.49) mg/mmol in men and 1.47 (IQR: 0.82–2.83) mg/mmol in women. In multivariate analysis, the adjusted odds ratio of the highest versus lowest NEAP quartile for microalbuminuria was 1.47 (95% confidence interval (CI): 1.08–1.99) in men and 1.54 (95% CI: 1.11–2.14) in women. For high normoalbuminuria or microalbuminuria, the adjusted odds ratio was 1.28 (95% CI: 1.02–1.59) in men and 1.39 (95% CI: 1.11–1.74) in women. From nutrient composition analysis, subjects with the highest potassium intake, but not protein intake, had lower adjusted odds ratios for the presence of microalbuminuria than those in the lowest quartile for potassium intake.

Conclusions

Higher NEAP was associated with albuminuria and its association might negatively relate to potassium intake in an adult Japanese population.

A novel strip meniscometry method for measuring aqueous tear volume in dogs: Clinical correlations with the Schirmer tear and phenol red thread tests

OBJECTIVES

The strip meniscometry test (SMT) is a novel method for quantitative measurement of tear volume with only five seconds. We aimed to evaluate clinical correlations of SMT with the gold standard Schirmer tear test (STT) and phenol red thread test (PRT) in dogs, including normal and tear-deficient eyes.

ANIMALS STUDIED

Left eyes from 621 outpatient dogs with and without ocular disorders were evaluated.

PROCEDURES

Each subject underwent SMT, PRT, and STT without topical anesthesia in the described order with five-minute intervals. The total population was divided into four groups by classifying tear deficiency severity based on STT results: "severe" (0-5 mm/min), "moderate" (6-10 mm/min), "subclinical" (11-14 mm/min), and "normal" (15 or more mm/min).

RESULTS

The strongest correlation coefficient was found between SMT-STT (0.676), followed by PRT-STT (0.637) and SMT-PRT (0.600) pairs. Mean(SD) scores of SMT, PRT, and STT in total population were 9.47 (4.08) mm/5 s, 33.30 (8.52) mm/15 s, and 16.47 (7.01) mm/min. Significant differences were found among STT-classified groups, both using SMT and PRT results. Receiver operating characteristic (ROC) curves revealed that SMT better agreed with STT than PRT; agreement increased with increasing STT severity. A cutoff for SMT was identified at 10 mm/5 s to discriminate normal eyes from tear-deficient eyes, yielding high sensitivities and acceptable specificities.

CONCLUSIONS

SMT could be superior to PRT for discriminating tear-deficient eyes. The high sensitivity of SMT could be useful as an initial diagnostic tool to rule out normal eyes with the short testing time.

Assessment of meibomian gland morphology by noncontact infrared meibography in Shih Tzu dogs with or without keratoconjunctivitis sicca

Objective

To investigate meibomian gland (MG) morphology by noncontact infrared meibography in Shih Tzu dogs with or without keratoconjunctivitis sicca (KCS).

Procedures

Fourteen eyes of 12 Shih Tzu dogs (mean age of 10.7 years, range of 7‐13 years) presented to Yakumo Animal Hospital or Triangle Animal Eye Clinic from 2011 to 2017 with clinical signs and a Schirmer tear test (STT) result consistent with KCS (<10 mm/min) were examined. Twenty‐eight eyes of 16 Shih Tzu dogs (mean age of 12.4 years, range of 8 to 15 years) with a STT > 15 mm/min served as healthy controls. Both groups of dogs underwent routine slitlamp biomicroscopy followed by noncontact infrared meibography of the upper eyelid with both desktop‐type and mobile‐type systems.

Chronic Basophilic Leukaemia in a Dog

A 13-year-old neutered female mixed-breed dog with a clinical history of emaciation, inappetence and vomiting for 2 months was presented. Blood tests showed marked leucocytosis with increased neutrophil and basophil count, mild thrombocytosis and anaemia. Seven days after the initial visit, the dog died and was submitted for necropsy examination. Grossly, the bone marrow was red in colour and hepatomegaly and splenomegaly with discolouration were observed. A bone marrow smear showed an increased proportion of basophilic lineage cells. Histologically, the bone marrow showed high cellular density and numerous basophilic lineage cells with a round or segmented nucleus. The cytoplasm contained basophilic granules exhibiting metachromasia on toluidine blue staining. Immunohistochemically, the neoplastic basophils were diffusely positive for vimentin and myeloperoxidase, but negative for CD3, BLA36, CD163, CD204 and c-kit. The immunohistochemical features of neoplastic basophils that had invaded the liver and spleen were similar to those of the basophils in the bone marrow. Based on the clinicopathological and histopathological findings, chronic basophilic leukaemia was diagnosed. The present case study provides insights into the pathological features of chronic basophilic leukaemia in dogs.

Circulating FABP4 is eliminated by the kidney via glomerular filtration followed by megalin-mediated reabsorption

Circulating fatty acid binding protein 4 (FABP4), secreted from adipocytes, is a potential biomarker for metabolic and cardiovascular diseases. Circulating FABP4 levels are positively associated with adiposity and adrenergic stimulation, but negatively with renal function. In this study, we addressed the issue of how the kidney regulates clearance of circulating FABP4. Tracing study revealed remarkable accumulation of ¹²⁵I-labeled FABP4 in the kidney. Exogenous FABP4 was exclusively detected in the apical membrane of proximal tubule epithelial cells (PTECs). Bilateral nephrectomy resulted in marked elevation of circulating FABP4 levels. Accelerated lipolysis by β-3 adrenergic stimulation led to a marked elevation in circulating FABP4 in mice with severe renal dysfunction. Megalin, an endocytic receptor expressed in PTECs, plays a major role in reabsorption of proteins filtered through glomeruli. Quartz-crystal microbalance study revealed that FABP4 binds to megalin. In kidney-specific megalin knockout mice, a large amount of FABP4 was excreted in urine while circulating FABP4 levels were significantly reduced. Our data suggest that circulating FABP4 is processed by the kidney via the glomerular filtration followed by megalin-mediated reabsorption. Thus, it is likely that circulating FABP4 levels are determined mainly by balance between secretion rate of FABP4 from adipocytes and clearance rate of the kidney.

Differences in activities of daily living between people with subacute stroke who received knee-ankle-foot and ankle-foot orthoses at admission

[Purpose] This study aimed to identify the preferential factor of activities of daily living disabilities for selecting between knee-ankle-foot orthosis and ankle-foot orthosis prescription in the early stage after admission. [Participants and Methods] This study included 442 inpatients who had a subacute stroke and received either knee-ankle-foot orthosis or ankle-foot orthosis after admission (mean age, 69 years). The functional independence measure was investigated within 1 week after admission. [Results] Inpatients who had a stroke and received knee-ankle-foot orthosis had significantly lower scores for all individual functional independence measure items than those who received ankle-foot orthosis. Logistic regression analysis revealed that functional independence measure transfer (bed, chair, and wheelchair) was closely associated with the difference in the prescribed lower limb orthosis after multivariate adjustment. [Conclusion] Compared with ankle-foot orthosis, knee-ankle-foot orthosis was prescribed to inpatients with more-severe disabilities, and the difference in the disability related to performing transfer activities was more noticeable than that in disability related to mobility between inpatients for whom knee-ankle-foot orthosis was prescribed and those for whom ankle-foot orthosis was prescribed. To provide effective rehabilitation for people who had a subacute stroke, for whom use of knee-ankle-foot orthosis or ankle-foot orthosis is recommended. The evaluation and intervention focused on standing performance related to performing transfer such as sit-to-stand, standing, moving while standing, and stepping might be a priority in the early stage after admission.

Difference in independent mobility improvement from admission to discharge between subacute stroke patients using knee-ankle-foot and those using ankle-foot orthoses

[Purpose] To verify differences in independent mobility improvements between people with subacute stroke with knee-ankle-foot orthoses (KAFOs) and those with ankle-foot orthoses (AFOs) from admission to discharge, and to identify the relationship between mobility improvements and their characteristics. [Participants and Methods] This study included 381 hospitalized patients with subacute stroke who required complete mobility assistance at admission and for whom KAFOs (KAFO group) or AFOs (AFO group) were prescribed after admission. The functional independence measure (FIM) score at admission and discharge, FIM gain, age, Brunnstrom stage (BS) of the paretic lower limb at admission, and the period from admission to prescription for lower limb orthoses were investigated. [Results] Repeated-measures two-way analysis of variance revealed a significant group × time interaction in the walk/wheelchair and stair-climbing items of the FIM. Improvements in the scores in the KAFO group were significantly lower than those in the AFO group. Age, BS, FIM at admission, and period from admission to lower limb orthosis prescription significantly correlated with FIM gain in the walk/wheelchair and stair-climbing items. [Conclusion] A more effective intervention using lower limb orthoses with consideration of the influence of age, motor paralysis, and activities of daily living at admission is required to promote the improvements of people with subacute stroke prescribed KAFOs or AFOs.

The known-groups validity of intensity-based physical activity measurement using an accelerometer in people with subacute stroke

[Purpose] This study aimed to assess the known-groups validity of the estimated metabolic equivalents during physical activities using accelerometer, Active Style Pro HJA 350-IT, in people with subacute stroke. [Subjects and Methods] Ten participants with subacute stroke and ten healthy people performed six activities (lying, sitting, standing, sitting with reaching task, standing with reaching task, and walking) and metabolic equivalents were estimated using the accelerometer during each activity. These estimated metabolic equivalents were compared with reported metabolic equivalents through compendiums or previous studies. Additionally, the estimated metabolic equivalents were compared between subacute stroke and healthy control participants. [Results] The estimated metabolic equivalents of both groups during maintaining posture showed significantly lower values in comparison with previous studies. There were no significant differences between the estimated metabolic equivalents during sitting with reaching tasks or standing with reaching tasks when compared with compendium metabolic equivalents across both groups. The estimated metabolic equivalents during walking were inevitable values significantly differed from previous study which conducted with stroke patients with lower gait abilities in both groups. [Conclusion] The estimated metabolic equivalents using accelerometer may be suitable to assess movement activity rather than motionless activity, and accelerometer demonstrated acceptable validity in people with subacute stroke.

Urinary Iron Excretion is Associated with Urinary Full-Length Megalin and Renal Oxidative Stress in Chronic Kidney Disease

BACKGROUND/AIMS

Megalin mediates the uptake of glomerular-filtered iron in the proximal tubules. Urinary full length megalin (C-megalin) excretion has been found to be increased in association with megalin-mediated metabolic load to the endo-lysosomal system in proximal tubular epithelial cells (PTECs) of residual nephrons. In the present study, we investigated the association between urinary iron and C-megalin in chronic kidney disease (CKD) patients, and the possible harmful effect of iron in renal tubules.

METHODS

Urinary levels of iron and C-megalin were measured in 63 CKD patients using automatic absorption spectrometry and a recently-established sandwich ELISA, respectively.

RESULTS

Although both urinary C-megalin and urinary total protein levels were correlated with urinary iron (C-megalin: ρ = 0.574, p <0.001; total protein: ρ = 0.500, p <0.001, respectively), urinary C-megalin alone emerged as an independent factor positively associated with urinary iron (β = 0.520, p <0.001) (R2 = 0.75, p <0.001). Furthermore, urinary iron was significantly and positively associated with urinary 8-hydroxydeoxyguanosine, an oxidative stress marker, while no association with other markers of renal tubular injury, i.e., β2-microglobulin and N-acetyl-β-D-glucosaminidase, was noted.

CONCLUSIONS

Our findings suggest that renal iron handling may be associated with megalin-mediated endo-lysosomal metabolic load in PTECs of residual nephrons and oxidative stress in renal tubules.

Urinary C-megalin for screening of renal scarring in children after febrile urinary tract infection

BackgroundFebrile urinary tract infection (fUTI) in children may cause renal scarring. This study aimed to investigate the usefulness of urinary biomarkers for diagnosing renal scarring after fUTI.MethodsThirty-seven children (median age: 1.36 years, range: 0.52-12.17 years, 25 boys) with a history of fUTI, who underwent renal scintigraphy for 4 months or longer after the last episode of fUTI, were analyzed. A spot urine sample was obtained on the day of renal scintigraphy to measure levels of total protein, N-acetyl-β-D-glucosaminidase (NAG), β₂-microglobulin (BMG), neutrophil gelatinase-associated lipocalin (NGAL), liver-type fatty acid binding protein (L-FABP), and C-megalin (full-length megalin). Results were corrected for urinary creatinine (Cr) and compared between the group with renal scarring (n=23) and that without scarring (n=14). Urinary levels of C-megalin were also measured in healthy control subjects.ResultsNo significant differences in total protein, NGAL, L-FABP, NAG, and BMG levels were found between the groups. However, C-megalin levels were significantly higher in the renal scarring group than in the non-renal scarring group and healthy controls (P<0.001). A cutoff value of 6.5 pmol/nmol of urinary C-megalin/Cr yielded 73.9% of specificity and 92.9% of sensitivity.ConclusionUrinary C-megalin is useful for diagnosing renal scarring caused by fUTI.

[Exosomal biomarkers for kidney disease.]

Development of minimally invasive biomarkers is necessary for early detection, prognosis prediction, severity assessment and treatment monitoring in different kidney diseases. Recently, many studies have been conducted worldwide on marker proteins and micro RNA(miRNA)contained in urinary extracellular vesicles(EVs)including exosomes. This article reviews urinary EV-contained biomarkers, including proximal tubular endocytic receptor megalin, for kidney diseases such as diabetic nephropathy.

A Randomized, Double-Blind, Crossover Pilot Trial of Rice Endosperm Protein Supplementation in Maintenance Hemodialysis Patients

In maintenance hemodialysis (MHD) patients, low protein intake is associated with protein-energy wasting, a risk factor that affects outcome. However, increased protein intake may lead to hyperphosphatemia and hyperkalemia, which are also mortality risk factors. Here, we evaluated the safety and effects of purified rice endosperm protein (REP), which contains less phosphorus and potassium than soy and casein proteins, as a supplemental protein source for MHD patients. This randomized, double-blind, placebo-controlled, crossover pilot study of REP supplementation (5 g/day × 4 weeks) was carried out in 50 Japanese adult MHD patients (1 dropped out); the primary outcome was the change in the urea kinetic-based normalized protein catabolic rate (nPCR), an indicator of protein intake in MHD patients. Intention-to-treat analyses of 24 patients in the REP-first group and 25 in the placebo-first group showed that REP supplementation increased nPCR significantly by 0.07 g/kg/day (95% confidence interval, 0.03–0.11), whereas changes in serum phosphorus and potassium concentrations were not different from the placebo. REP supplementation did not show a significant effect on other nutritional or metabolic parameters and no specific complications. In conclusion, purified REP with efficient bioavailability may be safe and useful for dietary supplementation in MHD patients.

The Ionospheric Connection Explorer Mission: Mission Goals and Design

The Ionospheric Connection Explorer, or ICON, is a new NASA Explorer mission that will explore the boundary between Earth and space to understand the physical connection between our world and our space environment. This connection is made in the ionosphere, which has long been known to exhibit variability associated with the sun and solar wind. However, it has been recognized in the 21st century that equally significant changes in ionospheric conditions are apparently associated with energy and momentum propagating upward from our own atmosphere. ICON's goal is to weigh the competing impacts of these two drivers as they influence our space environment. Here we describe the specific science objectives that address this goal, as well as the means by which they will be achieved. The instruments selected, the overall performance requirements of the science payload and the operational requirements are also described. ICON's development began in 2013 and the mission is on track for launch in 2017. ICON is developed and managed by the Space Sciences Laboratory at the University of California, Berkeley, with key contributions from several partner institutions.