Effect of storage conditions on the stability of recombinant human MCP-1/CCL2

Storage conditions affect the composition of the lyophilized secretome of multipotent mesenchymal stromal cells

The widespread use of multipotent mesenchymal stromal cell-derived secretome (MSC-sec) requires optimal preservation methods. Lyophilization offers benefits like concentrating the secretome, reducing the storage volume, and making storage conditions more flexible. This study evaluated the influence of storage duration and temperature on lyophilized MSC-sec. The conditioned medium from Wharton's jelly MSCs was stored at - 80 °C or lyophilized with or without trehalose. Lyophilized formulations were kept at - 80 °C, - 20 °C, 4 °C, or room temperature (RT) for 3 and 30 months. After storage and reconstitution, the levels of growth factors and cytokines were assessed using multiplex assay. The storage of lyophilized MSC-sec at - 80 °C ensured biomolecule preservation for 3 and 30 months. Following 3 month storage at 4 °C and RT, a notable decrease occurred in BDNF, bNGF, and sVCAM-1 levels. Prolonged 30 month storage at the same temperatures significantly reduced BDNF, bNGF, VEGF-A, IL-6, and sVCAM-1, while storage at - 20 °C decreased BDNF, bNGF, and VEGF- A levels. Trehalose supplementation of MSC-sec improved the outcome during storage at 4 °C and RT. Proper storage conditions were crucial for the preservation of lyophilized MSC-sec composition. Short-term storage at various temperatures maintained over 60% of the studied growth factors and cytokines; long-term preservation was only adequate at -80 °C.

Effects of Hydrochlorothiazide and Metformin on Aquaresis and Nephroprotection by a Vasopressin V2 Receptor Antagonist in ADPKD: A Randomized Crossover Trial

BACKGROUND AND OBJECTIVES

The vasopressin V2 receptor antagonist tolvaptan is the only drug that has been proven to be nephroprotective in autosomal dominant polycystic kidney disease (ADPKD). Tolvaptan also causes polyuria, limiting tolerability. We hypothesized that cotreatment with hydrochlorothiazide or metformin may ameliorate this side effect.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We performed a clinical study and an animal study. In a randomized, controlled, double-blind, crossover trial, we included 13 tolvaptan-treated patients with ADPKD. Patients were treated for three 2-week periods with hydrochlorothiazide, metformin, or placebo in random order. Primary outcome was change in 24-hour urine volume. We also measured GFR and a range of metabolic and kidney injury markers.

RESULTS

Patients (age 45±8 years, 54% women, measured GFR of 55±11 ml/min per 1.73 m2) had a baseline urine volume on tolvaptan of 6.9±1.4 L/24 h. Urine volume decreased to 5.1 L/24 h (P<0.001) with hydrochlorothiazide and to 5.4 L/24 h (P<0.001) on metformin. During hydrochlorothiazide treatment, plasma copeptin (surrogate for vasopressin) decreased, quality of life improved, and several markers of kidney damage and glucose metabolism improved. Metformin did not induce changes in these markers or in quality of life. Given these results, the effect of adding hydrochlorothiazide to tolvaptan was investigated on long-term kidney outcome in an animal experiment. Water intake in tolvaptan-hydrochlorothiazide cotreated mice was 35% lower than in mice treated with tolvaptan only. Combination treatment was superior to "no treatment" on markers of disease progression (kidney weight, P=0.003 and cystic index, P=0.04) and superior or equal to tolvaptan alone.

CONCLUSIONS

Both metformin and hydrochlorothiazide reduced tolvaptan-caused polyuria in a short-term study. Hydrochlorothiazide also reduced polyuria in a long-term animal model without negatively affecting nephroprotection.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2022_03_21_CJN11260821.mp3.

Cytokine concentrations are related to level of mental distress in inpatients not using anti-inflammatory drugs

OBJECTIVE

Cross-sectional data show elevated levels of circulating cytokines in psychiatric patients. The literature is divided concerning anti-inflammatory drugs' ability to relieve symptoms, questioning a causal link between inflammatory pathways and psychiatric conditions. We hypothesised that the development of circulating cytokine levels is related to mental distress, and that this relationship is affected by the use of anti-inflammatory drugs.

METHODS

The study was a longitudinal assessment of 12-week inpatient treatment at Modum Bad Psychiatric Center, Norway. Sera and self-reported Global Severity Index (GSI) scores, which measure psychological distress, were collected at admission (T0), halfway (T1) and before discharge (T2). Other variables known to distort the neuroimmune interplay were included. These were age, gender, diagnosis of PTSD, antidepressants and anti-inflammatory drugs. A total of 128 patients (92 women and 36 men) were included, and 28 were using anti-inflammatory medication. Multilevel modelling was used for data analysis.

RESULTS

Patients with higher levels of IL-1RA and MCP-1 had higher GSI scores (p = 0.005 and p = 0.020). PTSD patients scored higher on GSI than non-PTSD patients (p = 0.002). These relationships were mostly present among those not using anti-inflammatory drugs (n = 99), with higher levels of IL-1RA and MCP-1 being related to higher GSI score (p = 0.023 and 0.018, respectively). Again, PTSD patients showed higher GSI levels than non-PTSD patients (p = 0.014).

CONCLUSIONS

Cytokine levels were associated with level of mental distress as measured by the GSI scores, but this relationship was not present among those using anti-inflammatory drugs. We found no association between cytokine levels and development of GSI score over time.

Rapid Progression of Autosomal Dominant Polycystic Kidney Disease: Urinary Biomarkers as Predictors

BACKGROUND

Markers currently used to predict the likelihood of rapid disease progression in patients with autosomal dominant polycystic kidney disease (ADPKD) are expensive and time consuming to assess and often have limited sensitivity. New, easy-to-measure markers are therefore needed that alone or in combination with conventional risk markers can predict the rate of disease progression. In the present study, we investigated the ability of tubular damage and inflammation markers to predict kidney function decline.

METHODS

At baseline, albumin, immunoglobulin G, kidney injury molecule 1, β2 microglobulin (β2MG), heart-type fatty acid-binding protein, neutrophil gelatinase-associated lipocalin, and monocyte chemotactic protein-1 -(MCP-1) were measured in 24-h urine samples of patients participating in a study investigating the therapeutic efficacy of lanreotide in ADPKD. Individual change in estimated glomerular filtration rate (eGFR) during follow-up was calculated using mixed-model analysis taking into account 13 -eGFRs (chronic kidney disease EPIdemiology) per patient. Logistic regression analysis was used to select urinary biomarkers that had the best association with rapidly progressive disease. The predictive value of these selected urinary biomarkers was compared to other risk scores using C-statistics.

RESULTS

Included were 302 patients of whom 53.3% were female, with an average age of 48 ± 7 years, eGFR of 52 ± 12 mL/min/1.73 m2, and a height-adjusted total kidney volume (htTKV) of 1,082 (736-1,669) mL/m. At baseline, all urinary damage and inflammation markers were associated with baseline eGFR, also after adjustment for age, sex and baseline htTKV. For longitudinal analyses only patients randomized to standard care were considered (n = 152). A stepwise backward analysis revealed that β2MG and MCP-1 showed the strongest association with rapidly progressive disease. A urinary biomarker score was created by summing the ranking of tertiles of β2MG and MCP-1 excretion. The predictive value of this urinary biomarker score was higher compared to that of the Mayo htTKV classification (area under the curve [AUC] 0.73 [0.64-0.82] vs. 0.61 [0.51-0.71], p = 0.04) and comparable to that of the predicting renal outcomes in -ADPKD score (AUC 0.73 [0.64-0.82] vs. 0.65 [0.55-0.75], p = 0.18). In a second independent cohort with better kidney function, similar results were found for the urinary biomarker score.

CONCLUSION

Measurement of urinary β2MG and MCP-1 excretion allows selection of ADPKD patients with rapidly progressive disease, with a predictive value comparable to or even higher than that of TKV or PKD mutation. Easy and inexpensive to measure urinary markers therefore hold promise to help predict prognosis in ADPKD.

Biological effect of tissue plasminogen activator (t-PA) and DNase intrapleural delivery in pleural infection patients

Background

Pleural infection (PI) is a major global disease with an increasing incidence, and pleural fluid (PF) drainage is essential for the successful treatment. The MIST2 study demonstrated that intrapleural administration of tissue plasminogen activator (t-PA) and DNase, or t-PA alone increased the volume of drained PF. Mouse model studies have suggested that the volume increase is due to the interaction of the pleura with the t-PA via the monocyte chemoattractant protein 1 (MCP-1) pathway. We designed a study to determine the time frame of drained PF volume induction on intrapleural delivery of t-PA±DNase in humans, and to test the hypothesis that the induction is mediated by the MCP-1 pathway.

Methods

Data and samples from the MIST2 study were used (210 PI patients randomised to receive for 3 days either: t-PA and DNase, t-PA and placebo, DNase and placebo or double placebo). PF MCP-1 levels were measured by ELISA. One-way and two-way analysis of variance (ANOVA) with Tukey's post hoc tests were used to estimate statistical significance. Pearson's correlation coefficient was used to assess linear correlation.

Results

Intrapleural administration of t-PA±DNase stimulated a statistically significant rise in the volume of drained PF during the treatment period (days 1-3). No significant difference was detected between any groups during the post-treatment period (days 5-7). Intrapleural administration of t-PA increased MCP-1 PF levels during treatment; however, no statistically significant difference was detected between patients who received t-PA and those who did not. PF MCP-1 expression was not correlated to the drug given nor the volume of drained PF.

Conclusions

We conclude that the PF volume drainage increment seen with the administration of t-PA does not appear to act solely via activation of the MCP-1 pathway.

Lithium ameliorates tubule-interstitial injury through activation of the mTORC2/protein kinase B pathway

Tubule-interstitial injury (TII) is a critical step in the progression of renal disease. It has been proposed that changes in proximal tubule (PT) albumin endocytosis plays an important role in the development of TII. Some reports have shown protective effects of lithium on kidney injury animal models that was correlated to proteinuria. We tested the hypothesis that lithium treatment ameliorates the development of TII due to changes in albumin endocytosis. Two experimental models were used: (1) TII induced by albumin overload in an animal model; (2) LLC-PK1 cells, a PT cell line. Lithium treatment ameliorates TII induced by albumin overload measured by (1) proteinuria; (2) collagen deposition; (3) area of tubule-interstitial space, and (4) macrophage infiltration. Lithium treatment increased mTORC2 activity leading to the phosphorylation of protein kinase B (PKB) at Ser473 and its activation. This mechanism enhanced albumin endocytosis in PT cells, which decreased the proteinuria observed in TII induced by albumin overload. This effect did not involve changes in the expression of megalin, a PT albumin receptor. In addition, activation of this pathway decreased apoptosis in LLC-PK1 cells, a PT cell line, induced by higher albumin concentration, similar to that found in pathophysiologic conditions. Our results indicate that the protective role of lithium treatment on TII induced by albumin overload involves an increase in PT albumin endocytosis due to activation of the mTORC2/PKB pathway. These results open new possibilities in understanding the effects of lithium on the progression of renal disease.

Globular C1q receptor (p33) binds and stabilizes pro-inflammatory MCP-1: a novel mechanism for regulation of MCP-1 production and function

The protein gC1qR (globular C1q receptor), also named p33, was originally identified as a binding partner of the globular heads of C1q in the complement system. gC1qR/p33 is abundantly expressed in many cell types, but the functional importance of this protein is not completely understood. Here, we investigate the impact of gC1qR/p33 on the production and function of the pathophysiologically important chemokine monocyte chemoattractant protein-1 (MCP-1) and the underlying molecular mechanisms. Knockdown of gC1qR/p33 negatively regulated the production of MCP-1, but had no effect on the expression of transcript for MCP-1 in human periodontal ligament cells, suggesting a translational/post-translational mechanism of action. Laser scanning confocal microscopy showed considerable cytosolic co-localization of gC1qR/p33 and MCP-1, and co-immunoprecipitation disclosed direct physical interaction between gC1qR/p33 and MCP-1. Surface plasmon resonance analysis revealed a high-affinity binding (K_D = 10.9 nM) between gC1qR/p33 and MCP-1. Using a transwell migration assay, we found that recombinant gC1qR/p33 enhances MCP-1-induced migration of human THP-1 monocytes, pointing to a functional importance of the interaction between gC1qR/p33 and MCP-1. An in vitro assay revealed a rapid turnover of the MCP-1 protein and that gC1qR/p33 stabilizes MCP-1, hence preventing its degradation. We propose that endogenous gC1qR/p33 physically interacts with MCP-1 causing stabilization of the MCP-1 protein and stimulation of its activity in human periodontal ligament cells, suggesting a novel gC1qR/p33-mediated pro-inflammatory mechanism of action.

Stability of pro- and anti-inflammatory immune biomarkers for human cohort studies

BACKGROUND

Although discovery research has identified the importance of dozens of pro- and anti-inflammatory immune mediators in the pathogenesis, maintenance, exacerbation and resolution of inflammatory diseases, most human cohort studies have incorporated few or no immunological intermediate phenotypes in their analyses. Significant hindrances have been (1) the limited panel of biomarkers known to be readily detected in healthy human populations and (2) the stability, hence utility, of such biomarkers to repeated analysis.

METHODS

The frequency and stability of 14 plasma biomarkers linked to in vivo immune regulation of allergic and autoimmune inflammatory disorders was determined in 140 healthy pediatric and adult participants. The impact of initial and multiple subsequent freeze/thaw cycles on pro-inflammatory (CCL2, CXCL10, IL-18, TNFα, IL-6), anti-inflammatory (IL-10, sTNF-RII, IL-1Ra), acute phase proteins (CRP, PTX3) and other biomarkers (sST2, IL-1RAcP) was subsequently quantified.

RESULTS

Multiple biomarkers capable of providing an innate immune signature of inflammation were readily detected directly ex vivo in healthy individuals. These biomarker levels were unaffected when comparing paired data sets from freshly obtained, never frozen plasma or serum and matched aliquots despite extensive freeze/thaw cycles. Neither age nor sex affected stability. Similarly, no quantitative differences were found following repetitive analysis of inflammatory biomarkers in culture samples obtained following in vitro stimulation with TLR and RLR ligands.

CONCLUSIONS

A broad panel of in vivo and ex vivo cytokine, chemokine and acute phase protein biomarkers that have been linked to human chronic inflammatory disorders are readily detected in vivo and remain stable for analysis despite multiple freeze thaw cycles. These data provide the foundation and confidence for large scale analyses of panels of inflammatory biomarkers to provide better understanding of immunological mechanisms underlying health versus disease.

A three-dimensional in vitro model to demonstrate the haptotactic effect of monocyte chemoattractant protein-1 on atherosclerosis-associated monocyte migration

Monocyte transendothelial migration is a multi-step process critical for the initiation and development of atherosclerosis. The chemokine monocyte chemoattractant protein-1 (MCP-1) is overexpressed during atheroma and its concentration gradients in the extracellular matrix (ECM) is critical for the transendothelial recruitment of monocytes. Based on prior observations, we hypothesize that both free and bound gradients of MCP-1 within the ECM are involved in directing monocyte migration. The interaction between a three-dimensional (3D), cell-free, collagen matrix and MCP-1; and its effect on monocyte migration was measured in this study. Our results showed such an interaction existed between MCP-1 and collagen, as 26% of the total MCP-1 added to the collagen matrix was bound to the matrix after extensive washes. We also characterized the collagen-MCP-1 interaction using biophysical techniques. The treatment of the collagen matrix with MCP-1 lead to increased monocyte migration, and this phenotype was abrogated by treating the matrix with an anti-MCP-1 antibody. Thus, our results indicate a binding interaction between MCP-1 and the collagen matrix, which could elicit a haptotactic effect on monocyte migration. A better understanding of such mechanisms controlling monocyte migration will help identify target cytokines and lead to the development of better anti-inflammatory therapeutic strategies.

Regulation of macrophage biology by lithium: a new look at an old drug

Lithium (Li) continues to be a standard small compound used for the treatment of neurological disorders. Besides neuronal cells, Li is also known to affect immune cell function. In spite of its clinical use, potential mechanisms by which Li modulates immune cells, especially macrophages and its clinical relevance in bipolar patients are not well understood. Here, we provide an overview of the literature with regard to Li's effects on monocytes and macrophages. We have also included some of our results showing that Li differentially modulates chemokine gene expression in the absence and presence of Toll-like receptor-4 stimulation in a human macrophage model. Given that Li has a wide range of intracellular targets both in macrophages as well as in other cell types, more studies are needed to further understand the mechanistic basis of Li's effect in neurological and other inflammatory diseases. These studies could undoubtedly identify new therapeutic targets for treating such diseases.