[Protective effect of recombinant Schistosoma japonicum cystatin against acute kidney injury associated with acute liver failure in mice]

OBJECTIVE

To evaluate the protective effect of recombinant Schistosoma japonicum cystatin (rSj-Cys) against acute kidney injury induced by acute liver failure and unravel the underlying mechanism, so as to provide insights into the clinical therapy of acute kidney injury.

METHODS

Twenty-four male C57BL/6J mice at ages of 6 to 8 weeks were randomly divided into the normal control group, rSj-Cys control group, lipopolysaccharide (LPS)/D-galactosamine (D-GaIN) model group and LPS/D-GaIN + rSj-Cys treatment group, of 6 mice each group. Mice in the LPS/D-GaIN group and LPS/D-GaIN + rSj-Cys group were intraperitoneally injected with LPS (10 μg/kg) and D-GaIN (700 mg/kg), and mice in the LPS/D-GaIN + rSj-Cys group were additionally administered with rSj-Cys (1.25 mg/kg) by intraperitoneal injection 30 min post-modeling, while mice in the rSj-Cys group were intraperitoneally injected with rSj-Cys (1.25 mg/kg), and mice in the normal control group were injected with the normal volume of PBS. All mice were sacrificed 6 h post-modeling, and mouse serum and kidney samples were collected. Serum creatinine (Cr) and urea nitrogen (BUN) levels were measured, and the pathological changes of mouse kidney specimens were examined using hematoxylin-eosin (HE) staining. Serum tumor necrosis factor (TNF)-α and interleukin (IL)-6 levels were detected using enzyme-linked immunosorbent assay (ELISA), and the expression of inflammatory factors and pyroptosis-related proteins was quantified in mouse kidney specimens using immunohistochemistry. In addition, the expression of pyroptosis-related proteins and nuclear factor-kappa B (NF-κB) signaling pathway-associated proteins was determined in mouse kidney specimens using Western blotting assay.

RESULTS

HE staining showed no remarkable abnormality in the mouse kidney structure in the normal control group and the rSj-Cys control group, and renal tubular injury was found in LPS/D-GaIN group, while the renal tubular injury was alleviated in LPS/D-GaIN+rSj-Cys treatment group. There were significant differences in serum levels of Cr (F = 46.33, P < 0.001), BUN (F = 128.60, P < 0.001), TNF-α (F = 102.00, P < 0.001) and IL-6 (F = 202.10, P < 0.001) among the four groups, and lower serum Cr [(85.35 ± 32.05) μmol/L], BUN [(11.90 ± 2.76) mmol/L], TNF-α [(158.27 ± 15.83) pg/mL] and IL-6 levels [(56.72 ± 4.37) pg/mL] were detected in the in LPS/D-GaIN + rSj-Cys group than in the LPS/D-GaIN group (all P values < 0.01). Immunohistochemical staining detected significant differences in TNF-α (F = 24.16, P < 0.001) and IL-10 (F = 15.07, P < 0.01) expression among the four groups, and lower TNF-α [(106.50 ± 16.57)%] and higher IL-10 expression [(91.83 ± 5.23)%] was detected in the LPS/D-GaIN + rSj-Cys group than in the LPS/D-GaIN group (both P values < 0.01). Western blotting and immunohistochemistry detected significant differences in the protein expression of pyroptosis-related proteins NOD-like receptor thermal protein domain associated protein 3 (NLRP3) (F = 24.57 and 30.72, both P values < 0.001), IL-1β (F = 19.24 and 22.59, both P values < 0.001) and IL-18 (F = 16.60 and 19.30, both P values < 0.001) in kidney samples among the four groups, and lower NLRP3, IL-1β and IL-18 expression was quantified in the LPS/D-GaIN + rSj-Cys treatment group than in the LPS/D-GaIN group (P values < 0.05). In addition, there were significant differences in the protein expression of NF-κB signaling pathway-associated proteins p-NF-κB p-P65/NF-κB p65 (F = 71.88, P < 0.001), Toll-like receptor (TLR)-4 (F = 45.49, P < 0.001) and p-IκB/IκB (F = 60.87, P < 0.001) in mouse kidney samples among the four groups, and lower expression of three NF-κB signaling pathway-associated proteins was determined in the LPS/D-GaIN + rSj-Cys treatment group than in the LPS/D-GaIN group (all P values < 0.01).

CONCLUSIONS

rSj-Cys may present a protective effect against acute kidney injury caused by acute liver failure through inhibiting inflammation and pyroptosis and downregulating the NF-κB signaling pathway.

Recombinant sugarcane cystatin CaneCPI-5 down regulates inflammation and promotes angiogenesis and collagen deposition in a mouse subcutaneous sponge model

Cystatins are natural inhibitors of cysteine peptidases that are found practically in all living organisms. CaneCPI-5 is a sugarcane cystatin with inhibitory activity against human cathepsins B, K and L, which are cysteine proteases highly expressed in a variety of pathological conditions, usually marked by persistent inflammation and processing of the extracellular matrix. This work evaluated the effects of daily administration of the recombinant cystatin CaneCPI-5 [0.01, 0.1 or 1.0 μg in 10 μL of Phosphate-Buffered Saline (PBS)] on the inflammatory, angiogenic and fibrogenic components during chronic inflammatory response induced by subcutaneous sponge implants. The anti-inflammatory effect of treatment with CaneCPI-5 was confirmed by reduction of the levels of the pro-inflammatory mediators TNF-α, CXCL1 and CCL2/JE/MCP-1, as well as the activity of the myeloperoxidase and n-acetyl-β-D-glucosaminidase. Treatment with CaneCPI-5 promoted angiogenesis in the implants, increasing the production of cytokines VEGF and FGF and the formation of new blood vessels. Finally, the administration of the recombinant cystatin favored the production of the pro-fibrogenic cytokine TGF-β1 and collagen deposition next to the implants. Together, these results show the potential therapeutic application of CaneCPI-5 as an anti-inflammatory agent, capable of favoring angiogenesis and fibrogenesis processes, necessary for tissue repair.

[The statin dosage for achieving goal of cholesterol-lowering based on risk stratification in patients with ischemic cerebrovascular diseases]

OBJECTIVE

To explore statin dosages for targeting goal of LDL-C lowering on the basis of stroke risk stratification and the dosage-effective relation of statin and LDL-C lowering in Chinese patients with ischemic stroke and transient ischemic attack (TIA).

METHODS

This is a prospective and open clinical trial patients with ischemic stroke/TIA within 6 months were enrolled and the dosages of atorvastatin were calculated based on risk stratification according to "Chinese Consensus for Prevention of Ischemic Stroke/TIA with Statin" (Chinese Consensus). A dose of 10 mg of atorvastatin daily to target LDL-C goal was taken as the standard dosage targeting goal (SDTG). Patients taking this dosage of atorvastatin constituted a SDTG group. Those who needed a daily dose of 20 mg or more of atorvastatin were randomized into an intensive dosage targeting goal (IDTG) group (atorvastatin 20 - 80 mg/d) and a standard dosage non-targeting goal (SDNTG) group (atorvastatin 10 mg/d without targeting goal). All patients took atorvastatin for 12 weeks. The primary outcome was the rate of targeting goal for LDL-C lowering at 2, 4 and 12 weeks, respectively and the secondary outcome was the occurence of recurrent stroke and other vascular events within 12 weeks. The main safety endpoint was serial adverse events including symptomatic intracranial hemorrhage.

RESULTS

Altogether 102 cases were enrolled and 99 cases were followed up for 12 weeks. According to the Chinese Consensus, the rate of high risk, very high risk-I and very high risk-II was 44%, 28% and 28%, respectively. Targeting rate for LDL-C lowering was 77% - 85% at each time point in the SDTG and IDTG groups, being significantly higher than those in the SDNTG group (12% - 16%, P < 0.01). No significant difference was found concerning the occurrence of recurrent stroke, other vascular events and safety endpoints among the three groups. The amplitude of LDL-C lowering was 32% - 35%, 46% - 49%, 51% - 52% and 60% - 65% with corresponding to daily dosage of 10 mg, 20 mg, 40 mg and 80 mg atorvastatin.

CONCLUSIONS

At least more than half of the patients after ischemic stroke/TIA need intensive statin therapy to target the LDL-C lowering goal. The dosage-effective relation of atorvastatin and LDL-C lowering in Chinese is similar to the reported data in other races.

Immunomodulatory peptide from cystatin, a natural cysteine protease inhibitor, against leishmaniasis as a model macrophage disease

Cystatin, a natural cysteine protease inhibitor, has strong antileishmanial activity, which is due to its potential to induce nitric oxide (NO) generation from macrophages. Cysteine protease-inhibitory activity and NO-up-regulatory activity correspond to different regions, as revealed by the dissection of cystatin cDNA into nonoverlapping fragments. By using synthetic overlapping peptides, the NO-up-regulatory activity was found to be confined to a 10-mer sequence. In addition to having reasonable inhibitory effects on amastigote multiplication within macrophages (50% inhibitory concentration, 5.2 microg/ml), 97 and 93% suppression, respectively, of liver and spleen parasite burdens was achieved with the 10-mer peptide at a dose of 0.5 mg/kg of body weight/day, given consecutively for 4 days along with a suboptimal dose of gamma interferon in a 45-day mouse model of visceral leishmaniasis. Peptide treatment modulated the levels of cytokine secretion by infected splenocytes, with increased levels of interleukin-12 and tumor necrosis factor alpha and increased inducible NO synthase production, and also resulted in resistance to reinfection. The generation of a natural peptide from cystatin with robust immunomodulatory potential may therefore provide a promising therapeutic agent for macrophage-associated diseases.

Protein therapy for Unverricht-Lundborg disease using cystatin B transduction by TAT-PTD. Is it that simple?

In this work we analysed the characteristics of the cell-permeable peptide TAT-PTD fused to cystatin B (CSTB) to evaluate its potential for protein therapy of Unverricht-Lundborg (UL) epilepsy. TAT-PTD-CSTB does not penetrate the cells despite initial evidence of time and concentration-dependent transduction. Therefore, it cannot be used as a form of replacement of the intracytoplasmic protein missing in UL. Importantly, we discuss precautions to avoid false-positive results when working with TAT-PTD for protein therapy of neurological diseases.

Towards novel anti-cancer strategies based on cystatin function

Cystatins have recently emerged as important players in a multitude of physiological and patho-physiological settings that range from cell survival and proliferation, to differentiation, cell signaling and immunomodulation. This group of cysteine protease inhibitors forms a large super-family of proteins composed of one, two, three, and, in some species, more than three cystatin domains. Over the last 20 years or so, members of the cystatin super-family have been primarily explored with respect to their capacity to inhibit intracellular cysteine proteases. Yet, this classical mode of action does not fully explain their remarkably diverse biological functions. Due to the space limitations, the author will discuss here the most recent findings that suggest that some of the single-domain, cytoplasmic and cell-secreted cystatins may play important roles in the promotion or suppression of tumor growth, invasion and metastasis. Based on the present understanding of cystatin function, novel avenues for anti-cancer strategies are proposed.

Pretreatment cystatin C in children with malignancy: can it predict chemotherapy-induced glomerular filtration rate reduction during the induction phase?

BACKGROUND

Monitoring of kidney function is essential during chemotherapy. Serum creatinine is of limited value in early detection of renal insufficiency. The cystatin C level has been proved to be a good marker for detection of mild reduction in glomerular filtration rate.

PURPOSE

To evaluate the validity of the pretreatment serum cystatin C level in predicting significant reduction of the glomerular filtration rate during the induction phase of chemotherapy.

PATIENTS AND METHODS

Serum levels of cystatin C and creatinine and corrected creatinine clearance were assessed in 34 children with different types of malignancy just before the start of chemotherapy and again in 33 of them 1 month later. Patients were compared with 14 healthy controls of matched age and sex.

RESULTS

Before chemotherapy, all patients when compared with controls had normal levels of cystatin C (P = 0.1) and creatinine (P = 0.62) and normal corrected creatinine clearance (P = 0.76). One month after chemotherapy, patients showed a significant increase in their cystatin C levels (P < 0.001) and a significant decrease in their corrected creatinine clearance (P < 0.001). However, creatinine levels did not change significantly (P = 0.65). Corrected creatinine clearance negatively correlated significantly with both cystatin C and creatinine levels (r = -0.622, P < 0.001; r = -0.346, P = 0.045, respectively) before chemotherapy and also 1 month after chemotherapy (r = -0.577, P < 0.001; r = -0.45, P = 0.009, respectively). When pretreatment levels of cystatin C and creatinine were used to predict patients who developed a reduction in corrected creatinine clearance of more than 20% after therapy, only the cystatin C level was statistically significant (P = 0.03). A cutoff point of 0.57 mg/L with sensitivity of 77.8%, specificity of 63%, and overall accuracy of 74% was suggested.

CONCLUSIONS

Children with malignant diseases develop significant reduction in their glomerular filtration rate during the induction phase of chemotherapy, although their serum creatinine level may not change significantly. Cystatin C, as a more sensitive marker than creatinine for the assessment of glomerular filtration rate, can be used to predict patients who would have a higher risk of renal impairment during the induction phase of chemotherapy and who thus would require more frequent renal function assessment to consider adjustment of the chemotherapy dose if indicated.