Fucoidan Alleviates Renal Fibrosis in Diabetic Kidney Disease via Inhibition of NLRP3 Inflammasome-Mediated Podocyte Pyroptosis

Background: Fucoidan (FPS) has been widely used to treat renal fibrosis (RF) in patients with diabetic kidney disease (DKD); however, the precise therapeutic mechanisms remain unclear. Recently, research focusing on inflammation-derived podocyte pyroptosis in DKD has attracted increasing attention. This phenomenon is mediated by the activation of the nucleotide-binding oligomerization domain (Nod)-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, leading to RF during DKD progression. Therefore, we designed a series of experiments to investigate the ameliorative effects of FPS on RF in DKD and the mechanisms that are responsible for its effect on NLRP3 inflammasome-mediated podocyte pyroptosis in the diabetic kidney.

Methods: The modified DKD rat models were subjected to uninephrectomy, intraperitoneal injection of streptozotocin, and a high-fat diet. Following induction of renal injury, the animals received either FPS, rapamycin (RAP), or a vehicle for 4 weeks. For in vitro research, we exposed murine podocytes to high glucose and MCC950, an NLRP3 inflammasome inhibitor, with or without FPS or RAP. Changes in the parameters related to RF and inflammatory podocyte injury were analyzed in vivo. Changes in podocyte pyroptosis, NLRP3 inflammasome activation, and activation of the adenosine monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin complex 1 (mTORC1)/NLRP3 signaling axis involved in these changes were analyzed in vivo and in vitro.

Results: FPS and RAP ameliorated RF and inflammatory podocyte injury in the DKD model rats. Moreover, FPS and RAP attenuated podocyte pyroptosis, inhibited NLRP3 inflammasome activation, and regulated the AMPK/mTORC1/NLRP3 signaling axis in vivo and in vitro. Notably, our data showed that the regulative effects of FPS, both in vivo and in vitro, on the key signaling molecules, such as p-AMPK and p-raptor, in the AMPK/mTORC1/NLRP3 signaling axis were superior to those of RAP, but similar to those of metformin, an AMPK agonist, in vitro.

Conclusion: We confirmed that FPS, similar to RAP, can alleviate RF in DKD by inhibiting NLRP3 inflammasome-mediated podocyte pyroptosis via regulation of the AMPK/mTORC1/NLRP3 signaling axis in the diabetic kidney. Our findings provide an in-depth understanding of the pathogenesis of RF, which will aid in identifying precise targets that can be used for DKD treatment.

Fucoidan Ameliorates Renal Injury-Related Calcium-Phosphorus Metabolic Disorder and Bone Abnormality in the CKD-MBD Model Rats by Targeting FGF23-Klotho Signaling Axis

Background: Recently, chronic kidney disease (CKD)-mineral and bone disorder (MBD) has become one of common complications occurring in CKD patients. Therefore, development of a new treatment for CKD-MBD is very important in the clinic. In China, Fucoidan (FPS), a natural compound of Laminaria japonica has been frequently used to improve renal dysfunction in CKD. However, it remains elusive whether FPS can ameliorate CKD-MBD. FGF23-Klotho signaling axis is reported to be useful for regulating mineral and bone metabolic disorder in CKD-MBD. This study thereby aimed to clarify therapeutic effects of FPS in the CKD-MBD model rats and its underlying mechanisms in vivo and in vitro, compared to Calcitriol (CTR). Methods: All male rats were divided into four groups: Sham, CKD-MBD, FPS and CTR. The CKD-MBD rat models were induced by adenine administration and uninephrectomy, and received either FPS or CTR or vehicle after induction of renal injury for 21 days. The changes in parameters related to renal dysfunction and renal tubulointerstitial damage, calcium-phosphorus metabolic disorder and bone lesion were analyzed, respectively. Furthermore, at sacrifice, the kidneys and bone were isolated for histomorphometry, immunohistochemistry and Western blot. In vitro, the murine NRK-52E cells were used to investigate regulative actions of FPS or CTR on FGF23-Klotho signaling axis, ERK1/2-SGK1-NHERF-1-NaPi-2a pathway and Klotho deficiency. Results: Using the modified CKD-MBD rat model and the cultured NRK-52E cells, we indicated that FPS and CTR alleviated renal dysfunction and renal tubulointerstitial damage, improved calcium-phosphorus metabolic disorder and bone lesion, and regulated FGF23-Klotho signaling axis and ERK1/2-SGK1-NHERF-1-NaPi-2a pathway in the kidney. In addition, using the shRNA-Klotho plasmid-transfected cells, we also detected, FPS accurately activated ERK1/2-SGK1-NHERF-1-NaPi-2a pathway through Klotho loss reversal. Conclusion: In this study, we emphatically demonstrated that FPS, a natural anti-renal dysfunction drug, similar to CTR, improves renal injury-related calcium-phosphorus metabolic disorder and bone abnormality in the CKD-MBD model rats. More importantly, we firstly found that beneficial effects in vivo and in vitro of FPS on phosphorus reabsorption are closely associated with regulation of FGF23-Klotho signaling axis and ERK1/2-SGK1-NHERF-1-NaPi-2a pathway in the kidney. This study provided pharmacological evidences that FPS directly contributes to the treatment of CKD-MBD.

[Role and related mechanism of resolvin D1 in lung ischemia reperfusion injury in rats]

Objective: To investigate the role and related mechanism of resolvin D1 (RvD1) in lung ischemia-reperfusion injury (LIRI) in rats. Methods: Forty male Sprague-Dawley rats, 7-8 weeks, weighing 220-280 g, were divided into 4 groups using a random number table method: sham operation group, lung ischemia reperfusion control group, normal saline group, and RvD1 group. The rat model of LIRI was produced by 45 min of occlusion of the left hilum of lungs followed by 150 min reperfusion. In sham group, no blocking of the left hilum of lung after thoracotomy; Normal saline 2 ml/kg and RvD1 100 μg/kg were injected respectively at 10 min of reperfusion in normal saline group and RvD1 group. Blood samples were collected from the femoral vein for determination of interleukin (IL)-6, tumor necrosis factor (TNF)-α, soluble inter-cell adhesion molecules (sICAM-1) concentrations at 150 min of reperfusion. The rats were sacrificed after collection of blood samples and then lung tissues were taken for observation of the pathological changes and for measurement of lung wet/dry weight ratio (W/D). The the contents of malondialdehyde (MDA), monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-2 and the activity of myeloperoxidase (MPO) in lung tissues were determined. The protein relative expression of nuclear factor (NF)-κB in lung tissues was detected by Western blot. Lung tissue cell apoptosis was detected with TUNEL method. Results: The plasma level of IL-6, TNF-α, sICAM-1 in normal saline group and RvD1 group were significantly higher than those in the Sham group [(110±7), (100±4) vs (72±3) ng/L, (151±8), (153±6) vs (104±5) ng/L, (2 690±133), (2 760±167) vs (1 953±125) ng/L]. Besides, NF-κB protein relative expression level of lung tissues up-regulated [(0.681±0.033), (0.664±0.024) vs (0.292±0.011)] (all P<0.05). The W/D, apoptosis index, MDA, MCP-1, MIP-2 contents and MPO activity in lung ischemia reperfusion control group, normal saline group and RvD1 group were significantly higher than those in the Sham group [(5.92±0.31), (5.85±0.24), (5.06±0.08) vs (4.14±0.10), (32.9±1.5)%, (31.9±1.3)%, (17.7±1.8)% vs (8.1±0.6)%, (72.1±2.3), (66.7±3.7), (34.0±1.4) vs (22.0±0.8) nmol/mg, (3.99±0.28), (3.86±0.25), (2.66±0.16) vs (1.47±0.17) pg/mg, (9.45±0.53), (9.68±0.62), (7.62±0.22) vs (4.70±0.41) pg/mg, (3.01±0.18), (2.92±0.19), (1.58±0.11) vs (0.98±0.07) U/g] (all P<0.05). The plasma levels of the cytokines mentioned above, the W/D, the apoptosis index, MDA, MCP-1, MIP-2 contents and MPO activity in RvD1 group were significantly lower than those in the lung ischemia reperfusion control group [(63±4) vs (110±7) ng/L, (90±8) vs (151±8) ng/L, (1 835±182) vs (2 690±133) ng/L, (5.06±0.08) vs (5.92±0.31), (17.7±1.8)% vs (32.9±1.5)%, (34.0±1.4) vs (72.1±2.3) nmol/mg, (2.66±0.16) vs (3.99±0.28) pg/mg, (7.62±0.22) vs (9.45±0.53) pg/mg, (1.58±0.11) vs (3.01±0.18) U/g]. Besides, NF-κB protein relative expression level of lung tissues down-regulated [(0.313±0.012) vs (0.681±0.033)] (all P<0.05). Inflammatory cell infiltration in LIRI groups increased significantly, while it was significantly reduced in RvD1 group. Conclusion: RvD1 can effectively alleviate the tissue damage caused by lung ischemia-reperfusion through down-regulating NF-κB expression, relieving inflammatory reaction and oxidative stress, reducing apoptosis in rats.

Correlation between the development of calcium oxalate stones and polymorphisms in the fibronectin gene in the Uighur population of the Xinjiang region of China

Here, we have investigated the correlation between calcium oxalate stone formation and Fn gene polymorphisms in urinary calculi patients among the Uighur population (Xinjiang region). In this case control study, genomic DNA extracted from the peripheral blood of 129 patients with calcium oxalate stones (patient group) and 94 normal people (control group) was used to genotype polymorphisms in the rs6725958, rs10202709, and rs35343655 sites of the Fn gene by polymerase chain reaction-restriction fragment length polymorphism. Subsequently, the association between different genotypes and susceptibility to calcium oxalate stone formation was compared among the patient and control groups. Single nucleotide polymorphisms (SNPs) were detected in the rs6725958, rs10202709, and rs35343655 sites of the Fn gene among the patient and control groups. The genotype distributions of the three loci complied with the Hardy-Weinberg equilibrium. The results of allele frequencies of the patient/control group for polymorphisms in the rs6725958 site of the Fn gene were C = 179 (69.92%)/119 (63.30%) and A = 77 (30.08%)/69 (36.70%), in the rs10202709 site were C = 245 (95.70%)/176 (93.63%) and T = 11 (4.30%)/12 (6.38%), and in the rs35343655 site of the Fn gene were A = 139 (54.30%)/87 (46.28%) and G = 117 (45.70%)/101 (53.72%). We observed no significant differences between the three SNPs and development of calcium oxalate stones. Polymorphisms in rs6725958, rs10202709, and rs35343655 of the Fn gene had no obvious effect on the susceptibility to the development of calcium oxalate stones in the Uighur population, residing in the Xinjiang region of China.

Five-year results of a randomized, single-center study of tacrolimus vs microemulsion cyclosporine in heart transplant patients

BACKGROUND

Previous multicenter, randomized trials, lacking standardized post-transplant protocols, have compared tacrolimus (Tac) and cyclosporine (CyA, Sandimmune) and demonstrated similar outcomes with some different adverse effects. The microemulsion form of CyA (mCyA, Neoral) has replaced Sandimmune CyA as the more widely utilized CyA formulation. This is the first 5-year follow-up study of a large, single-center trial (n = 67) under a standardized post-transplant protocol comparing Tac and mCyA.

METHODS

Sixty-seven heart transplant patients were randomized to Tac (n = 33) or mCyA (n = 34), both in combination with corticosteroids and azathioprine without cytolytic induction. Five-year end-points included survival, Grade > or = 3A or treated rejection, angiographic cardiac allograft vasculopathy (CAV; any lesion > or = 30% stenosis), renal dysfunction (creatinine > or = 2.0 mg/dl), use of two or more anti-hypertensive medications, percent diabetic and lipid levels.

RESULTS

Five-year survival, freedom from Grade > or = 3A or any treated rejection and angiographic CAV, mean cholesterol level and percent diabetic were similar between the two groups. The Tac group had a significantly lower 5-year mean triglyceride level (Tac 97 +/- 34 vs mCyA 175 +/- 103 mg/dl, p = 0.011) and average serum creatinine level (Tac 1.2 +/- 0.5 mg/dl vs mCyA 1.5 +/- 0.4 mg/dl, p = 0.044). There was a trend toward fewer patients requiring two or more anti-hypertensive drugs in the Tac group (Tac 33% vs mCyA 59%, p = 0.065).

CONCLUSIONS

Tac and mCyA appear to be comparable with regard to 5-year survival, freedom from rejection and CAV. However, compared with mCyA, Tac appears to reduce the adverse effect profile for hypertriglyceridemia and renal dysfunction and the need for hypertensive medications.

Reference typing report for complement receptor 1 (CR1)

A total of 100 Chinese blood donors (50 from Shen-Zhen and 50 from Taiwan) were studied by the participants in addition to 9 reference samples. A new nomenclature for the CR1 structural alleles was recommended by the participants which would use a numbering system, e.g. CR1*1. The structural allele frequencies in the Chinese were: CR1*1 (190 kD) 0.96, CR1*2 (220 kD) 0.03, CR1*3 (160 kD) 0.01 and CR1*4 (250 kD) 0.00. The HindIII expression polymorphism was also studied and the high expressing allele had a gene frequency of 0.71 while the low expressor gene frequency was 0.28. Erythrocyte copy numbers were quantified and compared between laboratories with good correlation (R = 0.55-0.88). The mean (+/- SD) erythrocyte copy number was 463 (+/- 229) in the Taiwan donors and 446 (+/- 207) in the Mainland Chinese.

Fate of DNA targeted to hepatocytes by asialoglycoprotein polylysine conjugates

The data indicate that partial hepatectomy results in a decrease in degradation of targeted DNA. This appears to be due to an inhibition of the endocytotic pathway shortly after hepatectomy and is associated with the accumulation of targeted DNA within a population of light endosomal vesicles. It is likely that these vesicles serve as a reservoir from which targeted DNA gradually escapes and can be found in the nucleus. The DNA targeted to liver is capable of expressing the marker gene, and the DNA in the vesicles is transfection competent, suggesting that a substantial portion is intact. Overall, the receptor-mediated delivery system is highly efficient in transporting foreign DNA to liver cells. Partial hepatectomy and the ensuing cellular events provide a means of inhibiting the degradative portion of the endocytotic pathway. Pharmacological agents that can mimic the cellular processes that occur after partial hepatectomy may be useful in increasing the duration of foreign gene expression without the trauma of surgery.