The Requirement and Protective Effects of Dietary Protein against Chronic Ammonia Exposure in Juvenile Genetically Improved Farmed Tilapia (Oreochromis niloticus).

Ammonia is a key risk factor in intensive aquaculture systems. This experiment is aimed at investigating the influence of dietary protein levels on genetically improved farmed tilapia (GIFT, Oreochromis niloticus) under chronic ammonia stress. GIFT juveniles of 4.00 ± 0.55 g were exposed to high ammonia level at 0.88 mg/L and fed with six diets comprising graded protein levels at 22.64%, 27.26%, 31.04%, 35.63%, 38.47%, and 42.66% for 8 weeks. The fish in negative control was fed the diet with 31.04% protein in normal water (0.02 mg ammonia/L water). Our results showed that high ammonia exposure (0.88 mg/L) caused significant decrease in fish growth performance, hematological parameters, liver antioxidant enzymes (catalase and glutathione peroxidase), and gill Na+- and K+-dependent adenosine triphosphatase (Na+/K+-ATP) activity. When fish were under high ammonia exposure, the weight gain rate, special growth rate, feed efficiency, and survival rate elevated significantly with dietary protein supplementation increase to 35.63%, whereas protein efficiency ratio, hepatosomatic index, and viscerosomatic index showed a decreased tendency. Dietary protein administration significantly enhanced crude protein but reduced crude lipid contents in the whole fish. Fish fed diets with 35.63%-42.66% protein had higher red blood cell counts and hematocrit percentage than fish fed 22.64% protein diet. The values of serum biochemical indices (lactate dehydrogenase, aspartate aminotransferase, and alanine aminotransferase), hepatic antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase), and gill Na+/K+-ATP activity were all elevated with the increment of dietary protein. Moreover, histological analysis indicated that dietary protein administration could prevent the ammonia-induced damages in fish gill, kidney, and liver tissues. Based on weight gain rate as a response criterion, the optimal dietary protein requirement for GIFT juveniles under chronic ammonia stress was 37.9%.

[Effects and mechanisms of total flavones of Abelmoschus manihot in inhibiting podocyte necroptosis and renal fibrosis in diabetic kidney disease].

Previous studies have shown that high blood glucose-induced chronic microinflammation can cause inflammatory podocyte injury in patients with diabetic kidney disease(DKD). Therein, necroptosis is a new form of podocyte death that is closely associated with renal fibrosis(RF). To explore the effects and mechanisms in vivo of total flavones of Abelmoschus manihot(TFA), an extract from traditional Chinese herbal medicine Abelmoschus manihot for treating kidney diseases, on podocyte necroptosis and RF in DKD, and to further reveal its scientific connotation with multi-pathway and multi-target, the authors randomly divided all rats into four groups: a namely normal group, a model group, a TFA group and a rapamycin(RAP) group. After the modified DKD rat models were successfully established, four group rats were given double-distilled water, TFA suspension and RAP suspension, respectively by gavage every day. At the end of the 4th week of drug treatment, all rats were sacrificed, and the samples of their urine, blood and kidneys were collected. And then, the various indicators related to podocyte necroptosis and RF in the DKD model rats were observed, detected and analyzed, respectively. The results indicated that, general condition, body weight(BW), serum creatinine(Scr), urinary albumin(UAlb), and kidney hypertrophy index(KHI) in these modified DKD model rats were both improved by TFA and RAP. Indicators of RF, including glomerular histomorphological characteristics, fibronectin(FN) and collagen type Ⅰ(collagen Ⅰ) staining extent in glomeruli, as well as the protein expression levels of FN, collagen Ⅰ, transforming growth factor-ß1(TGF-ß1) and Smad2/3 in the kidneys were improved respectively by TFA and RAP. Podocyte damage, including foot process form and the protein expression levels of podocin and CD2AP in the kidneys was improved by TFA and RAP. In addition, tumor necrosis factor-α(TNF-α)-mediated podocyte necroptosis in the kidneys, including the morphological characteristics of podocyte necroptosis, the extent and levels of the protein expression of TNF-α and phosphorylated mixed lineage kinase domain like pseudokinase(p-MLKL) was improved respectively by TFA and RAP. Among them, RAP had the better effect on p-MLKL. More importantly, the activation of the receptor interacting serine/threonine protein kinase 1(RIPK1)/RIPK3/MLKL signaling axis in the kidneys, including the expression levels of its key signaling molecules, such as phosphorylated receptor interacting serine/threonine protein kinase 1(p-RIPK1), p-RIPK3, p-MLKL and cysteinyl aspartate specific proteinase-8(caspase-8) was improved respectively by TFA and RAP. Among them, the effect of TFA on p-RIPK1 was superior. On the whole, in this study, the authors demonstrated that TFA alleviates podocyte necroptosis and RF in DKD through inhibiting the activation of the TNF-α-mediated RIPK1/RIPK3/MLKL signaling axis in diabetic kidneys. The authors' findings provide new pharmacological evidence to reveal the scientific connotation of TFA in treating RF in DKD in more depth.

[Effect and mechanism of Dahuang Zhechong Pills in improving liver aging in rats by regulating ROS-mediated PI3K/Akt/FoxO4 signaling pathway].

Recent studies have shown that the occurrence and development of common liver diseases, including non-alcoholic fatty liver disease, cirrhosis, and liver cancer, are related to liver aging(LA). Therefore, to explore the effect and mechanism of Dahuang Zhechong Pills(DHZCP), a traditional classic prescription in improving LA with multiple targets, the present study randomly divided 24 rats into a normal group, a model group, a DHZCP group, and a vitamin E(VE) group, with six rats in each group. The LA model was induced by continuous intraperitoneal injection of D-galactose(D-gal) in rats. For the LA model rats, the general situation was evaluated by aging phenotype and body weight(BW). LA was assessed by the pathological characteristics of hepatocyte senescence, hepatic function indexes, the staining characteristics of phosphorylated histone family 2A variant(γ-H2AX), and the expression levels of cell cycle arrest proteins(P21, P53, P16) and senescence-associated secretory phenotype(SASP) in the liver. The activation of the reactive oxygen species(ROS)-mediated phosphatidylinositol-3 kinase(PI3K)/protein kinase B(Akt)/forkhead box protein O4(FoxO4) signaling pathway was estimated by hepatic ROS expression feature and the protein expression levels of the key signaling molecules in the PI3K/Akt/FoxO4 signaling pathway. The results showed that after the treatment with DHZCP or VE for 12 weeks, for the DHZCP and VE groups, the characterized aging phenotype, BW, pathological characteristics of hepatocyte senescence, hepatic function indexes, relative expression of ROS in the liver, protein expression levels of key signaling molecules including p-PI3K, p-Akt, and FoxO4 in the liver, staining characteristics of γ-H2AX, and the protein expression levels of P16, P21, P53, interleukin-6(IL-6), and tumor necrosis factor-α(TNF-α) in the liver were improved, and the effects of DHZCP and VE were similar. Based on the D-gal-induced LA model in rats, this study demonstrates that DHZCP can ameliorate LA with multiple targets in vivo, and its effects and mechanism are related to regulating the activation of the ROS-mediated PI3K/Akt/FoxO4 signaling pathway in the liver. These findings are expected to provide new pharmacological evidence for the treatment of DHZCP in aging-related liver diseases.

[Effect and mechanism of Dahuang Zhechong Pills against testicular aging in rats by inhibiting necroptosis signaling pathway].

To explore the effect and mechanism of Dahuang Zhechong Pills(DHZCP), a classical prescription, in improving testicular aging(TA) in vivo, the authors randomly divided 24 male rats into four groups: the normal, model, DHZCP and vitamin E(VE) groups. The TA rat model was established by continuous gavage of D-galactose(D-gal). During the experiment, the rats in the DHZCP and VE groups were given DHZCP suspension and VE suspension, respectively by gavage, while those in the normal and model groups were gavaged saline separately every day. After the co-administration of D-gal and various drugs for 60 days, all rats were sacrificed, and their blood and testis were collected. Further, various indexes related to TA and necroptosis of testicular cells in the model rats were examined and investigated, which included the aging phenotype, total testicular weight, testicular index, histopathological features of testis, number of spermatogenic cells, sex hormone level, expression characteristics of reactive oxygen species(ROS) in testis, expression levels and characteristics of cyclins in testis, and protein expression levels of the key molecules in receptor-interacting serine/threonine-protein kinase 1(RIPK1)/receptor-interacting serine/threonine-protein kinase 3(RIPK3)/mixed lineage kinase domain like pseudokinase(MLKL) signaling pathway in each group. The results showed that, for the TA model rats, both DHZCP and VE improved their aging phenotype, total testicular weight, testicular index, pathological features of testis, number of spermatogenic cells, serum testosterone and follicle stimulating hormone levels, expression characteristics of ROS and protein expression levels and characteristics of P21 and P53 in testis. In addition, DHZCP and VE improved the protein expression levels of the key molecules in RIPK1/RIPK3/MLKL signaling pathway in testis of the model rats. Specifically, DHZCP was better than VE in the improvement of RIPK3. In conclusion, in this study, the authors found that DHZCP, similar to VE, ameliorated D-gal-induced TA in model rats in vivo, and its mechanism was related to reducing necroptosis of testicular cells by inhibiting the activation of RIPK1/RIPK3/MLKL signaling pathway. This study provided preliminary pharmacological evidence for the development and application of classical prescriptions in the field of men's health.

[Effects and mechanisms of Supplemented Gegen Qinlian Decoction Formula against podocyte pyroptosis and insulin resistance in model rats with diabetic kidney disease].

This study explored the in vivo effects and mechanisms of the modern classical prescription Supplemented Gegen Qinlian Decoction Formula(SGDF) against diabetic kidney disease(DKD). Sixty rats were randomly divided into the normal group, model group, SGDF group, and rosiglitazone(ROS) group. The modified DKD rat model was established by employing the following three methods: exposure to high-fat diet, unilateral nephrectomy, and intraperitoneal injection of streptozotocin(STZ). After modeling, rats in the four groups were treated with double distilled water, SGDF suspension, and ROS suspension, respectively, by gavage every day. At the end of the 6 th week of drug administration, all the rats were sacrificed for collecting urine, blood, and kidney tissue, followed by the examination of rat general conditions, urine and blood biochemical indicators, glomerulosclerosis-related indicators, podocyte pyroptosis markers, insulin resistance(IR)-related indicators, and key molecules in the insulin receptor substrate(IRS) 1/phosphatidylinositol-3-kinase(PI3 K)/serine threonine kinase(Akt) signaling pathway. The results showed that SGDF and ROS improved the general conditions, some renal function indicators and glomerulosclerosis of DKD model rats without affecting the blood glucose(BG). Besides, they ameliorated the expression characteristics and levels of podocyte pyroptosis markers, alleviated IR, and up-regulated the protein expression levels of the key molecules in IRS1/PI3 K/Akt pathway to varying degrees. In conclusion, similar to ROS, SGDF relieves DKD by targeting multiple targets in vivo. Specifically, it exerts the therapeutic effects by alleviating podocyte pyroptosis and IR. This study has preliminarily provided the pharmacological evidence for the research and development of new drugs for the treatment of DKD based on SGDF.

[Multi-targeted therapeutic effects of Huangkui Capsules on insulin resistance and urine microalbumin in early diabetic kidney disease patients].

To observe the multi-targeted therapeutic effects of Huangkui Capsules(HKC)on insulin resistance(IR)and urine microalbumin in the early diabetic kidney disease(DKD)patients. The case data from the 83 DKD patients at G2 and A2 stage were collected respectively and analyzed retrospectively. According to the different treatment,all patients were divided into the control(A)group(40 cases)and the treated(B)group(43 cases). Among them,the A group patients were received "routine basic treatment";the B group patients were received "routine basic treatment+HKC". For the 2 group patients,firstly,the baseline parameters before receiving the treatment were compared respectively,and then,the changes of the total scores of traditional Chinese medicine(TCM) syndromes and the indicators of IR,urine protein,renal function,blood lipids and safety after receiving the treatment for 8 weeks were compared,respectively. Furthermore,for the all patients,the correlation analysis between IR and urine protein or IR and the total scores of TCM syndromes was carried out,respectively. The results showed that,for the B group patients received "routine basic treatment",their total scores of TCM syndromes,urine protein indicators including urine microalbumin(micro-UAlb) and urine microalbumin/urinary creatinine(UACR),IR indicators including fasting serum insulin(FIN)and homeostasis model assessment of insulin resistance(HOMA-IR)were significantly improved,respectively. For the all DKD patients,before and after the treatment,the main IR indicators(FIN and HOMA-IR)were positively correlated with urine protein indicators(micro-UAlb and UACR). The main IR indicators(FIN and HOMA-IR) were also positively correlated with the total scores of TCM syndromes. In addition,2 treatments had no significant effects on renal function,blood lipids and safety indicators in the all DKD patients. Overall, "routine basic treatment+HKC" can ameliorate IR and reduce urine microalbumin in the early DKD patients. Its therapeutic targets may be not only proteinuria,but also IR,which is the upstream risk factor of proteinuria.

[Exploring molecular mechanisms of fucoidan in improving human proximal renal tubular epithelial cells aging by targeting autophagy signaling pathways].

Fucoidan(FPS) is an effective component of the Chinese patent medicine named Haikun Shenxi, which treats schronic renal failure in clinics, and has the potential anti-aging effects. However, it is still unclear whether FPS can improve renal aging, especially the molecular mechanism of its anti-aging. The human proximal renal tubular epithelial cells(HK-2) in vitro were divided into normal group(N), D-gal model group(D), low dose of FPS group(L-FPS), high dose of FPS group(H-FPS) and vitamin E group(VE), and treated by the different measures, respectively. More specifically, the HK-2 cells in each group were separately treated by 1 mL of 1% fetal bovine serum(FBS) or D-galactose(D-gal, 75 mmol·L~(-1)) or D-gal(75 mmol·L~(-1))+FPS(25 µg·mL~(-1)) or D-gal(75 mmol·L~(-1))+FPS(50 µg·mL~(-1)) or D-gal(75 mmol·L~(-1))+VE(50 µg·mL~(-1)). After the treatment for 24 h, firstly, the effects of D-gal on senescence-associated ß-galactosidase(SA-ß-gal) staining characteristics and klotho, P53 and P21 protein expression le-vels, as well as adenosine monophosphate activated protein kinase(AMPK)-uncoordinated 51-like kinase 1(ULK1) signaling pathway activation in the HK-2 cells were detected, respectively. Secondly, the effects of FPS and VE on SA-ß-gal staining characteristics and klotho, P53 and P21 protein expression levels in the HK-2 cells exposed to D-gal were investigated, respectively. Finally, the effects of FPS and VE on microtubule-associated protein 1 light chain 3(LC3) protein expression level and AMPK-ULK1 signaling pathway activation in the HK-2 cells exposed to D-gal were examined severally. The results indicated that, for the HK-2 cells, the dose of 75 mmol·L~(-1) D-gal could induce the changes of SA-ß-gal staining characteristics and klotho, P53 and P21 protein expression levels. That is causing cells aging. FPS and VE could both ameliorate the changes of SA-ß-gal staining characteristics and klotho, P53 and P21 protein expression levels in the HK-2 cells exposed to D-gal. That is anti-cells aging, here, the functions of FPS and VE are similar. D-gal could not only induce cell aging but also increase LC3Ⅱ, phosphorylated-AMPK(p-AMPK) and phosphorylated-ULK1(p-ULK1) protein expressions, and activate autophagy-related AMPK-ULK1 signaling pathway. FPS and VE could both improve the changes of LC3Ⅱ, p-AMPK and p-ULK1 protein expression levels in the HK-2 cells exposed to D-gal. That is inhibiting autophagy-related AMPK-ULK1 signaling pathway activation. On the whole, for the human proximal renal tubular epithelial cells aging models induced by D-gal, FPS similar to VE, can ameliorate renal cells aging by possibly inhibiting autophagy-related AMPK-ULK1 signaling pathway activation. This finding provides the preliminary pharmacologic evidences for FPS protecting against renal aging.

Corrigendum: Fucoidan ameliorates renal injury-related calcium-phosphorus metabolic disorder and bone abnormality in the CKD-MBD model rats by targeting FGF23-Klotho signaling axis.

[This corrects the article DOI: 10.3389/fphar.2020.586725.].

Inhibition of ferroptosis of renal tubular cells with total flavones of Abelmoschus manihot alleviates diabetic tubulopathy.

Ferroptosis-related renal tubular lesions play important roles in diabetic kidney disease (DKD) progression, and these pathophysiological responses are collectively described as diabetic tubulopathy (DT), which lacks an effective treatment. Total flavones from Abelmoschus manihot (TFA), a natural extract that extensively used in patients with chronic kidney disease, has been used for treatment of renal tubular injury in DKD; however, whether TFA alleviates DT and its potential mechanisms remain unclear. Hence, we investigated the effects of TFA, compared to dapagliflozin, in DT management both in vivo and in vitro, using a DKD rat model and the NRK-52 E cells. Following modeling, the DKD rats received TFA, dapagliflozin, or vehicle for 6 weeks. For the in vitro research, the NRK-52 E cells were exposed to advanced glycation end products (AGEs) plus ferrostatin-1 (Fer-1), dapagliflozin, or TFA. Changes in biochemical parameters and renal tubular injury were analyzed in vivo, while changes in ferroptosis of renal tubular cells and the ferroptosis-related proteins expression were analyzed both in vivo and in vitro. We found that TFA and dapagliflozin improved biochemical parameters, renal tubular injury, and ferroptosis in the DKD rats. Moreover, TFA and dapagliflozin inhibited ferroptosis by ameliorating iron deposition, lipid peroxidation capacity, and ferroptosis-related proteins expression in vitro, which was similar to the effects of Fer-1. Collectively, this study demonstrated that TFA treated DT in a manner similar to dapagliflozin by inhibiting ferroptosis of renal tubular cells via improving iron deposition and antioxidant capacity. Our findings provide new pharmacological evidence for TFA application in DT treatment.

Combined detection of urinary biomarkers noninvasively predicts extent of renal injury in patients with early diabetic kidney disease with kidney qi deficiency syndrome: A retrospective investigation.

Incipient diagnosis and noninvasive forecasts using urinary biomarkers are important for preventing diabetic kidney disease (DKD) progression, but they are also controversial. Previous studies have shown a potential relationship between urinary tubular biomarkers (UTBs) and traditional Chinese medicine (TCM) syndrome in patients with DKD. Thus, we further evaluated the clinical significance of combined detection of urinary biomarkers in noninvasively predicting the extent of renal damage in patients with early DKD with kidney qi deficiency syndrome, and preliminarily explored the potential biological link between UTBs and TCM syndrome in DKD. We categorized 92 patients with Type 2 diabetes mellitus into three groups as follows: 20 patients with normoalbuminuria, 50 patients with microalbuminuria, and 22 patients with macroalbuminuria. We found that, in all groups, 24 hr urinary albumin (24hUAlb) and urinary albumin-to-creatinine ratio (UACR) showed stepwise and significant increases. Urinary cystatin C (UCysC), urinary N-acetyl-ß-d-glucosaminidase (UNAG), and urinary retinol-binding protein (URBP) synchronously increased gradually, consistent with the degree of albuminuria in all groups. Moreover, 24hUAlb and UACR were positively correlated with UCysC, UNAG, and URBP, respectively. In 72 patients with Type 2 DKD with albuminuria, a positive correlation was observed between UNAG and URBP, UCysC was also positively correlated with UNAG and URBP, respectively. Additionally, TCM syndrome distributional characteristics in all patients were consistent with clinical manifestations of kidney qi deficiency syndrome. Therefore, the combined detection of UCysC, UNAG, URBP, and UAlb may be used as a practical clinical technique to noninvasively forecast the extent of renal injury in patients with early Type 2 DKD with kidney qi deficiency syndrome. UTBs may be one of the biological bases of the specific TCM syndromes in DKD.

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.

Inhibition of Renal Tubular Epithelial Mesenchymal Transition and Endoplasmic Reticulum Stress-Induced Apoptosis with Shenkang Injection Attenuates Diabetic Tubulopathy.

Background: The proximal renal tubule plays a critical role in diabetic kidney disease (DKD) progression. Early glomerular disease in DKD triggers a cascade of injuries resulting in renal tubulointerstitial disease. These pathophysiological responses are collectively described as diabetic tubulopathy (DT). Thus, therapeutic strategies targeting DT hold significant promise for early DKD treatment. Shenkang injection (SKI) has been widely used to treat renal tubulointerstitial fibrosis in patients with chronic kidney disease in China. However, it is still unknown whether SKI can alleviate DT. We designed a series of experiments to investigate the beneficial effects of SKI in DT and the mechanisms that are responsible for its effect on epithelial-to-mesenchymal transition (EMT) and endoplasmic reticulum (ER) stress-induced apoptosis in DT. Methods: The modified DKD rat models were induced by uni-nephrectomy, streptozotocin intraperitoneal injection, and a high-fat diet. Following the induction of renal injury, these animals received either SKI, rosiglitazone (ROS), or vehicle, for 42 days. For in vitro research, we exposed NRK-52E cells to high glucose (HG) and 4-phenylbutyric acid (4-PBA) with or without SKI or ROS. Changes in parameters related to renal tubular injury and EMT were analyzed in vivo. Changes in the proportion of apoptotic renal tubular cells and ER stress, and the signaling pathways involved in these changes, were analyzed both in vivo and in vitro. Results: SKI and ROS improved the general condition, the renal morphological appearance and the key biochemical parameters, and attenuated renal injury and EMT in the rat model of DKD. In addition, SKI and ROS alleviated apoptosis, inhibited ER stress, and suppressed PERK-eIF2α-ATF4-CHOP signaling pathway activation both in vivo and in vitro. Notably, our data showed that the regulatory in vitro effects of SKI on PERK-eIF2α-ATF4-CHOP signaling were similar to those of 4-PBA, a specific inhibitor of ER stress. Conclusion: This study confirmed that SKI can alleviate DT in a similar manner as ROS, and SKI achieves this effect by inhibiting EMT and ER stress-induced apoptosis. Our findings thereby provide novel information relating to the clinical value of SKI in the treatment of DT.

Total Flavones of Abelmoschus manihot Remodels Gut Microbiota and Inhibits Microinflammation in Chronic Renal Failure Progression by Targeting Autophagy-Mediated Macrophage Polarization.

BACKGROUND: Recently, progression of chronic renal failure (CRF) has been closely associated with gut microbiota dysbiosis and intestinal metabolite-derived microinflammation. In China, total flavones of Abelmoschus manihot (TFA), a component of Abelmoschus manihot, has been widely used to delay CRF progression in clinics for the past two decades. However, the overall therapeutic mechanisms remain obscure. In this study, we designed experiments to investigate the renoprotective effects of TFA in CRF progression and its underlying mechanisms involved in gut microbiota and microinflammation, compared with febuxostat (FEB), a potent non-purine selective inhibitor of xanthine oxidase. METHODS: In vivo, the CRF rat models were induced by uninephrectomy, potassium oxonate, and proinflammatory diet, and received either TFA suspension, FEB, or vehicle after modeling for 28 days. In vitro, the RAW 264.7 cells were exposed to lipopolysaccharide (LPS) with or without TFA or FEB. Changes in parameters related to renal injury, gut microbiota dysbiosis, gut-derived metabolites, and microinflammation were analyzed in vivo. Changes in macrophage polarization and autophagy and its related signaling were analyzed both in vivo and in vitro. RESULTS: For the modified CRF model rats, the administration of TFA and FEB improved renal injury, including renal dysfunction and renal tubulointerstitial lesions; remodeled gut microbiota dysbiosis, including decreased Bacteroidales and Lactobacillales and increased Erysipelotrichales; regulated gut-derived metabolites, including d-amino acid oxidase, serine racemase, d-serine, and l-serine; inhibited microinflammation, including interleukin 1ß (IL1ß), tumor necrosis factor-α, and nuclear factor-κB; and modulated macrophage polarization, including markers of M1/M2 macrophages. More importantly, TFA and FEB reversed the expression of beclin1 (BECN1) and phosphorylation of p62 protein and light chain 3 (LC3) conversion in the kidneys by activating the adenosine monophosphate-activated protein kinase-sirtuin 1 (AMPK-SIRT1) signaling. Further, TFA and FEB have similar effects on macrophage polarization and autophagy and its related signaling in vitro. CONCLUSION: In this study, we demonstrated that TFA, similar to FEB, exerts its renoprotective effects partially by therapeutically remodeling gut microbiota dysbiosis and inhibiting intestinal metabolite-derived microinflammation. This is achieved by adjusting autophagy-mediated macrophage polarization through AMPK-SIRT1 signaling. These findings provide more accurate information on the role of TFA in delaying CRF progression.

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.

Predictors of short-term outcomes related to central subfield foveal thickness after intravitreal bevacizumab for macular edema due to central retinal vein occlusion.

AIM: To investigate the predictive factors for short-term effects of intravitreal bevacizumab injections on central subfield foveal thickness (CSFT) in patients with macular edema (ME) secondary to central retinal vein occlusion (CRVO). METHODS: This was a retrospective study in 60 eyes treated with intravitreal bevacizumab injections for ME due to CRVO. Follow-up was three months. The Early Treatment Diabetic Retinopathy Study (ETDRS) score and CSFT measured by spectral-domain optical coherence tomography (SD-OCT) were used to observe the changes in best-corrected visual acuity (BCVA). Baseline BCVA, CSFT, age, CRVO duration and the presence of cystoid macular edema (CME) or subretinal fluid (SRF) were analyzed as potential predictive factors of the effects of intravitreal bevacizumab injections. RESULTS: BCVA improved from 0.9 logMAR at baseline to 0.6 logMAR at 3mo, which was associated with a significant reduction in CSFT from 721 µm to 392 µm 3mo after injection. About 50% of CME cases and more than 90% of SRF cases responded to treatment with a complete resolution at 3mo. Age (P=0.036) and low baseline CSFT (P=0.037) were associated with a good 3-month prognosis. Patients >60 years old achieved better CME resolution (P=0.031) and lower CSFT at 3mo (305 µm vs 474 µm, P=0.003). CONCLUSION: Intravitreal bevacizumab significantly improved visual acuity and CSFT in patients with CRVO after 3mo. Older age and lower baseline CSFT were good predictors of short-term CSFT outcomes. The retinal thickness response to bevacizumab might depend on the resolution of CME rather than SRF.