[Effect of renal function on sarcopenia in elderly male patients with chronic kidney disease]

Objective: To evaluate the effect of renal function on sarcopenia in elderly male patients with chronic kidney disease (CKD). Methods: A total of 105 male CKD patients aged ≥65 years who were admitted to the Chinese PLA General Hospital between October 1, 2018 and January 30, 2019 were included in this study. Using two different equations to estimate glomerular filtration rate (GFR), respectively. According to the sarcopenia criteria, the participants were categorized as the non-sarcopenia group (n=72) and the sarcopenia group (n=33), respectively. The association of estimated GFR (eGFR) and the sarcopenia in the male CKD patients was analyzed using the model of multivariate logistic regression. Results: Among the 105 patients, the median age was 74 (68, 77) years old. The prevalence of sarcopenia was 31.4% (33/105). According to the multivariate logistic regression analysis, eGFR based on serum creatinine and Cys-C (eGFRscr-cys) lower than 45 ml·min(-1)·(1.73 m(2))(-1) (OR=4.17, 95%CI:1.08-16.02, P=0.038) and eGFR based on Cys-C (eGFRcys) lower than 45 ml·min(-1)·(1.73 m(2))(-1) (OR=3.99, 95%CI:1.08-14.75, P=0.038) were independent risk factors for underlying sarcopenic, respectively. The area under the receiver operating characteristics curve (AUC) revealed that eGFRscr-cys (AUC=0.67) was more suitable than eGFRcys (AUC=0.64) to predict the sarcopenia in elderly male patients with CKD. Conclusion: The increased incidence of sarcopenia in elderly men with CKD is accompanied with deterioration of renal function.

[Clinical analysis of kidney injury in patients with COVID-19]

Objective: To investigate the relationship between novel coronavirus pneumonia (COVID-19) and kidney injury. Methods: A retrospective analysis was performed on confirmed COVID-19 patients in the Central Theater Command General Hospital of Chinese PLA on March 12, 2020. A total of 87 hospitalized confirmed COVID-19 patients were enrolled in the study, and they were hospitalized for at least one week. The recorded information included clinical data and indicators of kidney-related laboratory tests. Results: The average age of patients was (65.2±17.1) years, and 34.5% (30/87) patients were ≥ 75 years old and 31.0% (27/87) patients were 60-74 years old. Male and female patients accounted for 59.8% (52/87) and 40.2% (35/87), respectively. There were 29.9% (26/87) and 12.6% (11/87) patients who had already showed mild elevation of blood urea nitrogen (BUN) and serum creatinine (SCr) at admission. Moreover, 25.3% (22/87) and 4.6% (4/87) patients still exhibited mild elevation of BUN and SCr one week after admission. However, 28.7% (25/87) patients showed an elevation of BUN one week later after admission, though their BUN levels were normal at admission. Likewise, 16.1% (14/87) patients showed an elevation of SCr one week later after admission, while their SCr levels were normal at admission. Only two patients had an increase of SCr ≥26.5 μmol/L, and both of them were over 75 years old. Conclusions: COVID-19 patients with severe acute kidney injury are uncommon. However, attention should be paid to acute kidney injury of the elderly patients in the diagnosis and treatment of COVID-19.

[Related factors of frailty in the elderly male patients with chronic kidney disease]

Objective: To investigate the characteristics of frailty in the elderly male patients with chronic kidney disease (CKD) and the effects of renal function on the incidence of frailty. Methods: A total of 105 non-dialysis CKD patients aged ≥65 years who were admitted to the Chinese PLA General Hospital between October 1, 2018 and January 30, 2019 were included in this study. Their clinical data and laboratory indicators were collected. Frailty was defined according to Fried frailty criteria. According to the frailty scores, the participants were categorized as non-frail (n=37), intermediately frail (n=37) and frail (n=31). The association of frailty and the level of estimated glomerular filtration rate (eGFR) in the patients was analyzed using the model of multivariate Logistic regression. Results: Among the 105 patients, the mean age was 74 (68, 77) years old. The incidence of frail and intermediate frail was 35.2% (37/105) and 29.5% (31/105), respectively. Multivariate logistic analysis showed statistically significant associations of frailty with age (OR=1.14, 95%CI:1.08-1.20, P<0.001), body mass index (OR=0.87, 95%CI:0.79-0.95, P=0.001) and the level of eGFR (OR=0.98, 95%CI:0.96-0.99, P=0.003) in those patients. The incidence of frail in patients with eGFR<45 ml·min(-1)·(1.73 m(2))(-1) and 45-59 ml·min(-1)·(1.73 m(2))(-1) was 1.02 (OR=2.02, 95%CI: 1.06~3.87) and 0.84 (OR=1.84, 95%CI: 1.05-3.22) times higher than that of eGFR≥60 ml·min(-1)·(1.73 m(2))(-1), respectively. Conclusion: The incidence of frailty in the elderly patients with CKD is affected by many factors, such as age, body mass index and renal function, and increases with decreased renal function.

[High glucose reduced the repair function of kidney stem cells conditional medium to the hypoxia-injured renal tubular epithelium cells]

OBJECTIVE

To evaluate the impacts of high glucose on the repair function of kidney stem cells (KSC) conditional medium to the hypoxia-injured renal tubular epithelium cells (RTEC).

METHODS

KSC were isolated from the renal papilla in 4-week-Sprague-Dawley rats. The KSC were pretreated in media with high glucose (30 mmol/L) or with normal glucose (5.6 mmol/L), respectively. The supernatants of the pre-treated KSC were collected as the conditional media. The hypoxia/reoxygenation (H/R) model of rat RTEC was established using the NRK-52E cell line. The effects of KSC conditional media on the H/R RTEC were investigated.

RESULTS

(1) The best H/R model of RTEC was established using hypoxia for 4 h and reoxygenation 2 h. (2) After hypoxia, the early and late cell apoptosis rates of the H/R RTEC were increased. The H/R RTEC were co-cultured with KSC conditional media for 12 h and 24 h, respectively. The H/R RTEC were co-cultured with DMEM/F12 as a control group. The cell apoptosis rate of H/R RTEC was lower after co-cultured with KSC conditional media (P<0.01), and the cell apoptosis rate of H/R RTEC in high glucose group was much higher than that in normal glucose group after co-cultured 24 h (P=0.02). (3) After hypoxia, the lactic dehydrogenase (LDH) and malondialdehyde (MDA) levels of the H/R RTEC supernatant were increased, and the superoxide dismutase (SOD) level decreased. The LDH and MDA levels were lower and the SOD level was higher after co-cultured with KSC conditional media for 12 h and 24 h, respectively (P<0.01). The LDH and MDA levels of H/R RTEC supernatant were much higher in the high glucose group than in the normal glucose group (P<0.05), and the SOD level of H/R RTEC supernatant was much lower in the high glucose group than in the normal glucose group (P<0.01).

CONCLUSION

KSC conditional media could repair the H/R injury of RTEC. The effects were mainly by inhibiting cell apoptosis, and reducing oxidative stress; the anti-cell apoptosis ability and the anti-oxidative stress capacity of the conditional medium were reduced after KSC were pre-treated with high glucose.

[Expression of citrate transporter mRNA in the kidneys of rats with metabolic acidosis]

The purpose of the present study was to examine whether metabolic acidosis affects the expression of rat renal Na(+)/citrate cotransporter. Female Wistar rats were pair-fed with normal rat chow and drinking water (control) or water with 0.28 mol/L NH4Cl (metabolic acidosis). The mRNA of two renal Na(+)/citrate cotransporters, which were respectively expressed on apical and basolateral membrane, were measured by Northern blot with two probes, SDCT1 and SDCT2. Animals were sacrificed on day 1,3 and 7. On the 1st day, the blood plasma HCO(-)3 of acidosis group decreased significantly (P<0.01), but the mRNA abundance did not change. On the 3rd day in the acidosis group, the blood plasma HCO(-)3 increased slightly more than that on the 1st day, but was still significantly lower than that of the control group (P<0.01). Both the probes detected some increase in mRNA of brush border and basolateral Na(+)/citrate cotransporter. On the 7th day, the blood plasma HCO(-)3 of the acidosis group continuously increased and there was no significant difference between the two groups. The abundance of brush border and basolateral Na(+)/citrate cotransporter mRNA increased, but there was no difference between those of the 3rd day and the 7th day. It is concluded that metabolic acidosis can induce increase of Na(+)/citrate cotransporter mRNA, which may be responsible for hypocitraturia.

Effects of ICAM-1 antisense oligonucleotide on the tubulointerstitium in mice with unilateral ureteral obstruction

Effects of ICAM-1 antisense oligonucleotide on the renal tubulointerstitium in mice with unilateral ureteral obstruction.

BACKGROUND

To extend our previous study of the therapy of the renal lesions of unilateral ureteral obstruction (UUO) in mice by an inhibitor of intercellular adhesion molecule-1 (ICAM-1), we investigated the blocking effects of ICAM-1 antisense oligonucleotides (ASONs) on the ICAM-1 expression in mouse kidney.

METHODS

First, ICAM-1 ASON was transducted into mouse renal tubular epithelial cells to investigate the effects of ICAM-1 ASON in vitro. Second, fluorescein isothiocyanate (FITC)-labeled ICAM-1 ASON was injected intravenously to determine the distribution of the ASON in vivo. Third, the expression of ICAM-1 in kidney and the changes of renal morphology were observed to investigate the therapeutic effects of ICAM-1 ASON on the UUO mice in vivo.

RESULTS

The expressions of ICAM-1 in the epithelial cells induced by interleukin-1beta were inhibited by ICAM-1 ASON at the dosages of 100 and 200 nmol/L. Twenty-four hours after an introvenous injection with FITC-labeled ICAM-1 ASON, the highest level of fluorescein was detected within the proximal tubules in mouse kidney. Results of immunohistology and Northern blot showed that the ICAM-1 expression was markedly reduced in the obstructed kidney after treatment with ICAM-1 ASON. The ASON also alleviated the infiltration of inflammatory cells and accumulation of the extracellular matrix in the tubulointerstitium of UUO mice without apparent side effects.

CONCLUSION

Our data demonstrate that ICAM-1 ASON is taken up primarily by the proximal tubular cells of mouse kidney. ICAM-1 ASON can selectively inhibit the ICAM-1 expression of the renal tubular cells both in vitro and in vivo.

Characterization of the receptor binding determinants of granulocyte colony stimulating factor

We performed a series of experiments using alanine-scanning mutagenesis to locate side chains within human granulocyte colony-stimulating factor (G-CSF) that are involved in human G-CSF receptor binding. We constructed a panel of 28 alanine mutants that examined all surface exposed residues on helices A and D, as well as all charged residues on the surface of G-CSF. The G-CSF mutants were expressed in a transiently transfected mammalian cell line and quantitated by a sensitive biosensor method. We measured the activity of mutant proteins using an in vitro proliferation assay and an ELISA binding competition assay. These studies show that there is a region of five charged residues on helices A and C employed by G-CSF in binding its receptor, with the most important residue in this binding patch being Glu 19. Both wild-type G-CSF and the E19A mutant were expressed in E. coli. The re-folded proteins were found to have proliferative activities similar to the analogous proteins from mammalian cells: furthermore, biophysical analysis indicated that the E19A mutation does not cause gross structural perturbations in G-CSF. Although G-CSF is likely to signal through receptor homo-dimerization, we found no compelling evidence for a second receptor binding region. We also found no evidence of self-antagonism at high G-CSF concentrations, suggesting that, in contrast to human growth hormone (hGH) and erythropoietin (EPO), G-CSF probably does not signal via a pure 2:1 receptor ligand complex. Thus, G-CSF, while having a similar tertiary structure to hGH and EPO, uses different areas of the four helix bundle for high-affinity interaction with its receptor.

Progressive renal lesions induced by administration of monoclonal antibody 1-22-3 to unilaterally nephrectomized rats

A new animal model of progressive glomerulosclerosis was developed by administering a single i.v., injection of MoAb 1-22-3 to unilaterally nephrectomized rats. Renal morphological analysis revealed that glomerular lesions characterized by mesangial cell proliferation and mesangial matrix expansion were induced in about 95% of the glomeruli. Approximately 20% of the glomeruli of the unilaterally nephrectomized rats showed sclerosis or segmental sclerosis by week 6 after MoAb injection and crescent formation was observed in some glomeruli (ca 4%). Cellular infiltration was also noted in some parts of the interstitium. Increased expression of transforming growth factor-beta (TGF-beta) was observed in the unilaterally nephrectomized rats treated with MoAb 1-22-3, but we could not demonstrate pathological involvement of platelet-derived growth factor (PDGF), even though early-stage mesangial cell proliferation was observed. The mechanism of mesangial cell proliferation in this model remains to be elucidated. The relatively short period of time needed to induce the sclerotic changes in considered to be a great advantage of this model for clarifying the mechanisms involved in the chronic progression of mesangial proliferative glomerulonephritis.

[Effects of Epimedium sagittatum on immunopathology and extracellular matrices in rats with chronic renal insufficiency]

Chinese herb medicine, Epimedium sagittatum (EP), was used to treat animal models of chronic renal insufficiency induced in Wistar rats with 7/8 nephrectomy. The results showed: 1. EP decreased significantly the level of BUN and serum creatinine in the rats. 2. EP inhibited the hypertrophy of glomeruli in the rats. 3. EP inhibited deposition of IgG, C3, Fib and FN along the glomerular capillary walls in these rats.

[Treatment of rapid progressive glomerulonephritis (RPGN) with pulse methylprednisolone (MP) and urokinase (UK): a renal rebiopsy study]

We have performed a case controlled study on the morphological and immunopathological alterations which can be induced by pulse MP combined with UK in RPGN by means of before and post therapy renal biopsies. The results showed renal function and histologic patterns improved. The histopathological (endothelium and mesangial cell proliferation, crescent and interstitial infiltration) and immunopathological (deposition of IgG, C3, Collegen type III, IV, Laminin and FN.) changes improved in all the patients after treatment with pulse MP and UK. The results indicated that pulse MP and UK therapy seems to be useful in treatment of RPGN in early stage and renal rebiopsy could lead to a better understanding of RPGN outcome.

In vivo import of firefly luciferase into the glycosomes of Trypanosoma brucei and mutational analysis of the C-terminal targeting signal

The compartmentalization of glycolytic enzymes into specialized organelles, the glycosomes, allows the bloodstream form of Trypanosoma brucei to rely solely on glycolysis for its energy production. The biogenesis of glycosomes in these parasites has been studied intensively as a potential target for chemotherapy. We have adapted the recently developed methods for stable transformation of T. brucei to the in vivo analysis of glycosomal protein import. Firefly luciferase, a peroxisomal protein in the lantern of the insect, was expressed in stable transformants of the procyclic form of T. brucei, where it was found to accumulate inside the glycosomes. Mutational analysis of the peroxisomal targeting signal serine-lysine-leucine (SKL) located at the C-terminus of luciferase showed that replacement of the serine residue (Serine548) with a small neutral amino acid (A, C, G, H, N, P, T) still resulted in an import efficiency of 50-100% of the wild-type luciferase. Lysine549 could be substituted with an amino acid capable of hydrogen bonding (H, M, N, Q, R, S), whereas the C-terminal leucine550 could be replaced with a subset of hydrophobic amino acids (I, M, Y). Thus, a peroxisome-like C-terminal SKL-dependent targeting mechanism may function in T. brucei to import luciferase into the glycosomes. However, a few significant differences exist between the glycosomal targeting signals identified here and the tripeptide sequences that direct proteins to mammalian or yeast peroxisomes.

Mouse ornithine decarboxylase is stable in Trypanosoma brucei

The cDNA encoding mouse ornithine decarboxylase (ODC) was incorporated into a transforming vector pTSA-NEO2 carrying a procyclic acidic repetitive protein promoter and a neomycin phosphotransferase gene. The plasmid thus constructed, pMOD300, was introduced into the procyclic forms of Trypanosoma brucei via electroporation, and the transformants, selected under G418, expressed an ODC activity 100 times above the background level. Contrary to the commonly observed short half-life of mouse ODC in mammalian cells, however, the mouse ODC activity expressed in T. brucei remained stable for at least 6 h when protein synthesis was inhibited by cycloheximide. Pulse labelings and chase experiments with the irreversible ODC inhibitor [3,4-3H]difluoromethylornithine followed by gel electrophoresis, or with L-[35S] methionine followed by immunoprecipitation and gel electrophoresis indicated that the stable mouse ODC expressed in T. brucei has the same subunit molecular weight as the native enzyme. By an in vitro assay of protein stability in rabbit reticulocyte lysates (Loetscher, P., Pratt, G., and Rechsteiner, M. (1991) J. Biol. Chem. 266, 11213-11220), the native mouse ODC and the enzyme expressed in T. brucei had the same degree of instability. Thus, the mouse ODC expressed in T. brucei is probably identical to the native mouse ODC. Its remarkable stability in T. brucei must be due to the absence in trypanosomes of the proteolytic machinery present in mammalian cells responsible for rapid degradation of mouse ODC.

[Effect of serum from IgA nephropathy patients on IL-1 production from P388 D1 cell lines]

The study was designed to investigate IL-1 production from P388D1 cell using serum from 40 cases with IgA nephropathy (IgAN) as stimulative factor. It was found that there was a relationship between IL-1 and renal morphological change. The result indicated that IL-1 production by P388D1 cell was much higher in the presence of the serum than that in the absence (CPM: 47597 +/- 26213 vs 36567 +/- 14377 P less than 0.05). The level of IL-1 correlated obviously to the renal morphologic changes (r = 0.406, P less than 0.05). It is suggested that in the serum of IgAN patients there are certain factors stimulating P388D1 cell to produce IL-1, which may contribute to the pathogenesis of IgAN.

[Analysis of lymphocyte subpopulation in chronic dialyzed end stage renal failure by flow cytometry]

To investigate the change of immune function in patients with ESRF, peripheral blood lymphocytes of 15 maintenance hemodialysis patients were analyzed using FITC labelled monoclonal antibodies and laser flow cytometry (FACS 440). Lymphocytes of phenotype CD 3 (Pan T cell), CD 4 (helper/inducer), CD 8 (suppressor/cytotoxic), CD 16 (NK cell), CD 25 (IL-2 Receptor) and HLA-DR were enumerated. The results were summarized as follows: (1) CD 3, CD 8 and CD 16 were decreased markedly in ESRF patients. (2) CD 4 and CD 25 showed a tendency of decrement also yet statistically insignificant, (3) Value for HLA-DR was higher than normal, probably related with the hemodialysis. (4) CD 4, CD 8 and CD 4/CD 8 in a transfused group were not different from those in a non-transfused group. (5) CD 4/CD 8 was negatively correlated with the serum creatinine level (r = -0.524). In conclusion, there is a marked suppression of immune function in ESRF patients as evidenced from the change of T cell subpopulation.

ECG waveform analysis by significant point extraction. I. Data reduction

We present a new technique for automatic data reduction and pattern recognition of time-domain signals such as electrocardiogram (ECG) waveforms. Data reduction is important because only a few significant features of each heart beat are of interest in pattern analysis, while the patient data collection system acquires an enormous number of data samples. We present a significant point extraction algorithm, based on the analysis of curvature, that identifies data samples that represent clinically significant information in the ECG waveform. Data reduction rates of up to 1:10 are possible without significantly distorting the appearance of the waveform. This method is unique in that common procedures help in both data reduction as well as pattern recognition. Part II of this work deals specifically with pattern analysis of normal and abnormal heart beats.

ECG waveform analysis by significant point extraction. II. Pattern matching

From a set of significant points which characterizes the ECG waveform, the pattern matching algorithm detects and classifies QRS complexes. R waves are detected from the analysis of global curvature. Next, the morphology of the QRS complex is determined. QRS complexes with different morphologies are classified by a correlation algorithm. This method is sensitive to changes in shape, such as that of abnormal QRS complexes. The algorithm should be useful in automated analysis of waveforms, such as ECG signals recorded in clinical environments.