Podocyte-targeted Heme Oxygenase (HO)-1 overexpression exacerbates age-related pathology in the rat kidney

Although Heme Oxygenase-1 (HO-1) induction in various forms of kidney injury is protective, its role in age-related renal pathology is unknown. In the ageing kidney there is nephron loss and lesions of focal glomerulosclerosis, interstitial fibrosis, tubular atrophy and arteriolosclerosis. Underlying mechanisms include podocyte (visceral glomerular epithelial cell/GEC) injury. To assess whether HO-1 can attenuate ageing - related lesions, rats with GEC-targeted HO-1 overexpression (GEC^HO-1 rats) were generated using a Sleeping Beauty (SB) transposon system and extent of lesions over a 12-month period were assessed and compared to those in age-matched wild-type (WT) controls. GEC^HO-1 rats older than 6 months developed albuminuria that was detectable at 6 months and became significantly higher compared to age-matched WT controls at 12 months. In GEC^HO-1 rats, lesions of focal segmental and global glomerulosclerosis as well as tubulointerstitial lesions were prominent while podocytes were edematous with areas of foot process effacement and glomerular basement membrane thickening and wrinkling. GEC^HO-1 rats also developed hemoglobinuria and hemosiderinuria associated with marked tubular hemosiderin deposition and HO-1 induction, while there was depletion of splenic iron stores. Kidney injury was of sufficient magnitude to increase serum lactate dehydrogenase (LDH) and was oxidative in nature as shown by increased expression of 8-hydroxydeoxyguanosine (8-OHdg, a byproduct of oxidative DNA damage) in podocytes and tubular epithelial cells. These observations highlight a detrimental effect of podocyte-targeted HO-1 overexpression on ageing-related renal pathology and point to increased renal iron deposition as a putative underlying mechanism.

Cilostazol Mediates Immune Responses and Affects Angiogenesis During the Acute Phase of Hind Limb Ischemia in a Mouse Model

BACKGROUND

Cilostazol is a drug of choice for the treatment of intermittent claudication that also affects innate and adaptive immune cells. The purpose of our study was the evaluation of cilostazol's impact on the immune and angiogenic response in murine models of hind limb ischemia.

METHODS

We used 108 immunodeficient NOD.CB17-Prkdcscid/J mice and 108 wild-type CB17 mice. At day 0 (D0), all animals underwent hind limb ischemia. Half of them in both groups received daily cilostazol starting at D0 and for the next 7 postoperative days, while the rest of them served as controls, receiving vehicle. Interleukin (IL) 2, IL-4, IL-6, IL-10, IL-17A, tumor necrosis factor α (TNF-α), and interferon γ (IFN-γ) serum concentrations were measured by flow cytometry on postsurgery days D1, D3, D5, and D7. On D7, both groups underwent positron emission tomography scan with ⁶⁸Ga-RGD. Mice were euthanatized and gastrocnemius muscles were obtained for histological evaluation.

RESULTS

There was a statistically significant augmentation (P < .05) in IL-4, IL-10, IL-6, and IFN-γ concentrations in treated CB17 animals, while IL-2 was significantly suppressed. Significant difference was detected between the CiBisch and Bisch groups on D1 and D7 (P < .05) in CD31 staining. In treated NOD.CB17 animals, TNF-α, IL-6, and IFN-γ presented significant augmentation, while ⁶⁸Ga-NODAGA-RGDfK uptake and CD31 expression were found significantly lower for both legs in comparison to the control.

CONCLUSION

Cilostazol seems to significantly increase angiogenesis in wild-type animals during the first postoperational week. It also influences immune cells, altering the type of immune response by promoting anti-inflammatory cytokine production in wild-type animals, while it helps toward inflammation regression in immunodeficient animals.

Effect of Heme Oxygenase-1 Deficiency on Glomerular Proteomics

BACKGROUND

The cytoprotective effect of heme oxygenase (HO)-1 in various forms of renal glomerular injury is established. However, little is known on the role of HO-1 in preserving glomerular structural/functional integrity in the absence of injury. The present study addressed this question in HO-1-deficient rats.

METHODS

HO-1-deficient rats were generated using zinc finger nuclease-mediated HO-1 gene (Hmox1) disruption and studied. Glomeruli were isolated from HO-1-deficient (Hmox1-/-) rats and their wild type (WT) littermates for proteomic analysis.

RESULTS

Glomerular lesions were characterized and differentially expressed proteins important for preserving integrity of the glomerular filtration barrier were identified. HO-1-deficient (Hmox1-/-) rats developed albuminuria with decreased glomerular filtration rate. In albuminuric rats, there were lesions resembling focal and segmental glomerulosclerosis (FSGS). Western blot analysis of the integral slit diaphragm proteins, nephrin and podocin revealed a significant decrease in nephrin, with no change in podocin. Proteomic analysis of glomerular protein lysates from Hmox1-/- and WT rats revealed differential expression of proteins previously linked with FSGS pathogenesis. Specifically, α-actinin-4, actin related protein 3, cytokeratins and novel candidates including transgelin-2 and lamins. Bioinformatic analysis predicted the upregulation of pathways implicated in platelet aggregation and fibrin clot formation.

CONCLUSION

HO-1 is a putative regulator of proteins important in preserving glomerular structural stability and integrity, and in minimizing the activity of proinflammatory pathways.

Primary Malignant Melanoma of Renal Pelvis with Extensive Clear Cell Change

Our presentation illustrates a rare case of primary renal pelvis malignant melanoma in a 35-year-old man. The diagnosis of malignant melanoma was based on immunophenotype and the detection of intracellular melanin pigment. The renal origin was proven by the presence of scattered melanocytes within the urothelium of the pelvis. The tumor exhibited extensive clear cell change that closely mimics clear cell renal cell carcinoma. The patient's clinical history did not disclose any signs of previous melanocytic skin or mucosa lesions. Differential diagnosis includes tumors capable of synthesizing melanin or expressing melanocytic markers.

Five tumor markers in lung cancer: significance of total and "lipid"-bound sialic acid

Total sialic acid (TSA) and "lipid-bound" sialic acid (LSA) were evaluated in comparison to carcinoembryonic antigen (CEA) and ferritin and neuron specific enolase (NSE) in 152 untreated patients with primary lung cancer, 107 benign pulmonary disease patients and 207 notmal controls. The mean concentrations of TSA, LSA and CEA in lung cancer patients, were significantly higher than in benign and normal controls (p less than 0.001), while the mean ferritin and NSE levels were significantly higher than in normal controls only (p less than 0.001). At the designated cut-off serum levels, sensitivities of the five markers for lung cancer were in decreasing order: TSA 86.5% (greater than 80 mg/dL), LSA 77% (greater than 20 mg/dL), CEA 46.4% (greater than 5 ng/mL), ferritin 36% (greater than 300 ng/mL) and NSE 34.5% (greater than 12.5 ng/mL). Using the benign pulmonary values as negative controls the specificity of each marker was as follows: CEA 88%, ferritin 72%, NSE 58%, TSA 44% and LSA 44%. In small cell lung cancer (SCLC) patients, NSE mean concentrations and sensitivity were significantly higher than in non-small lung cancer (NSCLC) patients (9.63 +/- 4.4 versus 23.54 +/- 16.9, p less than 0.001 and 74% versus 21.4% respectively). While in NSCLC patients only CEA levels correlated well with the stage of the disease, in SCLC patients concentrations of TSA, LSA and ferritin were significantly higher in extensive than in limited disease stages. These preliminary data suggest that, although TSA and LSA are highly sensitive markers in lung cancer, their specificity is low.

Total and lipid-bound sialic acid in the cerebrospinal fluid of patients with brain tumors

Total sialic acid (TSA) and lipid-bound sialic acid (LSA) were determined in the cerebrospinal fluid (CSF) from 63 patients with various neurological diseases. Of these, 27 had brain tumors: 20 had glioma, and 7 pituitary adenoma. TSA levels were significantly increased in the CSF of 18 of the 20 glioma patients (p less than 0.001), while in the adenoma patients were indistinguishable from the controls; with a 90 and 0% test sensitivity respectively. Conversely, the LSA concentrations were significantly elevated, both, in the glioma and pituitary adenoma patients (p less than 0.001), with a 68 and 100% test sensitivity respectively. These preliminary data suggest that measurement of TSA and LSA in the CSF should prove useful for the diagnosis of brain tumors and, perhaps, in the follow-up of patients undergoing treatment for brain tumors.