Renal iron overload in rats with diabetic nephropathy

Diabetic nephropathy (DN) remains incurable and is the main cause of end-stage renal disease. We approached the pathophysiology of DN with systems biology, and a comprehensive profile of renal transcripts was obtained with RNA-Seq in ZS (F1 hybrids of Zucker and spontaneously hypertensive heart failure) rats, a model of diabetic nephropathy. We included sham-operated lean control rats (LS), sham-operated diabetic (DS), and diabetic rats with induced renal ischemia (DI). Diabetic nephropathy in DI was accelerated by the single episode of renal ischemia. This progressive renal decline was associated with renal iron accumulation, although serum and urinary iron levels were far lower in DI than in LS. Furthermore, obese/diabetic ZS rats have severe dyslipidemia, a condition that has been linked to hepatic iron overload. Hence, we tested and found that the fatty acids oleic acid and palmitate stimulated iron accumulation in renal tubular cells in vitro. Renal mRNAs encoding several key proteins that promote iron accumulation were increased in DI. Moreover, renal mRNAs encoding the antioxidant proteins superoxide dismutase, catalase, and most of the glutathione synthetic system were suppressed, which would magnify the prooxidant effects of renal iron loads. Substantial renal iron loads occur in obese/diabetic rats. We propose that in diabetes, specific renal gene activation is partly responsible for iron accumulation. This state might be further aggravated by lipid-stimulated iron uptake. We suggest that progressive renal iron overload may further advance renal injury in obese/diabetic ZS rats.

Renal C3 complement component: feed forward to diabetic kidney disease

BACKGROUND

Diabetic nephropathy is the main cause of end-stage renal disease and has reached epidemic proportions.

METHODS

Comprehensive genomic profiling (RNAseq) was employed in the ZS (F1 hybrids of Zucker and spontaneously hypertensive heart failure) model of diabetic nephropathy. Controls were lean littermates.

RESULTS

Diabetic nephropathy in obese, diabetic ZS was accelerated by a single episode of renal ischemia (DI). This rapid renal decline was accompanied by the activation of the renal complement system in DI, and to a lesser extent in sham-operated diabetic rats (DS). In DI there were significant increases in renal mRNA encoding C3, C4, C5, C6, C8, and C9 over sham-operated lean normal controls (LS). Moreover, mRNAs encoding the receptors for the anaphylatoxins C3a and C5a were also significantly increased in DI compared to LS. The classic complement pathway was activated in diabetic kidneys with significant increases of C1qa, C1qb, and C1qc mRNAs in DI over LS. In addition, critical regulators of complement activation were significantly attenuated in DI and DS. These included mRNAs encoding CD55, decay accelerating factor, and CD59, which inhibit the membrane attack complex. C3, C4, and C9 proteins were demonstrated in renal tubules and glomeruli. The complement RNAseq data were incorporated into a gene network showing interactions among C3-generating renal tubular cells and other immune competent migratory cells.

CONCLUSIONS

We conclude that local activation of the complement system mediates renal injury in diabetic nephropathy.

Intravenous renal cell transplantation with SAA1-positive cells prevents the progression of chronic renal failure in rats with ischemic-diabetic nephropathy

Diabetic nephropathy, the most common cause of progressive chronic renal failure and end-stage renal disease, has now reached global proportions. The only means to rescue diabetic patients on dialysis is renal transplantation, a very effective therapy but severely limited by the availability of donor kidneys. Hence, we tested the role of intravenous renal cell transplantation (IRCT) on obese/diabetic Zucker/SHHF F1 hybrid (ZS) female rats with severe ischemic and diabetic nephropathy. Renal ischemia was produced by bilateral renal clamping of the renal arteries at 10 wk of age, and IRCT with genetically modified normal ZS male tubular cells was given intravenously at 15 and 20 wk of age. Rats were euthanized at 34 wk of age. IRCT with cells expressing serum amyloid A had strong and long-lasting beneficial effects on renal function and structure, including tubules and glomeruli. However, donor cells were found engrafted only in renal tubules 14 wk after the second infusion. The results indicate that IRCT with serum amyloid A-positive cells is effective in preventing the progression of chronic kidney disease in rats with diabetic and ischemic nephropathy.

Comprehensive genomic profiling in diabetic nephropathy reveals the predominance of proinflammatory pathways

Despite advances in the treatment of diabetic nephropathy (DN), currently available therapies have not prevented the epidemic of progressive chronic kidney disease (CKD). The morbidity of CKD, and the inexorable increase in the prevalence of end-stage renal disease, demands more effective approaches to prevent and treat progressive CKD. We undertook next-generation sequencing in a rat model of diabetic nephropathy to study in depth the pathogenic alterations involved in DN with progressive CKD. We employed the obese, diabetic ZS rat, a model that develops diabetic nephropathy, characterized by progressive CKD, inflammation, and fibrosis, the hallmarks of human disease. We then used RNA-seq to examine the combined effects of renal cells and infiltrating inflammatory cells acting as a pathophysiological unit. The comprehensive systems biology analysis of progressive CKD revealed multiple interactions of altered genes that were integrated into morbid networks. These pathological gene assemblies lead to renal inflammation and promote apoptosis and cell cycle arrest in progressive CKD. Moreover, in what is clearly a major therapeutic challenge, multiple and redundant pathways were found to be linked to renal fibrosis, a major cause of kidney loss. We conclude that systems biology applied to progressive CKD in DN can be used to develop novel therapeutic strategies directed to restore critical anomalies in affected gene networks.

Molecular biology and immunology of fungal allergens

Fungi are non-chlorophyllus microorganisms, which constitutes the main source of outdoor and indoor allergens. The antigens present in the spores and fragments of hyphae induce allergic responses in sensitized patients. The frequently recognized fungi associated with asthma include Alternaria, Cladosporium, Aspergillus, and Penicillium. With the advent of molecular biology techniques a number of fungal genes encoding relevant allergens have been cloned and the expressed allergens purified and characterized. In this review, we have presented the recent developments, where recombinant allergens have been used in the precise diagnosis of fungal allergy. We have also discussed the role played by these allergens and the T- and B-cell epitopes in the immune mechanism in fungal allergy.

Development of a scalable image formation pipeline for multiscale gigapixel photography

We report on the image formation pipeline developed to efficiently form gigapixel-scale imagery generated by the AWARE-2 multiscale camera. The AWARE-2 camera consists of 98 "microcameras" imaging through a shared spherical objective, covering a 120° x 50° field of view with approximately 40 microradian instantaneous field of view (the angular extent of a pixel). The pipeline is scalable, capable of producing imagery ranging in scope from "live" one megapixel views to full resolution gigapixel images. Architectural choices that enable trivially parallelizable algorithms for rapid image formation and on-the-fly microcamera alignment compensation are discussed.

Intravenous renal cell transplantation for rats with acute and chronic renal failure

Acute kidney injury (AKI) and chronic renal failure (CKD) are the most challenging problems in nephrology. Multiple therapies have been attempted but these interventions have minimal effects on the eventual outcomes, and all too often the result is end-stage renal disease (ESRD). The only effective therapy for ESRD is renal transplantation but only a small fraction of patients receive transplants. In this work we introduce a novel approach to transplantation designed to regenerate kidneys afflicted by severe AKI or CKD: intravenous renal cell transplantation (IRCT) with adult rat primary renal cells reprogrammed to express the SAA gene localized and engrafted in kidneys of rat recipients that had severe AKI or CKD. IRCT significantly resolved renal dysfunction and limited kidney damage, inflammation, and fibrosis. Severe CKD was successfully improved by IRCT using kidney cells from donor rats or by renal cell self-donation in a form of autotransplantation. We propose that IRCT with adult primary renal cells reprogrammed to express the SAA gene can be used to effectively treat AKI and CKD.

The effectiveness and cost of single and multi-factorial cardiovascular risk factor modification to guideline targets in type 2 diabetes

AIMS

Cardiovascular disease is the main cause of morbidity and mortality in type 2 diabetes (T2DM), at huge cost to the NHS. We investigated the potential effect on population cardiovascular risk and associated costs of single and multi-factorial intervention, to target levels, in individuals with T2DM.

METHODS

Baseline population means and proportions for cardiovascular risk factors were calculated for 159 patients with T2DM from 3 general practices. Predicted 10year cardiovascular risk, and associated costs were calculated using the LIP2687 risk calculator, based on Framingham and UKPDS equations. Systolic blood pressure, HbA(1C), total cholesterol and HDL-cholesterol were altered to NICE and SIGN target levels and the model run again. The difference in outcomes was observed.

RESULTS

45%, 76% and 38% of patients met NICE targets for cholesterol, systolic blood pressure and HbA1c, respectively. As expected, comparing the two guidelines, fewer patients met the 'stricter' targets (P=0.0001). Treatment-to-target produced no significant difference in cardiovascular risk or costs, although greater reductions in outcomes were seen with multi-factorial intervention.

CONCLUSION

This small study suggests that intervention in only those patients with the highest cardiovascular risk brings little reduction in population cardiovascular risk and associated health costs. Multi-factorial intervention in all patients with T2DM, regardless of baseline values, is likely to bring greater reductions. This raises the question as to whether the current emphasis on treatment to target should be modified to encourage multi-factorial intervention in all patients with T2DM, even those with baseline values below target levels.

Swim stress activates serotonergic and nonserotonergic neurons in specific subdivisions of the rat dorsal raphe nucleus in a temperature-dependent manner

Physical (exteroceptive) stimuli and emotional (interoceptive) stimuli are thought to influence stress-related physiologic and behavioral responses through different neural mechanisms. Previous studies have demonstrated that stress-induced activation of brainstem serotonergic systems is influenced by environmental factors such as temperature. In order to further investigate the effects of environmental influences on stress-induced activation of serotonergic systems, we exposed adult male Wistar rats to either home cage control conditions or a 15-min swim in water maintained at 19 °C, 25 °C, or 35 °C and conducted dual immunohistochemical staining for c-Fos, a marker of immediate-early nuclear activation, and tryptophan hydroxylase (TPH), a marker of serotonergic neurons. Changes in core body temperature were documented using biotelemetry. As expected, exposure to cold (19 °C) swim, relative to warm (35 °C) swim, increased c-Fos expression in the external lateral part of the parabrachial nucleus (LPBel), an important part of the spinoparabrachial pathway involved in sensation of cold, cutaneous stimuli, and in serotonergic neurons in the raphe pallidus nucleus (RPa), an important part of the efferent mechanisms controlling thermoregulatory warming responses. In addition, exposure to cold (19 °C) swim, relative to 35 °C swim, increased c-Fos expression in the dorsal raphe nucleus, ventrolateral part/periaqueductal gray (DRVL/VLPAG) and dorsal raphe nucleus, interfascicular part (DRI). Both of these subregions of the dorsal raphe nucleus (DR) have previously been implicated in thermoregulatory responses. Altogether, the data are consistent with the hypothesis that midbrain serotonergic neurons, possibly via activation of afferents to the DR by thermosensitive spinoparabrachial pathways, play a role in integration of physiologic and behavioral responses to interoceptive stress-related cues involved in forced swimming and exteroceptive cues related to cold ambient temperature.

Ultrasound-guided transversus abdominis plane blocks for laparoscopic appendicectomy in children: a prospective randomized trial

BACKGROUND

The effect of adding transversus abdominis plane (TAP) blocks to local anaesthetic infiltration on morphine consumption and postoperative pain in children undergoing laparoscopic appendicectomy is unknown.

METHODS

After random allocation, 93 children aged 7-16 were randomized to receive ultrasound-guided TAP blocks placed before surgery or not (control). All subjects had port sites infiltrated with ropivacaine and were prescribed i.v. patient-controlled analgesia (PCA) with morphine and oral paracetamol for postoperative pain. The primary outcome was the proportion of subjects using >200 µg kg(-1) morphine. Secondary outcomes included PCA morphine use, pain scores, time intervals to the first use of PCA and other analgesics, sedation scores, postoperative nausea or vomiting, and time to hospital discharge.

RESULTS

The procedure duration was longer in the TAP group (111 compared with 97 min for controls, P=0.03). The duration in the recovery ward and that of the hospital stay were similar. There was no difference in the proportion of subjects requiring >200 µg kg(-1) of PCA morphine [control 31/45 (69%), TAP 29/42 (69%), P=0.99]. There was no significant difference in PCA morphine use, time intervals to the first use of PCA or other analgesics, or amounts of other analgesics. More patients in the TAP group had complicated appendicitis [TAP 13/42 (31%), control 5/45 (11%), P=0.02]. Pain scores were reduced for the TAP group in the recovery ward only (median score 0 vs 2, 95% confidence interval 0-3, P=0.03).

CONCLUSIONS

TAP blocks increased anaesthesia time by 14 min on average but offered no clinically important benefit over local anaesthetic port-site infiltration to paediatric patients undergoing laparoscopic appendicectomy.

Rapid progression of diabetic nephropathy is linked to inflammation and episodes of acute renal failure

BACKGROUND/AIMS

Chronic kidney disease (CKD) from diabetic nephropathy is characterized by progressive loss of renal function. The renal decline has been viewed as a linear fall, presumably dependent on metabolic, hemodynamic and dietary stresses. However, renal injury in diabetic nephropathy can be rapidly aggravated by unpredictable external and internal factors, a state of affairs inconsistent with a linear loss of function. Acute renal injury and subsequent inflammation are potential factors, and we investigated their presence in renal biopsies from patients with nephropathy.

METHODS

In a protocol approved by the Indiana University School of Medicine Institutional Review Board, renal biopsy specimens, estimated GFR, proteinuria and renal survival were examined in patients with diabetic nephropathy.

RESULTS

Prominent clusters of inflammatory cells, particularly macrophages, were detected in the renal biopsy specimens. CKD progressed rapidly but not linearly, in that CKD was characterized by a succession of seemingly random episodes of self-limited acute renal failure. Episodes of acute kidney injury were associated with progression to end-stage renal disease.

CONCLUSIONS

We propose that diabetic nephropathy is complicated by unpredictable and possibly random episodes of usually self-limited acute renal failure, and by subsequent renal inflammation, which appear to accelerate progression and eventual kidney loss.

A retrospective audit of three different regional anaesthetic techniques for circumcision in children

Postoperative analgesia for male circumcision surgery has been traditionally provided by a landmark-based dorsal penile nerve block (DPNB-LM) or by caudal epidural analgesia (CEA). In this study we report on a retrospective analysis of the effectiveness and safety of CEA, DPNB-LM and ultrasound-guided dorsal penile nerve block (DPNB-US) in our institution over a six-year period. Information was gathered from each patient's medical record. A total of 216 circumcisions were performed on patients aged from five months to 15 years. One hundred and fifteen patients received CEA, 46 DPNB-LM and 55 DPNB-US. Patients in the DPNB-LM group required rescue morphine administration in the recovery unit more frequently (30.4%) than either the DPNB-US (3.5%) or CEA groups (3.6%). Similarly, the DPNB-LM group required a larger total dose of morphine, and had longer recovery ward stays than CEA or DPNB-US groups. Time to first analgesia was greatest for the CEA group while there was no significant difference between time to first analgesia for DPNB-LM and DPNB-US. Sixty-three percent of patients in the DPNB-LM group, 1.7% of CEA and 5.5% of the DPNB-US required intraoperative opiates (P < 0.0001). There was no difference in time to hospital discharge.

Intravenous cell therapy for acute renal failure with serum amyloid A protein-reprogrammed cells

Serum amyloid A protein (SAA), a prominent component of the acute-phase response, is strongly expressed in developing and repairing kidneys and promotes tubulogenesis. Accordingly, we reprogrammed relatively undifferentiated NRK52E cells with the mouse SAA1.1 gene and transplanted SAA-positive and -negative cells into rats with acute renal failure. We found that SAA-positive cells accelerated renal recovery in three models of acute renal failure: gentamicin nephrotoxicity, cisplatin-mediated renal injury, and ischemia-reperfusion renal injury. The dramatic improvement of renal failure was demonstrable within 2 days, consistent with an early paracrine effect. However, abundant donor cells were also found integrated in the healing tubular architecture after 7 days. We conclude that infusions of SAA-positive cells promote renal recovery after acute renal failure and offer a potentially powerful and novel therapy of renal failure.

Treatment of the post-ischaemic inflammatory syndrome of diabetic nephropathy

BACKGROUND

Diabetes mellitus and its complications are a public health problem of epidemic proportions. Both diabetes and chronic kidney disease (CKD) increase the risk of acute kidney injury (AKI). Months after a single episode of acute ischaemia to the diabetic kidney, we have found an accelerated progression of nephropathy, with impaired function, severe renal inflammation, microvascular dysfunction, fibrosis and apoptotic cell death. We termed this entity the post-ischaemic inflammatory syndrome. We now test the hypothesis that blocking inflammation ameliorates the post-ischaemic inflammatory syndrome.

METHODS

Obese-diabetic ZS rats (F(1) hybrids of spontaneously hypertensive heart failure and Zucker fatty diabetic rats) were treated with mycophenolate mofetil (MMF), subjected to renal ischaemia or sham surgery, and monitored via the powerful technique of intravital microscopy.

RESULTS

Amelioration of post-ischaemia inflammation with MMF therapy improved long-term renal function, microvascular dysfunction, fibrosis and apoptosis.

CONCLUSION

These data support the hypothesis that the post-ischaemic inflammatory syndrome accelerates diabetic CKD, is a critical determinant of injury, and can be successfully treated.

Flavoured cigarettes, sensation seeking and adolescents' perceptions of cigarette brands

OBJECTIVES

This study examined the interactive effects of cigarette package flavour descriptors and sensation seeking on adolescents' brand perceptions.

METHODS

High school students (n = 253) were randomly assigned to one of two experimental conditions and sequentially exposed to cigarette package illustrations for three different brands. In the flavour descriptor condition, the packages included a description of the cigarettes as "cherry", while in the traditional descriptor condition the cigarette brands were described with common phrases found on tobacco packages such as "domestic blend." Following exposure to each package participants' hedonic beliefs, brand attitudes and trial intentions were assessed. Sensation seeking was also measured, and participants were categorised as lower or higher sensation seekers.

RESULTS

Across hedonic belief, brand attitude and trial intention measures, there were interactions between package descriptor condition and sensation seeking. These interactions revealed that among high (but not low) sensation seekers, exposure to cigarette packages including sweet flavour descriptors led to more favourable brand impressions than did exposure to packages with traditional descriptors.

CONCLUSIONS

Among high sensation seeking youths, the appeal of cigarette brands is enhanced through the use of flavours and associated descriptions on product packaging.

Postischemic inflammatory syndrome: a critical mechanism of progression in diabetic nephropathy

Diabetes is a major epidemic, and diabetic nephropathy is the most common cause of end-stage renal disease. Two critical components of diabetic nephropathy are persistent inflammation and chronic renal ischemia from widespread vasculopathy. Moreover, acute ischemic renal injury is common in diabetes, potentially causing chronic kidney disease or end-stage renal disease. Accordingly, we tested the hypothesis that acute renal ischemia accelerates nephropathy in diabetes by activating proinflammatory pathways. Lean and obese-diabetic ZS rats (F(1) hybrids of spontaneously hypertensive heart failure and Zucker fatty diabetic rats) were subjected to bilateral renal ischemia or sham surgery before the onset of proteinuria. The postischemic state in rats with obesity-diabetes was characterized by progressive chronic renal failure, increased proteinuria, and renal expression of proinflammatory mediators. Leukocyte number in obese-diabetic rat kidney was markedly increased for months after ischemia. Intrarenal blood flow velocity was decreased after ischemia in lean control and obese-diabetic rats, although it recovered in lean rats. At 2 mo after ischemia, blood flow velocity decreased further in sham-surgery and postischemia obese-diabetic rats, so that RBC flow velocity was only 39% of control in the obese-diabetic rats after ischemia. In addition, microvascular density remained depressed at 2 mo in kidneys of obese-diabetic rats after ischemia. Abnormal microvascular permeability and increases in interstitial fibrosis and apoptotic renal cell death were also more pronounced after ischemia in obese-diabetic rats. These data support the hypothesis that acute renal ischemia in obesity-diabetes severely aggravates chronic inflammation and vasculopathy, creating a self-perpetuating postischemia inflammatory syndrome, which accelerates renal failure.

Acute-phase response protein serum amyloid A stimulates renal tubule formation: studies in vitro and in vivo

Serum amyloid A protein (SAA) surges 1,000-fold in the blood of acute-phase animals, and yet its function during these acute events remains unknown. We report herein that SAA stimulates a developmental program in cultured NRK-52E cells that culminates in differentiated and functional tubules that feature a proximal tubule phenotype. We also found strong SAA expression in states of tubule formation (in utero stage) and regeneration (recovery from ischemia-reperfusion injury). These data lend support to a novel view of a more localized renal acute-phase reaction, where renal SAA may act as a paracrine or autocrine molecule that promotes tubule formation during development and repair.

LOX-1 and inflammation: a new mechanism for renal injury in obesity and diabetes

The early nephropathy in obese, diabetic, dyslipidemic (ZS) rats is characterized by tubular lipid accumulation and pervasive inflammation, two critically interrelated events. We now tested the hypothesis that proximal tubules from ZS obese diabetic rats in vivo, and proximal tubule cells (NRK52E) exposed to oxidized LDL (oxLDL) in vitro, change their normally quiescent epithelial phenotype into a proinflammatory phenotype. Urine of obese diabetic rats contained more lipid peroxides, and LOX-1, a membrane receptor that internalizes oxidized lipids, was mobilized to luminal sites. Levels of ICAM-1 and focal adhesion kinase, which participate in leukocyte migration and epithelial dedifferentiation, respectively, were also upregulated in tubules. NRK52E cells exposed to oxLDL showed similar modifications, plus suppression of anti-inflammatory transcription factor peroxisome proliferator-activated receptor-delta. In addition, oxLDL impaired epithelial barrier function. These alterations were prevented by an anti-LOX-1 antibody. The data support the concept that tubular LOX-1 activation driven by lipid oxidants in the preurine fluid is critical in the inflammatory changes. We suggest that luminal lipid oxidants and abnormal tubular permeability may be partly responsible for the renal tubulointerstitial injury of obesity, diabetes, and dyslipidemia.

Anti-LOX-1 therapy in rats with diabetes and dyslipidemia: ablation of renal vascular and epithelial manifestations

LOX-1 is a multifunctional membrane receptor that binds and internalizes oxidized LDL (oxLDL). We tested the hypothesis that blockade of LOX-1 with an anti-LOX-1 antibody limits nephropathy in male rats with diabetes and dyslipidemia (ZS rats; F1hybrid product of Zucker fatty diabetic rats and spontaneous hypertensive heart failure rats). Lean ZS rats were controls, while untreated obese ZS (OM), ZS obese rats injected with nonspecific rabbit IgG (OM-IgG; 2 μg intravenous injection given weekly), and obese ZS rats given anti-LOX-1 rabbit antibody (OM-Ab; 2 μg intravenous injection given weekly) were the experimental groups. The rats were treated from 6 to 21 wk of age. All obese groups had severe dyslipidemia and hyperglycemia. Kidneys of obese rats expressed LOX-1 in capillaries and tubules, were larger, accumulated lipid, had intense oxidative stress, leukocyte infiltration, depressed mitochondrial enzyme level and function, and peritubular fibrosis (all P < 0.05 vs. lean ZS rats). Injections with LOX-1 antibody limited these abnormalities ( P < 0.01 vs. data in OM or OM-lgG rats). In vitro, renal epithelial LOX-1 expression was verified in a cultured proximal tubule cell line. Our study indicates that anti-LOX-1 (vascular and epithelial) therapy may effectively reverse critical pathogenic elements of nephropathy in diabetes and dyslipidemia.