Effectiveness of Telemonitoring in Reducing Hospitalization and Associated Costs for Patients With Heart Failure in Finland: Nonrandomized Pre-Post Telemonitoring Study.

BACKGROUND: Many patients with chronic heart failure (HF) experience a reduced health status, leading to readmission after hospitalization despite receiving conventional care. Telemonitoring approaches aim to improve the early detection of HF decompensations and prevent readmissions. However, knowledge about the impact of telemonitoring on preventing readmissions and related costs remains scarce. OBJECTIVE: This study assessed the effectiveness of adding a telemonitoring solution to the standard of care (SOC) for the prevention of hospitalization and related costs in patients with HF in Finland. METHODS: We performed a nonrandomized pre-post telemonitoring study to estimate health care costs and resource use during 6 months on SOC followed by 6 months on SOC with a novel telemonitoring solution. The telemonitoring solution consisted of a digital platform for patient-reported symptoms and daily weight and blood pressure measurements, automatically generated alerts triggering phone calls with secondary care nurses, and rapid response to alerts by treating physicians. Telemonitoring solution data were linked to patient register data on primary care, secondary care, and hospitalization. The patient register of the Southern Savonia Social and Health Care Authority (Essote) was used. Eligible patients had at least 1 hospital admission within the last 12 months and self-reported New York Heart Association class II-IV from the central hospital in the Southern Savonia region. RESULTS: Out of 50 recruited patients with HF, 43 completed the study and were included in the analysis. The hospitalization-related cost decreased (49%; P=.03) from €2189 (95% CI €1384-€2994; a currency exchange rate of EUR €1=US $1.10589 is applicable) during SOC to €1114 (95% CI €425-€1803) during telemonitoring. The number of patients with at least 1 hospitalization due to HF was reduced by 70% (P=.002) from 20 (47%) out of 43patients during SOC to 6 (14%) out of 43 patients in telemonitoring. The estimated mean total health care cost per patient was €3124 (95% CI €2212-€4036) during SOC and €2104 (95% CI €1313-€2895) during telemonitoring, resulting in a 33% reduction (P=.07) in costs with telemonitoring. CONCLUSIONS: The results suggest that the telemonitoring solution can reduce hospital-related costs for patients with HF with a recent hospital admission.

The plant product quinic acid activates Ca2+ -dependent mitochondrial function and promotes insulin secretion from pancreatic beta cells.

BACKGROUND AND PURPOSE: Quinic acid (QA) is an abundant natural compound from plant sources which may improve metabolic health. However, little attention has been paid to its effects on pancreatic beta-cell functions, which contribute to the control of metabolic health by lowering blood glucose. Strategies targeting beta-cell signal transduction are a new approach for diabetes treatment. This study investigated the efficacy of QA to stimulate beta-cell function by targeting the basic molecular machinery of metabolism-secretion coupling. EXPERIMENTAL APPROACH: We measured bioenergetic parameters and insulin exocytosis in a model of insulin-secreting beta-cells (INS-1E), together with Ca2+ homeostasis, using genetically encoded sensors, targeted to different subcellular compartments. Islets from mice chronically infused with QA were also assessed. KEY RESULTS: QA triggered transient cytosolic Ca2+ increases in insulin-secreting cells by mobilizing Ca2+ from intracellular stores, such as endoplasmic reticulum. Following glucose stimulation, QA increased glucose-induced mitochondrial Ca2+ transients. We also observed a QA-induced rise of the NAD(P)H/NAD(P)+ ratio, augmented ATP synthase-dependent respiration, and enhanced glucose-stimulated insulin secretion. QA promoted beta-cell function in vivo as islets from mice infused with QA displayed improved glucose-induced insulin secretion. A diet containing QA improved glucose tolerance in mice. CONCLUSIONS AND IMPLICATIONS: QA modulated intracellular Ca2+ homeostasis, enhancing glucose-stimulated insulin secretion in both INS-1E cells and mouse islets. By increasing mitochondrial Ca2+ , QA activated the coordinated stimulation of oxidative metabolism, mitochondrial ATP synthase-dependent respiration, and therefore insulin secretion. Bioactive agents raising mitochondrial Ca2+ in pancreatic beta-cells could be used to treat diabetes.

Isx9 Regulates Calbindin D28K Expression in Pancreatic ß Cells and Promotes ß Cell Survival and Function.

Pancreatic ß-cell dysfunction and death contribute to the onset of diabetes, and novel strategies of ß-cell function and survival under diabetogenic conditions need to be explored. We previously demonstrated that Isx9, a small molecule based on the isoxazole scaffold, drives neuroendocrine phenotypes by increasing the expression of genes required for ß-cell function and improves glycemia in a model of ß cell regeneration. We further investigated the role of Isx9 in ß-cell survival. We find that Isx9 drives the expression of Calbindin-D28K (D28K), a key regulator of calcium homeostasis, and plays a cytoprotective role through its calcium buffering capacity in ß cells. Isx9 increased the activity of the calcineurin (CN)/cytoplasmic nuclear factor of the activated T-cells (NFAT) transcription factor, a key regulator of D28K, and improved the recruitment of NFATc1, cAMP response element-binding protein (CREB), and p300 to the D28K promoter. We found that nutrient stimulation increased D28K plasma membrane enrichment and modulated calcium channel activity in order to regulate glucose-induced insulin secretion. Isx9-mediated expression of D28K protected ß cells against chronic stress induced by serum withdrawal or chronic inflammation by reducing caspase 3 activity. Consequently, Isx9 improved human islet function after transplantation in NOD-SCID mice in a streptozotocin-induced diabetes model. In summary, Isx9 significantly regulates expression of genes relevant to ß cell survival and function, and may be an attractive therapy to treat diabetes and improve islet function post-transplantation.

Ins1(Cre) knock-in mice for beta cell-specific gene recombination.

AIMS/HYPOTHESIS: Pancreatic beta cells play a central role in the control of glucose homeostasis by secreting insulin to stimulate glucose uptake by peripheral tissues. Understanding the molecular mechanisms that control beta cell function and plasticity has critical implications for the pathophysiology and therapy of major forms of diabetes. Selective gene inactivation in pancreatic beta cells, using the Cre-lox system, is a powerful approach to assess the role of particular genes in beta cells and their impact on whole body glucose homeostasis. Several Cre recombinase (Cre) deleter mice have been established to allow inactivation of genes in beta cells, but many show non-specific recombination in other cell types, often in the brain. METHODS: We describe the generation of Ins1(Cre) and Ins1(CreERT2) mice in which the Cre or Cre-oestrogen receptor fusion protein (CreERT2) recombinases have been introduced at the initiation codon of the Ins1 gene. RESULTS: We show that Ins1(Cre) mice induce efficient and selective recombination of floxed genes in beta cells from the time of birth, with no recombination in the central nervous system. These mice have normal body weight and glucose homeostasis. Furthermore, we show that tamoxifen treatment of adult Ins1(CreERT2) mice crossed with Rosa26-tdTomato mice induces efficient recombination in beta cells. CONCLUSIONS/INTERPRETATION: These two strains of deleter mice are useful new resources to investigate the molecular physiology of pancreatic beta cells.

Neph3 associates with regulation of glomerular and neural development in zebrafish.

Neph3 (filtrin) is a membrane protein expressed in the glomerular epithelial cells (podocytes), but its role in the glomerulus is still largely unknown. To characterize the function of Neph3 in the glomerulus, we employed the zebrafish as a model system. Here we show that the expression of neph3 in pronephros starts before the onset of nephrin and podocin expression, peaks when the nephron primordium differentiates into glomerulus and tubulus, and is then downregulated upon glomerular maturation. By histology, we found that neph3 is specifically expressed in pronephric podocytes at 36hpf. Furthermore, disruption of neph3 expression by antisense morpholino oligonucleotides results in distorted body curvature and transient pericardial edema, the latter likely reflecting perturbation of glomerular osmoregulatory function. Histological analysis of neph3 morphants reveals altered glomerular morphology and dilated pronephric tubules. The phenotype of neph3 morphants, curved body and pericardial edema, is rescued by wild-type zebrafish neph3 mRNA. In addition to glomerulus, neph3 is highly expressed in the developing brain and specific regions of mature midbrain and hindbrain. In line with this, neph3 morphants show aberrant brain morphology. Collectively, the expression of neph3 in glomerulus and brain together with the morphant phenotype imply that neph3 is a pleiotropic gene active during distinct stages of tissue differentiation and associates directly in the regulation of both glomerular and neural development.

Trans-interaction of nephrin and Neph1/Neph3 induces cell adhesion that associates with decreased tyrosine phosphorylation of nephrin.

Slit diaphragms are specialized junctions between glomerular epithelial cells (podocytes) that are crucial for glomerular ultrafiltration. The Ig superfamily members nephrin and Neph1 are essential components of the slit diaphragm, whereas the role of Neph1 homologue Neph3 in the slit diaphragm is unknown. In the present paper we show that Neph3 homodimerizes and heterodimerizes with nephrin and Neph1. We further investigated whether these interactions play a role in cell adhesion by using mouse L fibroblasts that lack endogenous cell-adhesion activity and found that Neph1 and Neph3 are able to induce cell adhesion alone, whereas nephrin needs to trans-interact with Neph1 or Neph3 in order to promote formation of cell-cell contacts. Tyrosine phosphorylation of nephrin was down-regulated after nephrin trans-interacted with either Neph1 or Neph3 leading to formation of cell-cell contacts. We further found that the expression of Neph3 was increased in nephrin-deficient mouse podocytes. The findings of the present paper show that nephrin and Neph1 or Neph3 trans-interactions promote cell-contact formation, suggesting that they may also function together in slit diaphragm assembly.

Lipid phosphatase SHIP2 downregulates insulin signalling in podocytes.

Podocyte injury plays an important role in the development of diabetic nephropathy. Podocytes are insulin-responsive and can develop insulin resistance, but the mechanisms are unknown. To study the role of CD2-associated protein (CD2AP) in podocyte injury, we performed a yeast two-hybrid screening on a glomerular library, and found that CD2AP bound to SH2-domain-containing inositol polyphosphate 5-phosphatase 2 (SHIP2), a negative regulator of insulin signalling. SHIP2 interacts with CD2AP in glomeruli and is expressed in podocytes, where it translocates to plasma membrane after insulin stimulation. Overexpression of SHIP2 in cultured podocytes reduces Akt activation in response to insulin, and promotes apoptosis. SHIP2 is upregulated in glomeruli of insulin resistant obese Zucker rats. These results indicate that SHIP2 downregulates insulin signalling in podocytes. The upregulation of SHIP2 in Zucker rat glomeruli prior to the age of onset of proteinuria suggests a possible role for SHIP2 in the development of podocyte injury.

beta-Catenin mediates adriamycin-induced albuminuria and podocyte injury in adult mouse kidneys.

BACKGROUND: Glomerular slit diaphragm (SD) represents a modified adherens junction composed of molecules belonging to both immunoglobulin and cadherin superfamilies. Cadherins associate with the cytosolic scaffolding protein beta-catenin, but the precise role of beta-catenin in mature or injured podocytes is not known. METHODS: The conditional podocyte-specific beta-catenin-deficient mouse line was generated using the doxycycline-inducible Cre-loxP system. Expression of the beta-catenin-deficient gene was turned off at the age of 8 weeks by doxycycline treatment and the kidney phenotype was analysed. In addition, beta-catenin-deficient and control mice were treated with adriamycin (ADR) and analysed for albuminuria and morphological alterations. RESULTS: Deletion of beta-catenin in mature podocytes did not change the morphology of podocytes nor did it lead to albuminuria. However, lack of beta-catenin attenuated albuminuria after ADR treatment. Electron microscopic examination showed increased podocyte foot process effacement associated with SD abnormalities in ADR-treated control mice compared to beta-catenin-deficient mice. CONCLUSIONS: These results show that beta-catenin in podocytes is dispensable for adult mice, but appears to be important in modulating the SD during ADR-induced perturbation of the filtration barrier.

Densin and beta-catenin form a complex and co-localize in cultured podocyte cell junctions.

Densin is a member of LAP (leucine-rich repeat and PDZ domain) protein family that localizes in kidney to slit diaphragms, which are essential components of the glomerular filtration barrier. We have previously shown that densin interacts with a crucial slit diaphragm protein, nephrin. Here, we searched for novel binding partners of densin by yeast-two hybrid assay and identified beta-catenin. The interaction was confirmed by reciprocal co-immunoprecipitation assay and the binding site in densin was determined by GST-pull down assays. The GST-tagged densin was also able to pull down P-cadherin together with beta-catenin from human kidney glomerular lysates. Furthermore, densin co-localized with beta-catenin and F-actin in cell-cell contacts in cultured mouse podocytes. During cell-cell contact disruption and reformation densin and beta-catenin were dislocated from and relocated back to plasma membrane in a similar fashion. These and our previous findings suggest that densin may associate with the cadherin-catenin and nephrin complex(es), and may be involved in the formation of the cell-cell contacts including the slit diaphragm.

Densin is a novel cell membrane protein of Sertoli cells in the testis.

Cell-cell interactions between Sertoli cells and germ cells are crucial for the maturation of germ cells in spermatogenesis but the structural and functional aspects of the interactions remain to be fully elucidated. Densin is a junction protein suggested to play a role in establishment of specific cell-cell contacts in the post-synaptic densities of the brain and the slit diaphragm of the kidney podocyte. In the present study, densin was discovered to be expressed in the testis of the man and the mouse. Expression of densin at the gene and the protein level was studied by using RT-PCR and Western blotting analyses, and the localization of densin was explored with immunofluorescence staining. RT-PCR and Western blotting analyses showed that densin is expressed at the gene and the protein levels. Immunofluorescence staining localized the expression of densin to the cell membranes of Sertoli cells suggesting that densin may be an adherens junction protein between Sertoli cells and developing germ cells. Densin is a novel testicular protein expressed in the cell membranes of Sertoli cells. Its functional role remains to be assessed.

Glomerular podocytes contain neuron-like functional synaptic vesicles.

Although patients with chronic renal failure are increasing worldwide, many aspects of kidney biology remain to be elucidated. Recent research has uncovered several molecular properties of the glomerular filtration barrier, in which podocytes, highly differentiated, ramified cells that enwrap the glomerular basement membrane, have been reported to be mainly responsible for filter's selectivity. We previously described that podocytes express Rab3A, a GTPase restricted to cell types that are capable of highly regulated exocytosis, such as neuronal cells. Here, we first demonstrate by a proteomic study that Rab3A in podocytes coimmmunoprecipitates with molecules once thought to be synapse specific. We then show that podocytes possess structures resembling synaptic vesicles, which contain glutamate, coexpress Rab3A and synaptotagmin 1, and undergo spontaneous and stimulated exocytosis and recycling, with glutamate release. Finally, from the results of a cDNA microarray study, we describe the presence of a series of neuron- and synapse-specific molecules in normal human glomeruli and confirm the glomerular protein expression of both metabotropic and ionotropic glutamate receptors. These data point toward a synaptic-like mechanism of communication among glomerular cells, which perfectly fits with the molecular composition of the glomerular filter and puts in perspective several previous observations, proposing a different working hypothesis for understanding glomerular signaling dynamics.

A novel protein, densin, expressed by glomerular podocytes.

With the recent molecular findings, the podocyte is emerging as a key cell type involved in glomerular damage, but protein complexes involved remain poorly understood. To systematically search for additional podocyte molecules interacting with nephrin, a key structural molecule of the interpodocyte filtration slit, precipitation of glomerular lysates was set out with anti-nephrin antibodies to identify members of the nephrin-associated protein complex. Proteins of the precipitate were subsequently identified with MALDI-TOF mass analysis. One of the proteins thus obtained showed identity with densin, a protein originally purified from rat forebrain postsynaptic density fraction and so far shown to be highly brain-specific. The expression of densin appeared distinctly in the glomerulus and cultured podocytes by RT-PCR. Immunoblotting studies revealed a specific band of 185 kD in brain and cultured podocytes; in human glomerulus, densin appeared as a 210-kD band. By immunocytochemistry, densin localizes in glomeruli in a podocyte-like pattern. Electron microscopic studies revealed densin localization in the slit diaphragm area. Due to its known involvement in the synaptic organization, maintenance of cell shape and polarity in nerve cells, together with its demonstrated interactions with alpha-actinin-4, densin may share the same functions in podocytes by associating with the nephrin interacting protein complex at the slit diaphragm.

Patterns of nephrin and a new proteinuria-associated protein expression in human renal diseases.

BACKGROUND: Many factors contribute to the pathogenesis of glomerular proteinuria, but no exact molecular mechanisms are known to date. The recently reported protein nephrin, encoded by the NPHS1 gene, appears to be crucial for the integrity of the glomerular filtration barrier. METHODS: Immunohistochemistry was used to detect possible changes in glomerular nephrin, and a new proteinuria-associated protein expression was developed in various diagnostic groups of human kidney biopsies. RESULTS: In normal control kidney, antibodies to intracellular and extracellular nephrin domain showed a typical podocyte pattern of reactivity, while the 18C7 antibody to a normally inaccessible proteinuria-associated epitope was negative. Instead, strong glomerular positivity by 18C7 was seen in membranous glomerulonephropathy, membranoproliferative glomerulonephritis, systemic lupus erythematosus and cryoglobulinemic nephritis, while with antibodies to either intracellular or extracellular nephrin domains, a down-regulation in nephrin expression pattern was shown. CONCLUSIONS: Unmasking or de novo expression of distinct glomerular proteins may be an important feature reflecting the pathophysiological events in these diseases with altered glomerular permeability, while only mild changes in the slit diaphragm protein nephrin appear to take place.