The results highlight the need to provide access to appropriate in-language advance care planning resources and promotion of advance care planning across the Chinese community.

Vascular endothelial growth factor (VEGF) acts primarily as an endothelial cell mitogen via the "endothelial cell-specific" receptors VEGFR-1 (flt-1) and VEGFR-2 (flk-1/KDR). Only a few nonendothelial cells have been shown to possess functional VEGF receptors. We therefore examined the rat renal tubular epithelial cell line NRK52-E. NRK52-E expressed VEGFR-1 and VEGFR-2 mRNA and protein by RT-PCR, Northern blotting, Western blotting, immunofluorescence, and ligand binding. Serum-starved NRK52-E incubated with VEGF showed a significant increase in [(3)H]thymidine incorporation compared with control (2.3-fold at 1-10 ng/ml, P < 0. 05; 3.3-fold at 50-100 ng/ml, P < 0.01). VEGF also protected NRK52-E from hydrogen peroxide-induced apoptosis and necrosis compared with control (annexin-V-FITC-positive cells, 39 vs. 54%; viable cells, 50. 5 vs. 39.7%). Immunohistochemical staining using a variety of antibodies showed expression of both VEGF receptors in normal rat renal tubules in vivo. Because VEGF induced a proliferative and an antiapoptotic response in renal tubular epithelial cells, these data suggest that VEGF may act as a survival factor for renal tubular epithelium in vivo.

The renal-specific NKCC2 (Na+-K+-2Cl- co-transporter 2) is regulated by changes in phosphorylation state, however, the phosphorylation sites and kinases responsible have not been fully elucidated. In the present study, we demonstrate that the metabolic sensing kinase AMPK (AMP-activated protein kinase) phosphorylates NKCC2 on Ser126 in vitro. Co-precipitation experiments indicated that there is a physical association between AMPK and the N-terminal cytoplasmic domain of NKCC2. Activation of AMPK in the MMDD1 (mouse macula densa-derived 1) cell line resulted in an increase in Ser126 phosphorylation in situ, suggesting that AMPK may phosphorylate NKCC2 in vivo. The functional significance of Ser126 phosphorylation was examined by mutating the serine residue to an alanine residue resulting in a marked reduction in co-transporter activity when exogenously expressed in Xenopus laevis oocytes under isotonic conditions. Under hypertonic conditions no significant change of activity was observed. Therefore the present study identifies a novel phosphorylation site that maintains NKCC2-mediated transport under isotonic or basal conditions. Moreover, the metabolic-sensing kinase, AMPK, is able to phosphorylate this site, potentially linking the cellular energy state with changes in co-transporter activity.

The AMP-activated protein kinase (AMPK) is a key controller of cellular energy metabolism. We studied its expression and regulation by salt handling in the kidney. Immunoprecipitation and Western blots of protein lysates from whole rat kidney using subunit-specific antibodies showed that the alpha1-catalytic subunit is expressed in the kidney, associated with the beta2- and either gamma1- or gamma2-subunits. Activated AMPK, detected by immunohistochemical staining for phospho-Thr172 AMPK (pThr172), was expressed on the apical surface of the cortical thick ascending limb of the loop of Henle, including the macula densa, and some parts of the distal convoluted tubule. Activated AMPK was also expressed on the basolateral surface of the cortical and medullary collecting ducts as well as some portions of the distal convoluted tubules. AMPK activity was increased by 25% in animals receiving a high-salt diet, and this was confirmed by Western blotting for pThr172. Low-salt diets were associated with reduced levels of the alpha-subunit of AMPK, which was highly phosphorylated on Thr172. Surprisingly, both low- and high-salt media transiently activated AMPK in the macula densa cell line MMDD1, an effect due to changes in osmolality, rather than Na+ or Cl- concentration. This study, therefore, demonstrates regulation of AMPK by both a high- and a low-salt intake in vivo and suggests a role for the kinase in the response to changes in osmolality within the kidney.

ObjectiveAdvance care planning (ACP) assists people to identify their goals, values and treatment preferences for future care. Ideally, preferences are documented in an advance care directive (ACD) and used by doctors to guide medical decision-making should the patient subsequently lose their decision-making capacity. However, studies demonstrate that ACDs are not always adhered to by doctors in clinical practice. We aim to describe the attitudes and perspectives of doctors regarding ACD adherence and the utility of ACDs in clinical practice.DesignFace-to-face semistructured interviews were conducted using three case-based vignettes to explore doctors’ decision-making and attitudes towards ACDs. Transcripts were analysed using a thematic analysis.SettingDoctors from a variety of medical specialties and with varying experience levels were recruited from a large tertiary hospital in Melbourne, Australia.ParticipantsA total of 21 doctors were interviewed, 48% female (10/21). Most (19/21) reported having experience using ACDs.ResultsFour themes were identified: aligning with patient preferences (avoiding unwanted care, prioritising autonomy and anticipating family opposition), advocating best interests (defining futile care, relying on clinical judgement, rejecting unreasonable decisions and disregarding legal consequences), establishing validity (doubting rigour of the decision-making process, questioning patients’ ability to understand treatment decisions, distrusting outdated preferences and seeking confirmation) and translating written preferences into practice (contextualising patient preferences, applying subjective terminology and prioritising emergency medical treatment).ConclusionsACDs provide doctors with opportunities to align patient preferences with treatment and uphold patient autonomy. However, doctors experience decisional conflict when attempting to adhere to ACDs in practice, especially when they believe that adhering to the ACD is not in the patients’ best interests, or if they doubt the validity of the ACD. Future ACP programmes should consider approaches to improve the validity and applicability of ACDs. In addition, there is a need for ethical and legal education to support doctors’ knowledge and confidence in ACP and enacting ACDs.

A fundamental aspect of acute renal ischemia is energy depletion, manifest as a falling level of ATP that is associated with a simultaneous rise in AMP. The energy sensor AMP-activated protein kinase (AMPK) is activated by a rising AMP-to-ATP ratio, but its role in acute renal ischemia is unknown. AMPK is activated in the ischemic heart and is reported to phosphorylate both endothelial nitric oxide synthase (eNOS) and acetyl-CoA carboxylase. To study activation of AMPK in acute renal ischemia, the renal pedicle of anesthetized Sprague-Dawley rats was cross-clamped for increasing time intervals. AMPK was strongly activated within 1 min and remained so after 30 min. However, despite the robust activation of AMPK, acute renal ischemia did not increase phosphorylation of the AMPK phosphorylation sites eNOS-Ser(1177) or acetyl-CoA carboxylase-Ser(79). Activation of AMPK in bovine aortic endothelial cells by the ATP-depleting agent antimycin A and the antidiabetic drug phenformin also did not increase phosphorylation of eNOS-Ser(1177), confirming that AMPK activation and phosphorylation of eNOS are dissociated in some situations. Immunoprecipitation studies demonstrated that the dissociation between AMPK activation and phosphorylation of eNOS-Ser(1177) was not due to changes in the physical associations between AMPK, eNOS, or heat shock protein 90. In conclusion, acute renal ischemia rapidly activates the energy sensor AMPK, which is known to maintain ATP reserves during energy stress. The substrates it phosphorylates, however, are different from those in other organs such as the heart.

Although synthesis of VEGF mRNA and protein is not increased during ischemia reperfusion injury, pre-existing VEGF in the tubular cell cytoplasm redistributes to the basolateral aspect of the cells. These data suggest that the kidney may have evolved unique patterns of VEGF regulation to cope with acute hypoxia.

Activation of nuclear factor‐kappa B (NF‐κB) is one of the most important pro‐inflammatory mechanisms in disease. In this study, we show that 5‐aminoimidazole‐4‐carboxamide ribonucleoside (AICAR), an intermediate in nucleoside metabolism, inhibits signalling by NF‐κB in three cell types, including bovine aortic endothelial cells (BAEC). The block in the NF‐κB signalling pathway occurred beyond degradation of IκB‐α and movement of p65 into the nucleus of BAEC. There was, however, reduced binding of NF‐κB from AICAR‐treated cells to a κB‐consensus oligonucleotide, suggesting that part of the mechanism was a reduction in NF‐κB DNA‐binding activity. Although AICAR is metabolized to ZMP and then adenosine, adenosine had no effect on activation of an NF‐κB reporter. ZMP, however, activates the metabolic stress‐sensing AMP‐activated protein kinase (AMPK). Transfection of active AMPK into BAEC reduced NF‐κB reporter activity compared with a kinase‐dead mutant, suggesting that part of the ability of AICAR to inhibit NF‐κB signalling is due to activation of AMPK. Inhibition of NF‐κB signalling may be important in the anti‐inflammatory action of drugs such as sulfasalazine and methotrexate, which led to the accumulation of AICAR within target cells.