Gene activity changes in ischemically preconditioned rabbit heart gene: discovery array study

This study tested the hypothesis that classic ischemic preconditioning can cause changes in gene expression patterns in the rabbit heart, assessed by gene array technology. Open-chest rabbits were randomly assigned to sham-operated and ischemically preconditioned groups. The sham-operated group received 5 hours and 20 minutes of no intervention, while the ischemically preconditioned group was subjected to two episodes of preconditioning ischemia (5 minutes each) separated by 5 minutes of reperfusion, followed by an additional 5 hours and 5 minutes of reperfusion. (33)P-labeled cDNA from the sham-operated hearts and the nonischemic and preconditioned areas of the ischemically preconditioned group was hybridized to filters spotted with 18,376 human cDNA clones. Altogether, 35 genes with significantly altered expression patterns were discovered. In the preconditioned area, genes for MAPKAP kinase 3 and cathepsin G were up-regulated. In the nonischemic area, genes for GTP exchange factor, Na(+), K(+)-ATPase, Zn finger protein 35, a representative of the CEA family, cytochrome c oxidase, mitogen-responsive phosphoprotein, and Ran-binding protein were up-regulated. None of the identified genes had been previously reported to be involved in ischemic preconditioning.     

Thyrotropin-releasing hormone cannot be detected in plasma from normal subjects

Different laboratories report widely varying average levels of TRH in plasma from normal man. However, arguments can be raised against the methods used to characterize the substances measured in all previous studies. Using a sensitive RIA and methanol extraction, immunoreactive TRH (iTRH) in serum from normal subjects averaged 49 +/- 26 pg/ml (mean +/- SD; n = 6). When SP-Sephadex purification was introduced, iTRH decreased to 1.8 +/- 0.7 pg/ml. These low quantities did not further decrease when incubated with TRH-degrading enzymes, demonstrating that the remaining iTRH was not identical to synthetic TRH. Investigations of iTRH in pools of normal plasma indicate that the level of true TRH in normal human plasma is below 0.4 pg/ml.     

Proteomic analysis of pharmacologically preconditioned cardiomyocytes reveals novel phosphorylation of myosin light chain 1

Proteomic analysis of rabbit ventricular myocytes revealed a novel posttranslational modification to myosin light chain 1 (MLC1), consisting of phosphorylation at two sites. Subproteomic extraction to isolate myofilament-enriched fractions enabled determination of the extent of phosphorylation, which increased from 25.7+/-1.6% to 34.0+/-2.7% (mean+/-SE, n=4; P<0.05) after adenosine treatment at levels sufficient to pharmacologically precondition the myocytes (100 micromol/L). Mass spectrometry of MLC1 tryptic digests identified two peptide fragments modified by phosphorylation. These two phosphopeptides were characterized by peptide mass fingerprinting to determine the phosphorylation sites within rabbit ventricular MLC1, which correspond to Thr69 and Ser200 of rat MLC1, and to Thr64 and Ser194 or 195 of human MLC1. This proteomic analysis of preconditioned myocardium has revealed a previously unsuspected in vivo posttranslational modification to MLC1.     

AlphaB crystallin translocation and phosphorylation: signal transduction pathways and preconditioning in the isolated rat heart

In this program of studies we have characterized in detail the translocation (assessed by Triton-insolubility) and phosphorylation (using serine-45 or -59 phosphospecific antibodies) of alphaB crystallin during myocardial ischemia [both with or without ischemic preconditioning (IPC)]. Pharmacological activators and inhibitors allowed us to characterize the signaling pathways involved in alphaB crystallin phosphorylation during ischemia. Ischemic preconditioning alone caused 30% of the heart's alphaB crystallin pool to translocate, providing a significant translocation 'head-start' in protected tissue. This enhanced translocation is coupled with increased (3-fold) alphaB crystallin phosphorylation at both serine residues. The possible role of alphaB crystallin in the protection afforded by ischemic preconditioning is supported by the signal transduction data; which showed preconditioning-induced alphaB crystallin phosphorylation can be blocked by tyrosine kinase inhibition (using genistein) and by p38 MAP kinase or PKC inhibition (using SB203580 or bisindolylmaleimide, respectively). The activation of both p38 MAP kinase and PKC are recognized requirements for the induction of preconditioning and their inhibition is known to block protection. Western immunoblotting analysis after isoelectric focusing electrophoresis, confirmed the observations made with the phosphospecific antibodies; but also showed that 27+/-4% of total cardiac crystallin was phosphorylated after 30 min of ischemia. AlphaB crystallin exists as large polymeric aggregates in cardiac tissue under basal conditions (approximately 1 MDa as determined by gel filtration chromatography). We induced phosphorylation of alphaB crystallin during aerobic perfusion by the administration of phenylephrine. However this treatment did not alter the molecular aggregate size of alphaB crystallin. It appears that alphaB crystallin molecular aggregate size is not simply regulated by phosphorylation. AlphaB crystallin may have a role to play in the myocardial protection induced by ischemic preconditioning, as both translocation and phosphorylation are both accelerated and enhanced by ischemic preconditioning.     

Sarcolemmal blebs and osmotic fragility as correlates of irreversible ischemic injury in preconditioned isolated rabbit cardiomyocytes

The hypothesis that irreversible ischemic injury is related to sub-sarcolemmal blebbing and an inherent osmotic fragility of the blebs was tested by subjecting isolated control and ischemically preconditioned (IPC) or calyculin A (CalA)-pretreated (protected) rabbit cardiomyocytes to ischemic pelleting followed by resuspension in 340, 170 or 85 mosmol medium containing trypan blue. At time points from 0-240 min, osmotic fragility was assessed by the percentage of trypan blue permeable cells. Membrane blebs were visualized with India ink preparations. Bleb formation, following acute hypo-osmotic swelling, developed by 75 min and increased with longer periods of ischemia. Osmotic fragility developed only after 75 min. Cells resuspended in 340 mosmol media did not form blebs and largely retained the ability to exclude trypan blue, even after 240 min ischemia. Although the latent tendency for osmotic blebbing preceded the development of osmotic fragility, most osmotically fragile cells became permeable without evident sarcolemmal bleb formation. The onset of osmotic fragility was delayed in protected cells, but protection did not reduce the bleb formation. It is concluded that blebbing and osmotic fragility are independent manifestations of ischemic injury. The principal locus of irreversible ischemic injury and the protection provided by IPC may lie within the sarcolemma rather than at sarcolemmal attachments to underlying adherens junctions.     

Antiviral treatment of chronic hepatitis B virus infection: infectious virus cannot be detected in patient serum after permanent responses to treatment

Fourteen chimpanzees were inoculated with pre- and posttreatment sera from seven patients with persistent hepatitis B virus infection and chronic hepatitis who had permanent responses of their infection to treatment with interferon and/or adenine arabinoside. Inoculation of pretreatment serum at a dilution of 10(-8) from a patient with a Type I response to treatment [disappearance of Dane particle DNA polymerase (DNAP) activity, HBeAg, and HBsAg from serum] resulted in infection, while undiluted posttreatment serum (all markers negative) failed to infect another animal. Pretreatment sera (DNAP, HBeAg, and HBsAg positive) from all six patients with a Type II response to treatment (disappearance of DNAP activity and HBeAg but not HBsAg from serum) led to infection in six chimpanzees after inoculation of serum dilutions varying between 10(-2) and 10(-7). Inoculation of undiluted posttreatment sera (HBsAg positive and DNAP and HBeAg negative) from the same six patients produced no evidence of hepatitis B virus infection in another six animals. These results indicate that a Type I or II response to treatment with these antiviral agents reduces the infectivity in the serum of patients with chronic hepatitis B to below the level of detection by this assay. Such changes should be useful in interrupting spread of the infection between individuals. Our findings suggest that the serum of some patients who, without treatment are HBsAg positive and DNAP and HBeAg negative, may also be free of detectable infectious hepatitis B virus.     

Ischemia-specific phosphorylation and myofilament translocation of heat shock protein 27 precedes alpha B-crystallin and occurs independently of reactive oxygen species in rabbit myocardium

Heat shock protein 27 (Hsp27) and alpha B-crystallin (alphaBC) are small heat shock proteins that stabilize the myofilament during stress. We utilized two-dimensional gel electrophoresis (2-DE), phospho-fluorescence staining, titanium dioxide (TiO(2)) phosphopeptide purification and mass spectrometry (MS) to fully characterize isoelectric point (pI) variants of Hsp27 and alphaBC in rabbit myocardium subjected to brief ischemia/reperfusion (I/R) injury. Four variants of Hsp27 were detected, two of which were phosphorylated: HSP1 (at three sites, Ser15, Ser78 and Ser82) and HSP2 (at Ser15 and Ser82, but not Ser78). Three variants of alphaBC were detected: alphaBC1 was phosphorylated (at Ser59 alone) and alphaBC2 was deamidated (at Asn146). No modifications were found in the remaining variants. Both phospho-Hsp27 variants increased in abundance in tissue subjected to brief I/R injury (15 min I/60 min R) and ischemia without subsequent reflow (15I/0R), and these increases were not affected by addition of the potent antioxidant, N-(2-mercaptopropionyl) glycine (MPG; 15I/60R + MPG and 15I/0R + MPG). Abundance of native and phosphorylated (but not deamidated) alphaBC was elevated following 15I/60R; however, these increases were ameliorated by the presence of MPG, and did not occur in tissue subjected to 15I/0R. Both phospho-Hsp27 variants and phospho-alphaBC translocated to the myofilament following 15I/60R. Increased myofilament association of phospho-Hsp27 was not influenced by MPG, and there was a greater proportion of HSP2 than HSP1 in this fraction. MPG inhibited phospho-alphaBC translocation and increased alphaBC association with the myofilament did not occur during 15I/0R. Increased phosphorylation of Hsp27 is ischemia-specific and not influenced by reactive oxygen species (ROS), while increased expression and phosphorylation of alphaBC are ROS-dependant.     

Putative anti-muscarinic antibodies cannot be detected in patients with primary Sjogren's syndrome using conventional immunological approaches

OBJECTIVE: To determine whether autoantibodies directed against muscarinic M3 receptors are present in the serum of patients with primary Sjogren's syndrome (pSS), and if so whether these autoantibodies inhibit secretion by intact salivary acinar cells. METHODS: IgG was purified by affinity chromatography using protein G from sera collected from 15 patients with pSS. Antibody detection was by Western blotting, whole-cell enzyme-linked immunosorbent assay (ELISA) and immunoblotting. The antisecretory activity of the IgG faction was determined using fura-2 microfluorimetry to measure changes in intracellular Ca(2+) activity ([Ca(2+)](i)) in human and mouse salivary gland acinar cells and in Chinese hamster ovary (CHO) cells transfected with human M3 receptors (CHO-M3). RESULTS: We found no specific M3 receptor recognition by the IgG fraction obtained from pSS patients using either Western blotting or ELISA or immunoblot techniques in which epitope conformation were preserved. Chronic exposure to pSS IgG had no effect on agonist-evoked Ca(2+) signals measured in human or mouse submandibular acinar cells or in CHO-M3 cells. However, acute application of IgG from Sjogren's syndrome patients produced a rapidly reversible reduction in the agonist-stimulated elevation in [Ca(2+)](i). CONCLUSION: These data represent the first demonstration of salivary acinar cell inhibition by pSS IgG; however, this inhibition was found to be reversible. Our data also show that pSS IgG binding to M3R cannot be visualized by conventional immunological approaches.     

Is there a component of coronary collateral flow which cannot be detected by radiolabelled microspheres?

The possibility of a component of collateral flow to the ischaemic myocardium that cannot be detected by the radiolabelled microsphere technique was examined in the cat, rat, and rabbit in vivo. Animals were anaesthetised and a coronary artery ligated. The regional distribution of blood flow was assessed by the simultaneous injection of 141Ce labelled microspheres and 86Rb. Blue dye was injected into the circulation to delineate the perfused tissue and the heart removed, frozen, and lyophilised, after which tissue was separated into ischaemic and non-ischaemic fractions and the radioactivity of each assessed. Flow to the ischaemic zone, expressed as a percentage of that in the non-ischaemic tissue, for 86Rb based assessments and 141Ce measurements was: for the cat 21.6(3.9)% and 12.4(1.4)% (n = 12 hearts); the rat 13.2(2.6)% and 5.2(1.8)% (n = 9); and the rabbit 7.2(0.8)% and 1.9(0.8)% (n = 5) respectively. In all species there was a statistically significant difference (p less than 0.01) between the results for the two markers. These results suggest either a microsphere insensitive component of collateral flow or some methodological inadequacy of one of the assessment techniques. The 86Rb data were corrected for possible artefacts due to the flow rate dependent extraction of the isotope. The new 86Rb values for collateral flow in the cat, rat, and rabbit were 15.2(2.9)% (NS vs microspheres), 9.5(1.9)% (p less than 0.05), and 5.2(0.5)% (p less than 0.05) respectively. Although these values were closer to the 141Ce microsphere values, significant differences between the two results still remained, possibly owing to other limitations of the 86Rb method.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prolonged synovitis in pediatric Lyme arthritis cannot be predicted by clinical or laboratory parameters

Ten percent of Lyme arthritis (LA) patients have continued synovitis despite antimicrobial therapy. The current study was designed to (1) investigate predictors of prolonged disease and (2) further define natural history of pediatric LA. Medical records of 94 children fulfilling Centers for Disease Control criteria for Lyme disease were reviewed, classified into groups according to duration of synovitis, and SPSS statistical software was used for analysis. Thirty-nine percent required >6 months and 13% required >12 months to resolve LA. Pearson correlation between duration of symptoms of LA pretreatment and duration of synovitis was not significant. When patients were stratified by group, no differences were found for age, antinuclear antibodies positivity, enzyme-linked immunosorbent assay titer, or reactivity of Western blot using parametric and nonparametric tests. Linear and logistic regression showed no predictors of disease duration. One third of pediatric LA patients require >6 months to resolve synovitis. Duration is not associated with delay in treatment, age, or seroreactivity.     

Differential distribution of estrogen and progesterone receptors in rabbit uterus detected by dual immunofluorescence

The action of sex steroids on the growth and differentiation of target tissues requires the presence of specific intracellular receptors. We compared the distribution of cells containing estrogen receptor (ER) and/or progesterone receptor (PR) in rabbit uterus by immunohistochemistry using monoclonal antibodies directed against these receptors. Initial experiments using serial cryostat sections surprisingly revealed the intensity of staining for ER to be inversely proportional to that of PR, as follows: ER, luminal and glandular epithelium greater than myometrium greater than stroma; PR, stroma greater than myometrium greater than glands greater than luminal epithelium. Localization was strictly confined to the nuclei of target cells. Single and dual immunofluorescent labeling of ER and PR in cryostat sections was accomplished using fluorochromes with differing emission spectra. Individual fields of dual labeled sections were examined for red [phycoerythrin (ER)] and green [fluorescein (PR)] fluorescence, with the same distribution as noted by single antibody immunohistochemistry. Myometrial nuclei displayed fluorescence of equivalent relative intensity for both antibodies. Further, sequential exposure photomicrography (exposure first in the spectrum of phycoerythrin emission, followed by exposure in the spectrum of fluorescein emission) revealed the presence of occasional stromal cells staining only for PR and some luminal cells staining only for ER. This differential distribution of ER and PR within various cell populations of rabbit is a novel observation and challenges current concepts of receptor regulation. Dual immunofluorescent localization of both ER and PR within individual cells provides a unique perspective from which to investigate the interactive influences of these sex steroid receptors at the cellular level.     

Pseudomonas aeruginosa and Burkholderia cepacia cannot be detected by PCR in the breath condensate of patients with cystic fibrosis

The collection of sputum for microbiological examination in young cystic fibrosis patients can be very difficult. However, a knowledge of bacterial flora colonizing the patient's airways is of paramount importance for proper antimicrobial therapy. It is also known that cystic fibrosis patients colonized by Pseudomonas species have a poorer prognosis than Pseudomonas-negative patients. Noninvasive ways of diagnosing airway inflammation that require only minimal cooperation of the patient might yield new possibilities for early detection of airway colonisation. The breath condensate method as a noninvasive diagnostic technique seems especially appropriate for use in children. Therefore, the aim of this study was to evaluate whether the breath condensate method could be used for detection of Pseudomonas species in children with cystic fibrosis. In total, 32 breath condensate and seven sputum samples were obtained from 13 cystic fibrosis patients with Pseudomonas aeruginosa- or Burkholderia cepacia-positive sputum culture (20 samples were obtained during forced expiration). PCR for combined detection of Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Burkholderia cepacia was performed. PCR results of all breath condensate samples were negative for Pseudomonas aeruginosa, Stenotrophomonas maltophilia, or Burkholderia cepacia, while all sputum sample results were positive. A minimum DNA quantity of 10 fg could be detected in dilution series of the positive control group. We conclude that the breath condensate method cannot be used as a tool for detection of Pseudomonas species.     

Mesenchymal stem cells are susceptible to human herpesviruses, but viral DNA cannot be detected in the healthy seropositive individual

Allogeneic stem cell transplantation is often complicated by reactivation of herpesviruses. Mesenchymal stem cells (MSC) are immunomodulatory and may be used to treat graft-versus-host disease. We investigated if herpesviruses infect and can be transmitted by MSC, and if MSC suppress immune responses to various infectious agents. Mesenchymal stem cells from healthy seropositive donors were evaluated with polymerase chain reaction for the most common herpesviruses: cytomegalovirus (CMV), herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2, Epstein-Barr virus (EBV) and varicella zoster virus. The cytopathological effect (CPE) was investigated and viral antigens analyzed by immunofluorescence after in vitro exposure to CMV, HSV-1 and EBV. We also studied MSC effect on lymphocyte stimulation induced by various infectious agents. No viral DNA could be detected in MSC isolated from healthy seropositive individuals. However, a CPE was noted and intracellular viral antigens detected after infection in vitro by CMV and HSV-1, but not by EBV. The CMV and HSV-1 infections were productive. Lymphocyte proliferation by herpesviruses, candida mannan and protein A from Staphylococcus aureus was suppressed by MSC. The data indicate that the risk of herpesvirus transmission by transplantation of MSC from healthy seropositive donors is low. However, MSC may be susceptible to infection if infused in a patient with CMV or HSV-1 viremia. MSC transplantation may compromise the host's defense against infectious agents.     

Symptom clusters cannot be used in distinguishing Helicobacter pylori positive or negative patients with functional dyspepsia

Background: A retrospective study was done in consecutive patients in order to seek out whether dyspepsia subgroups (reflux-like, ulcer-like, and, dysmotility-like dyspepsia) can be useful in describing Helicobacter pylori positive and negative functional dyspepsia.Methods: Consecutive patients who underwent upper gastrointestinal endoscopy were included if no macroscopic lesions in oesophagus, stomach or duodenum were seen. Antral biopsy specimens were taken for detection of H. pylori. A validated questionnaire was used. Results: Six hundred patients fulfilled the inclusion criteria. Three hundred were positive for H. pylori. In the H. pylori positive (HP+) patients only 3 (1.2%) had `pure' reflux-like dyspepsia, 17 (6.9%) had ulcer-like dyspepsia and 10 (4%) suffered from dysmotility-like dyspepsia. In the H. pylori negative (HP−) patients these figures were 6 (2.3%), 17 (6.6%) and 7 (2.7%), respectively (ns). The majority of patients had a combination of complaints belonging to the three subgroups. Reflux-like dyspepsia was present in 179 (73%) HP+ dyspeptics and 195 (76%) HP−'s (ns). Ulcer-like dyspepsia was present in 213 (88%) HP+ cases and 233 (92%) HP−'s (ns). Dysmotility-like dyspepsia was present in 197 (81%) HP+'s and 212 (82%) HP−'s (ns).Conclusions: It is concluded that it is not possible to identify patients suffering from H. pylori infection on basis of symptom clusters.     

Constitutive phosphorylation of I kappa B alpha by casein kinase II.

The NF-kappa B/Rel proteins are sequestered in the cytoplasm in association with the phosphorylated form of I kappa B alpha. Upon induction with a wide variety of agents, the activity of NF-kappa B/Rel proteins is preceded by the rapid degradation of I kappa B alpha protein. We report the identification and partial purification of a cellular kinase from unstimulated or stimulated murine cells, which specifically phosphorylates the C terminus of I kappa B alpha. There are several consensus sites for casein kinase II (CKII) in the C-terminal region of I kappa B alpha. Additionally, the activity of the cellular kinase is blocked by antibodies against the alpha subunit of CKII. No phosphorylation of the C-terminal region of I kappa B alpha can be detected if the five possible serine and threonine residues that can be phosphorylated by CKII are mutated to alanine. A two-dimensional tryptic phosphopeptide map of I kappa B alpha from unstimulated cells was identical to that obtained by in vitro phosphorylation of I kappa B alpha with the partially purified cellular kinase. We propose that constitutive phosphorylation of I kappa B alpha is carried out by CKII.     

Absence of low-molecular-weight alpha crystallin in nuclear region of old human lenses.

Examination of old human lenses indicates that low-molecular-weight alpha crystallin is not present in the inner 30-40%, the nucleus, of the lens. The remainder of such lenses, the periphery, contains normal levels of this protein. This finding is in marked contrast to observations in young lenses, where a large quantity of this protein is found throughout the tissue.     

Athyroid Pax8-/- mice cannot be rescued by the inactivation of thyroid hormone receptor alpha1

The Pax8(-/-) mouse provides an ideal animal model to study the consequences of congenital hypothyroidism, because its only known defect is the absence of thyroid follicular cells. Pax8(-/-) mice are, therefore, completely athyroid in postnatal life and die around weaning unless they are substituted with thyroid hormones. As reported recently, Pax8(-/-) mice can also be rescued and survive to adulthood by the additional elimination of the entire thyroid hormone receptor alpha (TRalpha) gene, yielding Pax8(-/-)TRalpha(o/o) double-knockout animals. This observation has led to the hypothesis that unliganded TRalpha1 might be responsible for the lethal phenotype observed in Pax8(-/-) animals. In this study we report the generation of Pax8(-/-)TRalpha1(-/-) double-knockout mice that still express the non-T(3)-binding TR isoforms alpha2 and Deltaalpha2. These animals closely resemble the phenotype of Pax8(-/-) mice, including growth retardation and a completely distorted appearance of the pituitary with thyrotroph hyperplasia and hypertrophy, extremely high TSH mRNA levels, reduced GH mRNA expression, and the almost complete absence of lactotrophs. Like Pax8(-/-) mice, Pax8(-/-)TRalpha1(-/-) compound mutants die around weaning unless they are substituted with thyroid hormones. These findings do not support the previous interpretation that the short life span of Pax8(-/-) mice is due to the negative effects of the TRalpha1 aporeceptor, but, rather, suggest a more complex mechanism involving TRalpha2 and an unliganded TR isoform.     

Differential effects of Clostridium difficile toxins A and B on rabbit ileum

The pathogenesis of Clostridium difficile enterocolitis appears to involve colonization of the bowel followed by release of toxin A, an enterotoxin, and toxin B, a cytotoxin. The purpose of this study was to determine the effect of purified toxins A and B on intestinal secretion, epithelial permeability, and morphology in perfused rabbit ileal loops. Intestinal permeability after toxin exposure was assessed by blood-to-lumen clearance of [3H]mannitol. Toxin A at doses of 5-100 micrograms/10 cm ileal loop caused a threefold to fivefold increase in [3H]mannitol permeability (p less than 0.001) vs. equal concentrations of toxin B or buffer control. In addition, perfusate from toxin A-exposed loops contained significantly more neutrophils (p less than 0.001) than toxin B or control loops. Toxin A caused severe epithelial cell necrosis with destruction of villi and polymorphonuclear infiltration. Electron microscopy of mucosa subjected to a low dose of toxin revealed widespread nonspecific dilatation of endoplasmic reticulum and mitochondrial swelling. In contrast to these effects of toxin A in ileal loops, in vitro experiments with ileal explants in short-term organ culture revealed that toxin A had no effect on epithelial cell permeability, protein synthesis, release of alkaline phosphatase, or morphology. Our results show that purified toxin A but not toxin B causes severe inflammatory enteritis in rabbit ileal loops, but has no discernable effect on rabbit ileum in vitro. We speculate that toxin A may contribute significantly to intestinal damage in C. difficile-associated colitis and diarrhea.     

Reduction in albuminuria with dapagliflozin cannot be predicted by baseline clinical characteristics or changes in most other risk markers

The sodium glucose co-transporter-2 inhibitor dapagliflozin has been shown to decrease urinary albumin-to-creatinine ratio (UACR). This effect, however, varies among individual patients. In this study, we assessed the baseline characteristics and concurrent changes in other cardiovascular risk markers that might be associated with UACR response to dapagliflozin. A pooled analysis of 11 phase 3 randomized, controlled clinical trials was performed. UACR change from baseline after 24 weeks treatment with dapagliflozin 10 mg/d in 531 patients with type 2 diabetes and UACR ≥30 mg/g at baseline was determined. UACR response was defined as >30% reduction from baseline at 24 weeks, whereas UACR non-response was defined as ≤30% reduction at 24 weeks. A total of 288 (54%) patients were classified as responders and 243 (46%) as non-responders. At 24 weeks, the UACR-adjusted mean change from baseline was −71.2% and 25.9% in responders and non-responders, respectively. Baseline characteristics were similar between both groups. Changes in HbA1c and body weight were comparable across groups. Responders showed a numerically larger reduction in estimated glomerular filtration rate and systolic blood pressure versus non-responders. UACR reduction to dapagliflozin is an individual characteristic that cannot be predicted by baseline clinical features or changes in metabolic variables. Whether UACR response would improve long-term renal and cardiovascular outcomes remains to be determined.