Myocardial work in chronic kidney disease: insights from the CPH-CKD ECHO Study.

BACKGROUND: Myocardial work is a novel echocardiographic measure that offers detailed insights into cardiac mechanics. We sought to characterize cardiac function by myocardial work in patients with chronic kidney disease (CKD). METHODS: We prospectively enrolled 757 patients with non-dialysis-dependent CKD and 174 age- and sex-matched controls. Echocardiographic pressure-strain loop analysis was performed to acquire the global work index (GWI). Linear regressions were performed to investigate the association between estimated glomerular filtration rate (eGFR) and urine albumin-creatinine ratio (UACR) to GWI. RESULTS: Patients with CKD had a mean age of 57 years, 61% were men, and median eGFR was 42 mL/min/1.73 m2. Overall, no difference in GWI was observed between patients and controls (1879 vs. 1943 mmHg%, p = 0.06). However, a stepwise decline in GWI was observed for controls vs. patients with CKD without left ventricular hypertrophy vs. patients with CKD and left ventricular hypertrophy (GWI, 1943 vs. 1887 vs. 1789 mmHg%; p for trend = 0.030). In patients with CKD, eGFR was not associated with GWI by linear regression. However, diabetes modified this association (p for interaction = 0.007), such that per 10 mL/min/1.73 m2 decrease in eGFR, GWI decreased by 22 (9-35) mmHg% (p = 0.001) after multivariable adjustments in patients without diabetes, but with no association between eGFR and GWI in patients with diabetes. No association was observed between UACR and GWI. CONCLUSION: Patients with CKD and left ventricular hypertrophy exhibited lower myocardial work compared to matched controls. Furthermore, decreasing eGFR was associated with decreasing myocardial work only in patients without diabetes. No association to UACR was observed.

The role of aetiology in cardiac manifestations of chronic kidney disease: the CPH-CKD ECHO study.

PURPOSE: We investigated the associations between cardiac parameters and aetiologies of CKD in an exploratory study. METHODS: The study population consisted of 883 participants, 174 controls and 709 patients with aetiologies of CKD including diabetic nephropathy/renovascular KD in diabetes mellitus, hypertensive/renovascular nephropathy, tubulointerstitial nephritis, glomerulonephritis/vasculitis, polycystic KD (PKD), and CKD of unknown origin. Echocardiographic measures included left ventricular (LV) ejection fraction, global longitudinal, area, and radial strain, E/e' ratio, and LV mass index. These were compared between each aetiological group and controls in unadjusted and adjusted analysis. RESULTS: In unadjusted analysis, patients with diabetic nephropathy/renovascular KD in diabetes mellitus, had impaired LV ejection fraction (Median [IQR]: 56% [49.9,60.69] vs. 60.8% [57.7,64.1]), global longitudinal (mean ± SD: 13.1 ± 3.5% vs. 15.5 ± 2.6%), area (24.1 ± 5.8% vs. 28.5 ± 4.2%), and radial strain (36.2 ± 11.2% vs. 44.1 ± 9.7%), and increased LV mass index (89.1 g/m2 [71.8,104.9] vs. 69,0 g/m2 [57.9,80.8]) and E/e' ratio (10.6 [8.5,12.6] vs. 7 [5.8,8.3], p < 0.001 for all) compared with controls. Associations were similar for CKD of unknown origin. Patients with hypertensive/renovascular nephropathy had impaired global longitudinal and area strain, and higher E/e' ratio. Patients with glomerulonephritis/vasculitis had higher LV mass index, while patients with PKD had better global longitudinal strain than controls. All findings remained significant in adjusted analysis, except for the impaired global longitudinal strain in hypertensive/renovascular nephropathy. CONCLUSION: Glomerulonephritis/vasculitis, hypertensive/renovascular nephropathy, CKD of unknown origin, and diabetic nephropathy/renovascular KD in diabetes mellitus were increasingly associated with adverse cardiac findings, while PKD and tubulointerstitial nephritis were not. Aetiology might play a role regarding the cardiac manifestations of CKD.

Blood biomarkers improve the prediction of prevalent and incident severe chronic kidney disease.

BACKGROUND: The prevalence of chronic kidney disease (CKD) is high. Identification of cases with CKD or at high risk of developing it is important to tailor early interventions. The objective of this study was to identify blood metabolites associated with prevalent and incident severe CKD, and to quantify the corresponding improvement in CKD detection and prediction. METHODS: Data from four cohorts were analyzed: Singapore Epidemiology of Eye Diseases (SEED) (n = 8802), Copenhagen Chronic Kidney Disease (CPH) (n = 916), Singapore Diabetic Nephropathy (n = 714), and UK Biobank (UKBB) (n = 103,051). Prevalent CKD (stages 3-5) was defined as estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2; incident severe CKD as CKD-related mortality or kidney failure occurring within 10 years. We used multivariable regressions to identify, among 146 blood metabolites, those associated with CKD, and quantify the corresponding increase in performance. RESULTS: Chronic kidney disease prevalence (stages 3-5) and severe incidence were 11.4% and 2.2% in SEED, and 2.3% and 0.2% in UKBB. Firstly, phenylalanine (Odds Ratio [OR] 1-SD increase = 1.83 [1.73, 1.93]), tyrosine (OR = 0.75 [0.71, 0.79]), docosahexaenoic acid (OR = 0.90 [0.85, 0.95]), citrate (OR = 1.41 [1.34, 1.47]) and triglycerides in medium high density lipoprotein (OR = 1.07 [1.02, 1.13]) were associated with prevalent stages 3-5 CKD. Mendelian randomization analyses suggested causal relationships. Adding these metabolites beyond traditional risk factors increased the area under the curve (AUC) by 3% and the sensitivity by 7%. Secondly, lactate (HR = 1.33 [1.08, 1.64]) and tyrosine (HR = 0.74 [0.58, 0.95]) were associated with incident severe CKD among individuals with eGFR < 90 mL/min/1.73 m2 at baseline. These metabolites increased the c-index by 2% and sensitivity by 5% when added to traditional risk factors. CONCLUSION: The performance improvements of CKD detection and prediction achieved by adding metabolites to traditional risk factors are modest and further research is necessary to fully understand the clinical implications of these findings.

Plasma activin A rises with declining kidney function and is independently associated with mortality in patients with chronic kidney disease.

Background: Plasma (p-)activin A is elevated in chronic kidney disease-mineral and bone disorder (CKD-MBD). Activin A inhibition ameliorates CKD-MBD complications (vascular calcification and bone disease) in rodent CKD models. We examined whether p-activin A was associated with major adverse cardiovascular events (MACE), all-cause mortality and CKD-MBD complications in CKD patients. Methods: The study included 916 participants (741 patients and 175 controls) from the prospective Copenhagen CKD cohort. Comparisons of p-activin A with estimated glomerular filtration rate (eGFR), coronary and thoracic aorta Agatston scores, and bone mineral density (BMD) were evaluated by univariable linear regression using Spearman's rank correlation, analysis of covariance and ordinal logistic regression with adjustments. Association of p-activin A with rates of MACE and all-cause mortality was evaluated by the Aalen-Johansen or Kaplan-Meier estimator, with subsequent multiple Cox regression analyses. Results: P-activin A was increased by CKD stage 3 (124-225 pg/mL, P < .001) and correlated inversely with eGFR (r = -0.53, P < 0.01). P-activin A was associated with all-cause mortality [97 events, hazard ratio 1.55 (95% confidence interval 1.04; 2.32), P < 0.05] after adjusting for age, sex, diabetes mellitus (DM) and eGFR. Median follow-up was 4.36 (interquartile range 3.64-4.75) years. The association with MACE was not significant after eGFR adjustment. Agatston scores and BMD were not associated with p-activin A. Conclusion: P-activin A increased with declining kidney function and was associated with all-cause mortality independently of age, sex, DM and eGFR. No association with MACE, vascular calcification or BMD was demonstrated.

Adult presentation of ornithine transcarbamylase deficiency: a possible cause of hyperammonemia after high-dose chemotherapy and stem cell transplantation.

Hyperammonemia is a rare and often fatal complication following the conditioning therapy in autologous and allogeneic stem cell transplant recipients. It is characterized by anorexia, vomiting, lethargy and coma without any other apparent cause. The diagnosis is often delayed because symptoms can be subtle and ammonia is usually not included among the routine analyzes. Previous reports have not identified the molecular mechanisms behind hyperammonemia in stem cell transplant recipients. Urea cycle disorders (UCDs) are inborn errors of metabolism leading to hyperammonemia that usually presents in early childhood, whereas first presentation in adults is less common. Here we describe an adult woman with hyperammonemia following autologous stem cell transplantation for multiple myeloma. No apparent cause of hyperammonemia was identified, including portosystemic shunting, liver dysfunction or recent hyperammonemia-inducing chemotherapy. Hyperammonemia, normal blood glucose as well as anion gap and a previous history of two male newborns that died early after birth, prompted biochemical and genetic investigations for a UCD. A heterozygous variant in the X-linked gene encoding ornithine transcarbamylase (OTC) was identified and was regarded as a cause of UCD. The patient improved after treatment with nitrogen scavengers and high caloric intake according to a UCD protocol. This case report suggests that UCD should be considered as a possible cause of hyperammonemia following stem cell transplantation.

Coronary and extra-coronary artery calcium scores as predictors of cardiovascular events and mortality in chronic kidney disease stages 1-5: a prospective cohort study.

BACKGROUND: Vascular calcification is a known risk factor for cardiovascular events and mortality in patients with chronic kidney disease (CKD). However, since there is a lack of studies examining several arterial regions at a time, we aimed to evaluate the risk of major adverse cardiovascular events (MACE) and all-cause mortality according to calcium scores in five major arterial sites. METHODS: This was a prospective study of 580 patients from the Copenhagen CKD Cohort. Multidetector computed tomography of the coronary and carotid arteries, the thoracic aorta, the abdominal aorta and the iliac arteries was used to determine vascular calcification at baseline. Calcium scores were divided into categories: 0, 1-100, 101-400 and >400. RESULTS: During the follow-up period of 4.1 years a total of 59 cardiovascular events and 64 all-cause deaths occurred. In Cox proportional hazards models adjusted for age, sex, estimated glomerular filtration rate, hypertension, diabetes mellitus, hypercholesterolemia and smoking, only the coronary and carotid arteries, and the thoracic aorta were independent predictors of the designated endpoints. When examining the potential of calcification in the five arterial sites for predicting MACE, the difference in C-statistic was also most pronounced in these three sites, at 0.21 [95% confidence interval (CI) 0.16%-0.26%, P < .001], 0.26 (95% CI 0.22%-0.3%, P < .001) and 0.20 (95% CI 0.16%-0.24%, P < .001), respectively. This trend also applied to all-cause mortality. CONCLUSIONS: The overall results, including data on specificity, suggest that calcium scores of the coronary and carotid arteries have the most potential for identifying patients with CKD at high cardiovascular risk and for evaluating new therapies.

Associations Between Albuminuria, Estimated GFR and Cardiac Phenotype in a Cohort with Chronic Kidney Disease: The CPH-CKD ECHO Study.

OBJECTIVE: Echocardiographic findings in chronic kidney disease (CKD) vary. We sought to estimate the prevalence of abnormal cardiac structure and function in patients with CKD and their association to estimated glomerular filtration rate (eGFR) and urine albumin/creatinine ratio (UACR). METHODS: We prospectively enrolled 825 outpatients with non-dialysis-dependent CKD, mean age 58± 13 yrs, and 175 matched healthy controls, mean age 60±12 yrs. Echocardiography included assessment of left ventricular (LV) hypertrophy, LV ejection fraction (LVEF), global longitudinal strain (GLS) and diastolic dysfunction according to ASE/EACVI guidelines. RESULTS: LV hypertrophy was found in 9% of patients vs. 1.7% of controls (p=0.005) was independently associated with UACR (p=0.002). Median LVEF was 59.4% (IQR 55.2, 62.8) in patients vs. 60.8% (57.7, 64.1) in controls (p=0.002). GLS was decreased in patients with eGFR <60ml/min/1.73m² (-17.6%±3.1%) vs. patients with higher eGFR (19.0%±2.2%, p<0.001), who were similar to controls. Diastolic dysfunction was detected in 55% of patients and in 34% of controls. LIMITATIONS: Non-random sampling, cross-sectional analysis. CONCLUSIONS: We report lower prevalence of hypertrophy than previous studies, but similar measurements of systolic and diastolic function. Cardiac remodeling in CKD may be influenced by treatment modalities, demographics, comorbidities and renal pathology.

The metabolic signature of cardiovascular disease and arterial calcification in patients with chronic kidney disease.

BACKGROUND AND AIMS: The relationship between chronic kidney disease (CKD) and cardiovascular events is well-established. Clinically recognised risk factors of cardiovascular disease cannot fully explain this association. The objective of the present cross-sectional study was to investigate associations between serum metabolites and prevalent cardiovascular disease, as well as subclinical cardiovascular disease measured as coronary artery calcium score (CACS) in patients with CKD. METHODS: More than 200 preselected metabolites were quantified using nuclear magnetic resonance spectroscopy in 725 patients and 174 controls from the Copenhagen CKD Cohort. CACS was determined by computed tomography. RESULTS: Mean age of patients was 57.8 years, and 444 (61.3%) were men. Most of patients had hypercholesterolemia, and 133 (18.3%) had type 2 diabetes. Overall, 85 metabolites were significantly associated with prevalent cardiovascular disease in a model adjusted for eGFR, age, and sex, as well as Bonferroni correction for multiple testing (p < 0.001). After further adjusting for diabetes, BMI, smoking, and cholesterol-lowering medication, the significance was lost for all but six metabolites (concentration of ApoA-1, cholesterol in total HDL and HDL2, total lipids and phospholipids in large HDL particles, and the ratio of phospholipids to total lipids in smaller VLDL particles). Of the 85 metabolites associated with prevalent cardiovascular disease, 71 were also associated with CACS in a similar pattern. Yet, in the model adjusted for all seven cardiovascular risk factors, only serum glucose levels and the ratio of triglycerides to total lipids in larger LDL particles remained significant. CONCLUSIONS: In patients with CKD, associations with prevalent cardiovascular disease were mainly found for HDL-related metabolites, while CACS was associated with glucose levels and increased triglycerides to total lipids ratio in LDL particles.

Prevalence of non-alcoholic fatty liver disease in patients with chronic kidney disease: a cross-sectional study.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease and represents a wide spectrum ranging from mild steatosis to non-alcoholic steatohepatitis with or without fibrosis to overt cirrhosis. Patients with NAFLD have a high risk of developing cardiovascular disease and chronic kidney disease (CKD). So far there has been scarce evidence of the prevalence of NAFLD among patients with CKD. We investigated the prevalence of moderate-severe hepatic steatosis graded according to the definition of NAFLD in a cohort of patients with CKD. METHODS: Hepatic liver fat content was evaluated by computed tomography (CT) scan in 291 patients from the Copenhagen CKD Cohort Study and in 866 age- and sex-matched individuals with normal kidney function from the Copenhagen General Population Study. Liver attenuation density <48 HU was used as a cut-off value for moderate-severe hepatic steatosis. RESULTS: The prevalence of moderate-severe hepatic steatosis was 7.9 and 10.7% (P = 0.177) among patients with CKD and controls, respectively. No association between liver fat content and CKD stage was found. In the pooled dataset from both cohorts, adjusted odds ratios for moderate-severe hepatic steatosis among persons with diabetes, overweight and obesity were 3.1 [95% confidence interval (CI) 1.6-5.9], 14.8 (95% CI 4.6-47.9) and 42.0 (95% CI 12.9-136.6), respectively. CONCLUSIONS: In a cohort of 291 patients with CKD, kidney function was not associated with the prevalence of moderate-severe hepatic steatosis as assessed by CT scan.

Left ventricular structure and function in patients with chronic kidney disease assessed by 3D echocardiography: the CPH-CKD ECHO study.

Cardiovascular disease is the leading cause of mortality amongst patients with chronic kidney disease (CKD). This is the first study using 3-dimensional echocardiography (3DE) to investigate associations between adverse changes of the left ventricle, and different stages of CKD. Participants were recruited from the Copenhagen CKD cohort study and the Herlev-Gentofte CKD cohort study. Patients were stratified according to GFR category (G1 + 2: eGFR ≥ 60 mL/min/1.73 m2, G3: eGFR = 30-59 mL/min/1.73 m2, and G4 + 5: eGFR ≤ 29 mL/min/1.73 m2), and according to albuminuria (A1: UACR < 30 mg/g, A2: 30-300 mg/g, A3: > 300 mg/g). Echocardiograms were analysed for left ventricular (LV) mass index (LVMi), LV ejection fraction (LVEF), and global strain measures. In adjusted analysis, eGFR groups were adjusted for confounders and albuminuria category, while albuminuria groups were adjusted for confounders and GFR category. The study population consisted of 662 outpatients with CKD and 169 controls. Mean age was 57 ± 13 years, and 61% were males. Mean LVEF and global longitudinal strain (GLS) were increasingly impaired across eGFR groups: LVEF = 60.1%, 58.4%, and 57.8% (p = 0.013), GLS = - 16.1%, - 14.8%, and - 14.6% (p < 0.0001) for G1 + 2, G3, and G4 + 5. LVMi and prevalence of LV hypertrophy increased with albuminuria severity: mean LVMi = 87.9 g/m2, 88.1 g/m2, and 92.1 g/m2 (p = 0.007) from A1-3. Adjusted analysis confirmed reduced LVEF in G3 compared with G1 + 2, and increased LVMi in A3 compared with A1. Increasingly impaired eGFR was associated with adverse changes in LV systolic function, while albuminuria was associated with adverse changes in LV mass assessed by 3DE. Their associations were independent of each other.

Carotid plaque thickness is increased in chronic kidney disease and associated with carotid and coronary calcification.

BACKGROUND: Chronic kidney disease accelerates both atherosclerosis and arterial calcification. The aim of the present study was to explore whether maximal carotid plaque thickness (cPTmax) was increased in patients with chronic kidney disease compared to controls and associated with cardiovascular disease and severity of calcification in the carotid and coronary arteries. METHODS: The study group consisted of 200 patients with chronic kidney disease stage 3 from the Copenhagen Chronic Kidney Disease Cohort and 121 age- and sex-matched controls. cPTmax was assessed by ultrasound and arterial calcification by computed tomography scanning. RESULTS: Carotid plaques were present in 58% of patients (n = 115) compared with 40% of controls (n = 48), p = 0.002. Among participants with plaques, cPTmax (median, interquartile range) was significantly higher in patients compared with controls (1.9 (1.4-2.3) versus 1.5 (1.2-1.8) mm), p = 0.001. Cardiovascular disease was present in 9% of patients without plaques (n = 85), 23% of patients with cPTmax 1.0-1.9 mm (n = 69) and 35% of patients with cPTmax >1.9 mm (n = 46), p = 0.001. Carotid and coronary calcium scores >400 were present in 0% and 4%, respectively, of patients with no carotid plaques, in 19% and 24% of patients with cPTmax 1.0-1.9 mm, and in 48% and 53% of patients with cPTmax >1.9 mm, p<0.001. CONCLUSIONS: This is the first study showing that cPTmax is increased in patients with chronic kidney disease stage 3 compared to controls and closely associated with prevalent cardiovascular disease and severity of calcification in both the carotid and coronary arteries.

Regional distribution and severity of arterial calcification in patients with chronic kidney disease stages 1-5: a cross-sectional study of the Copenhagen chronic kidney disease cohort.

BACKGROUND: Patients with chronic kidney disease (CKD) and arterial calcification are considered at increased risk of adverse cardiovascular outcomes. However, the optimal site for measurement of arterial calcification has not been determined. The primary aim of this study was to examine the pattern of arterial calcification in different stages of CKD. METHODS: This was an observational, cross-sectional study that included 580 individuals with CKD stages 1-5 (no dialysis) from the Copenhagen CKD Cohort. Calcification of the carotid, coronary and iliac arteries, thoracic and abdominal aorta was assessed using non-contrast multidetector computed tomography scans and quantified according to the Agatston method. Based on the distribution of Agatston scores in the selected arterial region, the subjects were divided into calcium score categories of 0 (no calcification), 1-100, 101-400 and > 400. RESULTS: Participants with CKD stages 3-5 had the highest prevalence of calcification and the highest frequency of calcium scores > 400 in all arterial sites. Calcification in at least one arterial site was present in > 90% of patients with CKD stage 3. In all five CKD stages prevalence of calcification was greatest in both the thoracic and abdominal aorta, and in the iliac arteries. These arterial sites also showed the highest calcium scores. High calcium scores (> 400) in all five arterial regions were independently associated with prevalent cardiovascular disease. In multivariable analyses, after adjusting for cardiovascular risk factors, declining creatinine clearance was associated with increasing calcification of the coronary arteries (p = 0.012) and the thoracic aorta (p = 0.037) only. CONCLUSIONS: Arterial calcification is highly prevalent throughout all five CKD stages and is most prominent in both the thoracic and abdominal aorta, and in the iliac arteries. Follow-up studies are needed to explore the potential of extracardiac calcification sites in prediction of cardiovascular events in the CKD population.

Meerkats (Suricata suricatta) are able to detect hidden food using olfactory cues alone.

Meerkats (Suricata suricatta) are known to strongly rely on chemical signals for social communication. However, little is known about their use of the sense of smell in foraging and food detection. The aim of the present study was therefore to assess whether captive meerkats are able to (1) detect hidden food using olfactory cues alone, (2) discriminate between the odor of real food and a single food odor component, and (3) build an association between the odor of real food and a novel odor. We employed the buried food test, widely used with rodents to assess basic olfactory abilities and designed to take advantage of the propensity of certain species to dig. We found that the meerkats were clearly able to find all four food types tested (mouse, chicken, mealworm, banana) using olfactory cues alone and that they successfully discriminated between the odor of real food (banana) and a food odor component (iso-pentyl acetate). In both tasks, the animals dug in the food-bearing corner of the test arena as the first one significantly more often than in the other three corners. No significant association-building between a food odor and a novel odor was found within the 60 trials performed per animal. We conclude that meerkats are able to use olfactory cues when foraging for hidden food. Further, we conclude that the buried food test, employed for the first time with a non-rodent species, is a useful means of assessing basic olfactory capabilities in meerkats.

Activity, social and sexual behaviour in Red Junglefowl selected for divergent levels of fear of humans.

The domesticated phenotype is a set of behavioural, morphological and physiological traits that is common for domesticated species. Previous research has found that selection for tameness only can give rise to correlated selection responses that resemble the domesticated phenotype. It has therefore been suggested that tameness may drive the domesticated phenotype as correlated traits. We selected Red Junglefowl for divergent levels of fear of human for eight generations and assessed possible correlated selection responses in other behaviours in semi-natural settings. Behavioural studies were carried out on birds from generations six to eight, and at different ages, in order to study possible effects on general activity, social behaviour and male courtship behaviour. We found that the differences between selection lines changed with age. Adult low fear birds were generally more active and high fear males showed a more intense courtship behaviour. Our study shows that several behaviours can be modified through correlated selection responses by selection on reduced fear of humans only, emphasising the putative role of tameness as a driver of domestication related phenotypes.

Apolipoprotein M in patients with chronic kidney disease.

BACKGROUND AND AIMS: Plasma apolipoprotein M (APOM) is bound to HDL-particles and has anti-atherogenic effects. The present study explored whether plasma APOM is reduced in patients with chronic kidney disease (CKD), and associated with cardiovascular disease (CVD). In addition, we tested the hypothesis that the excretion of APOM into the urine is increased in patients with kidney disease. METHODS: Plasma samples were collected from a cohort of patients with CKD stages 1 to 5D (N = 409) and controls (N = 35). Urine was collected from 47 subjects. Plasma APOM was measured with sandwich ELISA and urine APOM with competitive ELISA. RESULTS: Plasma APOM levels were reduced in patients with CKD stages 3-5D as compared to patients with CKD stages 1 + 2 and controls (p < 0.01). CKD patients with known CVD displayed even further reduction in plasma APOM levels than CKD patients without known CVD (p < 0.001). Fast-phase liquid chromatography showed that plasma APOM was primarily associated with HDL-cholesterol (HDL-C) across CKD stages. Accordingly, when plasma APOM values were corrected for HDL-C, a significant difference only persisted between patients with CKD stage 3 and stages 1 + 2 (p < 0.05), and the difference between CKD patients with and without known CVD disappeared. Urine APOM/creatinine ratio was not significantly increased in patients with kidney disease. CONCLUSIONS: The results show that the difference in plasma APOM levels observed between patients with mild and advanced CKD may mainly be due to differences in plasma HDL-C. Whether APOM plays a role in human uremic atherogenesis warrants further experimental studies.

Reduced granulation tissue and wound strength in the absence of α11ß1 integrin.

Previous wound healing studies have failed to define a role for either α1ß1 or α2ß1 integrin in fibroblast-mediated wound contraction, suggesting the involvement of another collagen receptor in this process. Our previous work demonstrated that the integrin subunit α11 is highly induced during wound healing both at the mRNA and protein level, prompting us to investigate and dissect the role of the integrin α11ß1 during this process. Therefore, we used mice with a global ablation of either α2 or α11 or both integrin subunits and investigated the repair of excisional wounds. Analyses of wounds demonstrated that α11ß1 deficiency results in reduced granulation tissue formation and impaired wound contraction, independently of the presence of α2ß1. Our combined in vivo and in vitro data further demonstrate that dermal fibroblasts lacking α11ß1 are unable to efficiently convert to myofibroblasts, resulting in scar tissue with compromised tensile strength. Moreover, we suggest that the reduced stability of the scar is a consequence of poor collagen remodeling in α11(-/-) wounds associated with defective transforming growth factor-ß-dependent JNK signaling.