Metabolic syndrome, insulin resistance, and chronic allograft dysfunction

Metabolic Risk Profile and Graft Function Deterioration 2 Years After Kidney Transplant

Importance

Studies exploring the association of body weight and metabolic status with graft function deterioration (GFD) after kidney transplantation have produced inconsistent findings. Few studies have examined whether metabolically healthy overweight or obesity (MHO) may contribute to GFD.

Objective

To evaluate associations of overweight or obesity and metabolic disorders with GFD in recipients of kidney transplant.

Design, Setting, and Participants

This multicenter retrospective cohort study was conducted from January 1, 2020, through June 30, 2021, with a follow-up period of 2 years after kidney transplantation. Participants included adult recipients of cadaveric kidney transplant in 4 transplantation centers in China. Participants were classified as 4 metabolic phenotypes according to their BMI and metabolic status. Data were analyzed from July to August 2023.

Exposures

Overweight and obesity were characterized by body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) of 24 or greater. Metabolic disorder was identified by existence of a minimum of 2 of 4 conditions: hypertension, hyperglycemia, increased triglyceride, and decreased high-density lipoprotein cholesterol.

Main Outcome and Measures

The main outcome was GFD, defined as a decrease in estimated glomerular filtration rate of at least 25% within 6 months to 2 years after transplant.

Results

A total of 1260 adult recipients of cadaveric kidney transplant (mean [SD] age, 43.97 [11.51] years; 755 [59.92%] male) were included in the study, and 127 (10.08%) participants experienced the primary outcome of GFD during follow-up. After accounting for confounding factors in multivariable analyses, overweight or obesity (odds ratio [OR], 1.64; 95% CI, 1.10-2.44; P = .02) and metabolic disorder (OR, 1.71; 95% CI, 1.12-2.63; P = .01) were associated with increased risk of GFD. The MHO subgroup exhibited a greater risk for GFD (OR, 2.37; 95% CI, 1.01-5.57; P = .048) compared with participants who did not have overweight or obesity or metabolic disorder. All components of metabolic disorder, with the exception of elevated triglyceride, were associated with GFD. There was a dose-response association of number of metabolic disorder components (OR per 1 additional condition, 1.40; 95% CI, 1.20-1.63; P < .001) and BMI (OR per 1-unit increase, 1.90; 95% CI, 1.03-1.15; P = .002) with increased risk for GFD. A nonlinear association was observed between BMI and risk of GFD.

Conclusions and Relevance

In this cohort study of recipients of cadaveric kidney transplant, individuals with overweight or obesity or metabolic disorder had a significantly higher risk of experiencing GFD. Individuals with MHO had an elevated risk for graft function deterioration. Additional studies with larger sample size and longer follow-up are necessary to validate our findings.

OUP accepted manuscript

Background

In living kidney transplantation there are two different individuals, a healthy donor and a renal transplant recipient. This is an excellent human model to study factors that influence kidney function in the context of reduced renal mass and the adaptation of two comparable kidneys to different metabolic demands.

Methods

We analyzed the changes in measured glomerular filtration rate (GFR, iohexol) from pretransplantation to 12 months after transplantation in 30 donor–recipient pairs. Each donor was compared with his/her recipient. We defined a priori three different groups based on GFR differences at 12 months: donor > recipient (Group A; 78 ± 8 versus 57 ± 8 mL/min), donor < recipient (Group B; 65 ± 11 versus 79 ± 11 mL/min) and donor ≈ recipient (Group C; 66 ± 7 versus 67 ± 7 mL/min). Other factors like donor/recipient mismatches in body mass index (BMI), surface area and gender were evaluated.

Results

In Group A donors were mostly male and recipients were female (75% each). Donors had a higher baseline weight than their recipients. During follow-up, weight remained stable in donors but increased 7% in recipients. In Group B donors were mostly female (60%) and recipients male. At baseline, donors had a lower weight than recipients. At 12 months, weight was stable in donors but increased in recipients. In Group C donors were mostly (75%) female and recipients male. At baseline, donors had a higher BMI than their recipients. At 12 months, BMI was stable in donors but increased 14% in recipients. In multivariable analysis, higher GFR at 12 months was associated with higher baseline weight and GFR in donors and with male gender and higher baseline weight in recipients.

Conclusions

Kidneys from living donors are more ‘plastic’ than originally thought and respond to metabolic demands and weight changes of their new host. These changes should be taken into account when assessing GFR outcomes in this population.

Dietary Diversity Score: Implications for Obesity Prevention and Nutrient Adequacy in Renal Transplant Recipients

Obesity affects both medical and surgical outcomes in renal transplant recipients (RTRs). Dietary diversity, an important component of a healthy diet, might be a useful nutritional strategy for monitoring patients with obesity. In this cross-sectional study, the data of 85 eligible RTRs were analyzed. Demographic data, routine laboratory data, and 3-day dietary data were collected. Participants were grouped into nonobesity and obesity groups based on body mass index (BMI) (for Asian adults, the cutoff point is 27 kg/m²). Dietary diversity score (DDS) was computed by estimating scores for the six food groups emphasized in the Food Guide. The mean age and BMI of participants were 49.7 ± 12.6 years and 24.0 ± 3.8 kg/m², respectively. In the study population, 20.0% (n = 17) were obese. DDS was significantly lower in obese participants than in those who were not obese (1.53 ± 0.87 vs. 2.13 ± 0.98; p = 0.029). In addition, DDS was correlated with nutrition adequacy of the diet. Multivariate analysis showed that the odds of obesity decreased with each unit increase in DDS (odds ratio, 0.278; 95% confidence interval, 0.101–0.766; p = 0.013). We conclude that patients with higher dietary diversity have a lower prevalence of obesity.

Body Shape Index Predicts Metabolic Syndrome and Insulin Resistance in Renal Transplant Recipients

Obesity is one of the most important metabolic diseases around the world. There are no reliable and inexpensive methods to evaluate obesity. All of the anthropometric measurements used have some limitations. In 2012, Krakauer et al developed a new method, called A Body Shape Index (ABSI), to identify abdominal obesity that is derived from weight, height, and waist circumference. In this study, we aimed to investigate the clinical usefulness of the ABSI to predict the presence of insulin resistance (IR) and metabolic syndrome (MetS) in renal transplant recipients. A total of 155 patients were included in the study. Prevalence of IR was 17.4%, and MetS was 62.6%. ROC results demonstrated the power of all anthropometric indices to discriminate patients with and without MetS and IR in the renal transplant populations. ROC curves showed that waist-to-height ratio (WHtR) had the optimal power to discriminate MetS and IR in women. WC had higher area under curve than all other anthropometric indices to predict MetS and IR in men. WC in men and WHtR in women has higher discriminatory capacity to predict MetS and IR in renal transplant recipients. An obvious difference was observed in the optimal anthropometric measures between the 2 sexes, suggesting that sex-specific measures should be used in practice. In order to evaluate the value of ABSI in determining metabolic risk factors, studies with larger, randomized, controlled body fat ratios are needed.

Does metabolic syndrome predict surgical complications? A protocol for a systematic review and meta-analysis

BACKGROUND

Metabolic syndrome (MetS) is defined by an accumulation of risk factors that include cardiovascular disease, diabetes, chronic high blood pressure, obesity, and hypercholesterolaemia which results in an increased risk of developing serious chronic diseases. MetS is widespread as it is estimated to affect up to 30% of the global population. For people with MetS who undergo surgery, an emerging body of literature points to significantly poorer postoperative outcomes compared with non-affected populations. Surgical patients with MetS are at significantly higher risk of a range of adverse outcomes including death, morbid cardiovascular events, coma, stroke, renal failure, myocardial infarction, and surgical site infections. Increased complication rates result in prolonged hospital stays, a greater need for post-hospitalisation care, and reduced effectiveness of surgical interventions.

METHODS/DESIGN

We will search the following electronic bibliographic databases: MEDLINE, EMBASE, ScienceDirect, and CINAHL, and the reference lists of included articles. We will also search for unpublished literature. Two authors will screen titles and abstract information independently and select studies according to established inclusion and exclusion criteria. Data will be extracted by the study investigators using Review Manager 5 and will include information on demographics, incidence, prevalence, and outcome variables. Subgroup analysis and sensitivity analysis will be performed to assess the heterogeneity of included studies. Meta-analysis will also be carried out if appropriate study groups are identified. A descriptive narrative for statistical data will also be provided to highlight findings of the systematic review and meta-analysis.

DISCUSSION

This study will report and summarise adverse outcomes among adult patients with MetS undergoing surgery across a range of surgical specialties. Developing insights into outcomes of this population of interest is necessary to develop guidelines towards better management of surgical patients with metabolic syndrome.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016051071.

Metabolic syndrome and non-alcoholic fatty liver disease after liver or kidney transplantation

Transplantation is a definitive treatment option for patients with end-stage liver disease, and for some patients with acute liver failure, hepatocellular carcinoma or end-stage renal disease. Long-term post-transplantation complications have become an important medical issue, and cardiovascular diseases (CVD) are now the leading cause of mortality in liver or kidney transplant recipients. The increased prevalence of metabolic syndrome (MS) likely plays a role in the high incidence of post-transplantation CVD. MS and its hepatic manifestation, non-alcoholic fatty liver disease (NAFLD), are prevalent among the general population and in pre- and post-transplantation settings. MS components are associated with recurrent or de novo NAFLD in transplant recipients, potentially influencing post-transplantation survival. Moreover, recent data reveal an important association between NAFLD and risk of incident of chronic kidney disease (CKD). Therefore, NAFLD identification could represent an additional clinical feature for improving the stratification of liver and kidney transplant recipients with regards to risks of CVD, CKD and renal allograft dysfunction. All MS components are potentially modifiable; therefore, it is crucial that hepatologists, nephrologists and primary care physicians become more engaged in managing post-transplantation metabolic complications. The present review discusses the recent clinical evidence regarding the importance of MS and its components after liver and kidney transplantation, as well as the link between MS and NAFLD after liver and kidney transplantation.

Relationships Between Metabolic Syndrome, Microalbuminuria, and C-Reactive Protein in Turkish Kidney Transplant Recipients

AIM

The aims of this study were to report the prevalence of metabolic syndrome (MS) in a cohort of Turkish kidney transplant recipients and to define the relationships between MS, microalbuminuria and C-reactive protein (CRP), which are cardiovascular risk factors, in kidney transplant setting.

METHODS

This cross sectional study included 170 adult renal transplantation recipients with a mean follow-up of 53.1 ± 49.9 months. The diagnosis of MS was made according to the National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATP III) criteria. Microalbuminuria was defined as a urinary albumin/creatinine ratio of 30-300 mg/g. CRP levels ≥6.0 were classified as high CRP.

RESULTS

Mean age was 39.3 ± 11 years. The prevalence of MS was 45.8% (n = 78). The prevalence of microalbuminuria was not different in patients with MS compared to those without MS (39.7% vs 37%, P = .428). In multivariate logistic regression analyses, systolic blood pressure (SBP) (odds ratio 1.68; 95% confidence interval [CI] 1.12-2.52; P = .011) and high fasting glucose (odds ratio 2.82; 95% confidence interval [CI] 1.16-6.86; P = .022) were significantly associated with microalbuminuria. When patients with MS and high CRP were compared with patients with normal CRP and without MS, microalbuminuria did not differ between the groups (P = .213).

CONCLUSION

The prevalence of MS in our kidney recipient cohort was found to be increased compared to general population. MS was not related to increased prevalence of microalbuminuria, even when combined with high CRP. Microalbuminuria was associated with elevated SBP and hyperglycemic status.

Metabolic syndrome and outcome after breast reconstruction

Metabolic syndrome with its core components including obesity, insulin resistance, dyslipidemia and hypertension; is has been proven as a multiplex risk factor for cardiovascular disease. It is also recently shown by meta-analysis for its association with increased risk of common cancers including breast cancer. Multiple studies have shown metabolic syndrome prone to have poor perioperative outcome and complications for multiple type of surgery including vascular and flap surgery due to compromising microvascular circulation in this group of patient. However, lack of data on consequences of metabolic syndrome on breast cancer surgery as well as in breast reconstructive surgery indicate the need of further study in this area for the improvement of outcome of breast cancer and reconstructive surgery.

Metabolic risk factors and long-term graft function after paediatric renal transplantation

The aim of this study was to evaluate metabolic risk factors and their impact on long-term allograft function in paediatric renal transplant (RTx) patients. We reviewed the medical records of 210 RTx patients who underwent transplantation at a median age of 4.5 years (range 0.7-18.2) and a median follow-up of 7.0 years (range 1.5-18.0). Data on lipid and glucose metabolism, uric acid levels, weight and blood pressure were collected up to 13 years post-RTx, and the findings were correlated with the measured glomerular filtration rate (GFR). Beyond the first year, GFR showed gradual deterioration with a mean decline of 2.4 ml/min/1.73 m(2)/year. Metabolic syndrome, overweight, hypertension and type 2 diabetes were diagnosed in 14-19%, 20-23%, 62-87% and 3-5% of the patients, respectively. These entities showed only mild association with the concomitant or long-term GFR values. Dyslipidaemia was common and hypertriglyceridaemia associated with a lower GFR at 1.5 and 5 years post-RTx (P = 0.008 and P = 0.017, respectively). Similarly, hyperuricaemia was frequent and associated significantly with GFR (P < 0.001). Except for hyperuricaemia and hypertriglyceridaemia, metabolic risk factors beyond the first postoperative year associated modestly with the long-term kidney graft function in paediatric RTx patients.

High glucose increases mesangial lipid accumulation via impaired cholesterol transporters

Diabetes, whether it occurs before or after transplantation, plays an important role to decrease graft function and survival. In addition renal lipid accumulation has been suggested to play a role in the development and progression of chronic renal allograft rejection. Intracellular lipid accumulation is governed by a balance between the influx and efflux of lipid. Cholesterol transporters, such as scavenger receptor (SR)-A1, CD36, and ATP binding cassette (ABC) A1 and G1 (ABCG1), coordinate to regulate cellular lipid status. Therefore, in the present study, we examined whether high glucose caused lipid accumulation in mesangial cells as a result of altered cholesterol transporters. Mouse mesangial cells were stimulated with 30 mmol/L D-glucose (high glucose); 100 μmol/L oleic acid (OA) used as a positive control. Cellular lipid accumulation was measured by Oil Red O staining. Protein and mRNA expression of cholesterol influx (SR-A1 and CD36) and efflux (ABCA1 and ABCG1) transporters were evaluated using Western blot analysis and real-time quantitative polymerase chain reaction, respectively. High glucose was shown to significantly increase lipid accumulation in mesangial cells at 24 hours as was observed for OA. SR-A1 and CD36 mRNA expression levels were 1.5-fold and 3.5-fold higher, respectively, in high glucose-stimulated than control mesangial cell, whereas ABCG1 mRNA expression decreased to 60% of controls; however, there was no decrease in ABCA1 mRNA. Altered protein expression of each transporter in mesangial cells cultured under conditions of high glucose concentrations was consistent with mRNA expression. Osmotic control using mannitol did not significantly affect any of the measured parameters in the present study. These results demonstrated that high glucose, in itself, can induce mesangial lipid accumulation; this effect may be associated with an impaired balance between the influx and efflux of cholesterol.

Is adiponectin a marker of preclinical atherosclerosis in kidney transplantation?

The aim of this study was to analyze the relationship between pre-transplant adiponectin (pre-ADP), abnormalities in glucose homeostasis (AGH) at three months post-transplantation, and preclinical atherosclerosis in non-diabetic patients prior to kidney transplantation (KT).

METHODS

We carried out a multicenter study in 157 non-diabetic KT patients (66.5% men; age: 50±13 yr). Pre-ADP levels were analyzed using radioimmunoassay. Carotid ultrasound was performed to determine carotid intima-media thickness (c-IMT). Oral glucose tolerance test was carried out to classify patients according ADA criteria.

RESULTS

Of the patients, 52.8% had AGH. Median pre-ADP was 19.5 (14-27) μg/mL. An inverse correlation was found between ADP and HOMA index (r=-0.432; p<0.001). Median c-IMT was 0.6 (0.48-0.71) mm. Significant inverse correlation existed between ADP and c-IMT on both sides (p<0.05). Patients with c-IMT >0.6 mm had more AGH (p=0.012) and lower ADP levels (p=0.02). We performed a logistic regression analysis using preclinical atherosclerosis (c-IMT ≥0.6 mm) as dependent variable and sex, age, BMI, ADP, AGH, and HOMA index as independent variables of altered c-IMT. Age, pre-ADP, and AGH were independent risk factors for elevated c-IMT.

CONCLUSIONS

Patients with AGH have a greater presence of preclinical atherosclerosis. ADP has an inverse relationship with AGH and is an independent marker of preclinical atherosclerosis.