Clinical Trial Details
— Status: Terminated
Administrative data
| NCT number |
NCT03757845 |
| Other study ID # |
1242439-2 |
| Secondary ID |
|
| Status |
Terminated |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
December 15, 2018 |
| Est. completion date |
March 24, 2023 |
Study information
| Verified date |
March 2023 |
| Source |
MaineHealth |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Diabetes Mellitus (DM) is a global epidemic associated with inflammation, aggressive
atherosclerosis and increased risk for, and severity of, coronary artery disease. Strategies
to improve glycemic control with insulin and/or oral hypoglycemic agents have not impacted
cardiovascular morbidity and mortality in type II DM patients with known heart disease. The
Investigators have found that the typical "Western" diet, which is high in saturated fats,
such as the lipid palmitate, but low in unsaturated fats, such as the lipid oleate, results
in changes to cell membrane lipid content and disruptions to membrane functional domains
-called caveolae- that are associated with insulin resistance and metabolic dysfunction. In
mice, the investigators found that palmitate induces both systolic and diastolic contractile
dysfunction. They have demonstrated, in cell cultures, that oleate prevents palmitate-induced
cell dysfunction. This may explain how a diet rich in unsaturated fats and plant-derived
flavonoids, such as the "Mediterranean" diet, can counter the adverse cardiovascular effects
of DM. This study builds in these prior findings and its central hypothesis is that, in DM, a
Mediterranean diet can induce rapid changes in cardiac cell membrane lipid composition and
signaling. This is a randomized dietary intervention in DM subjects scheduled for coronary
artery bypass grafting (CABG) surgery, to examine the effects of a short-term modified
Mediterranean diet (ModMeD), compared to the standard cardiac DM diet (SCaDMD), on receptor
tyrosine kinase signaling, serum and cellular lipid content, and membrane/caveolae function.
Description:
Study Design: The study is a prospective, un-blinded, randomized interventional clinical
trial comparing ModMeD to standard cardiac diet in 48 (24 per arm) inpatients with type II DM
scheduled for CABG at MMC and who are scheduled to stay in the hospital for four (4) or more
days prior to surgery.
While it is not feasible to blind the subjects or clinicians, laboratory investigators
processing specimens and analyzing biological responses to the intervention will be blinded.
Specifically, tissue samples will be de-identified and coded before transferring to the
laboratory.
Primary Objective: To determine if a Mediterranean diet causes rapid changes in lipid content
(as determined by mass spectrometry) and in cardiac cell activity (as determined by ERBB2
expression level) among patients with TIIDM undergoing CABG surgery at MMC.
Study Arms:
1. Standard Cardiac DM Diet (SCaDMD) during the inpatient stay (before and after CABG
surgery)
2. Mediterranean Diet (MedD) during the inpatient stay (before and after CABG surgery)
Subject recruitment: 48 inpatient adults will be enrolled (age ≥ 18 years diagnosed with type
II DM with hemoglobin A1c level greater than 7.5% and coronary artery disease with planned
surgical revascularization (CABG)) at MMC. Other inclusion criteria include planned
pre-surgical hospital stay of at least 4 days, and willingness to have the Mediterranean Diet
restricted menu for the duration of their inpatient stay.
Informed Consent Process: Via an IRB-approved partial HIPAA waiver, the clinical team will
screen for eligible patients who are scheduled for CABG surgery. Eligible subjects will be
approached by their clinical team to gauge interest in study participation. Patients who
indicate interest will be approached by a study team member to explain the study fully and
obtain informed consent. Patients who sign the informed consent form for this research will
have agreed to: 1) have baseline body measurements 2) be randomized to consume a
Mediterranean diet or the standard cardiac DM diet during their hospital stay, 3) undergo a
biopsy procedure at the time of their CABG and to donate ventricular myocardium tissue
approximately the size of a grain of rice, 4) donate tissue usually discarded during surgery
(cardiac right atrial tissue, skeletal muscle and fat), 5) donate a total of 30 ml of blood
collected at 3 time points: prior to, during, and 4 days post CABG surgery, 6) to fill out
questionnaires about their food consumption and 7) allow the review of their medical record
for their cardiovascular health information. The informed consent will include itemized
patient responsibilities such as completing dietary questionnaire accurately, and adhering to
diet restrictions, including the requirement that patient families do not bring outside food
items to patients. Interested patients and their families will be given ample opportunity to
ask questions.
Study Procedures
Dietary Questionnaire: Upon obtaining informed consent all subjects will complete a dietary
questionnaire (DHQ II) provided to them by a registered dietitian staffing Cardiology
Inpatient floors at MMC. The DHQ II is an online food frequency questionnaire advanced by the
NIH (https://epi.grants.cancer.gov/dhq2/about). The original DHQI was developed by the Risk
Factor Assessment Branch and validated to show that it provides reasonable nutrient estimates
26-29. The DHQII is an updated version with 10 more food items (134 instead of 124) and 8
dietary supplements. The DHQII has 4 versions that differ by time frame and portion size
questions. We will utilize the one-month option (Appendix A) that includes portion sizes.
This is a self-administered questionnaire to be completed by the patient that takes about an
hour. Subjects will be offered the online version via portable tablet or a paper version.
DHQII data will be analyzed using the Diet*Calc software program freely available from the
NCI (https://epi.grants.cancer.gov/dhq2/dietcalc/). This program generates nutrient and food
group intake estimates for the standard versions of the DHQII used in this study. Data from
the dietary questionnaire will allow us to conduct a number of exploratory analyses that have
not been attempted before. For example, we will look for associations between the abundance
of certain lipid species with patient unsaturated and saturated fat intake.
Baseline anthropometrics: Height (m) and weight (kg) will be measured using standard clinical
equipment and will be verified by a study team member. This information will be used to
calculate body mass index (BMI), at the time of enrollment. A study team member will also
measure waist and hip circumference.
Randomization: After subjects have been screened for eligibility and have provided informed
consent, they will be randomized in a 1:1 ratio to one of two dietary interventions.
Randomization will be implemented by the study statistician and will be involve
stratification by gender in alternating blocks of 4 and 6. nQuery randomizer will be used to
create the randomization scheme; the randomization list will be transferred to sealed,
opaque, sequentially numbered envelopes, one set for each stratum. At the time of
randomization, the next numbered envelope will be opened to determine study group assignment.
Study dietitians will ensure diet assignments are communicated and followed.
Standard Cardiac DM Diet (SCaDMD): As per current nutritional guidelines, all subjects will
receive standard instruction and the dietary menu (Appendix B) from an MMC dietitians. based
upon their diagnoses of DM and coronary disease. Patients will be prescribed a cardiac diet,
which is a lower fat diet, and if desired by the practitioner, additional sodium or
carbohydrate restrictions may be included on a case by case basis. Study dietitians will
supervise will the recording of record food consumption daily from enrollment until day 4
post CABG surgery by 1) direct questioning, 2) review of food orders placed by the patient,
and 3) examination of food trays upon completion of meals.
Mediterranean Diet (MedD): The MMC registered dietitians have created a sub-menu (Appendix C)
from the existing MMC inpatient menu that is compliant with the Mediterranean diet as
described by Casas et al. (2016)20 and was used in the PREDIMED trial. The only difference
between the Mediterranean diet used in this study that used in the PREDIMED trial is the
exclusion of wine and sofrito, a sauce used as a base in Spanish, Italian, Portuguese and
Latin American cooking. This was due to the limits of MMC cafeteria. Upon randomization,
study dietitians will meet with the subject to review the ModMeD and guide their food
selection. Study dietitians will also meet with floor nurses to explain the difference
between the standard diet and the Mediterranean diet and to explain the study procedures to
record food consumption. Study dietitians will supervise the recording of food consumption
daily from enrollment until day 4 post CABG surgery by 1) direct questioning, 2) review of
food orders placed by the patient, and 3) examination of food trays upon completion of meals.
Biologic Sample collection: Ventricular cardiac tissue, atrial cardiac tissue, and skeletal
intercostal muscle will be collected from study participants during their CABG surgery. Blood
samples will be collected at three time points: 1) at enrollment (on the day of the
questionnaire and anthropomorphic measurements), 2) on the day of surgery, and 3) before
discharge from the hospital. All samples will be de-identified, coded, packaged per Category
B regulations and transported by courier to MMCRI. Samples will be received, logged and
processed by trained lab personnel. Any excess tissue not utilized for this study will be
banked and distributed by the BioBank for non-specified research if patient consent has been
obtained for this purpose.
Specimen handling: Blood specimens will be left at room temperature for 15-20 minutes and
then centrifuged for 30 minutes. The supernatant (serum) will be collected and stored on ice
for transport to MMCRI. We have performed tests to evaluate the stability of lipids in blood
serum and have found that lipids are stable for up to 3 hours at room temperature. All tissue
will be frozen as soon as possible and transported frozen on dry ice to MMCRI. All serum and
tissue samples will be stored at -80ºC. Experience has shown that samples remain unchanged
for more than 1 year under these conditions. Sample analysis will be performed when all
samples have been collected.
Ventricular tissue: Anterior left ventricular (LV), free wall epicardial biopsies (1.5mm x
1.5-7mm deep/length) will be obtained from patients undergoing bypass surgery by their
cardiac surgeon at the time of the surgery25,30. Specifically, the biopsy will be performed
after cardiopulmonary bypass perfusion is initiated and once the aorta has been clamped and
cardioplegia administered. An area approximately the size of a grain of rice on the surface
of the anterior wall of the left ventricle free of epicardial fat will be chosen for the
biopsy. The biopsy will be performed in parallel with other procedures to prepare the patient
for grafts and will not add to the overall surgery time. The tissue will be placed in
physiological buffer solution for cell isolations or lipid extraction for lipidomic
profiling. Cell isolations will be performed as soon as possible after tissue is received at
MMCRI. Tissue that will be used for lipid extractions can be frozen at -80ºC.
Atrial tissue: The atrial tissue will come from the discarded right atrial appendage (RAA)
during surgery. Atrial tissue is considerably larger than the ventricular biopsy and allows
us to subdivide each sample. One piece will be placed into physiologic buffer for cell
isolation. A second piece will be placed in formalin and used for immunofluorescence. The
third will be stored in RNAlater® Solution to stabilize RNA until extraction. The final piece
will be frozen for isolation of caveolae fractions, lipidomic and protein profiling, and
western blotting.
Skeletal intercostal muscle tissue: Intercostal muscle is removed during surgery in order to
access the left internal mammary artery, which is used to provide a bypass graft. The
discarded intercostal skeletal muscle will be divided into two pieces, one frozen for
isolation of caveolae fractions, lipidomic and protein profiling, and western blotting, and
the second either placed in formalin and used for immunofluorescence, placed in physiologic
buffer for cell isolation, or placed in RNAlater® Solution to stabilize RNA until extraction.
Blood: A baseline blood sample will be drawn via venipuncture once before surgery (on the day
of diet questionnaire administration when patient is having daily clinically-indicated blood
draws) to evaluate monocyte expression of CAV as well as plasma lipidomic profiles. Follow-up
blood samples will be taken at two other times points: the day of the surgery via a central
line and 4 days after the surgery and before discharge via venipucture. Blood samples will be
collected into 2 5-ml tubes, an ACD (Acid Citrate Dextrose) anticoagulant tube and a
red-capped SST tube and refrigerated or processed within 3h.
Data Collection: The medical records of the participants will be reviewed to abstract
demographic and clinical data as specified below. Patient data collection will occur at
enrollment and approximately 1 month post surgery (for a maximum of three six months). The
data will be entered into a study specific, HIPAA-compliant, REDCap database, along with
intervention-specific data (questionnaire data, anthropomorphic measurements and diet
information). These data, which includes patient names and other identifiers, will only be
accessible to clinical investigators. Laboratory data will be maintained separately. Clinical
data will be coded and exported for collation with laboratory data and analysis without other
personal identifiers. The link to the code will be accessible only to clinical investigators.
Personally identifiable information
1. Name
2. Date of birth
3. Medical record number
4. Day of hospital admittance
5. Date of surgery
6. Date of discharge 7.7.2 Demographics
1. Age (years) 2. Gender (F/M) 3. Race/Ethnicity (OMB categories) 4. Smoking history
(never/former/current; if former/current, pack years) 7.7.2 Medical History
1. Date of diagnosis
2. HbA1c levels
3. Standard lipid profile data 7.7.2 Medication Information at time of enrollment
1. Anti-diabetic medication (drugs, dose, frequency) 2. Lipid-lowering medication (drugs,
dose, frequency) 3. Anti-hypertensive medication (drugs, dose, frequency) 7.7.3
Trial-specific data
1. Dietary questionnaire scores for nutrient and food group intake
2. Anthropomorphic measurements (height, weight, BMI, hip & waist circumference)
3. Daily diet adherence (yes or no; if no what food item was not in adherence)
4. Daily caloric intake
5. Weight during intervention
6. Time of blood sample procurements
7. Research laboratory data (ERBB2 expression data, lipidomics data) 7.7.4 Clinical
outcomes
1. Medications at discharge 2. Post-operative morbidity and survival at 30 days post surgery
8.0 Laboratory Procedures
8.1 Expression levels of ERBB and other proteins: Cell surface ERBB2 expression in atrial
endothelial cells will be assessed by flow cytometry. Also, levels of ERBB2, CAV1/3, and
IRS-1, will be determined by Western blot using specific antibodies (CAV1: BD# 610058, mouse
or Cell Signaling; CAV3: BD# 610420, mouse IRS-1: BD#611395, mouse. pY989-IRS-1: Santa Cruz,
SC-17200-R, rabbit, total ERBB2: Life Technologies. pERBB2/Tyr1248: Millipore, 06-229, in
combination with goat anti-rabbit IgG conjugated FITC, Abcam, ab6717). pAkt levels will be
assessed in circulating monocytes collected from whole blood as well as in isolated atrial
and ventricular endothelial cells.
Additional lipid and protein analysis: Lipid composition of the baseline plasma samples will
be compared with that obtained from the corresponding atrial and ventricular tissue samples
to assess the degree that fasting circulating lipids represent tissue content.
Non-myocyte single cell suspension will be prepared from atrial tissue using collagenase
II/Dispase II digestion as described36. ERBB receptor and CAV1 and 2 levels in conjunction
with cell-specific markers will be measured by flow cytometry.
Statistical Considerations
Sample size/Power: Pilot data was used to determine the likely levels of several measures in
our study population and have chosen one to use for a power analysis, cell surface ERBB2
expression in atrial endothelial cells. Pilot data using fluorescence based flow cytometry
revealed a mean of 9.56 and SD of 3.14 for this measure in diabetic patients (Fig. 3). Thus,
target sample size of 24 patients in each study group will allow for detection of a
difference of 2.64 in this measure (hypothesized to be similar in the control group to our
preliminary data and higher in the intervention group) with 80% power and a significance
level of 0.05. Secondary analyses of plasma lipid content and monocyte signaling will be
repeated measures analysis, which will add additional power given that we will have multiple
observations per person, and take away some power given the necessity for adjusting p values
for multiple comparisons by time point.
Analyses: This will be an intention-to-treat analysis. The success of randomization will be
evaluated by comparing patient characteristics at baseline using proportions or means and SDs
using by chi-square tests or Student's t-tests, as appropriate. Within group changes (i.e.
delta score) and between group differences in measures taken at serial time points (blood
serum) will be analyzed by mixed model repeated measures ANOVA; the mixed model will be
required because patients are likely to have different duration of dietary exposure and,
therefore, different numbers of repeated measures. Variables of interest are time, treatment
group, and the time by treatment interaction. Model results will be used to estimate mean
values and change over time for within-group and between-group comparisons. Graphical
techniques and time point-specific p values will be used to identify the time course of any
observed changes, e.g., how quickly the dietary intervention might lead to differences in the
measures examined. Significance will be identified at the P<0.05 level, with appropriate
adjustment for multiple comparisons where applicable. In the lipidomic analyses a false
discovery rate of 0.05 will be set and FDR-corrected P values will be reported. The linear
relationship between the change in specific signaling measures (ERBB levels) and the change
in lipid species (SM and other classes) will be examined using Pearson's correlation
coefficient. Analysis will be conducted in SAS.
