Omega-3 Fatty Acids and Insulin Sensitivity

• Sponsor: Mayo Clinic (Other)
• Overall Status: Completed
• CT.gov ID: NCT01686568
• Collaborator: National Center for Advancing Translational Science (NCATS) (NIH), National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) (NIH), Building Interdisciplinary Research Careers in Women's Health (Other)
• Enrollment: 31
• Location: 1
• Arms: 2
• Actual Duration (Months): 29.5
• Patients Per Site Per Month: 1

Study Details

Study Description

Brief Summary

This study is being done to understand the effects of dietary omega-3 fats on insulin sensitivity in adult men and women.

Condition or Disease	Intervention/Treatment	Phase
Insulin Resistance	Drug: Omega-3; Drug: placebo	Phase 3

Detailed Description

Dietary omega-3 polyunsaturated fatty acids (n-3 PUFA), which include eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from fish oil, prevent insulin resistance in rodents, but data in humans is ambiguous. No existing studies have systematically evaluated the influence of n-3 PUFAs on insulin sensitivity and beta cell function in insulin resistant, non-diabetic humans. The Investigators hypothesize that 6 months of oral supplementation of purified EPA/DHA (3.9g/day) will significantly improve hepatic and peripheral insulin sensitivity and beta cell responsiveness in insulin-resistant, non-diabetic individuals. Based on recent work in mice, the investigators also hypothesize that EPA/DHA will increase the content and function of mitochondria in skeletal muscle, measured using a combination of in vivo and in vitro methods. Overall, the investigators hypothesize that EPA+DHA supplementation will improve hepatic and peripheral insulin sensitivity in insulin resistant humans, and this improvement will be associated with mitochondrial biogenesis and attenuated lipid accumulation in skeletal muscle and liver.

A sub-study was added in which participants receiving dietary omega-3 fatty acids or placebo supplements underwent abdominal subcutaneous adipose tissue biopsies to measure the content of total, pro- (M1) and anti- (M2) inflammatory macrophages (immunohistochemistry), crown-like structures (immunohistochemistry), and senescent cells (β-galactosidase staining), as well as a two-step euglycemic, pancreatic clamp with a stable-isotope labeled precursor ((U-13C)palmitate) infusion to determine the insulin concentration needed to suppress palmitate flux by 50% (IC50(palmitate)f).

Study Design

• Study Type: Interventional
• Actual Enrollment: 31 participants
• Allocation: Randomized
• Intervention Model: Parallel Assignment
• Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
• Primary Purpose: Treatment
• Official Title: Dietary Omega-3 Fatty Acids as a Therapeutic Strategy in Insulin Resistant Humans
• Actual Study Start Date: Dec 21, 2012
• Actual Primary Completion Date: Oct 30, 2014
• Actual Study Completion Date: Jun 8, 2015

Arms and Interventions

Arm	Intervention/Treatment
Experimental: Omega-3 Patients in this group will receive oral supplementation with EPA+DHA (3.9grams/day) for 6 months.	Drug: Omega-3; Patients in this group will receive oral supplementation with EPA+DHA (3.9grams/day) for 6 months.; Other Names: Essential fatty acids Omega-3 fatty acids Omega-3 polyunsaturated fatty acids PUFAs Lovaza
Placebo Comparator: Placebo Patients in this group will be supplemented with placebo capsules containing ethyl oleate.	Drug: placebo

Outcome Measures

Primary Outcome Measures

1. Insulin Sensitivity by Hyperinsulinemic-euglycemic Clamp at Baseline and 6 Month Follow up [Baseline, after 6 months of treatment]

   A 2-stage insulin clamp will be performed with titration of dextrose to maintain euglycemia. D2 glucose will be infused to evaluate hepatic glucose production at baseline and in response to insulin. Hyperinsulinemic-euglycemic clamp technique: The plasma insulin concentration is acutely raised and maintained by a continuous infusion of insulin. Meanwhile, the plasma glucose concentration is held constant at basal levels by a variable glucose infusion. When the steady-state is achieved, the glucose infusion rate (GIR) equals glucose uptake by all the tissues in the body and is therefore a measure of tissue insulin sensitivity.

Secondary Outcome Measures

1. Beta Cell Function From Insulin Secretion Following Ingestion of a Mixed Meal at Baseline and 6 Month Follow up [baseline, after 6 months of treatment]

   Following consumption of a mixed meal, beta cell function will be evaluated from serial measurements of C-peptide. C-peptide was measured using a two-side immunometric assay using electrochemiluminescence detection.

2. Mitochondrial Function Determined by Muscle Biopsy at Baseline and 6 Month Follow up [Baseline, after 6 months of treatment]

   Measurements of oxygen consumption in isolated mitochondria will be performed using a polarographic oxygen electrode.

3. Insulin Concentration Needed to Suppress Palmitate Appearance Rates (IC50(Palmitate)f) [approximately after 6 months of treatment]

   Sensitivity of adipose tissue lipolysis to insulin suppression, was calculated as the insulin concentration needed to suppress palmitate appearance rates (ie, flux) by 50% (IC50(palmitate)f).

4. Senescent Cells [approximately after 6 months of treatment]

   Tissue burden of senescent cells, which was measured by staining for senescence-associated B-galactosidase activity and expressed as the number per 100 nucleated positive cells.

5. Immunohistochemistry Assessments of Macrophage Burden [approximately after 6 months of treatment]

   One week after the pancreatic clamp study, participants were provided a standardized meal before an overnight fast. The next morning an abdominal adipose tissue biopsy was collected, and the samples were analyzed for adipocyte size. Immunohistochemistry was used to assess macrophage burden (total (CD68), M1 (CD14) and M2 (CD206) macrophages per 100 adipocytes).

6. Macrophage Crown-like Structures [approximately after 6 months of treatment]

   Macrophages surrounding dying or dead adipocytes form crown-like structures (CLSs). One week after the pancreatic clamp study, participants were provided a standardized meal before an overnight fast. The next morning an abdominal adipose tissue biopsy was collected, and the samples were analyzed for adipocyte size. Immunohistochemistry was used to assess the number of crown-like structures per 10 images.

Eligibility Criteria

Criteria

• Ages Eligible for Study: 18 Years to 65 Years
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: Yes

Inclusion criteria:

1. Age 18-65 years

2. Insulin resistant (Homeostasis Model Assessment (HOMA) Insulin Resistance (IR) ≥2.6)

Exclusion criteria:

1. Current use of omega-3 nutritional supplements

2. Fasting plasma glucose ≥126 mg/dL

3. Active coronary artery disease

4. Participation in structured exercise (>2 times per week for 30 minutes or longer)

5. Smoking

6. Medications known to affect muscle metabolism (e.g., beta blockers, corticosteroids, tricyclic-antidepressants, benzodiazepines, opiates, barbiturates, anticoagulants)

7. Renal failure (serum creatinine > 1.5mg/dl)

8. Chronic active liver disease (AST>144 IU/L and alanine transaminase (ALT)>165 IU/L)

9. Anti-coagulant therapy (warfarin/heparin)

10. International normalized ratio (INR) >3

11. Use of systemic glucocorticoids

12. Chronic use of NSAIDS or aspirin

13. Pregnancy or breastfeeding

14. Alcohol consumption greater than 2 glasses/day

15. Hypothyroidism

16. Fish or shellfish allergy

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	Mayo Clinic in Rochester	Rochester	Minnesota	United States	55905

Sponsors and Collaborators

• Mayo Clinic
• National Center for Advancing Translational Science (NCATS)
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
• Building Interdisciplinary Research Careers in Women's Health

Investigators

• Principal Investigator: Ian Lanza, PhD, Mayo Clinic

Study Documents (Full-Text)

None provided.

More Information

Publications

None provided.

• Responsible Party: Ian R. Lanza, Assistant Professor of Medicine, Mayo Clinic
• ClinicalTrials.gov Identifier: NCT01686568
• Other Study ID Numbers: 12-004590; KL2TR000136; U24DK100469; DK50456; DK40484; 5T32DK007352; 5UL1TR000135
• First Posted: Sep 18, 2012
• Last Update Posted: Mar 3, 2017
• Last Verified: Jan 1, 2017

• Studies a U.S. FDA-regulated Drug Product: Yes
• Studies a U.S. FDA-regulated Device Product: No
• Additional relevant MeSH terms: Insulin Resistance

Study Results

Participant Flow

Recruitment Details	Participants were recruited from the Mayo Clinic in Rochester, Minnesota.

Arm/Group Title	Omega-3	Placebo
Arm/Group Description	Patients in this group will receive oral supplementation with EPA + Docosahexaenoic acid (DHA) (3.9grams/day) for 6 months.	Patients in this group will be supplemented with placebo capsules containing ethyl oleate.
Period Title: Main Study
STARTED	16	15
COMPLETED	14	11
NOT COMPLETED	2	4
Period Title: Main Study
STARTED	14	11
COMPLETED	12	9
NOT COMPLETED	2	2

Baseline Characteristics

Arm/Group Title	Omega-3	Placebo	Total
Arm/Group Description	Patients in this group will receive oral supplementation with EPA+DHA (3.9grams/day) for 6 months.	Patients in this group will be supplemented with placebo capsules containing ethyl oleate.	Total of all reporting groups
Overall Participants	14	11	25
Age (years) [Mean (Standard Deviation) ]
Mean (Standard Deviation) [years]	35.3 (2.9)	32.6 (2.5)	34.1 (9.7)
Sex: Female, Male (Count of Participants)
Female	9 64.3%	9 81.8%	18 72%
Male	5 35.7%	2 18.2%	7 28%
Region of Enrollment (participants) [Number]
United States	14 100%	11 100%	25 100%

Outcome Measures

1. Primary Outcome

Title	Insulin Sensitivity by Hyperinsulinemic-euglycemic Clamp at Baseline and 6 Month Follow up
Description	A 2-stage insulin clamp will be performed with titration of dextrose to maintain euglycemia. D2 glucose will be infused to evaluate hepatic glucose production at baseline and in response to insulin. Hyperinsulinemic-euglycemic clamp technique: The plasma insulin concentration is acutely raised and maintained by a continuous infusion of insulin. Meanwhile, the plasma glucose concentration is held constant at basal levels by a variable glucose infusion. When the steady-state is achieved, the glucose infusion rate (GIR) equals glucose uptake by all the tissues in the body and is therefore a measure of tissue insulin sensitivity.
Time Frame	Baseline, after 6 months of treatment

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Omega-3	Placebo
Arm/Group Description	Patients in this group will receive oral supplementation with EPA+DHA (3.9grams/day) for 6 months.	Patients in this group will be supplemented with placebo capsules containing ethyl oleate.
Measure Participants	14	11
Baseline	10.92 (1.04)	10.39 (0.76)
6 Month Follow Up	10.16 (1.02)	10.80 (0.73)

2. Secondary Outcome

Title	Beta Cell Function From Insulin Secretion Following Ingestion of a Mixed Meal at Baseline and 6 Month Follow up
Description	Following consumption of a mixed meal, beta cell function will be evaluated from serial measurements of C-peptide. C-peptide was measured using a two-side immunometric assay using electrochemiluminescence detection.
Time Frame	baseline, after 6 months of treatment

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Omega-3	Placebo
Arm/Group Description	Patients in this group will receive oral supplementation with EPA+DHA (3.9grams/day) for 6 months.	Patients in this group will be supplemented with placebo capsules containing ethyl oleate.
Measure Participants	14	11
Baseline	537.17 (45.33)	488.90 (45.47)
6 Month Follow Up	561.33 (48.21)	504.39 (35.93)

3. Secondary Outcome

Title	Mitochondrial Function Determined by Muscle Biopsy at Baseline and 6 Month Follow up
Description	Measurements of oxygen consumption in isolated mitochondria will be performed using a polarographic oxygen electrode.
Time Frame	Baseline, after 6 months of treatment

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Omega-3	Placebo
Arm/Group Description	Patients in this group will receive oral supplementation with EPA+DHA (3.9grams/day) for 6 months.	Patients in this group will be supplemented with placebo capsules containing ethyl oleate.
Measure Participants	14	11
Baseline	496.81 (26.54)	564.86 (42.10)
6 Month Follow Up	406.38 (40.39)	495.12 (39.79)

4. Secondary Outcome

Title	Insulin Concentration Needed to Suppress Palmitate Appearance Rates (IC50(Palmitate)f)
Description	Sensitivity of adipose tissue lipolysis to insulin suppression, was calculated as the insulin concentration needed to suppress palmitate appearance rates (ie, flux) by 50% (IC50(palmitate)f).
Time Frame	approximately after 6 months of treatment

Outcome Measure Data

Analysis Population Description

The number of subjects analyzed for this outcome measure for the placebo arm was 8 instead of 9. One subject did not have blood drawn for this outcome measure.

Arm/Group Title	Omega-3	Placebo
Arm/Group Description	Patients in this group will receive oral supplementation with EPA+DHA (3.9grams/day) for 6 months.	Patients in this group will be supplemented with placebo capsules containing ethyl oleate.
Measure Participants	12	8
Baseline	22	25
Post-intervention	18	19

5. Secondary Outcome

Title	Senescent Cells
Description	Tissue burden of senescent cells, which was measured by staining for senescence-associated B-galactosidase activity and expressed as the number per 100 nucleated positive cells.
Time Frame	approximately after 6 months of treatment

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Omega-3	Placebo
Arm/Group Description	Patients in this group will receive oral supplementation with EPA+DHA (3.9grams/day) for 6 months.	Patients in this group will be supplemented with placebo capsules containing ethyl oleate.
Measure Participants	12	9
Baseline	4 (3)	4 (3)
Post-intervention	4 (3)	4 (2)

6. Secondary Outcome

Title	Immunohistochemistry Assessments of Macrophage Burden
Description	One week after the pancreatic clamp study, participants were provided a standardized meal before an overnight fast. The next morning an abdominal adipose tissue biopsy was collected, and the samples were analyzed for adipocyte size. Immunohistochemistry was used to assess macrophage burden (total (CD68), M1 (CD14) and M2 (CD206) macrophages per 100 adipocytes).
Time Frame	approximately after 6 months of treatment

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Omega-3	Placebo
Arm/Group Description	Patients in this group will receive oral supplementation with EPA+DHA (3.9grams/day) for 6 months.	Patients in this group will be supplemented with placebo capsules containing ethyl oleate.
Measure Participants	12	9
Total (CD68) baseline	31 (8)	33 (5)
Total (CD68) post intervention	33 (8)	31 (5)
M1 (CD14) baseline	11 (6)	13 (4)
M1 (CD14) post intervention	14 (6)	12 (5)
M2 (CD206) baseline	28 (5)	29 (7)
M2 (CD206) post intervention	29 (9)	29 (5)

7. Secondary Outcome

Title	Macrophage Crown-like Structures
Description	Macrophages surrounding dying or dead adipocytes form crown-like structures (CLSs). One week after the pancreatic clamp study, participants were provided a standardized meal before an overnight fast. The next morning an abdominal adipose tissue biopsy was collected, and the samples were analyzed for adipocyte size. Immunohistochemistry was used to assess the number of crown-like structures per 10 images.
Time Frame	approximately after 6 months of treatment

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Omega-3	Placebo
Arm/Group Description	Patients in this group will receive oral supplementation with EPA+DHA (3.9grams/day) for 6 months.	Patients in this group will be supplemented with placebo capsules containing ethyl oleate.
Measure Participants	12	9
Baseline	0	1
Post-intervention	0	1

8. Post-Hoc Outcome

Title	EPA and DHA Concentrations in Plasma
Description	Post hoc analyses were conducted to test whether EPA and DHA concentrations in plasma in response to intervention explained variation in outcome measures of adipose tissue lipolysis insulin sensitivity and inflammatory markers post-intervention.
Time Frame	approximately after 6 months of treatment

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Omega-3	Placebo
Arm/Group Description	Patients in this group will receive oral supplementation with EPA+DHA (3.9grams/day) for 6 months.	Patients in this group will be supplemented with placebo capsules containing ethyl oleate.
Measure Participants	12	9
EPA Baseline	0.95 (0.22)	1.2 (0.27)
EPA Post-Intervention	6.0 (0.92)	1.1 (0.19)
DHA Baseline	0.89 (0.23)	1.2 (0.39)
DHA Post-Intervention	3.5 (0.84)	0.90 (0.18)

9. Post-Hoc Outcome

Title	EPA and DHA Concentrations in Adipose Tissue
Description	Post hoc analyses were conducted to test whether EPA and DHA concentrations in subcutaneous abdominal adipose tissue in response to intervention explained variation in outcome measures of adipose tissue lipolysis insulin sensitivity and inflammatory markers post-intervention.
Time Frame	approximately after 6 months of treatment

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Omega-3	Placebo
Arm/Group Description	Patients in this group will receive oral supplementation with EPA+DHA (3.9grams/day) for 6 months.	Patients in this group will be supplemented with placebo capsules containing ethyl oleate.
Measure Participants	12	9
EPA baseline	0.06 (0.00)	0.07 (0.01)
EPA Post-Intervention	0.19 (0.02)	0.07 (0.01)
DHA Baseline	0.14 (0.01)	0.15 (0.01)
DHA Post-Intervention	0.28 (0.02)	0.16 (0.02)

Adverse Events

Time Frame	6 months
Arm/Group Title	Omega-3		Placebo
Arm/Group Description	Patients in this group will receive oral supplementation with EPA+DHA (3.9grams/day) for 6 months.		Patients in this group will be supplemented with placebo capsules containing ethyl oleate.
All Cause Mortality
	Omega-3		Placebo
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	/ (NaN)		/ (NaN)
Serious Adverse Events
	Omega-3		Placebo
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/14 (0%)		0/11 (0%)
Other (Not Including Serious) Adverse Events
	Omega-3		Placebo
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/14 (0%)		0/11 (0%)

Limitations/Caveats

[Not Specified]

More Information

Certain Agreements

All Principal Investigators ARE employed by the organization sponsoring the study.

There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.