Nutrients, insulin and muscle wasting during critical illness

Size: px

Start display at page:

Download "Nutrients, insulin and muscle wasting during critical illness"

Bartholomew Cameron
6 years ago
Views:

1 32 nd annual meeting of the Belgian Society of Intensive Care Medicine June 15, 212 Nutrients, insulin and muscle wasting during critical illness Sarah Derde

2 Introduction Critical illness: feeding-resistant hypercatabolism Imbalance between protein synthesis and breakdown Introduction

3 Introduction Critical illness: feeding-resistant hypercatabolism Imbalance between protein synthesis and breakdown Skeletal muscle = main protein source Introduction

4 Introduction Critical illness: feeding-resistant hypercatabolism Imbalance between protein synthesis and breakdown Skeletal muscle = main protein source Severe muscle weakness Introduction

5 Introduction Critical illness: feeding-resistant hypercatabolism Imbalance between protein synthesis and breakdown Skeletal muscle = main protein source Severe muscle weakness Introduction

6 Introduction Critical illness: feeding-resistant hypercatabolism Imbalance between protein synthesis and breakdown Skeletal muscle = main protein source Severe muscle weakness Introduction

7 Introduction Critical illness: feeding-resistant hypercatabolism Imbalance between protein synthesis and breakdown Skeletal muscle = main protein source Severe muscle weakness Introduction

8 Introduction Critical illness: feeding-resistant hypercatabolism Imbalance between protein synthesis and breakdown Skeletal muscle = main protein source Severe muscle weakness rehabilitation: delayed mortality risk after hospital discharge: quality of life Introduction

9 Muscle weakness Myofibrillar protein synthesis breakdown Ubiquitin proteasome system Autophagy Introduction

10 Protein degradation pathways: Ubiquitin-proteasome system + Short-lived proteins myofibrils Muscle wasting MuRF-1 Atrogin-1 proteasome peptides Lysosomal system Introduction

11 Protein degradation pathways: Autophagy Lysosome Degradation of own cellular components within lysosomes Elongation isolation membrane autophagosome autolysosome removing damaged proteins energy supply Atg12-Atg5-Atg16 LC3-II ubiquitinated protein p62 + accumulation toxic protein aggregates Introduction

12 Role of autophagy in muscle wasting? Excessive activation could aggravate muscle wasting Impairment/inhibition could evoke atrophy and myopathy muscle fiber degeneration muscle weakness Effect of autophagy during prolonged critical illness? Introduction

13 Inhibitors of catabolism Critical illness Insulin Insulin resistance Nutrients Dysfunctional gastro-intestinal tract Intravenous nutrition: ineffective to safely counteract hypercatabolism increases hyperglycemia organ failure / death promotes catabolism Introduction

14 General hypothesis Intravenous nutrition, while maintaining normoglycemia, safely counteracts muscle wasting during prolonged critical illness

15 Objectives 1. Effect of strict blood glucose control with intensive insulin therapy on muscle wasting in fed critically ill patients 2. Efficacy in counteracting protein degradation and safety of intravenous nutritional interventions in an animal model Effect of fasting versus intravenous glucose load physiological range normoglycemia hyperglycemia Impact of altering nutritional substrate composition

16 Hypothesis I Muscle atrophy in fed critically ill patients can be attenuated by intensive insulin therapy Derde et al, Crit Care Med 212, 4:79-89 Vanhorebeek et al, J Clin Endocrinol Metab 211, 96:E633-E645 Study 1: Insulin therapy and muscle wasting

Patient population 2 randomized controlled studies Blood glucose control Surgical ICU 1548 patients Medical ICU 12 patients insulin therapy Conventional Intensive 215

17 Patient population 2 randomized controlled studies Blood glucose control Surgical ICU 1548 patients Medical ICU 12 patients insulin therapy Conventional Intensive 215 mg/dl 8-11 mg/dl 75/98 Nonsurvivors Nonsurvivors 69/36 ICU stay >14 days 64/252 m. Rectus abdominis biopsy m. Vastus lateralis biopsy Study 1: Insulin therapy and muscle wasting

18 Muscle protein synthesis Myofiber size and morphology Muscle protein degradation Study 1: Insulin therapy and muscle wasting

19 Synthesis of myofibrillary proteins MyHC I MyHC IIa actin relative mrna level relative mrna level relative mrna level Myosin/actin : P.5 versus control Study 1: Insulin therapy and muscle wasting Healthy control Conventional insulin therapy Intensive insulin therapy

20 Myofiber size: fiber cross-sectional area Vastus lateralis Rectus abdominis % of myofibers % of myofibers cross sectional area (µm²) cross sectional area (µm²) Study 1: Insulin therapy and muscle wasting Healthy control Critically ill :conventional insulin therapy Critically ill: intensive insulin therapy

(28) IIT 16 (32) Presence of adipocytes (n, %) Rectus abdominis Control 4

21 Morphological analysis of skeletal muscle: necrosis adipocytes inflammation Inflammation and/or necrosis (n, %) Present Control () CIT 2 (28) IIT 16 (32) Presence of adipocytes (n, %) Rectus abdominis Control 4 (36) CIT 55 (76) IIT 3 (6) P-value.9.1 Study 1: Insulin therapy and muscle wasting

22 Myofiber degeneration Vacuolization % of myofibers () Myofibers with centralized nuclei % myofibers Control Conventional insulin therapy Intensive insulin therapy Study 1: Insulin therapy and muscle wasting : p.5 versus control// () : p.1 versus control// : p.5 sick versus control

23 Protein degradation: autophagy Vacuolization ubiquitin 5 nm Impaired autophagy staining intensity relative protein level p62 Control Critically ill CIT : p.5 versus control ( ): p.1 sick versus control Control Conventional insulin therapy Intensive insulin therapy Study 1: Insulin therapy and muscle wasting

24 Protein degradation : Ubiquitin-proteasome system relative mrna level relative mrna level Healthy control Conventional insulin therapy Intensive insulin therapy MuRF 1 ( ) Protein degradation: results ( ) Atrogin 1 2 S proteasome activity : p.5 versus control// ( ): P.1 sick versus control

25 Conclusions gene expression myofibrillary proteins myosin/actin ratio Myofiber size autophagy Prolonged critical illness activity 2 S proteasome Study 1: Insulin therapy and muscle wasting

26 2. Efficacy to attenuate protein degradation and safety of intravenous nutrition in an animal model of prolonged critical illness

27 Hypothesis 1 Increasing the intravenous glucose load, within the physiological range and while maintaining normoglycemia, safely counteracts muscle catabolism Derde et al, Crit Care Med 21, 38: Study 2: increasing the intravenous glucose load

Experimental setup 1 kcal/day 4 glucose 35 proteins lipids 3 25 2 15 1 5 glucose load glycemia n (-) 13 Low 13 Moderate Normal 1 High

28 Experimental setup 1 kcal/day 4 glucose 35 proteins lipids glucose load glycemia n (-) 13 Low 13 Moderate Normal 1 High Study 2: increasing the intravenous glucose load 12 High High 8 mg/dl Blood glucose days (baseline)

29 Safety evaluation: survival & organ function Muscle protein degradation Study 2: increasing the intravenous glucose load

30 Safety:Survival and organ function glucose load glycemia n (-) 13 LowModerate Normal 13 1 High High 12 High 8 % Survival days p=.4 p=.1 % change from baseline Liver (ALT) Kidney (Creatinine) Myocardium (HFABP) % change from baseline ng/ml # : p <.5 versus all other groups// : p <.5 versus high/hg rabbits// #: p <.5 versus healthy control rabbits// : healthy reference range Study 2: increasing the intravenous glucose load

31 Muscle proteolysis Weight loss Urea % % change from baseline $ glucose load (-) Low Moderate High High glycemia n 13 Normal High 8 : p<.5 versus high/hg rabbits p <.5 versus moderate/ng rabbits//:$: p <.5 versus no/ng rabbits// #: p <.5 versus healthy control rabbits // +:p <.5 versus low/ng rabbits // : healthy reference range// : p <.5 versus all other groups Study 2: increasing the intravenous glucose load

32 Muscle proteolysis: Ub-proteasome MuRF-1 / GAPDH # $ $ $ # $ Proteasome activity $ # 5 # Atrogin-1 / GAPDH $ # $ # $ # $ # glucose load glycemia n (-) 13 Low Moderate Normal 13 1 High 12 High High 8 : p<.5 versus high/hg rabbits p <.5 versus moderate/ng rabbits//:$: p <.5 versus no/ng rabbits// #: p <.5 versus healthy control rabbits // +:p <.5 versus low/ng rabbits // : healthy reference range Study 2: increasing the intravenous glucose load

33 Conclusion Increasing intravenous glucose load within physiological range while normoglycemia is maintained Safe with regard to organ function and survival Reduces biochemical markers of catabolism as compared with fasting Optimum may be reached with moderate glucose intake High glucose load / hyperglycemia: protective effect nutrition Study 2: increasing the intravenous glucose load

34 Hypothesis 3 Impact of feeding on the catabolic pathways may be nutrient-specific Derde et al, Endocrinology. 212 May;153(5): Study 3: altering substrate composition

35 Experimental setup 2 randomisation Continous parenteral nutrition according to randomization Titrating glucose levels to normoglycemia kcal/day F G AA A L Glucose Amino acids Lipids mean bloodglucose (mg/dl) F 2 G 18 AA 16 L days (baseline) Control Study 3: altering substrate composition

36 Safety evaluation: survival & weight loss Muscle fiber size: cross-sectional area Muscle protein degradation Ubiquitin proteasome pathway autophagy

37 Safety: Survival and weight loss Survival: no mortality difference among groups Feeding attenuated weight loss observed in fasted critically ill rabbits Study 3: altering substrate composition

38 Muscle fiber size: cross-sectional area % of myofibers cross sectional area (pixels²) fasted critically ill fed critically ill, extra glucose fed critically ill, extra lipids fed critically ill,extra amino acids Study 3: altering substrate composition healthy reference range

Muscle proteolysis: Ub-proteasome relative mrna level 4 3 2 1 MuRF 1 relative activity 2. 2S proteasome activity 1.5

39 Muscle proteolysis: Ub-proteasome relative mrna level MuRF 1 relative activity 2. 2S proteasome activity relative mrna level 5 Atrogin fasted critically ill fed critically ill, extra glucose fed critically ill, extra lipids fed critically ill,extra amino acids healthy reference range : p.5 versus healthy control rabbits ; p.5 versus fasted critically ill rabbits; p.5 versus critically ill rabbits from the glucose group Study 3: altering substrate composition

Muscle proteolyis: autophagy absent / low

reference range Staining relative intensity

5 versus critically ill rabbits from the

40 Muscle proteolyis: autophagy absent / low moderate severe relative protein level p62 % of rabbits Rabbits with severe vacuolization F G L AA healthy reference range Staining relative intensity ubiquitin : p.5 versus healthy control rabbits ; p.5 versus fasted critically ill rabbits; p.5 versus critically ill rabbits from the glucose group Healthy control Critically ill (AA) Study 3: altering substrate composition

41 Conclusions Moderate amount of intravenous nutrition Suppression atrophy at level of gene expression and activity minor effect of nutrient composition: AA most effective? reduced fiber size most preserved with extra AA Suppression of autophagy accumulation toxic protein aggregates /damaged organelles in skeletal muscle most pronounced with AA Most anti-catabolic intervention (AA) may have been most toxic Study 3: altering substrate composition

42 General conclusion and perspectives Prevention of hyperglycemia in the fed condition is crucial to prevent mortality Intravenous nutrition while maintaining normoglycemia catabolism BUT possible toxic side effects by inhibition autophagy!! clinical setting? Pharmacological intervention to stimulate autophagy

Acknowledgements Promoter:Prof. dr. G. Van den Berghe Co-promoter: Prof. dr. I. Vanhorebeek Prof. dr. V. Darras (Laboratory of Comparative Endocrinology, KUL) Prof. dr. L.

43 Acknowledgements Promoter:Prof. dr. G. Van den Berghe Co-promoter: Prof. dr. I. Vanhorebeek Prof. dr. V. Darras (Laboratory of Comparative Endocrinology, KUL) Prof. dr. L. Larsson (University Uppsala, Sweden) Prof. dr. W. Martinet (Universiteit Antwerpen) LEGENDO Excellent technical assistance: E. Ververs, I. Derese The colleagues of the Laboratory of Intensive Care Medicine This work was supported by : The Fund for Scientific Research (FWO) The Research Council of the Katholieke Universiteit Leuven Long-term structural research financing via the Methusalem program

Harm by hyperglycemia, early (parenteral) nutrition or both? from bed to bench and back

Harm by hyperglycemia, early (parenteral) nutrition or both? from bed to bench and back G. Van den Berghe MD, PhD Department of Intensive Care Medicine University of Leuven (KU Leuven) Leuven, Belgium