Long-term parenteral nutrition in unrestrained nonhuman primates: an experimental model

Long-term parenteral nutrition in unrestrained primates: an experimental model13 Karen

E Friday

and

ABSTRACT

A freely

developed (TPN)-induced

for

prolonged

TPN

mates.

Edward

The

jacket

TPN .d’.

and

serum

for

Serum

at baseline

tether

system

to 8.3

albumin

nonhuman

49

± 7 d (i

glucose

decreased

mm,

No

total

significant

protein,

changes

bihirubin,

were

alanine

in six

animals.

Thus,

longed

TPN

support

may

nonhuman KEY

investigated

Primates,

WORDS

disease

model,

animal

in serum

acid TPN

prealbuand

complications in a freely

Am J Clin Nuir

primate.

amino acid

at

5’-

Major complications indiarrhea, and premature

metabolic be

0.01)

38 ± 1 g/L

aminotransferase,

nucleotidase during TPN infusion. cluded catheter sepsis, hyperglycemia, death

<

1990;5

parenteral

development, the

rat

is inexpensive,

has

bone

and

metabolism

making

it an inadequate

human

primates

is easy

unlike model

have

bone

to maintain.

that

been TPN

used (10,

for the 14-16),

to study

human

metabolism

bone

similar

tions

of long-term metabolic

mobile

port

1 2 Macaca

teral

nutrition

along

with

TPN bone

and

the

disease.

to man

of human primates

animal

setting

of TPN-in-

techniques

utilized

primates

are

to os-

immobilization as nonhuman primate metabolic comphica-

nonhuman

outcome

and metahave

contribute (I 7), and

pathophysiology

The

fascicularis in a research

Non-

of metabolic alterations during were performed in chaired ani-

teopenia (1 8). In an attempt to eliminate a confounding variable, an unrestrained model was developed to investigate the duced

(13),

disease.

mals, a setting where immobilization alone will negative calcium balance (17), muscle atrophy

of pro-

1:470-6.

investigation these studies

However,

of human

should make an excellent model for the study bohic bone diseases (1 3). Although nonhuman

from

(p

from

seen

pri± SEM),

increased

± 1.9 mmoh/L

baseline to 29 ± 1 g/L (p < 0.001) during 2.75% TPN and 30 ± 2 g/L (p < 0.01) during 5% amino infusion.

was

described

and

complications

Twelve adult male nonhuman were selected for investigation.

primates All animals

to sup-

with

paren-

in this

report

of study.

hyperahimentation,

nutrition

Methods Introduction Advances mitted the

Subjects

in clinical nutrition during safe parenteral administration

to maintain ods oftime

good

(

enteral

nutrition

vivors,

including

and

metabolic

bolic

bone

nutritional status Several complications

1-3).

(TPN)

have

TPN bone

disease

disease

has

not

in humans over oflong-term

been

induced

the past 20 y have perof nutrients essential

identified

in long-term

hepatocellular

(7, 8). Although been

well

long peritotal parsur-

disease this

(4-6)

form

characterized,

to cause severe and sometimes debilitating bone individuals (8, 9). Attempts to identify metabolic

acteristics plagued

ofTPN-induced by confounding

TPN

are

a heterogeneous

disease in humans Patients receiving

group

with

a variety

diseases (9), often require able degrees ofgastrointestinal

multiple medications, nutrient absorption

although

are the subject

human

patients

of TPN-induced founding model Several vestigate is most

470

bone

variables

and,

disease,

they

therefore,

of underlying

ofchoice also

are not

host

pain char-

have been long-term

and

the

most

con-

appropriate

for investigation. animal metabolic widely

used

models have alterations because

been successfully utilized to induring TPN (2, 10-12). The rat

it has

a rapid

phase

Am

ofgrowth

J C/in

and

laboratory

serum and

had

values

electrolytes, bihirubin.

Nuir

I From Department

normal for

white

blood Six

physical blood

urea

of nine

cell

nitrogen,

animals

healthy

examinations count,

with

and

nor-

hematocrit,

creatinine,

glucose,

antibody

evidence

showed

the Division of Metabolism, Endocrinology, of Medicine, and the Regional Primate

University

ofWashington,

2 Supported

by

Healthcare

and

1990:5

Institutes

of

riosclerosis

Training

AM32794,

grant

Homecare

Inc.

an

affiliate

of

Baxter

the Graduate School Research Fund at the and the following research grants from the

of Washington;

National

and Nutrition, Research Center,

Seattle. Caremark

Corporation;

University

have vari(1 , 3). Thus,

for the study

the most

mal

weights

of metait has been

known in some

bone variables.

stable

(M fascicularis) were

Health:

Grant

RROO166

Nutrition,

Lipid

5T32

HL07028,

to

Regional

the

Metabolism,

New Primate

Investigator Research

and

Arte-

Award Center,

Clinical Nutrition Research Unit grant AM35816, and the Diabetes Endocrinology Research Grant AMI7047. 3 Address reprint requests to EW Lipkin, Division of Metabolism, Endocrinology, and Nutrition, University of Washington, RG-26, Seattle,WA 98195. Received December 5, 1988. Accepted for publication April 12, 1989.

1:470-6.

Printed

in USA.

© 1990 American

Society

for Clinical

Nutrition

Downloaded from www.ajcn.org by guest on July 10, 2011

82 ± 2 kcal.kg mmoh/L

and

of total parenteral nutrition disease and complications of

fascicularis

received

3.6 ± 0.2

TPN,

mobile

I 2 Macaca

in

providing during

W Lipkin

the investigation metabolic bone

animals

nonhuman

TPN ofpast

infection

with

simian

acquired

drome (AIDS) but none ofthe mic before the investigation. for by the Regional ofWashington. The

Primate protocol

Review

ofthe

Committee

Central

venous

under

right

catheters

ofthe site vein

in the

were surgically

anesthesia,

left

venous Two

internal

site ofvascular

to the penetration,

eters were tunneled exited

the skin.

Jacket

and tether

right

and

or

left

then

ad-

right or left femoral for animals 1-3 and requir-

catheters, a different vein was animals received replacement vein.

The

location

of the

was radiologically verified in intravenous dye. The cathewall

then

and

muscle

the distal

subcutaneously

fascia

portions

near

ofthe

to the midback

the cath-

where

ofTPN

they

Cyanocobalamin

The intravenous line was protected with a rigid back plate near the skin exit site and a flexible metal tether that accompathe tubing

which

kept

dling

to the top

the

ofthe

rigid

ofthe

back

catheters

cage.

plate

by the

The

animal

in position

animals.

wore

and

The

ajacket,

prevented

catheter

han-

and

exit

site

were protected by using this technique, yet the animal was allowed unrestricted activity within the cage. The surgical mcision,

catheter

weekly

tunnel,

ketamine

anesthesia. Research

catheter

of infection Thejacket

hized for various mate

and

for evidence

and

investigational Center

exit

while

site

the

were

system

projects

under

has been

at the

uti-

Regional

ofWashington

Pri(19).

mate Research was constructed ing portions of included a base ter opening

stand

tached

was

designed

by the

Regional

Center at the University ofWashington ofa stainless steel housing with internal stainless steel and Teflon. The rotating plate with ball bearing, tether connector,

for the

intravenous

for infusion

above

about

stand

and

tubing,

bags (19). The

below

it rotated

pump

stand

freely

holder,

and

and

animal

solutions

and nutritional

sup-

at-

moved

support is listed

providing

acids

5% amino

over design.

Four

solution

acids

animals and

seven

and

2.75%

amino

received

5% amino

animals

received

in Table

TPN

infusion in a cross-

acid TPN 2.75%

amino

TPN initially. One animal (# 5) received only the 2.75% acid TPN because of premature death before crossover amino acid

acid TPN

solution. and

Animal 100

mL

I received

of lipid

<

emulsion

1.2 I.4 1.0 17.0 5.0 7.0 20.0 140.0

CA. Chicago. IL.

Franklin

Park, IL.

Company, Hill, NJ.

Pharmaceutical

Cherry

Baxter,

Chicago,

nously

during

of another of the

TPN 0.45%

as their acid amino

to the

1 d of 4.25%

(Intrahipid,

12.5

ofthe

kcal.

full

kg

infusion

remained

consumed Louis,

animals

or

Kankakee,

IL.

received

2-10

during

the

was delivered normal

through

saline

was delivered

through

Infusion

were

rates

with

intrave-

TPN

infusion

as

was delivered

to

Initial

TPN

was

at

d

I

then

increased

for glucose

one

provided

over

5- 10 d if

by dipstick.

Chow

several

(Purina

days

ofslow

lumen

while

Animals

Mills, TPN

Inc.

St

infusion.

either 0.22% or (animals 1-10) at half the TPN rate.

U heparin/L

1000

the alternate controlled

with

port

a Holter

tracorporeal Medical Specialties, Inc. cated on the swivel portion ofthe cage. firmed daily by measuring the volume to calculating

changes in solution hated as TPN volume

acid

TPN

Monkey first

mg hydro-

chlorothiazide/d

protocol. rates,

negative

25 g Purina MO)

I

mg

5% amino

experimental

‘-80-90

the urine

IL). Five orally a portion

1 h in addition

The TPN composition given to the animals 1. Eleven animals (# 2-12) received prolonged

amino

(19). It rotatstand a cen-

his cage.

Intravenous

5%

Pri-

everything

as the

0.7 I 0.0

IL.

El Monte,

chlorothiazide/d

50% rotating

80.0

(u)**

II Solopak Laboratories, Elkins-Sinn,

48 I

I .0

t Abbott Laboratories, North § Lyphomed Inc. Rosemont,

provide

A cage-top

initial

t IMS Ltd. South

**

0.2 I .0-4.0

200.0 0-1000

Lab, Inc. Deerfield,

#{182} Armour

1.2 0.6-1.6

(zg)

sodium

Travenol

part

Swivel

port

*

912

examined

animals

tether

at the University

were

25 2.75 or 5

(pg)

Phytonadion

Heparin

nies

per liter of solution

Dextrose (%)* Crystalline amino acids (%)* Calcium gluconate (mg)t Sodium chloride (g) Magnesium sulfate (g) Copper sulfate (mg)II Zinc sulfate (mg) II Potassium chloride (g) Potassium phosphate (mg) Pediatric multivitamins(MVI)1 Ascorbic acid (mg) Retinol (mg) Ergocalciferol (ag) Thiamine (mg) Riboflavin (mg) Pyridoxine (mg) Niacinamide (mg) Dex panthenol (mg) Vitamin E (mg) Biotin (Lg) Folic acid (ia)

while

4- 12. In animals

jugular

vessel

the

I

Composition

roller

pump

(Ex-

King of Prussia, PA) loInfusion rates were conofsolution infused over

infusion

rates

based

on

daily

bag weights. Total plus saline volume

fluid intake was calcuplus apple water for 24 h then expressed as total fluid intake kg ‘ d I In an attempt to reduce the incidence of catheter-related sepsis, intravenous tubing external to thejacket and tether was replaced aseptically .

every

2-3

d with

each

new

mals 7-12 received 40-50 weight of apple consumed daily

consumption

was

liter

of TPN

.

in animals

5-12.

Ani-

g apple/d as a source of fiber. The daily was recorded and an average calculated.

Apples

were

estimated

to

Downloaded from www.ajcn.org by guest on July 10, 2011

sutured

placed,

vein

The

for animals

catheter tip in the right atrium two animals by using radioopaque were

into

jugular

right atrium. ofcatheterization

ing replacement central used for catheterization.

ters

TABLE

of Washington.

or internal

subclavian

catheters

syn-

were vireand cared

471

PRIMATES

Research Center at the University was approved by the Animal Care

general

subclavian,

vanced to the area vein was the initial the

deficiency

nine animals screened Animals were housed

University

silastic

were

femoral,

NONHUMAN

catheter

Double-lumen animals

immune

IN

472

FRIDAY

AND

LIPKIN

were only analyzed 88 d. Frozen

for animals

serum

was

for later

analysis

of serum

(23),

alanine

aminotransferase

and

available, multiple values ing the pre-TPN and TPN mm,

albumin,

and

for all animals

total

zation

period

infusion

at -20

prealbumin

(22),

(24)

were

averaged

study

periods.

2.75%

Nitrogen

and

intake

for 24-70 When

for each

Mean

support

#{176}C

5’-nucleotidase

concentrations. animal

dur-

serum

prealbu-

were

reported

and

nitrogen

bal-

after a minimum 2-d stabili5% amino acid infusions at full

was

calculated

plus measured apple nitrogen over 72 h. was measured from 72-h urine and stool dermal nitrogen would have appeared in nitrogen by virtue ofthe metabolic cage. gen concentrations (25) and total urine

TPN #{176}C then

concentrations

7 d ofTPN

in five animals

during

rate.

who received

stored

protein

surviving

ance was calculated

2-12

initially

were measured nitrogen with

as TPN

nitrogen

Total nitrogen output collections. Hair and the urine and/or stool Apple and stool nitro-

by the Kjeldahl chemiluminescense

technique (26, 27).

pressed acid

as mL.

Complications Complications

FIG I Metabolic

cage with primate

.

illustrating

thejacket

and tether

kg

.d’]

for each

animal

during

each

amino

infusion.

and animal

outcome

of

experimental

the

protocol

were

docu-

mented. Four animals with premature death were evaluated by autopsy at the Regional Primate Research Center. Ifsepsis was suspected clinically (animal lethargy, glycosuria, or abnormal white blood cell and neutrophil counts), blood cultures from the central catheter and femoral vein sites were obtained.

system.

Statistics contain

(per

gram)

0.85

g water

fiber (2 1 ), or 7.7 mg crude

etary

Metabolic

(20), fiber

0.6

kcal

(20),

1 5 mg

di-

(20).

cage

Animals resided in separate metabolic cages, which allowed for collection ofurine and stool samples during metabolic studies (Fig I). Water intake was measured daily. Stool was recovered from the stainless steel floor and urine was collected after exiting the cage via a sloping floor. The animal cage size measured 85 (height) (width) X 65 cm (length). X

Metabolic

indices

Animal

weights

tion

ofTPN

Data are represented as mean ± SEM and were analyzed the two-tailed Student’s paired t test (28). Nonnormal serum glucose data were compared with the Sign test (28). Data analysis was performed with Statistix II (NH Analytical Software, Roseville, MN). Differences were considered significant atp < 0.05. with

55

Results The animals

remained

weight

stable during prolonged TPN 82 ± 2 kcal kg d’ while 85 ± 2 kcal kg’ d. Apple kilocalories in four animals. The mean was 49 ± 7 d (range, 1-88 d). Daily averaged 25.7 ± 0.7 mmoh/kg during

support (Table 2). TPN supplied total average caloric intake was were

obtained

at the time

ofsurgical

immediately

before

catheter

the initia-

placement.

Thereaf-

supplied length

5 ± 1% oftotal of TPN infusion

nitrogen

intake

-

.

.

.

ter, weekly weights were obtained during animal inspection after ketamine anesthesia and at the completion ofTPN support

TPN 2.75%

in live weekly

animals. weight

Weekly

blood

Total fluid intake averaged 124 ± 4 mL kg d. Insensible fluid losses accounted for 34 ± 6 mL. kg’ .d. The experimental protocol was interrupted by premature death in six animals (Table 2). Four animals died ofsepsis. The first animal expired with pulmonary congestion and edema within 12 h ofinfusing 100 mL ofthe lipid emulsion. After the removal of the lipid emulsion infusion from the experimental protocol (in animals 2-12), pulmonary edema was not diagnosed. An additional animal died of unknown causes after 49 d ofTPN. Four animals (# 2, 4, 6, and 7) required replacement of nine central venous catheters because of catheter dislodge-

port ofthe while

under

cient

for

stabilization

In animals was used to samples

central

venous

period.

Serum

the

obtained

catheter

anesthesia

drawing)

premature

calculate

were

ketamine blood

with

from

final

through

the

TPN the

last

weight. proximal

(or by femoral

venipuncture

if the

was

catheter

animals

glucose,

death,

surviving total

bilirubin,

not

suffi-

a 7-d

TPN

albumin,

and total protein were obtained before and weekly during TPN support after a 7-d stabilization period. Serum during TPN was not available for laboratory analysis from animal 1 because of premature death after I d ofTPN; therefore, serum chemistries

TPN

and

46.4

± 1 .4 mmol/kg

with .

5% TPN .

infusion.

Downloaded from www.ajcn.org by guest on July 10, 2011

Averages of two to four separate 72-h collection periods were used to determine nitrogen and insensible fluid losses [volume of (TPN + 0.22 or 0.45% saline + apple water) - urine, ex-

TPN TABLE Animal

IN

NONHUMAN

473

PRIMATES

2 characteristics Weight

Animal

PreTPN*

TPN

Post-TPNt

duration

TPN

d

kg

kilocalories

kcal. kg’

1 2 3

5.6 6.7 4.7

5.6 6. 1 4.8

1 42 39

4

5.5

5.8

Total

kilocalories

kcal. kg’

. d’

-

-

98 89

98 89

88

75

75

.

Outcome

Pulmonary edema/premature death Staphylococcus aureus sepsis/death

aureus

4.8

4.2

24

77

77

5.2

5.8

82

82

82

7

5.6

6.2

46

85

87

8 9 10 11

5.0 5.0 4.6 4.2

4.3 5.2 5. 1 4.5

47 54 49 61

80 76 84 84

85 81 89 88

12

4.4

4.8

5.1±0.2

5.2±0.2t

C

Baseline

weight

75

80

82±2

85±2

TPN.

before

t Final weight during

55

TPN.

ment

tidase

cause

(six catheters), thrombosed catheter (one catheter), or beof infected catheters (two catheters). Catheter-related sepsis developed in three ofsix animals receiving nine femoral or internal jugular catheters (animals 1-7) and was frequently accompanied by animal removal ofsutures and skin infection. Twelve subclavian catheter insertions in nine animals (#4-12) were associated with sepsis in two animals, resulting in the death of one animal (# 5). Catheter-related sepsis in the other animal (# 6) infused with a subclavian catheter was successfully treated before death with intravenous antibiotics once sepsis was suspected, and removal ofthe catheter after sepsis was confirmed with blood cultures. The institution of aseptic catheter care for animals 5- 1 2 did not prevent catheter-related sepsis in animals 5 and 6. However, the last six animals studied (# 8-

ing TPN

12) showed

no evidence

ofcatheter-associated

animals developed diarrheal stool stools per d) ‘-2 wk after withdrawal did

not develop

in animals

infection.

(multiple of oral

consuming

apple.

Three

watery brown intake. Diarrhea Transient

glycos-

uria (urine glucose 1 3.9 mmol/L), noted in eight animals, resolved in five animals after reductions in the TPN infusion rates and was associated with catheter infection in five animals. Serum chemistry values(Tables 3 and 4)are reported at baseline before TPN and during TPN for the I 1 animals surviving the 7-d TPN stabilization period with a mean TPN duration of 53 ± 6 d (range,

24-88

increased

3.6

from

sepsis/death

Catheter removed because of sepsis and dislodgement: healthy at completion S. aureus sepsis/death Diarrhea, catheter removed because ofsepsis and dislodgement: healthy at completion Diarrhea, subcutaneous infusion with abscess: catheter replaced: healthy at completion Healthy at completion Healthy at completion Premature death, cause unknown Healthy at completion Healthy at completion

d). Mean ± 0.2

mmol/L during TPN (p rum total bihirubin, alanine =

mmol/L 0.006,

serum

glucose

before TPN n = 1 1) (Table

aminotransferase,

concentrations to 8.3

±

1.9

3). Mean seand 5’-nucleo-

were

not significantly

infusion

(Table

changed 3). Mean

from serum

baseline

values

dur-

prealbumin

and

total

protein during TPN were not significantly line concentrations but albumin decreased

changed from basefrom pre-TPN concentrationsof38 ± 1 to29 ± I g/L(p