Downloaded from https://academic.oup.com/ajcn/article-abstract/50/6/1401/4695064 by barrettrabinow@gmail.com on 16 May 2020
`
`Hypercysteinemia
`after
`oral
`cysteine
`
`delayed
`and
`loads13
`
`sulfur
`
`excretion
`
`in cirrhotics
`
`Diane
`
`L Tribble,
`
`Dean
`
`P Jones,
`
`Abbas
`
`Ardehali,
`
`Ruth M Feeley,
`
`and DanielRudman
`
`via
`
`transsulfuration
`hepatic
`the
`methionine
`from
`cysteine
`of
`Biosynthesis
`ABSTRACt’
`cysteine
`in the
`require
`might
`who
`therefore
`patients,
`cirrhotic
`in some
`is impaired
`pathway
`in the
`liver,
`the
`occurs
`primarily
`of cysteine
`also
`metabolism
`further
`diet.
`However,
`because
`administered
`oral
`in cirrhosis.
`We
`be
`impaired
`could
`acid
`this
`amino
`metabolic
`clearance
`of
`cyst(e)ine
`and
`healthy
`volunteers.
`Plasma
`and
`(free
`patients
`loads
`of L-cysteine
`to cirrhotic
`#{189}cystine)
`protein-bound
`cysteine,
`and
`urinary
`sulfur-containing
`constituents
`mea-
`and
`were
`subjects
`exhibited
`a greater
`maximal
`cyst(e)-
`plasma
`Cirrhotic
`sured
`at various
`times
`postload.
`half-life
`(t#{189})and
`a delayed
`excretion
`of metabolic
`elimination
`inc
`concentration
`and
`plasma
`was
`The
`postload
`increase
`in total
`plasma
`cyst(e)ine
`end
`products
`an oral L-cysteine
`load.
`after
`accounted
`for primarily
`by an increase
`in the
`disulfide
`form (cystine).
`These
`studies
`show that
`Am J Cliii Nutr
`ability
`clear
`cyst(e)ine
`from
`the
`plasma.
`cirrhotics
`have
`an
`impaired
`1989;50:
`1401-6.
`
`to
`
`KEY WORDS
`
`Hypercysteinemia,
`
`sulfur,
`
`cirrhosis
`
`omis-
`that
`established
`al
`by Rose
`studies
`Early
`of healthy
`diet
`from
`the
`acids
`amino
`any
`ofeight
`sion
`of
`nitrogen
`bal-
`negative
`in a reversible
`adult
`males
`resulted
`that
`humans
`are
`un-
`studies
`showed
`ance.
`Subsequent
`novo.
`With
`the
`de
`acids
`these
`amino
`able
`synthesize
`parenteral
`nu-
`and
`enteral
`defined
`advent
`of chemically
`ofbetter
`cri-
`development
`and
`tritional
`formulations
`nutriture,
`other
`protein
`individual
`teria
`defining
`for
`nonessential
`have
`as
`amino
`acids
`originally
`classified
`in certain
`clinical
`condi-
`been
`found
`to be
`indispensible
`tions
`and
`referred
`to as conditionally
`essential
`(2) or
`are
`(3).
`acquired
`indispensable
`amino
`acids
`biosynthe-
`cysteine
`Methionine
`utilization,
`and
`hence
`of
`these
`are
`impaired
`in
`cirrhotics
`(4). A subset
`sis,
`became
`hypocysteinemic
`when
`maintained
`tients
`cysteine-free
`total
`parenteral
`nutrition
`(TPN)
`tions
`and
`showed
`signs
`ofdeteriorating
`nutritional
`despite
`provision
`of
`excess
`calories
`and
`repletion
`the
`protein
`N (5).
`Simultaneous
`declines
`have
`been
`noted
`the
`concentrations
`ofa-aminobutync
`acid,
`taurine,
`compounds
`glutathione
`plasma,
`three
`derived
`several
`cysteine
`Improvement
`nutritional
`(6).
`can
`be
`ables
`a positive
`N balance
`attained
`and
`wk
`cysteine
`(cystine)
`supplementation
`(5).
`ingly,
`a source
`ofcysteine
`has
`been
`suggested
`as
`sary
`component
`ofthe
`cirrhotic
`diet
`(2-5).
`most
`Because
`currently
`available
`elemental
`tional
`formulas
`either
`or
`contain
`only
`
`of
`
`and/
`revision
`formula
`cystine),
`(as
`cysteine
`amounts
`mix-
`these
`providing
`when
`supplementation
`or
`cysteine
`However,
`indicated.
`may
`be
`cirrhotic
`patients
`tures
`to
`there-
`by hepatic
`enzymes;
`is degraded
`primarily
`cysteine
`cirrhotic
`processing
`by
`the
`disorders
`cysteine
`in
`fore,
`Elevated
`plasma
`cys-
`could
`cause
`hypercysteinemia.
`liver
`patients
`consuming
`was
`noted
`in
`some
`cirrhotic
`teine
`on the
`relative
`amounts
`foods
`(2) and,
`depending
`mixed
`in the
`plasma,
`could
`con-
`various
`forms
`ofcysteine
`ofthe
`complications
`including
`to
`additional
`medical
`tribute
`function
`ofplasma
`proteins
`alterations
`in the
`widespread
`thiol
`and
`disulfide
`status
`groups.
`thiol
`The
`with
`critical
`patients
`in
`favor
`of
`the
`in
`is altered
`cirrhotic
`of
`cysteine
`forms
`[cystine,
`cysteine-mixed
`disulfides,
`and
`disulfide
`cysteine
`(6)].
`Problems
`also
`could
`arise
`protein-bound
`build-up
`offree
`and
`protein-bound
`ho-
`from
`a secondary
`mocysteine,
`a transsulfuration
`intermediate
`proximal
`to
`cysteine.
`metabolite
`been
`implicated
`in causing
`This
`damage
`to proteins
`and
`vascular
`endothelium
`and
`other
`tissues
`(7).
`
`has
`to the
`
`of Nutrition,
`and Division
`of Biochemistry
`(cid:1) From the Department
`School
`of Medi-
`Department
`University
`Health,
`Emory
`ofCommunity
`cine, Atlanta,
`and
`the Department
`ofMedicine,
`University
`of Califor-
`San Francisco.
`nia,
`2 Supported
`by NIH grant
`3 Address
`reprint
`requests
`Medical
`College
`ofWisconsin,
`ReceivedMarch
`15, 1988.
`Accepted
`for publication
`
`RR 39.
`to D Rudman,
`Milwaukee,
`
`Department
`WI 53226.
`
`of Medicine,
`
`December
`
`14, 1988.
`
`pa-
`on
`
`formula-
`status
`
`of
`in
`and
`from
`van-
`within
`Accord-
`a neces-
`
`1
`
`nutri-
`minor
`
`Introduction
`
`to
`
`in
`
`of
`
`et
`
`(1)
`
`the
`
`in
`
`lack
`
`Am J C/in Nuir
`
`1989;50:
`
`1401-6.
`
`Printed
`
`in USA. © 1989 American
`
`Society
`
`for Clinical
`
`Nutrition
`
`1401
`
`Eton Ex. 1040
`1 of 6
`
`

`

`1402
`
`TABLE
`Clinical
`cirrhosis
`
`1
`data
`
`ofthe
`
`four
`
`patients
`
`with
`
`biopsy-proven
`
`micronodular
`
`TRIBBLE
`
`ET AL
`
`consecutive
`Six
`tion.
`Blood
`samples
`load.
`ofthe
`load
`tration
`ofplasma
`analysis
`the
`During
`tests,
`cirrhotic
`ical
`encephalopathy.
`motor
`skills were
`
`course
`subjects
`
`1
`
`2
`
`3
`
`4
`
`50
`F
`
`3
`Yes
`
`No
`98
`0.5 1
`27
`27
`
`41
`M
`4
`Yes
`
`No
`93
`0.54
`31
`2 1
`
`61
`M
`
`6
`Yes
`
`Yes
`110
`0.63
`20
`2 1
`
`55
`M
`
`8
`Yes
`
`Yes
`106
`0.59
`15
`34
`
`(y)
`
`diagnosis
`initial
`since
`ofencephalopathy
`ofbleeding
`esophageal
`
`Age(y)
`Sex
`Time
`History
`History
`varices
`Bodyweight(%idealbodywt)
`Serum albumin
`(mmol/L)5
`Serum
`bilirubin
`(zmol/L)5
`Blood NH3 (jzmol/L)5
`
`S Fasting
`
`venous
`
`blood.
`
`The
`ofcirrhotic
`
`ofthis
`purpose
`patients
`
`study
`to oral
`
`was
`loads
`
`to examine
`of L-cysteine.
`
`the
`
`response
`
`Experimental
`
`design
`
`and
`
`implementation
`
`Subjects
`
`and
`patients
`cirrhotic
`offour
`consisted
`population
`study
`The
`group
`cirrhotic
`1 y. The
`42-6
`subjects
`aged
`control
`healthy
`five
`biopsy-
`with
`male
`adults
`female
`and
`three
`one
`comprised
`physical
`by
`cirrhosis
`who,
`micronodular
`(alcoholic)
`proven,
`of hepa-
`show any
`evidence
`not
`and
`laboratory
`assessment,
`did
`dis-
`varices,
`ascites,
`hepatorenal
`titis,
`encephalopathy,
`bleeding
`for
`had
`abstained
`from alcohol
`ease,
`or diabetes
`mellitus.
`They
`had
`and
`3 mo
`according
`to
`history
`from
`patient
`family.
`All
`being
`a history
`of hepatic
`encephalopathy
`and were
`therefore
`are
`diet.
`treated
`with
`a protein-restricted
`Their
`clinical
`features
`control
`summarized
`in Table
`1 . The
`group
`consisted
`of one
`adult
`female
`and
`four
`adult male
`volunteers
`aged
`24-36
`y with
`no history
`of hepatobiliary
`disease.
`Results
`ofall
`conventional
`liver
`tests
`(serum
`bilirubin,
`alkaline
`phosphatase,
`glutamate
`and
`oxaloacetate
`aminotransferase,
`lactate
`dehydrogenase,
`all control
`prothrombin
`time)
`were
`within
`normal
`range
`for
`the
`subjects.
`investigation
`was
`conducted
`with
`approval
`of
`the
`The
`Emory
`University
`Human
`Investigations
`Committee
`and with
`the
`informed
`consent
`ofall
`subjects.
`
`Experimental
`
`procedures
`
`containing
`for weight
`mainte-
`equation,
`
`for 5 d on
`equilibrated
`were
`All participants
`a diet
`calories
`adequate
`2 g Na(cid:1)
`with
`g protein
`and
`40
`required
`for weight
`caloric
`intake
`maintenance.
`The
`Harris
`and
`Benedict
`by
`the
`nance
`was
`calculated
`and
`age (8).
`weight,
`which
`adjusts
`for height,
`beginning
`urine
`samples
`were
`collected
`Six consecutive
`6-h
`of S-con-
`for
`analysis
`ofbasal
`excretion
`4th
`at 0800
`on
`the
`day
`commencing
`At 0800
`on the 6th day
`after
`taming
`constituents.
`diet,
`(40.6
`mg/kg
`the
`40-g-protein
`an
`oral
`bolus
`of L-cysteine
`was
`weight)
`given
`in
`150 mL of carbohydrate-free
`ideal
`body
`of
`same
`vehicle.
`The
`concentration
`the
`cysteine
`load
`was
`the
`load
`as
`that
`of
`the methionine
`(50 mg/kg
`ideal
`body
`weight)
`Emory
`previously
`utilized
`at
`the
`Clinical
`Research
`Center
`(4).
`Breakfast,
`lunch,
`and
`dinner
`were
`delivered
`at 0.5,
`4, and
`9 h
`postload,
`respectively.
`Subjects
`were
`instructed
`urine
`collections
`began
`
`void
`to
`immediately
`
`h before
`0.5
`after
`cysteine
`
`the
`
`load;
`oral
`administra-
`
`samples
`urine
`6-h
`immediately
`drawn
`were
`times
`postload
`at various
`and
`concentrations.
`acid
`amino
`study
`and
`particularly
`ofthe
`carefully
`observed
`were
`No
`significant
`changes
`in any
`ofthe
`cirrhotic
`
`were
`
`collected
`before
`(up
`
`post-
`adminis-
`to 8 h)
`
`for
`
`after
`signs
`for
`orientation
`in
`patients.
`
`load
`the
`of din-
`
`or
`
`noted
`
`Downloaded from https://academic.oup.com/ajcn/article-abstract/50/6/1401/4695064 by barrettrabinow@gmail.com on 16 May 2020
`
`Analytical
`
`procedures
`
`concentrations.
`acid
`amino
`ofplasma
`Determination
`into
`heparinized
`tubes.
`drawn
`samples
`were
`lO-mL
`blood
`treated
`with
`iodoacetic
`acid
`was
`immediately
`blood
`sample
`mL of a 500 mg/mL
`to
`prevent
`rapid
`autooxidation
`solution)
`Both
`S-carboxymethyl
`derivative.
`of cysteine
`by
`forming
`the
`were
`Samples
`10 mm to pellet
`the
`cells.
`samples
`centrifuged
`for
`ofthe
`#{176}Cuntil
`filtered
`and
`frozen
`-80
`(1 .5 mL)
`plasma
`were
`at
`Plasma
`analysis.
`samples
`were
`maintained
`at
`#{176}Cfor
`-80
`analysis.
`wk before
`Under
`these
`conditions
`the
`plasma
`amino
`acid
`concentrations
`are
`stable
`for
`8 mo
`(5).
`an amino
`Plasma
`aminograms
`were measured
`with
`Palo Alto,
`alyzer
`(Model
`121,
`Beckman
`Instruments,
`Plasma
`cysteine
`concentrations
`(as
`the S-carboxymethyl
`(9).
`al
`ative)
`were
`measured
`by
`the method
`of Brigham
`et
`tein-bound
`cysteine
`was
`determined
`by the
`spectrophotometric
`ofMalloy
`et al
`(10)
`and Gaitonde
`(1 1).
`method
`creati-
`and
`Analysis
`ofurinary
`sulfur-containing
`compounds
`frozen
`nine. Two
`lO-mL samples
`ofeach
`6-h urine
`sample were
`the
`at
`-80
`#{176}Cfor
`later
`analysis
`ofamino
`acids
`and
`taurine
`(5);
`remainder
`were
`stored
`for
`later
`analysis
`of S and
`creatinine.
`Inorganic
`S (H2S
`and
`SO42)
`was measured
`by the method
`(12). Urinary
`used
`Folin
`creatinine
`values
`were
`to
`correct
`on
`inaccurate
`urine
`collections.
`Creatinine
`was measured
`automated
`Technicon
`analyzer
`in a manner
`similar
`to that
`scribed
`by Chasson
`al
`(13).
`
`Two
`One
`(0.1
`
`6
`
`an-
`acid
`CA)
`(5).
`deriv-
`Pro-
`
`of
`for
`an
`de-
`
`et
`
`Pharmacokinetic
`
`evaluation
`
`and
`
`statistical
`
`analyses
`
`(Ks)
`
`of distri-
`and
`the
`line
`on
`vs
`
`volume
`and
`from the
`slope
`regression
`concentration
`acid
`calculated
`by multiply-
`(t#{189})was
`determined
`
`of elimination
`constant
`rate
`The
`were
`determined
`ofcysteine
`(Vd)
`bution
`of
`the
`least-squares
`respectively,
`y intercept,
`of plasma
`amino
`a semilogarithmic
`plot
`time.
`The metabolic
`clearance
`rate was
`K(cid:1)
`ing
`by Vd.
`The
`elimination
`half-life
`from tY2 = 0.693/Kr.
`The
`two-group
`evaluate
`group
`centrations
`and
`were
`compared
`ance
`(14).
`
`test
`t
`differences
`urinary
`by using
`
`or Mann-Whitney
`in
`basal
`plasma
`S excretion.
`Postload
`a repeated
`measures
`
`to
`used
`U test was
`amino
`acid
`con-
`plasma
`profiles
`analysis
`of vari-
`
`Results
`
`Plasma
`
`amino
`
`acid
`
`concentrations
`
`fasting
`preload,
`The
`listed
`are
`centrations
`subjects
`the
`control
`1 . Cirrhotics
`ure
`branched-chain
`leucine;
`p
`< 0.01)
`but
`(p
`0.05),
`<
`tyrosine
`(p
`
`<
`
`amino
`(basal)
`differences
`in Table
`are
`illustrated
`and
`cirrhotics
`concentrations
`exhibited
`lower
`amino
`acids
`(p
`< 0.05
`for
`isoleucine
`0. 10
`for
`valine)
`and
`taurine
`in
`plasma
`higher
`concentrations
`ofplasma
`methionine
`phenylalanine
`(p
`0.01),
`serine
`(p
`0.05),
`<
`<
`0.005),
`cyst(e)ine
`(free
`cysteine
`+ cys-
`
`plasma
`2 and
`
`con-
`acid
`between
`in Fig-
`of
`the
`and
`(p
`
`and
`
`<
`
`Eton Ex. 1040
`2 of 6
`
`(cid:18)
`(cid:17)
`

`

`IMPAIRED
`
`CYSTEINE
`
`USE
`
`BY CIRRHOTICS
`
`1403
`
`2
`TABLE
`Basal
`plasma
`
`5
`
`amino
`
`acid
`
`concentrations
`
`in control
`
`and
`
`cirrhotic
`
`Plasma
`
`am mo acid
`
`concentration
`
`Amino
`
`acid
`
`Control
`
`Cirrhotic
`
`(cid:1)mo//L
`
`0
`
`2
`
`4
`
`6
`
`8
`
`Time
`
`(hr)
`
`0E C0
`
`C4
`
`)
`
`UC0U 4
`
`)
`
`E4
`
`’
`(U
`
`0(cid:1)
`
`cysteine
`Free
`load.
`an oral L-cysteine
`after
`cyst(e)ine
`determined
`cysteine
`(0) were
`and
`protein-bound
`after
`the
`oral
`L-cysteine
`load.
`text
`at various
`times
`for
`control
`subjects
`and
`cirrhotics
`shown
`respectively.
`Total
`plasma
`cyst(e)ine
`values
`shown
`both
`groups.
`Total
`plasma
`and
`cirrhotics
`are
`significantly
`different
`val-
`
`as
`The
`in
`
`are
`((cid:1)) mean
`cyst(e)ine
`control
`
`from
`
`for
`
`Alanine
`Glutamine
`Glycine
`Isoleucine
`Leucine
`Methionine
`Phenylalanine
`Serine
`Taurine
`Threonine
`Tyrosine
`TPCII
`
`±
`
`±
`
`433.6±25.5
`606.
`1 ± 54.5
`± 23.8
`272.7
`77.8
`4.9
`128.8±
`15.3
`47.7
`0.35
`53.0
`6.6
`73.0
`8.4
`95.1
`17.1
`126.0±
`3.2
`0.55
`56.8
`214.8±
`13.5
`
`±
`
`±
`
`±
`
`±
`
`±
`
`±
`
`±
`
`367.3±51.9
`56 1 .0 ± 29.3
`295.9
`± 20.3
`4.8t
`46.8
`13.7t
`2.8t
`12.8t
`4.3t
`9.2(cid:1)
`12.7
`6.0(cid:1)
`
`94.2±
`63.2
`89.4
`94.3
`46.1
`135.2±
`129.7
`±
`288.9±27.l(cid:1)
`
`±
`
`±
`
`5i(cid:1)±SEM.
`t Significantly
`:j: Significantly
`§ Significantly
`II TPC,
`total
`cysteine).
`#{182}
`Significantly
`
`different
`different
`different
`
`from
`from
`from
`
`control
`control
`control
`
`values,
`values,
`values,
`
`p < 0.05.
`p < 0.01.
`p <
`0.005.
`
`plasma
`
`cysteine
`
`(cysteine
`
`+ cystine
`
`+
`
`protein-bound
`
`different
`
`from
`
`control
`
`values,
`
`p < 0.025.
`
`cyste-
`con-
`that
`
`Downloaded from https://academic.oup.com/ajcn/article-abstract/50/6/1401/4695064 by barrettrabinow@gmail.com on 16 May 2020
`
`+ cysteine
`tine
`p
`0.025).
`me,
`<
`comitant
`with
`
`mixed
`The
`a decrease
`
`disulfides
`in
`increase
`in plasma
`
`+ protein-bound
`plasma
`cyst(e)ine
`taurine
`suggests
`
`2. Plasma
`FIG
`(#{149}),cystine
`(A),
`described
`in the
`mean
`concentrations
`panels
`A and
`B,
`± SEM are
`also
`cystine
`values
`of
`ues(p <0.001).
`
`impaired
`
`in cirrhotic
`
`patients
`
`rel-
`
`was
`utilization
`cysteine
`subjects.
`to control
`ative
`oral
`30 mm after
`within
`Plasma
`cyst(e)ine
`increased
`1 h in
`both
`was
`maximal
`at
`cysteine
`administration
`and
`(Fig
`2);
`however,
`cirrhot-
`control
`subjects
`and
`cirrhotics
`increase
`in cyst(e)ine
`than
`ics
`exhibited
`a twofold
`greater
`first-order
`elimination
`the
`control
`subjects.
`After
`was
`significantly
`cyst(e)ine
`occurred;
`elimination
`by
`both
`the
`plasma
`in the
`cirrhotic
`group
`as
`shown
`rate
`(Table
`3).
`life
`and
`the metabolic
`clearance
`due
`The
`elevation
`in
`plasma
`cyst(e)ine
`was
`primarily
`to an
`increase
`in cystine
`2). Plasma
`cystine
`was max-
`
`4)
`-
`(U
`
`,(cid:1)
`-
`-
`(cid:1) (cid:1)
`
`4)
`=4)
`
`-
`
`(cid:1)-
`
`4)
`
`-
`.(cid:1)
`E
`
`L.
`4)
`
`.
`
`(cid:1) (cid:1) (cid:1)
`4)
`#{163} (cid:1)
`-
`5’
`
`C)
`
`I-.
`
`>
`
`Amino
`
`Acid
`
`4)
`
`(U
`
`> 4
`
`)
`
`E 0z 0
`
`FIG 1 . Percent
`from
`acids
`amino
`plasma
`basal
`ofcii-rhotic
`deviation
`subjects
`in control
`((cid:1)zmol/L)
`plasma
`values
`The mean
`control
`values.
`values
`cirrhotic
`mean
`ofthe
`were
`set at 100% and
`the percent
`deviations
`TPC is total
`and
`plasma
`cysteine
`were
`calculated
`for
`each
`amino
`acid.
`includes
`free
`cysteine,
`cysteine
`as
`cystine,
`and
`protein-bound
`cysteine.
`(see text).
`
`significant
`
`values
`
`are marked
`
`with
`
`an
`
`asterisk
`
`Statistically
`
`L-
`
`of
`
`slower
`half-
`
`1 h,
`
`(Fig
`
`3
`TABLE
`Pharmacokinetic
`oral
`bolus
`
`variables
`of L-cysteine5
`
`ofplasma
`
`cyst(e)ine
`
`elimination
`
`after
`
`an
`
`Maximal
`concentration
`
`plasma
`
`/.LFflO//L
`
`t 1/2
`
`h
`
`Control
`Cirrhotict
`
`336.0
`664.5
`
`± 37. 1
`64.
`1
`
`±
`
`3.48
`± 0.34
`5. 18 ± 0.98
`
`Metabolic
`clearance
`
`rate
`
`L/h
`
`1 .4 1 ±0.15
`0.94
`± 0.16
`
`5i(cid:1)±SEM.
`t Significantly
`
`different
`
`from
`
`controls
`
`for
`
`all
`
`values,
`
`p <
`
`.0 1.
`
`Eton Ex. 1040
`3 of 6
`
`(cid:1)
`(cid:1)
`(cid:1)
`(cid:1)
`

`

`TRIBBLE
`
`ET AL
`
`Time
`
`(hr)
`
`1404
`
`4)
`
`34
`
`’
`.5
`
`0
`.C
`I.-
`
`cysteine
`FIG 3. Plasma
`plasma
`load. The mean
`by
`dividing
`free
`cysteine
`various
`bound
`cysteine
`at
`Control
`values,
`open
`bars;
`ues are
`significantly
`different
`
`an oral L-cysteine
`after
`status
`thiol:disulfide
`ratio was
`calculated
`cysteine
`thiol-disulfide
`as
`cystine
`and
`protein-
`the
`cysteine
`present
`± SEM.
`i
`times
`postload.
`Values
`represent
`cirrhotic
`values,
`shaded
`bars. Cirrhotic
`val-
`from control
`values
`(p < 0.005).
`
`by
`
`Downloaded from https://academic.oup.com/ajcn/article-abstract/50/6/1401/4695064 by barrettrabinow@gmail.com on 16 May 2020
`
`0-6
`
`6-12
`
`12-18
`
`18-24
`
`0-24
`
`Time
`
`(hr)
`
`FIG 4. Percent
`of sulfur
`cysteine
`load. H2S, S042
`the
`text.
`The mean
`increase
`basal
`L-cysteine
`load
`over
`the
`sponding
`time
`period
`is divided
`open
`bars;
`cirrhotic
`values,
`shaded
`cantly
`different
`from
`control
`values
`terisk.
`
`urine
`in the
`excreted
`load
`determined
`and
`taurine
`were
`(±SEM)
`in total
`S excretion
`urinary
`S excretion
`during
`by the
`total
`S load.
`Control
`are
`bars.
`Cirrhotic
`values
`< 0.05) where marked
`(p
`
`an oral
`after
`as described
`in
`after
`an oral
`the
`corre-
`values,
`signifi-
`with
`as-
`
`L-
`
`that
`reveal
`not
`shown)
`cystine,
`were
`excreted
`
`only
`the
`of
`cysteine,
`in the
`
`insignificant
`S-containing
`homocys-
`urine
`of ci-
`
`and
`7)
`(1 5-1
`viously
`data
`1%;
`(<
`amounts
`methionine,
`acids
`amino
`and
`cystathionine
`teine,
`group.]
`ther
`load was
`cysteine
`S from the
`ofthe
`percent
`Thirty-one
`the
`first
`within
`of control
`subjects
`excreted
`in the
`urine
`with
`each
`4). This
`percentage
`decreased
`6 h postload
`(Fig
`56% was
`consecutive
`6-h
`urine
`sample.
`Approximately
`A sim-
`excreted
`within
`24 h of cysteine
`administration.
`within
`group
`ilar
`amount
`was
`excreted
`by the
`cirrhotic
`but
`of S in
`the
`this
`24-h
`the
`distribution
`period
`(54%)
`was
`four
`6-h
`urine
`samples
`different.
`Corresponding
`to
`the
`slower
`rate
`of cyst(e)ine
`clearance
`from the
`less
`S was
`excreted
`in the
`urine
`within
`the
`first
`24
`h, S excretion
`was
`not
`significantly
`different
`basal
`values
`in either
`group
`although
`only
`load
`had
`been
`accounted
`for
`in the
`urine.
`et al (18)
`Krijgsheld
`ac-
`to
`inability
`reported
`a similar
`discrep-
`The
`count
`for
`all S after
`an
`oral
`cysteine
`load.
`is probably
`not
`ancy
`between
`cysteine
`intake
`and
`output
`S because
`this
`is a
`due
`to a concomitant
`increase
`in fecal
`The
`cysteine
`may
`very
`minor
`route
`of S excretion
`(19).
`the
`form
`pro-
`body
`have
`been
`retained
`in
`the
`in
`teins
`and/or
`glutathione
`(a-glutamyl-cysteinyl-glycine)
`(20,
`21).
`
`plasma,
`6 h. After
`from
`the
`of
`
`the
`
`S
`
`half
`
`of
`
`Discussion
`A recent
`rhotic
`patients
`
`strategy
`has
`
`in the
`been
`
`treatment
`the
`use
`
`of hospitalized
`tailor-made
`
`of
`
`cir-
`nutn-
`
`at
`
`to
`
`imal
`subjects
`creased
`in
`both
`values
`thiol
`cystine
`both
`time
`control
`Urinary
`fifth
`
`elevated
`remained
`1 h and
`and
`cirrhotics.
`8 h
`in
`and
`returned
`rapidly
`Because
`cysteine
`groups.
`to a greater
`extent
`than
`disulfide
`(moles
`cysteine
`and
`protein-bound
`cysteine)
`groups
`after
`the
`L-cysteine
`load
`point
`the
`ratio
`thiol
`to
`disulfide
`of
`subjects
`than
`in cirrhotics.
`sulfur-containing
`metabolites.
`days
`ofdietary
`equilibration,
`S averaged
`0.50
`g/d
`± 0.03
`g/d
`for
`and
`0.39
`±
`0.04
`accounted
`for
`(cid:1)-85%
`the
`of
`the
`remainder
`was
`comprised
`percentages
`similar
`to
`
`(cid:1)-
`
`are
`
`to
`
`for
`Free
`preload
`increased
`did
`cystine,
`per moles
`was
`(Fig
`
`control
`h in
`‘-(cid:1)-4
`in-
`also
`cysteine
`4 h
`by
`values
`preload
`over
`ratio
`the
`cysteine
`increased
`3). At
`was
`greater
`
`of
`as
`in
`every
`in
`
`fourth
`the
`On
`excretion
`urinary
`for control
`SEM)
`(1±
`(Table
`4).
`cirrhotics
`S in
`both
`urinary
`of
`taurine.
`mostly
`those
`reported
`pre-
`
`and
`oftotal
`subjects
`S042
`groups;
`[These
`
`TABLE
`Basal
`and
`
`4
`
`post-ba
`
`d urinary
`
`su lfur
`
`excretion
`
`Control
`
`Cirrhotic
`
`Total
`S
`
`Inorganic
`S
`
`Taurine
`
`Total
`S
`
`Inorganic
`S
`
`Taurine
`
`Basal
`Postload
`
`0.50
`2.ll(cid:1)
`
`g/d
`
`0.43
`l.84(cid:1)
`
`0.07
`0.25(cid:1)
`
`0.38
`l.42(cid:1)
`
`g/d
`
`0.32
`l.37
`
`0.06
`0.07
`
`S Significantly
`
`different
`
`from
`
`basal
`
`values,
`
`p < 0.01.
`
`Eton Ex. 1040
`4 of 6
`
`

`

`IMPAIRED
`
`CYSTEINE
`
`USE
`
`BY CIRRHOTICS
`
`1405
`
`Downloaded from https://academic.oup.com/ajcn/article-abstract/50/6/1401/4695064 by barrettrabinow@gmail.com on 16 May 2020
`
`subjects
`study
`present
`which
`g) diet,
`tein
`(40
`of hepatic
`with
`a history
`higher
`concentrations
`the
`activities
`creases
`in
`ble
`for
`the
`catabolism
`Accordingly,
`the
`present
`teine
`tolerance
`in cirrhotics
`to
`be
`extended
`to
`higher
`take.
`Provision
`rhotic
`patient
`cal
`treatment
`cause
`of
`the
`that
`accompany
`thesis
`from
`of
`a source
`these
`studies
`hypercyst(e)inemia,
`unless
`the
`dosage
`
`the
`
`equilibrated
`were
`used
`in
`is often
`encephalopathy.
`intake
`of
`protein
`enzymes
`of numerous
`amino
`acids
`ofthe
`dietary
`ofimpaired
`demonstration
`on
`a low-protein
`diet
`concentrations
`protein
`
`of
`
`to a low-pro-
`cirrhotic
`patients
`Adaptation
`involves
`responsi-
`(35,
`36).
`cys-
`needs
`in-
`
`to
`in-
`
`that
`of a diet
`is a fundamental
`plan.
`This
`is often
`severe
`protein
`and
`liver
`disease.
`methionine
`may
`cysteine
`some
`indicate,
`such
`with
`ofcysteine
`
`repletion
`supports
`component
`difficult
`amino
`Impaired
`necessitate
`cirrhotic
`a supplement
`possible
`toxic
`is carefully
`
`of
`ofthe
`to achieve
`intolerances
`acid
`cysteine
`biosyn-
`the
`provision
`patients.
`Yet,
`could
`lead
`consequences
`adjusted.
`
`cir-
`the
`mcdi-
`be-
`
`of
`as
`to
`
`B
`
`to
`
`References
`
`I . Rose WC. The
`amino
`Rev
`1957;27:63l-47.
`PJ. Nutrient
`2. Rudman
`D, Williams
`Rev
`1985;43:l-14.
`teral
`nutrition.
`Nutr
`concepts
`JD.
`Newer
`3. Laidlaw
`SA, Kopple
`amino
`acids. Am J Clin Nutr
`l987;46:593-605.
`for
`al. Evidence
`et
`4. Horowitz
`JH,
`Rypins
`EB,
`Henderson
`JM,
`pairment
`of
`transsulfuration
`pathway
`in cirrhosis.
`Gastroenterol-
`ogy 1981:81:668-75.
`M, Ansley
`5. Rudman
`D, Kutner
`hypocystinemia,
`Hypotyrosinemia,
`nutrition
`parenteral
`during
`total
`ology 198 l;81:1025-35.
`6. Chawla
`RK,
`Lewis
`FW, Kutner
`man D. Plasma
`cysteine,
`cystine,
`troenterology
`1 984;
`84:770-6.
`Kang
`SS, Wang
`PWK,
`Curley
`protein-bound
`homocyst(e)ine
`1982;
`16:370-2.
`A biometric
`FG.
`8. Harris
`JA,
`Benedict
`DC: Carnegie
`man. Washington,
`Brigham
`MP,
`Stein WH,
`Moore
`and
`cystine
`in
`human
`blood
`1633-8.
`10. Malloy
`free
`15.
`1 1 . Gaitonde
`nation
`amino
`12. Hawk
`chemistry.
`Chasson
`by means
`Technol
`14. Mattson
`tions. Oak
`lob V, Coon
`
`acid
`
`requirements
`
`ofadult
`
`man.
`
`Nutr Abstr
`
`deficiencies
`
`during
`
`total
`
`paren-
`
`of
`
`the
`
`indispensable
`
`im-
`
`J, Janson
`and
`ofcirrhotic
`
`R, Chipponi
`failure
`to
`patients.
`
`J, Bain RP.
`nitrogen
`retain
`Gastroenter-
`
`MH,
`and
`
`Bate DM,
`glutathione
`
`Roy RGB,
`in cirrhosis.
`
`Rud-
`Gas-
`
`of D-penicillamine
`effect
`K. The
`in
`homocystinurics.
`Pediatr
`
`on
`Res
`
`metabolism
`ofbasal
`study
`19 19:279-89.
`Institution,
`S. The
`concentrations
`plasma.
`J Clin
`
`of
`
`cysteine
`l960;32:
`
`Invest
`
`DK,
`Rassin
`MH,
`bound
`plasma
`
`GE.
`Gaull
`cyst(e)ine.
`
`for measurement
`A method
`Anal
`Biochem
`1981;
`1 12:407-
`
`and
`
`in
`
`of
`
`method
`MK. A spectrophotometric
`of other
`cysteine
`in
`the
`presence
`of
`acids.
`Biochem
`J 1967;
`104:627-33.
`Practical
`PB, Oser
`BL, Summerson
`WH.
`1947.
`12th ed. New York:
`Blakiston,
`AL, Grady
`HJ,
`Stanley
`MA.
`Determination
`of
`automated
`chemical
`analysis.
`Tech
`196 1;30:207-
`12.
`concepts,
`DE.
`Statistics:
`difficult
`Park,
`IL: Bolchazy-Carducci
`WW,
`Sloan
`M. Altered
`
`for direct
`naturally
`
`determi-
`occurring
`
`physiological
`
`creatinine
`of
`Regist
`Med
`
`Bull
`
`understandable
`Publishers,
`clearance
`of
`
`explana-
`
`1986.
`free amino
`
`acids
`
`7.
`
`9.
`
`13.
`
`1 5.
`
`repletion
`nutritional
`and
`spe-
`of protein
`purpose
`of
`The
`of cirrhotic
`pa-
`determine
`the
`intake
`of
`
`of
`L-
`
`was
`in
`and
`
`t1/2
`in to-
`pri-
`both
`the
`state
`of cys-
`
`and
`for
`
`affect
`which
`formulations,
`tional
`consequences
`the
`minimizing
`while
`intolerances
`(22-25).
`amino
`acid
`cific
`the
`examine
`response
`study
`was
`to
`this
`thus
`ofL-cysteine,
`and
`to oral
`loads
`tients
`the
`feasibility
`of
`supplementing
`nutritional
`acid.
`these
`patients
`with
`this
`amino
`ability
`the
`in
`We
`found
`a significant
`impairment
`administered
`cirrhotic
`patients
`to
`process
`orally
`the
`elimination
`cysteine,
`as
`reflected
`in a higher
`plasma
`increase
`and
`a lower metabolic
`clearance
`rate.
`The
`load
`tal
`plasma
`cyst(e)ine
`after
`the
`L-cysteine
`cystine
`marily
`due
`to
`an
`increase
`in
`plasma
`groups.
`Impaired
`plasma
`cysteine
`elimination
`accompanying
`alteration
`in the
`cysteine
`oxidation
`could
`result
`in 1) high
`circulating
`concentrations
`teine
`in cirrhotic
`patients
`receiving
`cysteine-containing
`meals;
`tau-
`decreased
`production
`the
`amino
`acid
`of
`2)
`rime, which
`may
`critical
`function
`of nervous
`be
`the
`for
`and
`cardiac
`tissue
`(26);
`and
`3) alterations
`in the
`oxida-
`tion
`state
`of
`plasma
`protein
`sulfhydryl
`groups
`and,
`hence,
`protein
`conformation
`and
`activity
`(27).
`Consis-
`is the
`tent with
`this
`possibility
`known
`toxicity
`of excess
`dietary
`cysteine
`in
`the mammal,
`manifested
`by
`neuro-
`(28).
`logic
`hepatic
`dysfunctions
`lesions
`and
`post-
`prolonged
`The
`pathophysiological
`the
`basis
`is
`not
`cirrhotics
`load
`elevation
`of
`plasma
`in
`cysteine
`immedi-
`known.
`Decreased
`hepatic
`ofcyst(e)ine
`uptake
`Re-
`ately
`after
`absorption
`is
`explanation.
`a plausible
`perfu-
`duced
`uptake
`could
`from diminished
`portal
`result
`cys-
`sion
`and/or
`a curtailed
`ability
`ofthe
`liver
`to remove
`uptake
`t(e)ine
`from
`the
`perfusate.
`Impaired
`cyst(e)ine
`to
`de-
`from
`the
`plasma
`potentially
`could
`secondary
`be
`showed
`plasma
`glutathione.
`Beatty
`et a!
`(29,
`30)
`creased
`by
`that
`liberation
`of cysteine
`from
`cystine,
`glutathione
`potentiates
`hepatic
`cysteine
`uptake.
`By a thiol-disulfide
`interchange
`reaction
`with
`glutathione,
`one mole
`of cys-
`to
`tine
`is converted
`one mole
`of
`cysteine-glutathione-
`and
`mixed
`disulfide
`one mole
`of
`free
`cysteine.
`Although
`the
`we did
`not
`have
`resources
`to measure
`plasma
`gluta-
`thione
`in this
`study,
`Chawla
`et al (6, 3 1) reported
`subnor-
`mal
`plasma
`glutathione
`concentrations
`in
`cirrhotic
`patients
`maintained
`on
`mixed
`foods,
`enteral
`either
`mixtures,
`or parenteral
`formulas.
`Decreased
`plasma
`glu-
`tathione
`in cirrhosis
`suggests
`decreased
`hepatic
`concen-
`trations
`because
`plasma
`glutathione
`concentrations
`have
`been
`shown
`to parallel
`hepatic
`concentrations
`in experi-
`mental
`animals
`(32).
`lower
`The
`significantly
`subjects
`than
`in the
`control
`ofcysteine
`block
`in conversion
`oxidation.
`carboxylation
`and
`in
`centrated
`platelets
`and
`taurine
`plasma
`require
`which
`plasma,
`not
`was
`the
`question
`taurine
`ther
`evaluation
`before
`The
`plasma
`essential
`to increase
`with
`increasing
`
`plasma
`could
`
`cirrhotics
`in the
`taunne
`a partial
`in part
`reflect
`by hepatic
`de-
`to taurine
`however,
`is con-
`Taunne,
`measurements
`of
`precise
`of
`platelet-free
`preparation
`Consequently,
`study.
`in our
`requires
`in cirrhotics
`will
`be possible.
`concentrations
`intake
`(33,
`
`of
`
`done
`status
`conclusions
`acid
`amino
`protein
`
`fur-
`
`tend
`In the
`
`34).
`
`Eton Ex. 1040
`5 of 6
`
`

`

`Downloaded from https://academic.oup.com/ajcn/article-abstract/50/6/1401/4695064 by barrettrabinow@gmail.com on 16 May 2020
`
`1406
`
`TRIBBLE
`
`ET AL
`
`16.
`
`17.
`
`19.
`
`20.
`
`21.
`
`from plasma
`l966;6:233-9.
`Cascino
`A, Cangiano
`L. Plasma
`amino
`Dis
`l978;23:591-8.
`CampbellJA.
`JW,
`SB, Cowan
`Dabry
`ZI,
`Shadarevian
`acids
`to
`urinary
`sulphur
`amino
`of
`of
`dietary
`intake
`1965;206:931-3.
`in man. Nature
`inorganic
`sulphate
`Scholtens
`E, Mulder
`Glazenburg
`EJ,
`I 8. Krijgsheld
`KR,
`dation
`of i- and D-cysteine
`to inorganic
`sulfate
`and
`rat.
`Biochem
`Biophys
`Acta
`198
`1 ;677:7-
`I 2.
`Yamaguchi
`K, Sakakibara
`5, Asamizu
`Induction
`of
`cysteine
`oxidase
`in
`liver.
`II. The
`measurement
`rat
`metabolism
`in vivo
`and
`the activation
`ofin
`vivo activity
`oxidase.
`Biochem
`Biophys
`Acta
`l973;297:48-59.
`Tateishi
`N, Higashi
`T, Naruse
`A, Nakashima
`moto
`Y. Rat
`liver
`glutathione:
`possible
`teine.
`J Nutr
`1977;
`107:51-60.
`Sakamoto
`K,
`A, Hikito
`Tateishi
`N, Higashi
`T, Naruse
`cysteine
`of dietary
`contributions
`of
`sulfur
`atoms
`to
`rat
`liver
`glutathione
`and
`proteins.
`J Biochem
`22. Bleier
`J, Smith
`J, Heymsfield
`SB. Repletion
`rhotic
`using
`high
`caloric
`density
`enteral
`formulae
`1979;3:512 (abstr).
`
`of patients
`
`with
`
`cirrhosis
`
`of
`
`the
`
`liver.
`
`J Surg
`
`Res
`
`C, Calcaterra
`imbalance
`
`acids
`
`V. Rossi-Fanelli
`in patients
`with
`
`F, Capocaccia
`liverdisease.
`
`Dig
`
`Relationship
`excretion
`
`of
`
`GJ.
`taurine
`
`The
`
`oxi-
`in the
`
`and
`
`activation
`of
`cysteine
`of cysteine
`
`J.
`
`K, Shiozaki
`as a reservoir
`
`H, Saka-
`of cys-
`
`role
`
`Y. Relative
`and methionine
`198
`l;90:l603-lO.
`of
`the
`cachetic
`(HCDF).
`
`cir-
`JPEN
`
`23.
`
`Achord
`coholic
`24. McGhee
`effects
`thy,
`tients.
`25. Millikan
`nutrition
`Ann
`Surg
`
`role
`the
`and
`JL. Malnutrition
`Am J Gastroenterol
`liver
`disease.
`WJ,
`JM, Millikan
`A, Henderson
`modular
`and
`a casein
`of Hepatic-Aid
`acids,
`and
`nitrogen
`plasma
`amino
`197:288-94.
`Ann
`Surg
`1983;
`JM, Warren
`WJ, Henderson
`with
`F080
`in cirrhotics
`with
`1983;
`197:294-304.
`
`ofnutritional
`l987;82:l-7.
`of the
`et al. Comparison
`diet
`on encephalopa-
`balance
`in cirrhotic
`
`support
`
`in al-
`
`pa-
`
`parenteral
`et al. Total
`WD,
`subclinical
`encephalopathy.
`
`26.
`
`27.
`
`29.
`
`30.
`
`31.
`
`33.
`
`35.
`
`Sturman
`KC,
`Hayes
`1:40 1-25.
`1981;
`distinct
`RB. How many
`Freedman
`involving
`cellular
`processes
`several
`change? FEBS Lett 1979;97:20l-lO.
`28. Wellner
`D, Meister
`A. A survey
`of
`metabolism
`and
`transport
`in man.
`911-68.
`Beatty
`thesis
`Biophys
`Beatty
`status
`1227-30.
`MH,
`CJ,
`Berry
`RK,
`Chawla
`transsulfuration
`pathway
`of
`trations
`and intravenous
`hyperalimentation
`J Clin Nutr
`l985;42:577-84.
`and
`32. Kaplowitz
`N. The
`importance
`one. Yale
`J Biol Med
`198 1 ;54:497-502.
`B, Rand
`Fernstrom
`JD, Wurtman
`Ri,
`Hammarstrom-Wiklund
`WM, Munro HN, Davidson
`CS. Diurnal
`variations
`in plasma
`con-
`amino
`acids:
`centrations
`oftryptophan,
`tyrosine,
`and
`other
`neutral
`effect ofdietary
`protein
`intake.
`Am J Clin Nutr
`1979;32:1912-22.
`34. Maher
`TJ, Glaeser
`BS, Wurtman
`Ri. Diurnal
`variations
`in plasma
`red cell
`concentrations
`of
`basic
`and
`amino
`acids
`and
`in
`neutral
`and
`glutamate:
`effects
`of dietary
`pro-
`concentrations
`of aspartate
`tein
`intake.
`Am J Clin Nutr
`1984;
`39:722-9.
`RT.
`Schimke
`Adaptive
`characteristics
`ofurea
`rat.
`J Biol Chem
`l962;237:459-68.
`36. Miller
`RH,
`Eisenstein
`RS, Harper
`intake
`on branched-chain
`keto
`acid
`rat.
`J Biol Chem
`l988;263:3454-61.
`
`JA.
`
`Taurine
`
`in metabolism.
`
`Annu
`
`Rev
`
`Nutr
`
`are responsible
`enzymes
`thiol:protein-disulfide
`
`the
`for
`inter-
`
`inborn
`Annu
`
`of
`errors
`Rev
`Biochem
`
`acid
`amino
`198 1 ; 50:
`
`Involvement
`by
`isolated
`
`PW, Reed DL.
`of glutathione
`1980;204:80-7.
`Influence
`Reed DL.
`PW,
`of
`isolated
`rat hepatocytes.
`
`ofcystathionine
`rat
`hepatocytes.
`
`in the biosyn-
`Arch
`Biochem
`
`of cysteine
`Biochem
`
`the glutathione
`upon
`Pharmacol
`198 l;30:
`
`Kutner
`
`Rudman
`products
`ofmalnourished
`
`Plasma
`D.
`during
`
`concen-
`nasoenteral
`patients.
`Am
`
`regulation
`
`of hepatic
`
`glutathi-
`
`cycle
`
`enzymes
`
`in the
`
`AE. Effects
`dehydrogenase
`
`of dietary
`activity
`
`protein
`of
`the
`
`Eton Ex. 1040
`6 of 6
`
`