CORRESPONDENCE

part of gestation.4,5 We recommend that
AT1-receptor antagonists be avoided
throughout pregnancy.
Jelena Martinovic, Alexandra Benachi,
Nicole Laurent, Farida Daïkha-Dahmane,*Marie Claire Gubler
Departments of Histoembryology and
Obstetrics, and *Institut National de la Santé etde la Recherche Médicale, Unité 423, Hospital
Necker Enfants Malades, Université René,
Descartes, 75743 Paris, France; Departmentsof Pathology and of Obstetrics, Hospital
Bocage, Dijon; Department of Histoembryology,
Hospital Robert Debré, Paris; and Departmentof Biochemistry, Hôpital Ambroise Paré, Paris
1

2

3

4

5

Saji H, Yamanaka M, Hagiwara A, Ijiri R.
Losartan and fetal toxic effects. Lancet 2001;
357: 363.
Hinchliffe SA, Sargent PH, Howard CV,
Chan YF, Hutton JL, Van Velzen D.
“Medullary ray glomerular counting” as amethod of assessment of humannephrogenesis. Pathol Res Pract 1992; 188:
775–82.
Pryde PG, Sedman AB, Nugent CE,
Barr M. Angiotensin-converting enzyme
inhibitor fetopathy. J Am Soc Nephrol 1993,
3: 1575–82.
Spence SG, Allen HL, Cukierski MA,
Manson JM, Robertson RT, Eydelloth RS.
Defining the susceptible period ofdevelopmental toxicity for the AT1-selective
angiotensin II receptor antagonist losartan inrats. Teratology 1995, 51: 367–82.
Sorensen AM, Christensen S, Jonassen TE,
Andersen D, Petersen JS. Teratogenic
effects of ACE inhibitors and angiotensin II
receptor antagonists. Ugeskr Laeger 1998,
160: 1460–64.

Testicular cancer andsyndrome X
Sir—Jourik A Gietema and colleagues(Jan 20, p 228)1 report an interestingfinding that long-term survivors ofmetastatic testicular cancer can develop
an unfavourable profile of cardiovascularrisk
factors
resembling
syndrome X. They conclude thatadministrationofcisplatin-based
combination chemotherapy as well as
subclinical hypogonadism seem to beimportant factors in pathogenesis.
Plasma concentrations of testosterone
in the chemotherapy group weresignificantly lower than those in thestage 1 group. Moreover, in theirchemotherapy-treated patients, insulin
concentrations and insulin-to-glucose
ratios correlated negatively with serum
testosterone concentrations.
We agree that decreased circulating
testosterone can cause insulin resistance.
We have reported a small series inwhich we showed that decreased
concentrations of testosterone after
castration contributed to insulin
resistance. We analysed events in six
patients whose diabetic control was
notably worsened by orchidectomy oradministration of a gonadotropinreleasing hormone analogue to treat
advanced prostate cancer, used in242

addition to antiandrogenic drugs.
Plasma concentrations of testosterone
became undetectable in all patients, andall but one patient had increased insulin
secretion. HbA1c before and after
castration was 6·3% (SD 0·6) and
10·2% (1·7), respectively.
Bilateral tumours are rare at
diagnosis, but in 2% of patients withtesticular germ-cell tumour, a metachronous new primary tumour willdevelop in the remaining testis. Evenpatients with testicular cancer in stage 1,
whose concentrations of testosterone
would decrease after bilateral orchidectomy, might result in insulin
resistance.
The effect of cisplatin in thepathogenesis of insulin resistanceremains to be elucidated, although
plasma concentrations of testosterone in
Gietema and colleagues’ chemotherapy
group were lower than in the stage 1
group. This difference probably reflects
direct damage to the testis by cisplatin,
which could be investigated in nontesticular cancer patients receiving
cisplatin, such as those with lung cancer.
Other
effects
ofcancerupon
development of insulin resistance, suchas induction of various cytokines
including interleukin 6, tumour necrosis
factor , and counter-regulatory
hormone, might also be important.
However, hypogonadism should not be
overlooked as an important cause of
insulin resistance in survivors of
testicular cancer.
Michiaki Fukui
Department of Endocrinology and Haematology,
Osaka General Hospital of West Japan Railway
Company, 1-2-22 Matsuzaki-cho, Abeno-ku,
Osaka 545-0053, Japan
1

Gietema JA, Meinardi MT,van der Graaf WTA, Sleijfer DT. Syndrome
X in testicular cancer survivors. Lancet 2001;
357: 228–29.

CD36 deficiency andinsulin resistance
Sir—Koji Miyaoka and colleagues(March 3, p 686)1 report phenotypic
data on carbohydrate metabolism
from their cohort of 26 Japanesepatients with genetic mutations
causing CD36 deficiency.
As Timothy Aitman points out in
his March 3 commentary,2 thequestion of whether or not insulin
resistance is present in these patientsis important, since data from one
rodent model, the spontaneously
hypertensiverat(SHR),
has
implicated a causal role for deficiencyof the rodent homologue (Cd36) inimpairmentofinsulinaction.3
However, some uncertainty remains.
We have reported that Cd36 sequenceand expression were normal inanother rodent model of hypertension
with insulin resistance (the strokeprone spontaneously hypertensive rat,
SHRSP), which suggests the existenceof other gene mutations leading to asimilar phenotype.4
Unfortunately,
Miyaokaandcolleagues’ data from patients with
CD36 deficiency are inconclusive.
First, few details are given of thematching procedures used and, inparticular, whether participants with
CD36 deficiency were individuallymatched with controls. The 26 cases
were on average 4 years older thancontrols: since age is an important
determinant of insulin sensitivity5 andserum lipids, inappropriate matching
could have contributed to theapparent differences between thegroups.
Conversely,
differences
between the sexes (42% of cases vs
29% of controls were female) might
have diminished the potential of thestudy to find differences in thesevariables.
Second, only five of 26 CD36deficientparticipants
underwentmeasurement of fasting insulin, oral
glucosetolerance
test,andhyperinsulinaemic
clamp
study.
Fasting plasma insulin concentrations
were all within the reference range
derived from normal controls. As
expected from a study with a small
number of participants with a wide
distribution of weight (body-massindex 17–33 kg/m2), the individual
insulin profiles across the glucose
tolerance tests were heterogeneous;
results were equally compatible with adefect in insulin secretion as with thepresence of insulin resistance.
Finally, the limited data reported
from the clamp studies is difficult tocompare with other published data
without some indication of the rate of
insulin infusion used. The argument
seems to rest on the observation that
all five cases individually had lower
values for whole-body glucose uptake
than the mean value for nine controls.
Although this finding is in keepingwith the hypothesis that insulin
resistance was present, the separation
between means (mean 5·1 [SD 1·59,
five cases] vs 8·6 mg kg21 min21 [0·50nine controls]) was not clear and may
be too small to allow abandonment of
the normal statistical requirement forformalrejection
of
the
null
hypothesis.
We agree with Miyaoka and coworkers that a case-control study witha larger number of people with CD36
deficiency is necessary. However,until such a study is done, putative
directorindirecteffectsof

THE LANCET • Vol 358 • July 21, 2001

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CORRESPONDENCE

CD36 deficiency on carbohydrate
metabolism
inhumanbeings,although biologically plausibly andmechanisticallyappealing,must
remain uncertain.
*John R Petrie, Mary Collison,John M Connell, Gwyn W Gould,
Anna F Dominiczak*Department of Medicine, Glasgow Royal
Infirmary, Glasgow G31 2ER, UK; and MRC
Cooperative Group on Cellular Signalling and
Molecular Genetics in Metabolic andCardiovascular Syndromes, University ofGlasgow, Glasgow(e-mail: jrp1s@clinmed.gla.ac.uk)
1

2

3

4

5

Miyaoka K, Kuwasako T, Hirano K-I,
Nozaki S, Yamashita S, Matsuzawa Y.
CD36 deficiency associated withinsulin resistance. Lancet 2001; 357:
686–87.
Aitman TJ. CD36, insulin resistance, andcoronary heart disease. Lancet 2001; 357:
651–52.
Aitman TJ, Glazier AM, Wallace CA,
et al.Identification of Cd36 (Fat) as an
insulin resistance gene causing defective
fatty acid and glucose metabolism in
hypertensive rats. Nat Genet 1999; 21:
76–83.
Collison M, Glazier AM, Graham et al.
Cd36 and molecular mechanisms of insulin
resistance in the stroke-prone
spontaenously-hypertensive rat. Diabetes
2000; 49: 2222–26.
Ferrannini E, Natali A, Capaldo B, et al.
Insulin resistance, hyperinsulinemia, andblood pressure: role of age and obesity:
European Group for the Study of Insulin
Resistance (EGIR). Hypertension 1997; 30:
1144–49.

Sir—Koji Miyaoka and colleagues1
and Timothy Aitman2 argue for the
possible association between CD36
and syndromes of insulin resistancebased on findings in human beingsand rodents with CD36 deficiency.
We have several comments.
We have previously shown in the
SHR model that there are two
separate SHR strains: the original
SHR strains with normal Cd36
(rodent homologue of human CD36)
and SHR with mutant Cd36 caused
by a spontaneous de novo mutation.3
The
comparisonofmetabolicphenotypes observed in the Cd36-null
SHR,3 as well as those reported in the
Cd36-null mice4 and in human beings
with CD36 deficiency1,5 is shown in
the table. In the inbred rodent models,increased non-esterified fatty acidconcentrations and the reciprocallydecreased glucose concentrations
seem to be a common feature.
However, the other phenotypes are
virtually inconsistent between the fourgroups, which might be partly
explained by the differences in themetabolic pathways among the species
and in the genetic and environmental
backgrounds between individuals.
Withtherelatively
unequaldistribution of the clinical phenotypes
among the patients described byasMiyaokaandcolleagues,1
exemplified by their wide range ofblood pressures, it seems difficult toascribe any particular phenotype tothe effects of CD36 deficiency but not
to any other possible confounding
factors. In this context, many Japanesepatients with CD36 deficiency havebeen selected from groups who
underwent cardiac scintigraphy on
suspicion of the presence of coronary
heart diseases or cardiomyopathy. If
this is the case in Miyaoka andcolleagues’ patients, their data need to
be interpreted cautiously because theymust be affected by a substantial
population stratification bias.
In view of the high prevalence ofhypertension (>50%), hyperlipidaemia (>50%), and hyperglycaemia(>30%) among the general Japanese
population in their 60s, according to
the latest National Nutrition Survey ofJapan, it may not be so surprising that
46% of Miyaoka and colleagues’
patients (mean age 64 years) had atleast two coronary risk factors.
Striking to us was their observationthat all five patients who underwent
glucoseclamp
studies
showeddecreases in the mean whole-body
glucose uptake that should best reflect
insulin sensitivity in skeletal muscles.
Increase in blood non-esterified fatty
acid concentrations and the resulting
increase in the content of triglycerides
in muscles cause insulin resistance invivo. This effect, however, would not
be the case in the deficiency of CD36,
because the muscle triglyceride
contents were not increased but wererather decreased, at least in the rodent

Rodent models
3

Cd36-null SHil
NEFA
FPG
Glucose tolerance
Triglycerides
HDL cholesterol
Blood pressure

Human being
4

Cd36-null mice

Miyaoka et al1

Yanai et al5

?

?

?

?

?

denote increased, decreased, and unchanged phenotype compared with controls; ?=unknown.
NEFA=non-esterified fatty acids; FPG=fasting plasma glucose.

Comparison of metabolic phenotypes in rodents and human beings with CD36
deficiency

THE LANCET • Vol 358 • July 21, 2001

models, probably because of theimpaired fatty acid uptake via CD36
in muscles. The metabolic sequel ofthis effect, which would possibly be
the increased fatty acid uptake in theliver, remains unclear in the patientswith CD36 deficiency and must be
investigated carefully.
Yoko Iizuka, *Takanari Gotoda,
Shun Ishibashi, Nobuhiro Yamada
Department of Metabolic Diseases, Universityof Tokyo, Tokyo; *Diabetes Center, Tokyo
Women’s Medical University, Tokyo 162-8666,
Japan; and Department of Internal Medicine,
University of Tsukuba, Tsukuba(e-mail: tknrgtd-tky@umin.ac.jp)
1

2

3

4

5

Miyaoka K, Kuwasako T, Hirano K-I,
Nozaki S, Yamashita S, Matsuzawa Y.
CD36 deficiency associated withinsulin resistance. Lancet 2001; 357:
686–87.
Aitman TJ. CD36, insulin resistance, andcoronary heart disease. Lancet 2001; 357:
651–52.
Gotoda T, Iizuka Y, Kato N, et al.
Absence of Cd36 mutation in the original
spontaneously hypertensive rats withinsulin resistance. Nat Genet 1999; 22:
226–28.
Febbraio M, Abumrad NA, Hajjar DP, etal. A null mutation in murine CD36
reveals an important role in fatty acid andlipoprotein metabolism. J Biol Chem 1999;
274: 19055–62.
Yanai H, Chiba H, Morimoto M,
Jamieson GA, Matsuno K. Type I
CD36 deficiency in humans is not
associated with insulin resistancesyndrome. Thromb Haemost 2000; 83:
786.

Sir—Koji Miyaoka and colleagues’
conclusions1 are not supported by our
published2,3 or unpublished results.
In our original study,2 four healthy
young
volunteers
with
CD36
deficiency (aged 21 years [SD 0·5])
were tested by oral glucose loadingand had normal insulin responses andnormal fasting glucose and lipid
concentrations. The CD36-deficientpatients identified by Miyaoka andcolleagues were elderly (mean 64
years), and 12 (46%) of 26 had atleast two coronary risk factors,
including
impaired
glucosemetabolism and hyperlipidaemia. We
question whether their 26 patientswere sampled without bias. If thepatients were detected among clinicalpatients who underwent cardiac
imaging with radiolabelled fatty acidanalogue, they would generally haveischaemic heart disease and coronary
risk factors.
Second, the mean lipid profiles fortheir 26 patients were characterisedbyincreased
triglycerideanddecreased HDL-cholesterol, which iscertainly typical for the insulin
resistance syndrome, and four ofthe five patients subjected to a
glucose clamp study also had

243

For personal use. Only reproduce with permission from The Lancet Publishing Group.

CORRESPONDENCE

hypertriglyceridaemia. However, in
our study on apparently healthyelderly volunteers, CD36 deficiency
in four was associated with decreased
triglyceride and increased HDLcholesterol, although not significantly
so.3 Thus, the lipid profiles seen in
Miyaoka and colleagues’ patientscannot be automatically attributed to
CD36 deficiency. The type IV (theircase 5) and the type IIb (cases 1–3)
hyperlipoproteinaemias are frequent
phenotypes of familial combined
hyperlipoproteinaemia (FCH), which
is known to associate with insulin
resistance.4
Finally, we have done oral glucose
loading studies in three matchedgroups of healthy young volunteers(aged 20·7 years [1·7]) composed ofnormal donors (n=16; CD36 present
in platelets and monocytes), type I
CD36 deficiency (CD36 absent on
both platelets and monocytes; n=5)
and type II CD36 deficiency (CD36
absent from platelets but present on
monocytes; n=16). We confirmed that
there were no significant differences
between the groups in serum insulin
concentrations at any time point nor
in major indices for insulin sensitivity,
such as integrated area under the
curve for insulin, fasting glucose toinsulin ratios, and the homoeostasis
model assessment (submitted for
publication). Nor were differences
detectable in their clinical features(age, sex, body-mass index, andblood pressures), haemoglobin A1C,
fasting
glucose,and
lipid
concentrations. Hence, we believethat CD36 deficiency cannot be a
proximate cause of human insulin
resistance.
However, we noted also thatplasma fatty acid clearance after
glucose loading is significantly
retarded in both types of CD36
deficiency. This effect could be
explained by impaired fatty aciduptake by muscle, and might result inincreased hepatic fatty acid entry. The
latter, in turn, could increase hepatic
gluconeogenesis.5*Hitoshi Chiba, Hidekatsu Yanai,
Hironobu Fujiwara, Kazuhiko Matsuno,
Kunihiko Kobayashi
Departments of *Laboratory Medicine andPaediatrics, Hokkaido University School of
Medicine, Sapporo 060-8648, Japan; andCollege of Medical Technology, Hokkaido
University, Sapporo(e-mail: chibahit@med.hokudai.ac.jp)
12

Miyaoka K, Kuwasako T, Hirano K,
Nozaki S, Yamashita S, Matsuzawa Y.
CD36 deficiency associated withinsulin resistance. Lancet 2001; 357:
686–87.
Yanai H, Chiba H, Morimoto M,
Jamieson GA, Matsuno K. Type I CD36

244

3

4

5

deficiency in humans is not associated withinsulin resistance syndrome. Thromb
Haemost 2000; 83: 786.
Yanai H, Chiba H, Morimoto M, et al.
Human CD36 deficiency is associated withelevation in low-density lipoproteincholesterol. Am J Med Genet 2000;
93: 299–304.
Ascaso JF, Real JT, Merchante A,
Rodrigo A, Carmena R. Lipoprotein
phenotype and insulin resistance in familial
combined hyperlipdemia. Metabolism 2000;
49: 1627–31.
Kruszynska YT, Mulford MI, Yu JG,
Armstrong DA, Olefsky JM. Effects ofnonesterified fatty acids on glucose
metabolism after glucose ingestion.
Diabetes 1997; 46: 1586–93.

Authors’ reply
Sir—One of the major issues for
medical science is to clarify themolecular and cellular mechanism fordevelopment of multiple risk factor
clustering (MRF) syndrome. In manycases people develop MRF syndromein middle age and subsequently
have atherosclerotic cardiovasculardiseases, whereas such clinical signs
are not always manifest at a younger
age. In these cases, the combinationof genetic factors and environmental
and acquired ones, as well as theimpact of each factor, is important.
Genetic factors include mutations or
polymorphisms in some genes,in addition to sex and race.
Environmental factors include age
and lifestyle, such as loss of physicalactivities and high calorie intake. The
genetic background, as well as foodcontent, might affect the results of theexperiments, as John Petrie and Yoko
Iizuka and their colleagues note.
So far, we have seen 28 patientswith type I CD36 deficiency.1 Ninepatients were identified by presenceof isoantibodies to CD36. The
remaining patients were identified by
the negative uptake of radiolabelledlong-chain fatty acid analogues.2 Even
when separated by sex, or when thepatients identified on scintigraphy
are excluded, our CD36-deficientpatients have higher concentrations ofplasma lipids, fasting plasma glucose,and blood pressure than normal
controls (unpublished data). The
difference of clinical phenotype
between
HitoshiChiba
andcolleagues’ study and ours might be
partly explained by the difference ofage and sex of the participants. The
young and healthy women with CD36
deficiency they are studying would fillin the blank of our study. They
seem to have noted subclinicalabnormalities and delayed and smaller
decay of plasma free fatty acidconcentrations after oral glucose
loading, even in these participants.
Fatty acid response after oral glucose

loading is thought to result from theinhibition of lipolysis in adipocytes byinsulin;3 therefore, we think that theobserved abnormal free fatty acidreaction could be related to possible
insulin resistance.
There is no definite way to measureinsulin resistance in daily clinics. We
use fasting concentrations of glucose
and insulin, which is easy, but theindex is not a direct parameter for
insulin resistance. We have usedthe euglycaemic hyperinsulinaemic
clamp,4 a more direct way, but themethod is complicated and time
consuming for patients and doctors.
We have also used the clamp test ina young CD36 deficient person,
and noted lower glucose uptake,which suggests insulin resistance(unpublished observation). We hopeto have some better way to measureinsulin resistance in the near future.
Finally,theCD36-deficiency
phenotype we report is milder thanother known phenotypes except rare
genetic insulin resistance syndromes
such as mutants of insulin receptor
and peroxisome proliferator activatedreceptor  gene.5 CD36 deficiency
could be an important genetic factor
for MRF syndrome, which we see
frequently. Investigation is needed ofthepathophysiologyofCD36
deficiency, especially the mechanismof insulin resistance, to understandthemolecular
mechanismfordevelopment of MRF syndromes andhow to assess insulin resistance in theclinics.
*Ken-ichi Hirano, Takahiro Kuwasako,
Hirokazu Kashiwagi, Shizuya Yamashita,
Yuji Matsuzawa*Department of Internal Medicine
and Molecular Science, Graduate
School of Medicine, Osaka University,
Osaka 565-0871, Japan(e-mail: khirano@kb3.so-net.ne.jp)
1

2

3

4

5

Kashiwagi H, Tomiyama Y, Nozaki S,
et al. Analysis of genetic abnormalities intype I CD36 deficiency in Japan:
Identification and cell biologicalcharacterization of two novel mutations
that cause CD36 deficiency in man. Hum
Genet (in press).
Yoshizumi T, Nozaki S, Fukuchi K, et al.
Pharmacokinetics and metabolism of
iodine-123-BMIPP fatty acid analogue
in normal and CD36 deficient subjects.
J Nucl Med 2000; 41: 1134–38.
Murray RK, Granner DK, Mayes PA,
Rodwell VW. Harper’s biochemistry, 24thedn. Connecticut: Appleton and Lance,
1996.
Miyaoka K, Kuwasako T, Hirano K, et al.
CD36 deficiency associated with insulin
resistance. Lancet 2001; 357: 686–87.
Barroso 1, Crowley VEF, Agostin I, et al.
Dominant negative mutations inhuman PPAR associated with severe
insulin resistance, diabetes mellitus,
and hypertension. Nature 1999; 402:
880–83.

THE LANCET • Vol 358 • July 21, 2001

For personal use. Only reproduce with permission from The Lancet Publishing Group.