Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3772_Библиотеки_им_академика_М_И_Перельмана
.pdf
3 Preclinical Model andHistopathology Translational Medicine andRenal Denervation
https://t.me/medicina_free
25
GFAP) and functional marker (tyrosine hydroxylase) would
be important for the comprehensive evaluation of preclinical
denervation therapy for efferent ber identication. An
immunostain against calcitonin gene-related peptide
(CGRP), which is a neurotransmitter of sensory nerves, can
be used as a marker of afferent bers in pigs [25]. However,
since the proportion of afferent nerve bers is small as compared to efferent nerve bers, it would be difcult to evaluate
treatment effect by using afferent nerve bers exclusively
[25]. Representative images of immunohistochemistry are
shown in Fig.3.4
For the assessment of treatment reactions to the vascular
and peri-vascular soft tissue including adjacent organs (kidney, lymph nodes, ureters, and renal veins), ordinal data can
be obtained for multiple parameters including endothelial
loss, arterial and venous medial injury, inammation, degenerative changes, and necrosis. Competent endothelium is the
most important luminal barrier against activation of coagulation pathways and adhesion of thrombi, it is important especially at early time points to assess its presence or absence.
Acute or chronic inammation can be a sign of irreversible
tissue damage and should be evaluated in association with
the presence of degenerative changes or necrosis. In addition, distances from affected tissue injury to the intimal luminal surface of the treated arterial segment can be measured
with digital morphometry in histologic sections, and these
measurements help determine the longitudinal depth of
injury (Fig.3.5).
Fig. 3.4 Semi-quantitative scoring criteria for immunostain against
tyrosine hydroxylase. Upper panels are representative images of injured
nerves stained by anti-tyrosine hydroxylase (TH) enzyme. Lower pan-
els are corresponding images of injured nerves with H&E and Movat
pentachrome stains. Reproduced with permission from Sakakura K
etal. JACC Cardiovasc Interv 2014;7:1184–93 [30]
26
https://t.me/medicina_free
Y. Sato et al.
b
c
a
d
e
Fig. 3.5 Representative images of distance from arterial lumen to various types of injury. (a) Low-power image of a treated renal artery and
surrounding perirenal area. (b) High-power images of injured arterioles
(red boxed area in a). The distance from the lumen to the injured arterioles was 4.4mm. (c) High-power image of nerve injury (yellow boxed
area in a). The distance from the lumen to the injured nerves was
Recent Catheter-Based RDN Technologies
There are three types of catheter-based RDN devices for
which the efcacy and safety of which are increasingly
being conrmed by randomized controlled trials (RCT)
with a sham procedure control arm. The Simplicity Spyral
(radiofrequency based catheter; Medtronic, Minneapolis,
MN), the Paradise System (ultrasound based catheter;
ReCor Medical, Palo Alto, CA), and the Peregrine System
(catheter-based microinfusion; Ablative Solutions, Inc, San
Jose, CA).
2.1mm. (d) High-power image of injured nerves (blue boxed area in a).
The distance from the lumen to the injured nerves was 4.1mm. (e)
High-power image of soft tissue injury (green boxed area in a). The
distance from the lumen to the injured tissue was 3.2mm. Reproduced
with permission from Sakakura K et al. JACC Cardiovasc Interv
2014;7:1184–93 [42]
Histopathology ofCatheter-Based
Radiofrequency Ablation Induced Lesions
RF energy is a form of alternating electrical current that produces an ablation area by two mechanisms: (1) direct resistive heating of the tissue in contact with the catheter tip, and
(2) thermal conduction or passive heat transfer to deeper tissue layers [35]. While direct resistive heating in regions
close to the RF current is rapid, passive heat transfer to
deeper tissue layers is a slower process [36]. Since the heat
transfer continues even after discontinuation of RF current
3 Preclinical Model andHistopathology Translational Medicine andRenal Denervation
https://t.me/medicina_free
27
Fig. 3.6 Renal artery imaging perangiography and optical coherence
tomography (OCT). Upper panel images: Angiography images at baseline (left), acute after radiofrequency therapy (mid) and subacute at 10
days follow-up (right). At the acute time point vessel notches are apparent at the lesion site (black arrow heads) accompanied by moderate
vessel spasm. At 10 days vessel notches are still discernable. Lower
panel images: OCT images of untreated arteries (left), arteries acutely
delivery, ablation area may expand following RF current cessation. Both bipolar mode and unipolar mode are used for the
generation of RF electrical current. RF current is delivered to
the target regions through transarterial electrode catheters
with a catheter tip ranging in length from 4 to 10mm.
Steigerwald etal. reported acute (45 min) and sub-acute
(10 days) histopathologic changes and optical coherence
tomographic (OCT) ndings following RF ablation in the
swine model [37]. Seven pigs underwent RF ablations of
after treatment (mid) and 10 days posttreatment (right). Lesion sites
were distinguishable from naive tissue in the presence of lumen retraction (white arrowheads). The arteries displayed thrombotic material (*)
and loss of signal intensity (white arrows) acutely after radiofrequency
treatment. Reproduced with permission from Steigerwald etal. Journal
of Hypertension 2012; 30: 2230–9 [37]
the renal arteries utilizing the Symplicity Catheter System
(Medtronic, Minneapolis, MN). In the acute phase, angiography showed vessel notches at the site of ablation where
the catheter tip had been positioned. OCT at acute phase
showed thrombotic material and a loss in signal intensity of
the media wall as a result of acute cell depletion and cellular edema, whereas thrombotic material was absent at
10-day follow-up (Fig. 3.6). Histologic ndings revealed
the presence of thrombus formation and depletion of endo-
28
ab
https://t.me/medicina_free
Y. Sato et al.
Fig. 3.7 von Willebrand factor immunohistochemical staining of arteries after radiofrequency-based renal sympathetic denervation. Upper
panel images show the luminal surface of the renal arteries (a) acutely
and (b) sub-acutely after treatment. Inserts represent images at higher
thelial cells, which were conrmed by absence of von
Willebrand factor (vWF) staining (Fig.3.7) [37]. The arterial media showed edematous cell swelling with a reduction
in cellularity [37] (Fig.3.8). Also, the adjacent adventitial
layer showed coagulation necrosis of the connective tissue
and cell depletion. The number of nerve fascicles around
the treated arteries were signicantly affected as compared
to the untreated arteries. Immunostaining against neurolament protein did not show abnormal staining pattern in the
acute injured nerves. In the sub-acute phase, re-endothelialization was evident by the presence of vWF staining (91%)
and thrombus was absent (Fig. 3.7) [37]. The recovered
media showed brotic scar tissue comprising 11% of the
media area, however substantial variability in the degree of
medial brosis was evident (Fig.3.8) [37]. Nerve fascicles
showed degenerative morphologic changes consisting of
vacuolization and thickening of the perineurium [37]. Also,
Immunostaining against neurolament protein showed
weak or loss of staining [37]. This study suggests the
importance of difference between acute and subacute in the
nerve injury and staining characteristics of pre-clinical porcine model following RF sympathetic denervation.
Rippy et al. reported on the chronic histopathologic
changes of RF ablation in swine [23]. Seven swine were
treated with the Symplicity Catheter System, with angiography and histopathology performed at 6-months. By angiography, there was no stenosis or other vascular complication
at 6-month follow-up [23]. Histopathology of the renal arteries at 6-months showed media injury consisting of brotic
replacement of the smooth muscle cells of the media with
disruption of the IEL (10–25%) [23]. Minimal intimal thickening was observed in treated renal arteries with complete
endothelialization [23]. Renal nerve injury at 6 months was
magnication. There is absence of von Willebrand factor staining
acutely following treatment, whereas there is strong staining present in
the subacute phase. Reproduced with permission from Steigerwald
etal. Journal of Hypertension 2012; 30: 2230–9 [37]
characterized by brosis of the nerve bers and perineural
thickening (Fig.3.6) [23].
We reported on a systematic and chronological investigation of histopathologic changes after RF ablation in
swine [38]. Forty-nine renal arteries from 28 swine were
treated with the Symplicity Catheter System and examined
histologically at 4 different time points (7, 30, 60, and 180
days). Semi-quantitative histological scoring was applied
[29] and assessment of arteries and associated tissue was
performed to characterize the chronological progression of
the radiofrequency lesions. Acute (7 days) nerve injury
was characterized by nerve necrosis (coagulation necrosis
with total or focal absence of nuclei within nerve bundles)
and degeneration (digestion chambers, vacuolization, pyknotic nuclei, and inammation). Nerve injury seen in
chronic phase (60 and 180 days) was characterized by
perineural brosis and nerve atrophy. Nerve injury after
radiofrequency ablation peaked at 7 days and declined
thereafter over time (Fig.3.9). Whereas functional nerve
damage evaluated using TH stain peaked at 7 days but sustained at 30 days, it recovered partially at later time points.
Renal artery and surrounding soft tissue injury was greatest at 7 days, and least at 180 days, suggesting gradual
recovery of the renal arterial wall and surrounding tissue
(Fig.3.10).
The ndings shown above suggest the long-term safety of
RF ablation. The Symplicity Spyral system is a newer generation device that was developed after the SYMPLICITY
HTN3 trial to overcome the disadvantages of the rst generation Symplicity system. Randomized, sham-controlled trials
have demonstrated efcacy and safety [17,
39, 40] and the
worldwide registry has shown long-term safety of this technology [41].
3 Preclinical Model andHistopathology Translational Medicine andRenal Denervation
https://t.me/medicina_free
29
Fig. 3.8 Histological cross-sections of the treated renal arteries.
Overview images represent elastica von Giesson-stained sections.
Higher magnied images are stained hematoxylin and eosin (scale bars
represent a length of 200mm). Black arrowheads point to the lesion
site, which engages approximately 20% of the vessel circumference.
Remnant nerve fascicles (N) are evident for both groups at the lesion
site. Upper panel images: Images of a renal artery cross-section acutely
after radiofrequency therapy. At the lesion site, the internal elastic lamina (IEL) shows minimal disruptions. Accumulation of thrombotic
material (Thr) is evident at locations absent of an endothelial layer. The
media is retracted and displays reduced cellular density and edema
(white arrow). The adventitia (Adv) exhibits coagulation of connective
tissue. Lower panel images: Images of a renal artery cross-section subacutely (10-day follow-up) after radiofrequency therapy. Surface endothelialization (EC) is restored and presence of thrombus is no longer
discernable. The intima is minimally thickened and the media shows
presence of brotic scar tissue comprising full media thickness. The
adventitia displays inammatory reaction and vasculogenesis (black
arrows). Reproduced with permission from Steigerwald etal. Journal of
Hypertension 2012; 30: 2230–9 [37]
30
https://t.me/medicina_free
Y. Sato et al.
Fig. 3.9 Representative images of injured nerves at various time
points. Upper panels are low-power images, and lower panels are
higher-power images of red boxed area in upper panels (H&E stain).
Nerve fascicle at 7-day shows coagulation necrosis and absence of
nuclei. Nerve fascicle at 30 days shows moderate perineural brosis,
vacuolization, and pyknotic nuclei. Nerve fascicle at 60 days shows
mild to moderate perineural brosis. Nerve fascicle at 180 days illustrates mild perineural brosis. There is dilatation of the capillaries at 60
and 180 days within the nerve fascicles and in the surrounding brous
tissue. Reproduced with permission from Sakakura K et al. Circ
Cardiovasc Interv 2015;8:e001813 [38]
3 Preclinical Model andHistopathology Translational Medicine andRenal Denervation
https://t.me/medicina_free
31
Fig. 3.10 Representative images of arterial injury at various time
points. Upper panels are low-power images, and lower panels are highpower images of red-boxed areas in upper panels (Movat stain). Renal
artery at 7 days shows transmural media damage with media thinning
and collagen denaturation which stains black on Movat pentachrome
Histopathology ofCatheter-Based
Ultrasound Ablation Induced Lesions
The Paradise Ultrasound Renal Denervation System is an
ultrasound-based catheter with a distal balloon that acts as a
coolant to protect the renal arterial wall. This system allows
circumferential ablation with deeper penetration depth
(Fig. 3.11) without the risk of 360-degree ablation to the
media which would cause a ring of brosis. This device
received CE-mark in 2012, and a randomized, shamcontrolled trial has shown promising efcacy and safety
results [19, 42]. We conducted a preclinical swine study to
evaluate histological changes in Paradise ultrasound systeminduced lesions [43]. Twenty-nine renal arteries from 15
swine were treated with various doses of ultrasound (i.e.,
stain. Renal arteries at 30, 60, and 180 days show transmural media
damage and proteoglycan replacement of smooth muscle cell loss in the
absence of media thinning. Reproduced with permission from Sakakura
K etal. Circ Cardiovasc Interv 2015;8:e001813 [30]
power and duration) and evaluated histological ndings
using the semi-quantitative scoring scheme [29] and ablation
area. In all ve different dose settings, circumferential nerve
damage was observed with no evidence of endothelial cell
loss and minimal to no arterial medial wall damage. The low
power-long duration group showed the greatest ablation area
and depth while the mid-power-short duration group showed
the least ablation area and the maximum depth of ablation
(Fig.3.12). This result suggested that the ablation area and
the maximum ablation depth were able to be controlled by
varying the ultrasound dose, while the coolant balloon system consistently spares the arterial wall. This fact is most
important in order to maintain the efcacy and safety of
ultrasound ablation. Ideally, the maximum ablation distance
should be long enough to affect most of the peri-arterial
32
https://t.me/medicina_free
Fig. 3.11 Representative
histology image of emission
site. The green delineated area
is the ablation area (shaded
green). Note even though
there is circumferential
ablation, the renal artery wall
is protected (green dotted
line). LN=lymph node;
RA=renal artery; RV=renal
vein; and IVC=inferior vena
cava. Reproduced with
permission from Sato Y etal.
Future Cardiol 2021 Apr 20.
https://doi.org/10.2217/
fca-2020-0228. Epub ahead of
print [45]
Y. Sato et al.
nerves but should not be too deep as to cause excessive deep
ablation that could injure adjacent organs. In fact,
retroperitoneal organ damage including focal psoas muscle
necrosis, small bowel transmural necrosis, and injury to the
ureter was observed depending on the degree of ultrasound
doses. The 90 percentile of all nerve distance from the renal
arterial lumen was 6.39 mm in main renal arteries and
6.73mm in accessory renal arteries [27, 44], the mid-powershort duration dose setting (7.4±2.0mm) was the safest prole without sacricing efcacy when considering the
anatomical distribution of peri-arterial nerves in renal
arteries.
3 Preclinical Model andHistopathology Translational Medicine andRenal Denervation
https://t.me/medicina_free
33
Fig. 3.12 Representative histologic images of emission site among
ve different dose groups. Panel A: Low power-long duration. A-1;
low-power image of renal artery and surrounding tissue (Movat stain).
A-2; high-power image of arterial media (blue boxed area in A-1).
Arterial media is intact (Movat stain). A-3 and A-4; high-power images
of injured nerve fascicle (red boxed area in A-1). Moderate (grade 3)
nerve injury is observed (A-3; Movat stain, A-4; H&E stain). Panel B:
Mid-low power-mid duration. B-1; low-power image of renal artery and
surrounding tissue (Movat stain). B-2; high-power image of arterial
media (blue boxed area in B-1). Arterial media is intact (Movat stain).
B-3 and B-4; high-power images of injured nerve fascicle (red boxed
area in B-1). Severe (grade 4) nerve injury is observed (B-3; Movat
stain, B-4; H&E stain). Panel C: Mid power-short duration. C-1; lowpower image of renal artery and surrounding tissue (Movat stain). C-2;
high-power image of arterial media (blue boxed area in C-1). Arterial
media is intact (Movat stain). C-3 and C-4; high-power images of
injured nerve fascicle (red boxed area in C-1). Severe (grade 4) nerve
injury is observed (C-3; Movat stain, C-4; H&E stain). Panel D: Midhigh power-short duration. D-1; low-power image of renal artery and
surrounding tissue (Movat stain). D-2; high-magnication image of
arterial media (blue boxed area in D-1). Arterial media is intact (Movat
stain). D-3 and D-4; high-power images of injured nerve fascicle (red
boxed area in D-1). Severe (grade 4) nerve injury is observed (D-3;
Movat stain, D-4; H&E stain). Panel E: High power-ultra short duration. E-1; low-power image of renal artery and surrounding tissue
(Movat stain). E-2; high-power image of arterial media (blue boxed
area in E-1). Arterial media is intact (Movat stain). E-3 and E-4; highpower images of injured nerve fascicle (red boxed area in E-1). Severe
(grade 4) nerve injury is observed (E-3; Movat stain, E-4; H&E stain).
LN = lymph nodes, V = vein. Reproduced with permission from
Sakakura K etal. EuroIntervention 2015;10:1230–8 [43]
34
https://t.me/medicina_free
Y. Sato et al.
Histopathology ofCatheter-Based EthanolMediated Perivascular Renal Sympathetic
Denervation
Fischell etal. reported the effects of ethanol-mediated perivascular renal sympathetic denervation in swine model at
14-days [14]. They used the Peregrine catheter-based microinfusion RDN system inserted percutaneously via the femoral artery into the renal arteries of adult swine under
uoroscopic guidance [14]. Three volumes of dehydrated
EtOH (98%) were used in this study: 0.15ml/artery (n= 3
pigs/6 renal arteries), 0.30ml/artery (n=3 pigs/6 renal arteries), and 0.60ml/artery (n = 3 pigs/6 renal arteries). Also,
saline injection was performed in the control animals as
sham treatment. Angiography at 14 days showed no abnormal ndings. Histopathological examination showed
marked, and deep, circumferential peri-arterial nerve injury
characterized by vacuolization, necrosis of the nerve bundles, with the development of perineural brosis and inammation, while no nerve injury was observed in the sham
treatment group. Histopathologic examination of the renal
artery showed absence of thrombi, dissections, aneurysms,
perforations, hematoma, or other device-related pathologies.
However, at the higher doses (0.30 and 0.60ml EtOH), there
was occasional, focal loss of some smooth muscle cells and
proteoglycan deposition in the outermost media, which typically originated at the adventitial surface and was associated
with the injection sites.
Early clinical studies of the Peregrine Systemhave shown
signicant blood pressure reduction and safety outcomes.
Two randomized, sham-controlled trials are ongoing
(NCT02910414, NCT03503773).
Summary
Renal sympathetic denervation has emerged as a promising
treatment for patients with hypertension, however, many
unanswered questions regarding the efcacy of radiofrequency ablation versus placebo controlled trials remain.
Nevertheless convincing preclinical results following perirenal sympathetic denervation in various animal models have
shown efcacy and safety. To date, radiofrequency ablation
is the most widely used modality in clinical as well as animal
models. However, other treatment modalities including
catheter- ultrasound and ethanol injection have been also
expanded. Histopathology studies of peri-renal sympathetic
nerves and norepinephrine levels in the kidney in preclinical
models have shown both necrosis and peri-and endo-neural
brosis correlating with norepinephrine reduction.
Morphologic studies will continue to play a crucial role in
the evaluation of both efcacy and safety of the new devices
being developed. Standardized semi-quantitative ordinal
grading systems are useful for the evaluation of the degree of
changes observed in the nerve, renal artery, and peri-arterial
soft tissue following renal denervation irrespective of the
method utilized.
References
1. Kearney PM, Whelton M, Reynolds K, Muntner P, Whelton PK,
He J.Global burden of hypertension: analysis of worldwide data.
Lancet. 2005;365:217–23.
2. Chobanian AV, Bakris GL, Black HR, etal. The seventh report of
the Joint National Committee on Prevention, Detection, Evaluation,
and Treatment of High Blood Pressure: the JNC 7 report. JAMA.
2003;289:2560–72.
3. Lewington S, Clarke R, Qizilbash N, Peto R, Collins R. Agespecic relevance of usual blood pressure to vascular mortality: a
meta-analysis of individual data for one million adults in 61 prospective studies. Lancet. 2002;360:1903–13.
4. Gu Q, Burt VL, Dillon CF, Yoon S.Trends in antihypertensive medication use and blood pressure control among United States adults
with hypertension: the National Health And Nutrition Examination
Survey, 2001 to 2010. Circulation. 2012;126:2105–14.
5. James PA, Oparil S, Carter BL, etal. Evidence-based guideline for
the management of high blood pressure in adults: report from the
panel members appointed to the eighth joint national committee
(JNC 8). JAMA. 2014;311:507–20.
6. Grassi G, Mancia G. New therapeutic approaches for resistant
hypertension. J Nephrol. 2012;25:276–81.
7. Saradis PA. Epidemiology of resistant hypertension. J Clin
Hypertens (Greenwich). 2011;13:523–8.
8. Calhoun DA, Jones D, Textor S, etal. Resistant hypertension: diagnosis, evaluation, and treatment. A scientic statement from the
American Heart Association Professional Education Committee
of the Council for High Blood Pressure Research. Hypertension.
2008;51:1403–19.
9. Worthley SG, Tsious CP, Worthley MI, etal. Safety and efcacy of
a multi-electrode renal sympathetic denervation system in resistant
hypertension: the EnligHTN I trial. Eur Heart J. 2013;34:2132–40.
10. Krum H, Schlaich M, Whitbourn R, etal. Catheter-based renal sympathetic denervation for resistant hypertension: a multicentre safety
and proof-of-principle cohort study. Lancet. 2009;373:1275–81.
11. Esler MD, Krum H, Sobotka PA, Schlaich MP, Schmieder RE,
Bohm M.Renal sympathetic denervation in patients with treatmentresistant hypertension (The Symplicity HTN-2 Trial): a randomised
controlled trial. Lancet. 2010;376:1903–9.
12. Ahmed H, Neuzil P, Skoda J, etal. Renal sympathetic denervation
using an irrigated radiofrequency ablation catheter for the management of drug-resistant hypertension. JACC Cardiovasc Interv.
2012;5:758–65.
13. Wang Q, Guo R, Rong S, et al. Noninvasive renal sympathetic
denervation by extracorporeal high-intensity focused ultrasound in
a preclinical canine model. J Am Coll Cardiol. 2013;61:2185–92.
14. Fischell TA, Vega F, Raju N, et al. Ethanol-mediated perivascular
renal sympathetic denervation: preclinical validation of safety and
efcacy in a porcine model. EuroIntervention. 2013;9:140–7.
15. Rocha-Singh K. Renal artery denervation: a brave new frontier.
Endovascular Today. 2012;45–53.
16. Bhatt DL, Kandzari DE, O’Neill WW, et al. A controlled trial
of renal denervation for resistant hypertension. N Engl J Med.
2014;370:1393–401.
17. Böhm M, Kario K, Kandzari DE, etal. Efcacy of catheter-based
renal denervation in the absence of antihypertensive medications
Соседние файлы в папке Библиотека им академика М.И. Перельмана