THE ITALIAN STUDY GROUP ON NEONATAL NEPHROLOGY
of THE ITALIAN SOCIETY OF NEONATOLOGY
THE KIDNEY THROUGH THE AGES
Published in the Proceeding of the 8th International Workshop of Neonatal Nephrology, april 6th-8th 1998, Rome Italy Il Pediatra XX( ): ,
Luigi Cataldi, M.D.
Professor of Pediatrics, Therapeutics and History of Medicine
Past-president of the Neonatal nephrology Study Group of the Italian Society of Neonatology
Department of Pediatrics, Catholic University of the Sacred Heart, and University Hospital Policlinico "Gemelli" - Largo Gemelli, 8, I-00168 Rome Italy, e-mail firstname.lastname@example.org
In this brief excursion we hope to map the progress made by some of the historical scientific figures in the struggle to identify, describe and understand the essential role of the kidney in human life.
My purpose is to summarize some of the kidney depictions made over the centuries, most of these illustrations are obtained from original, and now rare, ancient and modern books and scientific papers that I have had the pleasure of reading and admiring in my experience in many libraries, museums, and antique book shops around the world.
Some historical milestones in renal structure and function from the Antiquity to the Renaissance
In the medieval and Renaissance periods anatomy studies were essential in teaching medical and surgical sciences, and their development. but it was the printing press (in the second half of the 15th century) which especially fostered the growth of medical literature.
Since antiquity physicians have collected, examined and recorded their findings related to urine (2 Cat W7th). However, recognition of the importance of the kidney is itself a relatively recent event, and ancient depictions of this organ are scarce. This could have been due to the fact that kidneys were not visualized because of their retroperitoneal location or because they were regarded in the 3rd and 4th millenia BC to be less important organs than the liver, heart, lungs and intestines.
The oldest votive example of the kidney is a 13th century BC bronze figure found during recent excavations in a Kition temple in Cyprus.()
Aristotle (384-322 BC) refers to the kidney in two of his works. Historia Animalium and De Partibus Animalium Aristotle wrote the first work between 347 BC and 343 BC and the second between 335 BC and 330 BC. This explains why, in the second work, Aristotle frequently refers to his first, where the kidney is not considered in detail, since, in the words of Aristotle himself, "The kidneys are not present for necessity in animals but have the function of perfecting the animal itself". However when examining the blood supply to the kidney he says that "Passages lead to the kidneys both from the great blood vessel and from the aorta, though they do not lead into the cavity. I have not so far mentioned this cavity in the middle of the kidney. In some animals it is larger, in others smaller; but there is none in the seal's kidneys. These are similar to those of oxen and are more solid than those of other animals. The passages which lead to the kidneys peter out in the mass of the kidneys themselves. That they do not continue through the kidneys is shown by the fact that they contain no blood nor does it congeal in them. (They contain, however, as has been said, a small cavity). From the cavity of the kidneys two sturdy passages lead into the bladder, and other strong continuous ones come from the aorta."
According to Aristotle, the kidney had two functions, to separate the surplus liquid from the blood and to modify this liquid which will be eliminated via the ureters, bladder and urethra. His view of the kidneys can be summarised as follows (Marandola).
Galen (130-200 A.D.) of Pergamon, known as "prince of Physician" addressed the question of the mechanism of urine formation in an even more adversarial and disputatious fashion. In his medical works (Galh nou apanta) He rejected the possibility that the kidneys filtered urine from the blood in a sieve-like fashion and instead concluded that the kidneys "attracted" urine (24).
Although Leonardo da Vinci (1452-1519) depicted the gross anatomical features of the abdominal organs (including the kidneys) more accurately and artistically than his predecessors, he provided no significant new information on the anatomy of the urinary system (64).
With the publication in Brussels of Andreas Vesalius' (1514-1564) De Humani Corporis Fabrica (1543), the Galenic tradition as overthrown. His observations of the real kidney enabled him to refute the long held idea that the production of urine was a result of the blood being filtered by a seive like action through the upper part of the kidney. Bartolomeo Eustachio (1524-1574) was an anatomy professor at Collegio della Sapienza in Rome. He completed and personally had executed 47 drawings for copper-plate engravings in 1552. Seven of these drawings were used in the publication of Opuscula Anatomica (1564) an exquisite work of 147 pages devoted to the kidney. He described the adrenal glands, he noted that the right kidney is lower than the left, his illustration of the intrarenal vasculature is clear and precise, he described the renal calyceal system and its relation to renal papillae and he described the renal collecting ducts with their "furrows and small canals". He was 150 years ahead of Bellini's contribution and surmised that these tiny structures had a purpose in moving urine from the kidney to the renal pelvis.
Giovanni Alfonso Borelli (1608-1679), the Neapolitan mathematician applied mechanical views to the human organism in a striking and influential fashion. Borelli’s famous work De motu animalium was published postumously (in 1680 and 1681), which analyzes the function of the viscera as machines. Included in the second part is a lengthy discussion of the mechanism of secretion in various organs, including the kidneys. (6a)
His Proposition CXL states (47a). "Urine is separated from the blood in the kidneys mechanically as a result of the narrowness and configuration of the vessels." He proposed a sieve-like, mechanism of filtration in the kidneys to separate out the urine which he conceived of as existing intermixed with blood".
Lorenzo Bellini (1643-1704) was an Italian anatomist and physiologist. In 1662 at 19 years of age, he published his best known work, Exercitatio Anatomica de Structura et Usu Renum, in which he showed that the kidney was not a solid organ but was composed of ducts (which now bear his name). Bellini sincerely believed his description to be the first, but 10 years after his death Eustachio's observations came to light and were published by Lancisi (1714). Nowadays it is universally recognised that the credit for the first description of the collecting tubules goes to Eustachio and that Bellini's contribution lies in his suggestion that urine is separated from the blood by a distinct anatomical arrangement which would become known as the kidney glomeruli.
In the 17th century, Frederik Ruysch (1638-1731) was an anatomist from Amsterdam. A plate from his Theatrum Anatomicum first published in 1701 shows his representation of the kidney and that he was the first to recognize the capillary tuft of the kidney.
William Cowper (1666-1709) published The Anatomy of the Humane Bodies which was the exact same publication as that of his Dutch contemporary Govert Bidloo (1649-1713) published in Amsterdam in 1685, with the only differences being Cowper’s potraits in place of Bidloo's. Obviously there were no copy-right laws then, but this is still recognised to be one of the most famous examples of plagiarism in all of medical history.
In the 18th century Giovanni Battista Morgagni (1682-1771) in his fundamental treatise De Sedibus et Causis Morborum per anatomen indagatis, published in Venice, 1761, the maestro Morgagni gave excellent descriptions of several renal disorders (amongst which "urinary suppression" such as obstructive nephropathy, calculi, tumors and more) . However, he was not the first to use this term 'urine suppression' in some case discussions: such a term was used about two hundred years prior to this by Girolamo Mercurialis (1530-1609) in his De morbis puerorum (childhood diseases) published in Venice in 1583. Today we can recognize the Morgagni description to be obstructive nephropathy. Some of the causes for obstructive uropathy which he noted were renal abnormalities (renal agenesis with contralateral compensatory hypertrophy, duplex renal system, vesicoureteral reflux, urethral valves, and even prune belly syndrome) . In addition, his vivid description of anatomical material, correlated with clinical histories allows us to offer plausible current-day identification for several renal abnormalities.
By far the most significant contributor to the developing knowledge of the structure of the kidney was Marcello Malpighi (1628-1694) born near Bologna a professor of anatomy and a physi\cian. In 1666 he published De viscerum structura exercitatio anatomica (45). In it he described the structure of several viscera, including the kidney and he demonstrated with the use of an early primitive microscope the existence of capillaries which had been predicted by Harvey some years earlier. This however was only made possible by Galilei's invention of the lens, revealing the medullas as being composed of a collection of many peculiar tubules that, if compressed at one end, released a liquid tasting just like urine, as described by Lorenzo Bellini in his work De Structura et Usu Renum. This experiment allowed Bellini to establish without doubt that the renal parenchyma was formed from tubules (sui generis fibris), reddish in the external part of the kidney and whitish near the pelvis, ending in a single, pea-shaped verruca-like body, perforated by a very large number of pores. A few years later, Marcello Malphigi went onto to describe in De Renibus (1666) the renal glomerule. The observations on the kidney followed on from those made on many other organs in his famous "A study of Glands". On the kidney, Malpighi wrote that the organ's parechyma was not homogeneous, but divided into conical lobules, now known as 'renal pyramids'.
Progresses in the last centuries
Alexander Schumlansky, who lived from 1748 to 1795, who is little known outside his native Russia, studied and received a doctoral degree in 1783 in Strasbourg, with the inaugural dissertation De Structura renum (1782) which was then published in 1788. De Structura renum is a small volume of 138 pages with 2 copper plates, printed in Strasbourg in 1788. It is divided into 47 sections on the macroscopic and microscopic structures of the kidney. He presented a detailed, comprehensive summary of the descriptions of the macroscopic anatomy of the kidney by previous workers going back to the time of Aristotle, and compared their findings with his own observations.
The plate that Schumlansky used to illustrate his findings contains two serious structural errors. One, not recognized at the time, is the absence of the loops of Henle, which were not discovered until 74 years later, and the consequent division of the convoluted tubules into proximal and distal segments. The other error was the proportion/ratio calculated to exist between the diameter of the maphighian body and the tubules. His plate shows the glomeruli to have a smaller diameter than the tubule, when in fact their diameter is much greater than that of the tubules. A few glomeruli are at the beginning of a tubule, but most are not and in fact there is no detail on this most important point.
The progress made in science by Frederich Gustav Jacob Henle (1809-1885) was outstanding. He studied medicine in Bonn and Heidelberg, and was greatly interested in medical research, he was particularly interested in studying the fine structure of human organs, and tissues, and their physiological functions. He was able to make significant contribution to medical knowledge thanks to the improvements made to light microscopy during the 19th century. In 1862 Henle discovered the epithelial nature of the convoluted and straight portion of the cortical tubule and of the medullary and papillary collecting tubules and the duct of Bellini. He established the presence of two types of tubules in the medullary tissue, one is the well known ductus papillaris or papillary collecting duct lined with a uniform epithelium in which the height of the cells increases continously towards the opening at the papillary tip. The other type of tubule has a much smaller diameter and is lined by small squamous cells. These latter tubules run parallel, to the collecting ducts but return in a narrow hairpin loop into the medullary tissue. Henle further stated that these loop-like tubules are arranged in a circular fashion around the collecting ducts.
The structural relationships between the glomerulus and the renal tubules were resolved by William Bowman (1816-1892). As a young man he was a demonstrator in Anatomy at King’s College, London, where he carried out a series of histological investigations which were so outstanding that he was elected a fellow of the Royal Society at the age of 25 years. He subsequently became the leading opthalmic surgeon in London. Using a microscope that magnified up to 300 times and a vascular injection method, he studied thin slices of kidneys from a variety of species. He accurately described the glomerular capillary tuft and its relations to the afferent and efferent arterioles, and he also described how it breaks up into a second capillary plexus closely applied to the basement membrane of the tubules. He also described the basement membrane of the tubules.
Over the last century there have been many more discoveries made about the kidney and its function but we must finish our trip through time here, asnd we do so convinced that the young researchers of today will go on to clarify even further its finest structure and function.
Cataldi L.: From the Matula to the radio-immunological essay: The evolution of the Urine Analysis. Il Pediatra XIX(7): 19-20, 1997
Aristotle Historia Animalium I, 17, 496b-497a.
Aristotle De Partibus III,7, 670b, 23, 24.
Marandola P., Musitelli S., Jallous H., et al: The Aristotelian Kidney Am J. Nephrol, 14: 302-306, 1994