The cell is the basic, irreducible, unit of life. Whether an organism is animal, plant, fungal or bacterial, the cell is its basic unit. While it can be broken down into its ‘parts’ for examination, none of those parts are capable of independent life, none are able to continue fulfilling their functions on their own. The cell and its ‘community of parts’ operate as a ‘social’ unit, as a whole. Each ‘part’ fulfills one or more roles in the ongoing life of the cell. This book is a review of cell biology, of the development of our, human, understanding of the life of the cell and its centrality to our understandings of what it is be alive, how it has and continues to transform our practice of medicine. The author, Siddhartha Mukherjee, is a doctor and researcher who has spent his professional life studying blood and its cancers, trying to understand and treat disease.
Mukherjee takes us through the last several hundred years of the development of the science of cell biology, a study which has undergone tremendous advances moving from our earliest simple descriptions of the cell, speculations on their functions, to our evolving modern understanding and what that means, to our understanding of the human body and our treatment of disease. Science has been doing this largely through its classic atomistic approach, looking to understand the whole, through an examination of its parts, from the cell to its organelles, down to the molecules that comprise them. Cells are identifiable by their shared basic structure, their defining, protecting and limiting membranes, the complex biochemical ‘soup’ which comprise the cytoplasm of their interiors, the genetic reservoir they contain, their cytoskeletons which make possible their movement and abilities to respond to their immediate environments, to threats, nutrients and supportive conditions; their capacities to divide and increase in number, their progeny inheriting their characteristics and functions; their ability to metabolize much that they require and ‘power’ themselves; their innate capacity to maintain their structures and internal biochemical balance staving off disease and degradation, in short their ‘drive’ to remain in ‘balance’, to sustain homeostasis.
An understanding of the evolution of the cell is essential to our understanding and the practice of medicine, so he takes on a quick tour of the several billions of years of ‘refining’ the basic cell, its structures and functions and…how more complex forms of cells, assemblages, what he terms multicellularity came to be. Through multicellularity Mukherjee introduces the concepts of ecology and ‘social systems’ at a cellular level and organismic level. This is the idea that individual cells began to join together into groups, wholes, to create a shared advantage. He refers to Darwin’s concept of the survival of the fittest, that cells that join together ‘cooperatively’, have gained survival advantages, and pass those advantages on through their lineages. Multicellular organisms have over millions of years evolved such advantageous changes in the forms of specialized tissues and organs, cells of which have, in a sense, given up some of their independence for the advantages of multicellularity…but these tissues and organs are still comprised of cells, cells which work in an extremely coordinated manner. Mukherjee also points out that this ‘joining’ was not a singular event, that it likely occurred countless times amongst the lineages. Nothing succeeds like success. Initially, once the cell evolved to a minimal stage, the capacity to ‘join’ became possible. This does not mean that at some future date, far in the future, there will be no single celled organisms left. Multicellularity is a product of the living milieu. Life has created the conditions it requires and the community works toward maintaining homeostasis for the entirety of the system in much the same way that it does within the single individual organism.
With this understanding, Mukherjee examines the world of disease, as disruptions at a cellular level in their functioning, of their homeostasis. A cell or organism which is unable to maintain homeostasis, falls into a state of disease. Through examination of diseases like diabetes, arthritis, cancer, sickle cell anemia and the body’s responses to various bacterial and viral diseases, the author looks at our capacities for healing, our immune response, the development of antibodies and importantly, how such systems are able to distinguish our ‘self’ from ‘foreign’ threat, so that our health defense systems do not attack our own bodies with destructive autoimmune responses. As he does this he gives the reader an idea of how complex disease and our responses to them are and how the ‘safeties’ and backup systems can sometimes, in working to maintain homeostasis, can stymie our efforts to combat the disease.
Today’s new therapies and treatments often focus on the body’s dysfunctional cells and how to correct them. A disease of the organism has its root in the disease and dysfunction of the cell. Previously drugs and treatments often addressed the symptoms of the disease from the level of the organ or organism. A liver disease, for example, was not understood at a cellular level. It was an organ failure and was often treated with a less specific approach. Over time doctors and researchers have found that a narrowly cellular specific approach is not always effective either, especially in the cases of disease that effect multiple types of cells, tissues and organs. Treatments and their protocols often run up against the body’s own defensive responses. Health, not just the absence of disease, is the result of very complex, overlapping, systems. Organs, tissues and cells ‘communicate’ through biochemical ‘signaling’ and adjust their attempts to maintain homeostasis as a whole. Because of these overlapping systems, treatment must take into account this level of complexity, or fail. If a person’s B cells in their liver fail they can’t produce insulin and the organism becomes unable to utilize the glucose in their blood to power their metabolism…cells, organs and systems begin to shut down throughout the body as it literally suffers starvation despite an otherwise abundant supply of nutrients. Sugars, available in the bloodstream, are not available to power growth and metabolism without insulin. If a person suffers from a form of leukemia, of blood cancer, a single approach may not work. Cancer is not one disease. It does not manifest from a single type of cellular failure. When stymied by treatment the cancer can often follow another cellular pattern of rampant growth. Targeting cancerous cells is not easy either as they are nearly identical to the organism’s healthy cells. An attack on the one may be an attack on the other. Treatment of disease then becomes a quest for cellular health, a correction from dysfunction…and that dysfunctional cell exists within an organism in which health is recognized as a process, a verb…a performance of perhaps billions of players.
Mukherjee writes of the ‘new human’, how through these evolving cell therapies we are slowly recreating ourselves, correcting failures, improving performance, augmenting longevity, sometimes altering DNA in particular tissues, replacing abnormal cells with rewritten cells developed from the patient’s on cells and tissues. In other cases anti-rejection drugs must be supplied to keep the patients body from rejecting the cells, tissues and organs supplied by another person, an ‘other’. Needed metabolites may be produced in a lab and secreted into the person by tiny mechanisms on demand. Stem cells ‘grafted’ on may be induced artificially from other normal, non differentiating cells, to replace the patient’s defective cells. As our understanding and technologies develop ethical questions, never previously imagined, come to the fore.
As he approaches the end of the book, Mukherjee, expresses some of his frustration with the state of medicine today, linked to his desire to heal his patients. Despite its amazing advances, medicine bangs up against the limits of its own approach and he calls for efforts to assemble all of the disparate pieces we have learned about the body, disease, life and health. He writes of ‘the song of the cell’ and how we cannot understand life and medicine until we understand how all of these pieces work together. Every piece, every function, effects the health of the whole. An organism is not simply an assemblage of its parts. In our complexity we have become something far more. We are neither simple nor direct systems, if this then that. Our biochemical switches, are ‘blends’ of billions of biochemical processes, stages, which together are ‘us’. We are living organic, biological, computers. In an organism one + one is not always two, of course that simple equation itself is misleading. Like the elephant examined piecemeal by a group of blind men by touch, an organism is far more than it appears. The links and feedback loops, the possibilities, compound and render ‘simple’ atomistic explanations inadequate or at the least, incomplete.
Mukherjee, with his emphasis on the organism’s powerful and necessary drive toward homeostasis, balance and health, is calling for a wholistic approach, a focus on health not simply a ridding of disease, but a promotion of the organism’s own capacities and vitality. The body’s response to disease is often limited by the very systems which work to sustain it. Health and disease exist in a balance. The body is in a continuous pattern of decline and renewal. This is a given. As nutrients are consumed through our metabolizing of them, toxic waste products are produced, cells and and their organelles, decline and must be repaired or replaced. Metabolism is mostly a process of oxidation, the ‘burning’ of carbohydrates in the presence of volatile oxygen. Oxygen the necessary element which can lead to the oxidation of necessary structures, which then require repair or replacement. In every case, depending on the cell and tissue type, all cells will slow and falter in their abilities to continue on. We live with an internal clock, that counts down our years. We are in a continuous state of internal flux. As we age beyond maturity the balance tends to favor decline. Perhaps by focusing our energies more on health, rather than on disease, we can better prepare and armor the body against attack and decline. Disease, of some sort, is inevitable. By prioritizing the health of the organism/person we improve our ability to resist disease, utilizing the body’s systems to maintain itself, reducing the strains and demands on the body made by disease.
This is a book for everybody. I have been a student of the life sciences. I read on the topics of ecology, evolution, botany, cell biology, quantum physics, the developing field of quantum biology, the thermodynamics of the organism. This is the first of Mukherjee’s books that I’ve read. It does require that you have some understanding of the biological sciences, but Mukherjee is an excellent writer, very informed on the topic and able to discuss it in accessible terms. This is his third book, after “The Emperor of All Maladies: A Biography of Cancer“ and “The Gene: An Intimate History” both of which were on the New York Times Bestseller list, so it is not overly academic. For me this is a must read. It brings light to a poorly understood and essential part of our world, our very lives, and is necessary if we ever hope to understand and resolve the problems of our times.
Now, I want someone to write this book with a focus on plants. For as much as they share, plants and animals have significant differences in their growth, cellular maintenance, wound response, the structures of their many multi-celled species, their tissues and ‘organs’, even in their metabolic pathways. Plants and animals do share the same basic cellular structure, their tendency toward multicellularity, their reliance on their genes and the building blocks of amino acids, peptide chains and proteins. Much of what Muckherjee discuses here translates into the world of plants. But there is much that is different.