To provide a simplified synopsis of the molecular mechanism of systemic gas exchange in laymans terms, upon inhalation of air it was widely thought oxygen binding to any of the heme sites triggers a conformational change in the globin/protein unit of hemoglobin which then enables the binding of additional oxygen to each of the other vacant heme sites. Upon arrival to the cell/tissues, oxygen release into the tissue is driven by "acidification" of the local pH (meaning a relatively higher concentration of acidic protons/hydrogen ions) caused by an increase in the biotransformation of carbon dioxide waste into carbonic acid via carbonic anhydrase. In other words, oxygenated arterial blood arrives at cells in the "hemoglobin R-state" which has deprotonated/unionized amino acid residues (regarding nitrogen/amines) due to the less-acidic arterial pH environment (arterial blood averages pH 7.407 whereas venous blood is slightly more acidic at pH 7.371). The "T-state" of hemoglobin is deoxygenated in venous blood partially due to protonation/ionization caused by the acidic environment hence causing a conformation unsuited for oxygen-binding (in other words, oxygen is ejected upon arrival to the cell because acid "attacks" the amines of hemoglobin causing ionization/protonation of the amine residues resulting in a conformation change unsuited for retaining oxygen). Furthermore, the mechanism for formation of carbaminohemoglobin generates additional acidic hydrogen ions that may further stabilize the protonated/ionized deoxygenated hemoglobin.
A recent study from the USA estimated the incidence of IPF to be between 6.8 and 16.3 per 100,000 persons. In the 27 European Union countries, a range of sources estimate an incidence of 4.6–7.4 people per 100,000 of the population, suggesting that approximately 30,000–35,000 new patients will be diagnosed with IPF each year.A recent single-centre, retrospective, observational cohort study including incident patients diagnosed with ILD at Aarhus University Hospital (Denmark) between 2003 and 2009 revealed  an incidence of  4.1 per 100,000 inhabitants/year for ILD. IPF was the most common diagnosis (28%) followed by connective tissue disease-related ILD (14%), hypersensitivity pneumonitis (7%) and non-specific interstitial pneumonia (NSIP) (7%). IPF incidence was 1.3 per 100,000 inhabitants/year.Due to a heterogeneous distribution of the disease across European countries, epidemiological data needs to be updated through a Europe-wide registry for ILD and IPF. Other animals
IPF has been recognized in several breeds of both dogs and cats, and has been best characterized in West Highland White Terriers. Veterinary patients with the condition share many of the same clinical signs as their human counterparts, including progressive exercise intolerance, increased respiratory rate, and eventual respiratory distress. Prognosis is generally poor. Research
A number of agents are currently being investigated in Phase II clinical trials for IPF, including the monoclonal antibodies simtuzumab, tralokinumab, lebrikizumab and FG-3019, a lysophosphatidic acid receptor antagonist (BMS-986020). A Phase II study of STX-100 is also ongoing.